Influence of the natural aluminium oxide layer on ... - ALU-WEB.DE
Influence of the natural aluminium oxide layer on ... - ALU-WEB.DE Influence of the natural aluminium oxide layer on ... - ALU-WEB.DE
Ebner Special Edition European Aluminium Congress 2011 22 to 23 November 2011, Maritim Hotel Düsseldorf TECHNOLOGIES FOR THE ALUMINIUM INDUSTRY Adressing market requirements in alumin- ium flat rolled products Heavy duty extrusion presses for large pr
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Ebner<br />
Special Editi<strong>on</strong><br />
European Aluminium C<strong>on</strong>gress 2011<br />
22 to 23 November 2011, Maritim Hotel Düsseldorf<br />
TECHNOLOGIES FOR THE<br />
<strong>ALU</strong>MINIUM INDUSTRY<br />
Adressing market requirements<br />
in alumin-<br />
ium flat rolled products<br />
Heavy duty extrusi<strong>on</strong><br />
presses for large<br />
pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile applicati<strong>on</strong>s<br />
Soldering and brazing <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> and its alloys
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SMS SIEMAG AG<br />
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Christian Wellner<br />
Executive Director <str<strong>on</strong>g>of</str<strong>on</strong>g> GDA<br />
Gesamtverband der Aluminiumindustrie<br />
e.V. (German Aluminium<br />
Associati<strong>on</strong>)<br />
Aluminium industry<br />
c<strong>on</strong>tinuing to grow<br />
in future<br />
Despite <str<strong>on</strong>g>the</str<strong>on</strong>g> current crisis in <str<strong>on</strong>g>the</str<strong>on</strong>g> banking<br />
and finance sector, <str<strong>on</strong>g>the</str<strong>on</strong>g> global <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
industry is c<strong>on</strong>tinuing to look optimistical-<br />
ly to <str<strong>on</strong>g>the</str<strong>on</strong>g> future. The industry is still <strong>on</strong> a<br />
path <str<strong>on</strong>g>of</str<strong>on</strong>g> solid growth despite a weakening<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> growth dynamics and a dampener<br />
being put <strong>on</strong> business expectati<strong>on</strong>s.<br />
Forecasts for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> c<strong>on</strong>tinue to be<br />
optimistic. The dynamic development is<br />
closely linked to <str<strong>on</strong>g>the</str<strong>on</strong>g> innovative capability<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> sector and <str<strong>on</strong>g>the</str<strong>on</strong>g> metal’s beneficial<br />
properties. Aluminium has established itself<br />
in numerous user markets. Whe<str<strong>on</strong>g>the</str<strong>on</strong>g>r it<br />
be in <str<strong>on</strong>g>the</str<strong>on</strong>g> most important market, <str<strong>on</strong>g>the</str<strong>on</strong>g> transport<br />
sector, in mechanical engineering,<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> electr<strong>on</strong>ics sector or in packaging,<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> companies have c<strong>on</strong>tinued to<br />
push technological development forward<br />
and opened up new uses and fields <str<strong>on</strong>g>of</str<strong>on</strong>g> applicati<strong>on</strong><br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> lightweight metal again<br />
and again. The worldwide c<strong>on</strong>sumpti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> will c<strong>on</strong>tinue to grow in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
next 10 to 15 years, with an annual global<br />
c<strong>on</strong>sumpti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> some 70 milli<strong>on</strong> t<strong>on</strong>nes<br />
expected by around 2020. Growing demand<br />
from Asia and <str<strong>on</strong>g>the</str<strong>on</strong>g> important user<br />
markets – automotive, mechanical engineering,<br />
building and c<strong>on</strong>structi<strong>on</strong>, packaging<br />
and solar energy – will help <str<strong>on</strong>g>the</str<strong>on</strong>g> lightweight<br />
metal achieve c<strong>on</strong>tinuous growth.<br />
Growing c<strong>on</strong>sumpti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> will<br />
result in enormous importance being given<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> development <str<strong>on</strong>g>of</str<strong>on</strong>g> innovative process<br />
technologies and plant c<strong>on</strong>cepts for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
producti<strong>on</strong> and processing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>.<br />
More complex material properties demand<br />
a high degree <str<strong>on</strong>g>of</str<strong>on</strong>g> technological expertise<br />
FOREWORD<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> development <str<strong>on</strong>g>of</str<strong>on</strong>g> special soluti<strong>on</strong>s.<br />
Future technological developments will<br />
also focus <strong>on</strong> resource efficiency and potential<br />
savings <str<strong>on</strong>g>of</str<strong>on</strong>g> CO 2 and energy in all<br />
processes. In future, too, we must repeatedly<br />
develop material properties fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r,<br />
create new products and optimise producti<strong>on</strong><br />
processes via investments in applicati<strong>on</strong>-oriented<br />
research and development.<br />
What innovative technologies can<br />
equipment suppliers <str<strong>on</strong>g>of</str<strong>on</strong>g>fer <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
industry? Will new processes or material<br />
developments open up new markets for<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g>? What new trends are emerging?<br />
Experts from <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> industry<br />
will be discussing <str<strong>on</strong>g>the</str<strong>on</strong>g>se and o<str<strong>on</strong>g>the</str<strong>on</strong>g>r questi<strong>on</strong>s<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g>ir equipment partners and suppliers<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g> European Aluminium C<strong>on</strong>gress<br />
‘Technologies for <str<strong>on</strong>g>the</str<strong>on</strong>g> Aluminium Industry’<br />
<strong>on</strong> 22-23 November 2011 in Düsseldorf.<br />
It provides <str<strong>on</strong>g>the</str<strong>on</strong>g> equipment suppliers and<br />
technology partners <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> producing<br />
and processing industry with a comprehensive<br />
platform to present and discuss<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>ir latest developments.<br />
The c<strong>on</strong>gress programme <str<strong>on</strong>g>of</str<strong>on</strong>g>fers <str<strong>on</strong>g>the</str<strong>on</strong>g> opportunity<br />
to exchange informati<strong>on</strong> and<br />
have detailed discussi<strong>on</strong>s with representatives<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> European <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> industry,<br />
its equipment manufacturers and o<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
suppliers.<br />
I wish all EAC c<strong>on</strong>gress participants an<br />
informative programme <str<strong>on</strong>g>of</str<strong>on</strong>g> presentati<strong>on</strong>s<br />
and I hope <str<strong>on</strong>g>the</str<strong>on</strong>g>y enjoy interesting discussi<strong>on</strong>s<br />
and make valuable c<strong>on</strong>tacts during<br />
both days <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>gress in Düsseldorf.<br />
<strong>ALU</strong>MINIUM · XX/2011 EAC CONGRESS 2011 3<br />
�
FOREWORD<br />
Aluminium industry c<strong>on</strong>tinuing to grow in future ............................... 3<br />
SESSION ROLLING INDUSTRY<br />
Foil slitting technology – an integrative approach ............................. 6<br />
Focus <strong>on</strong> rolling mill efficiency: design and c<strong>on</strong>trol...........................10<br />
Batch-type and c<strong>on</strong>tinuous floater furnace facilities for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
alloy strip ..................................................................................13<br />
Addressing market requirements in <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> flat products ...............16<br />
SESSION MEASURING & CONTROL<br />
L<strong>on</strong>ger campaigns with improved m<strong>on</strong>olithics for lining<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> melt-hold furnaces .......................................................19<br />
Optimizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> an <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> rolling mill with a high speed<br />
X-ray thickness gauge ..................................................................22<br />
State-<str<strong>on</strong>g>of</str<strong>on</strong>g>-<str<strong>on</strong>g>the</str<strong>on</strong>g>-art casthouse producti<strong>on</strong> management ..........................26<br />
M<strong>on</strong>itoring <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> extrusi<strong>on</strong> dies cleaning process<br />
by an optic sensor .......................................................................28<br />
SESSION EXTRUSION<br />
<str<strong>on</strong>g>Influence</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> raw material c<strong>on</strong>stituti<strong>on</strong> <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> quality <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
gloss alloy-type extrusi<strong>on</strong> billets – a report from practice ................. 31<br />
Heavy duty extrusi<strong>on</strong> presses for large pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile applicati<strong>on</strong>s .................34<br />
Extrusi<strong>on</strong> line from a single source for intelligent pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles ............. 36/38<br />
Integrated processing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles subsequent to<br />
hot extrusi<strong>on</strong> ..............................................................................40<br />
Flexible automated material flow in extrusi<strong>on</strong> operati<strong>on</strong>s ...................44<br />
SESSION APPLICATION-ORIENTED TECHNOLOGIES<br />
Laser cleaning and surface modificati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> –<br />
first step to a green plant ............................................................48<br />
Corrosi<strong>on</strong> behaviour <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> materials in aqueous<br />
cleaning soluti<strong>on</strong>s .......................................................................50<br />
Soldering and brazing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> and its alloys ............................54<br />
<str<strong>on</strong>g>Influence</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>natural</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> <strong>on</strong> brazeability ............57<br />
SESSION MELTING, RECYCLING & HEAT TREATMENT<br />
The new generati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> heat treatment<br />
plants – a vanguard c<strong>on</strong>cept ........................................................60<br />
New standards in gas-fired heating <str<strong>on</strong>g>of</str<strong>on</strong>g> moulds, ladles, launders<br />
and melting furnaces through flameless burner technology ................63<br />
Effects <str<strong>on</strong>g>of</str<strong>on</strong>g> gaseous pyrolysis products <strong>on</strong> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> recycling yield ......66<br />
SESSION SOFTWARE & SIMULATION<br />
Optimizing <str<strong>on</strong>g>the</str<strong>on</strong>g> energy c<strong>on</strong>sumpti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> coil annealing<br />
furnaces by ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical modelling <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> annealing process ............70<br />
Numerical analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> seam welds <str<strong>on</strong>g>of</str<strong>on</strong>g> industrial extrusi<strong>on</strong> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles ...72<br />
Imprint ......................................................................................53<br />
List <str<strong>on</strong>g>of</str<strong>on</strong>g> advertisers<br />
CONTENTS<br />
<strong>ALU</strong>MINIUM · XX/2011 EAC CONGRESS 2011 5<br />
6<br />
38<br />
50<br />
F. W. Brökelmann Aluminiumwerk<br />
GmbH & Co. KG<br />
BWG Bergwerk- und Walzwerk-<br />
61<br />
Maschinenbau GmbH<br />
Danieli Fröhling Josef Fröhling<br />
4<br />
GmbH & Co.KG 15<br />
Drache Umwelttechnik GmbH 71<br />
Ebner Industrie<str<strong>on</strong>g>of</str<strong>on</strong>g>enbau GmbH, Austria 18/19<br />
Eisenmann AG<br />
Kampf Schneid- und<br />
21<br />
Wickeltechnik GmbH & Co. KG<br />
Kind & Co. Edelstahlwerk<br />
25<br />
Kommanditgesellschaft 45<br />
LOI Thermprocess GmbH 9<br />
S+C Extrusi<strong>on</strong> Tooling Soluti<strong>on</strong>s GmbH 35<br />
SMS Meer GmbH 76<br />
SMS Siemag AG 2
ROLLING INDUSTRY<br />
Foil slitting technology – an integrative approach<br />
Walter Brockhorst and Gabriele Barten, Achenbach Buschhütten GmbH<br />
System supplier Achenbach Buschhütten<br />
Achenbach sees itself as system supplier<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> machinery for producing n<strong>on</strong>-ferrous<br />
metal rolling mills and foil slitting machines.<br />
Achenbach’s initial communicati<strong>on</strong><br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g>ir customers is threefold:<br />
‘We are <str<strong>on</strong>g>the</str<strong>on</strong>g> Specialists!’, ‘We are Leaders<br />
in technology and quality!’ and ‘We are<br />
your Partner!’ The brandname Achenbach<br />
provides orientati<strong>on</strong> and security<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> customers. Achenbach is a familyowned<br />
and family-run company having<br />
approx. 310 employees. Achenbach rolling<br />
mills and machinery are operated in<br />
nearly 60 countries all over <str<strong>on</strong>g>the</str<strong>on</strong>g> world.<br />
Company development and missi<strong>on</strong><br />
Our missi<strong>on</strong> is ‘Technology for Future C<strong>on</strong>cepts’,<br />
which c<strong>on</strong>trols and coordinates think-<br />
ing and acting at Achenbach. Achenbach has<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> technological know-how to realize <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
future ideas <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>ir customers for producing<br />
strips, foils as well as foil products in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
form <str<strong>on</strong>g>of</str<strong>on</strong>g> most modern machinery. The aim is<br />
to provide our customers with first-class and<br />
tailor-made rolling mills and machinery in<br />
order to open up success potentials for <str<strong>on</strong>g>the</str<strong>on</strong>g>ir<br />
company’s future. High machine performance<br />
and numerous references have ensured <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
excellent reputati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> Achenbach:<br />
• Established as a hammer mill in 1452,<br />
Achenbach has been manufacturing metal<br />
rolling mills since 1888. After <str<strong>on</strong>g>the</str<strong>on</strong>g> Sec<strong>on</strong>d<br />
World War, Achenbach became <str<strong>on</strong>g>the</str<strong>on</strong>g> specialist<br />
for n<strong>on</strong>-ferrous metals, such as <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> or<br />
copper and copper alloys. Achenbach is <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
world market leader for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> thin-strip<br />
and foil rolling mills for more than 20 years<br />
now.<br />
• On this basis, Achenbach extended its product<br />
range in 2006. First came <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> foil<br />
doublers, separators and slitting machines<br />
for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> foils, <str<strong>on</strong>g>the</str<strong>on</strong>g>n slitting machines<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>verting industry (slitting machines<br />
for m<strong>on</strong><str<strong>on</strong>g>of</str<strong>on</strong>g>oils, laminates, n<strong>on</strong>-woven as well<br />
as all adhesive and n<strong>on</strong>-adhesive materials)<br />
were added. The c<strong>on</strong>vincing market entry was<br />
facilitated by <str<strong>on</strong>g>the</str<strong>on</strong>g> trend-setting new developments<br />
with regard to design and c<strong>on</strong>structi<strong>on</strong>.<br />
Nearly 20 machines <str<strong>on</strong>g>of</str<strong>on</strong>g> this type have already<br />
been successfully commissi<strong>on</strong>ed.<br />
Integrative technology<br />
As a system supplier, Achenbach follows an<br />
integrative approach to <str<strong>on</strong>g>of</str<strong>on</strong>g>fer overall technical<br />
soluti<strong>on</strong>s. ‘Everything from <strong>on</strong>e single source’<br />
gives <str<strong>on</strong>g>the</str<strong>on</strong>g> chance to optimally design <str<strong>on</strong>g>the</str<strong>on</strong>g> pro-<br />
ducti<strong>on</strong> process as a whole, from <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling<br />
process via <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting process up to <str<strong>on</strong>g>the</str<strong>on</strong>g> fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
processing.<br />
Achenbach develops and manufactures<br />
rolling mills, slitting machines as well as important<br />
auxiliary systems <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g>ir single premises<br />
in Buschhütten. Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> knowledge regarding<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> rolling mill is decisive for developing<br />
trendsetting slitting machines <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>e<br />
hand. Vice versa, experiences in winding and<br />
slitting <str<strong>on</strong>g>of</str<strong>on</strong>g> rolled and even c<strong>on</strong>verting materials<br />
give valuable informati<strong>on</strong> for designing <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
rolling mills. On <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r hand, <str<strong>on</strong>g>the</str<strong>on</strong>g> knowledge<br />
from manufacture, assembly and commissi<strong>on</strong>ing<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> this machinery form <str<strong>on</strong>g>the</str<strong>on</strong>g> basis<br />
for future developments.<br />
By covering all four fields, Achenbach deduces<br />
synergy effects in two directi<strong>on</strong>s for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
benefit <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> customers:<br />
1. Synergy effects between <str<strong>on</strong>g>the</str<strong>on</strong>g>oretic design<br />
and practical realizati<strong>on</strong>: support and extensi<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> technology and quality leadership. It is<br />
a questi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> trustworthiness to not <strong>on</strong>ly design<br />
machines, but also to manufacture <str<strong>on</strong>g>the</str<strong>on</strong>g>m.<br />
2. Synergy effects between processing and<br />
c<strong>on</strong>verting industry: c<strong>on</strong>tinuously growing demands<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> quality <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting products<br />
in combinati<strong>on</strong> with highly sensitive materials<br />
underline <str<strong>on</strong>g>the</str<strong>on</strong>g> importance <str<strong>on</strong>g>of</str<strong>on</strong>g> a mutual knowhow<br />
transfer.<br />
This is exactly what Achenbach means by<br />
an integrative approach in foil slitting technology.<br />
The reproducibility due to <str<strong>on</strong>g>the</str<strong>on</strong>g> overall<br />
data flow and <str<strong>on</strong>g>the</str<strong>on</strong>g> optimizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
flow within <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong> is <str<strong>on</strong>g>the</str<strong>on</strong>g> customers’<br />
benefit.<br />
By meeting <str<strong>on</strong>g>the</str<strong>on</strong>g>se demands, Achenbach is<br />
qualified as a supplier not <strong>on</strong>ly for first-class<br />
stand-al<strong>on</strong>e systems but also for highly-complex<br />
machinery ‘<strong>on</strong> greenfield sites’ or <str<strong>on</strong>g>the</str<strong>on</strong>g>ir<br />
modernizati<strong>on</strong>. With more than 120 years<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> experience in mechanical engineering,<br />
Achenbach is a qualified partner for sophisticated<br />
special requirements and is traditi<strong>on</strong>ally<br />
always ready to face tricky modernizati<strong>on</strong><br />
projects.<br />
Market requirements<br />
With respect to <str<strong>on</strong>g>the</str<strong>on</strong>g> different kinds <str<strong>on</strong>g>of</str<strong>on</strong>g> foil slitting<br />
machines its demand can be qualitatively<br />
characterized as follows: growing technical<br />
requirements toge<str<strong>on</strong>g>the</str<strong>on</strong>g>r with more specific<br />
desires and needs <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> customers, define a<br />
highly-complex c<strong>on</strong>text. This is reflected in<br />
6 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011<br />
Images: Achenbach
<str<strong>on</strong>g>the</str<strong>on</strong>g> following developments and desires <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
customers:<br />
• c<strong>on</strong>tinuously higher speeds <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> single<br />
machines<br />
• fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r reducti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> n<strong>on</strong>-productive times<br />
• highly sensitive materials, which require a<br />
more specialized design<br />
• trend to smaller batch sizes<br />
• increasing demand for integrated<br />
additi<strong>on</strong>al functi<strong>on</strong>s such as simultaneous<br />
oiling or perforati<strong>on</strong> for fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r processing<br />
• growing importance <str<strong>on</strong>g>of</str<strong>on</strong>g> resource efficiency,<br />
here reducti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> energy c<strong>on</strong>sumpti<strong>on</strong><br />
• high operati<strong>on</strong>al safety as strict side<br />
c<strong>on</strong>diti<strong>on</strong>.<br />
C<strong>on</strong>siderable c<strong>on</strong>flicts <str<strong>on</strong>g>of</str<strong>on</strong>g> objectives result in<br />
optimizati<strong>on</strong> problems which require innovative<br />
soluti<strong>on</strong>s.<br />
Achenbach Optifoil product line<br />
Achenbach’s resp<strong>on</strong>se is a system <str<strong>on</strong>g>of</str<strong>on</strong>g> nine basic<br />
machine types: As ‘Optifoil’ product line,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>se machines types are <str<strong>on</strong>g>the</str<strong>on</strong>g> basis to fulfil all<br />
slitting jobs for a wide variety <str<strong>on</strong>g>of</str<strong>on</strong>g> materials:<br />
tailored to <str<strong>on</strong>g>the</str<strong>on</strong>g> individual customer’s needs,<br />
highly-productive and in top quality, especially<br />
with regard to <str<strong>on</strong>g>the</str<strong>on</strong>g> straight-edged finished<br />
roll rewinding and absolutely clean cuts:<br />
• Optifoil Varioslit – <str<strong>on</strong>g>the</str<strong>on</strong>g> flexible all-rounder<br />
for all foil slitting jobs<br />
• Optifoil Varioslit Plus – <str<strong>on</strong>g>the</str<strong>on</strong>g> high-produc-<br />
tive all-rounder for all foil slitting jobs<br />
• Optifoil Fibreslit – <str<strong>on</strong>g>the</str<strong>on</strong>g> specialist for slitting<br />
tasks in <str<strong>on</strong>g>the</str<strong>on</strong>g> paper and textile industry<br />
• Optifoil Jumboslit – <str<strong>on</strong>g>the</str<strong>on</strong>g> specialist for all<br />
slitting jobs <str<strong>on</strong>g>of</str<strong>on</strong>g> jumbo rolls<br />
Optifoil Jumboslit<br />
• Optifoil Inspector – <str<strong>on</strong>g>the</str<strong>on</strong>g> specialist for<br />
surface c<strong>on</strong>trol<br />
• Optifoil Lightslit – <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting specialist for<br />
thin metal foils<br />
• Optifoil Heavyslit – <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting specialist<br />
for thick metal foils and large roll diameters<br />
• Optifoil Separator and Doubler for<br />
producing even thinnest metal foils.<br />
The brand name Achenbach generally represents<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> following quality features:<br />
• complete reliability resulting from<br />
superior quality <str<strong>on</strong>g>of</str<strong>on</strong>g> all comp<strong>on</strong>ents<br />
• first-class measuring, drive and c<strong>on</strong>trol<br />
comp<strong>on</strong>ents<br />
• energy-saving and emissi<strong>on</strong>-minimized<br />
engineering<br />
• maximum availability by <strong>on</strong>line fault<br />
diagnosis as well as service and support<br />
during <str<strong>on</strong>g>the</str<strong>on</strong>g> whole operati<strong>on</strong>al period<br />
• effective operati<strong>on</strong> and easy maintenance<br />
due to modular design.<br />
Success factors in foil slitting technology<br />
In principal five key factors are setting <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
trends for <str<strong>on</strong>g>the</str<strong>on</strong>g> quality <str<strong>on</strong>g>of</str<strong>on</strong>g> slitting technology:<br />
(1) Optimum slitting quality at highest speeds<br />
Robust design: It is <strong>on</strong>e prec<strong>on</strong>diti<strong>on</strong> and is<br />
mainly reflected in <str<strong>on</strong>g>the</str<strong>on</strong>g> mechanical design <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> single comp<strong>on</strong>ents such as bottom knife<br />
shaft, bottom knife slitting tools and top knife<br />
selecti<strong>on</strong> as well as <str<strong>on</strong>g>the</str<strong>on</strong>g> definiti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting<br />
tool diameter; in both cases, a special design is<br />
inevitable. Regarding <str<strong>on</strong>g>the</str<strong>on</strong>g> design <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting<br />
tools, a too high moment <str<strong>on</strong>g>of</str<strong>on</strong>g> inertia is to be<br />
avoided <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>e hand. On <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r hand,<br />
ROLLING INDUSTRY<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> smooth run <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting unit in c<strong>on</strong>tinuous<br />
operati<strong>on</strong> at maximum speeds is to be<br />
secured.<br />
Manifold fine adjustment: The fine adjustment<br />
with a slitting geometry tailored to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
respective material is decisive for <str<strong>on</strong>g>the</str<strong>on</strong>g> excellent<br />
slitting quality; for this purpose Achenbach<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g>fers opti<strong>on</strong>ally an electr<strong>on</strong>ic setting device<br />
realized by a positi<strong>on</strong>ing device. By means <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
this or <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 4-axes-setting, <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting tools<br />
can be adapted even to <str<strong>on</strong>g>the</str<strong>on</strong>g> most difficult material<br />
features in <str<strong>on</strong>g>the</str<strong>on</strong>g> setup time <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> machine.<br />
This manifold fine adjustments are especially<br />
important for highly-sensitive materials such<br />
as s<str<strong>on</strong>g>of</str<strong>on</strong>g>t <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> or multi-<str<strong>on</strong>g>layer</str<strong>on</strong>g> composite<br />
materials.<br />
Highest precisi<strong>on</strong>: Even if highest precisi<strong>on</strong><br />
with slitting tolerances < 1/100 mm is required,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> slitting cassettes is advantageous to<br />
guarantee <str<strong>on</strong>g>the</str<strong>on</strong>g> perfect cut at high speeds. This<br />
especially goes for slitting tasks with higher<br />
material thickness.<br />
(2) Highest reliability at<br />
maximum machine utilizati<strong>on</strong><br />
This is guaranteed by <str<strong>on</strong>g>the</str<strong>on</strong>g> robust design <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> machine frame as any kind <str<strong>on</strong>g>of</str<strong>on</strong>g> vibrati<strong>on</strong><br />
is safely avoided. The principle <str<strong>on</strong>g>of</str<strong>on</strong>g> stability is<br />
also a must-have for purchase parts, i.e. <strong>on</strong>ly<br />
high-class quality drive comp<strong>on</strong>ents, slitting<br />
and winding tools, etc. are used. The highly<br />
efficient use <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> installed energy performance<br />
as well as <str<strong>on</strong>g>the</str<strong>on</strong>g> optimum interacti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> all<br />
mechanical, electric and hydraulic modules<br />
is ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r advantage. The integrative quality<br />
c<strong>on</strong>trol according to DIN ISO 9001, which<br />
c<strong>on</strong>tinuously checks <str<strong>on</strong>g>the</str<strong>on</strong>g> in-house manufactured<br />
comp<strong>on</strong>ents as well as purchase parts,<br />
represents <str<strong>on</strong>g>the</str<strong>on</strong>g> first-class mechanical engineering<br />
Achenbach is standing for. The customers’<br />
benefits are extremely high machine speeds<br />
and process stability.<br />
(3) Quick finished roll handling<br />
Highest process speeds are <str<strong>on</strong>g>the</str<strong>on</strong>g> first factor for<br />
high productivity, low n<strong>on</strong>-productive times<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> sec<strong>on</strong>d. With an increasing degree <str<strong>on</strong>g>of</str<strong>on</strong>g> technology<br />
and decreasing batch sizes, <str<strong>on</strong>g>the</str<strong>on</strong>g> aim <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
reducing <str<strong>on</strong>g>the</str<strong>on</strong>g> n<strong>on</strong>-productive times becomes<br />
more and more important. That means to<br />
facilitate an optimum handling cycle for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
customer. Achenbach <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>of</str<strong>on</strong>g>fers a wide<br />
product range including roll handling, roll turret<br />
and roll stripping devices, which simplify<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> handling by combining automatic material<br />
clamping and integrated cross-cutting units. In<br />
order to quicken <str<strong>on</strong>g>the</str<strong>on</strong>g> finished roll handling<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>re are special handling devices for heavy<br />
weights and for small rolls. Perfectly combined,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> result is a fully-automatic handling cycle<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 7
ROLLING INDUSTRY<br />
Optifoil Heavyslit with rotary frame<br />
for unloading and immediately palletizing with<br />
a defined schedule. In any case, <str<strong>on</strong>g>the</str<strong>on</strong>g> reducti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> handling times is <str<strong>on</strong>g>the</str<strong>on</strong>g> customer’s benefit.<br />
(4) Shortest times for material changes<br />
The customers <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting machine operators<br />
increasingly demand ‘Just-in-Time Deliveries’.<br />
Small batch sizes and short reacti<strong>on</strong> times<br />
are becoming a competitive advantage: To be<br />
competitive it is not enough to be good – you<br />
must be flexible. Achenbach has accepted this<br />
challenge. With <str<strong>on</strong>g>the</str<strong>on</strong>g> tailor-made machines <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Optifoil product line, <str<strong>on</strong>g>the</str<strong>on</strong>g> customers can<br />
process smaller batches <str<strong>on</strong>g>of</str<strong>on</strong>g> various slitting<br />
products with highest productivity. While <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
slitter has to quickly adapt to various slitting<br />
widths, <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> foil separators focus<br />
<strong>on</strong> different material thicknesses and material<br />
widths.<br />
The automatic material threading device is<br />
<strong>on</strong>e example for modules guaranteeing that,a<br />
splice table with adhesive tape unwinder is<br />
ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r <strong>on</strong>e. Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r examples are: recipe<br />
storage for various slitting widths and winding<br />
data or a combined drive technology with<br />
two motors <strong>on</strong> <strong>on</strong>e winding shaft. By means<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> that, foil materials with different strip thicknesses<br />
can be separated with c<strong>on</strong>tinuous winding<br />
tightness; throughout <str<strong>on</strong>g>the</str<strong>on</strong>g> entire diameter<br />
range as well as throughout a large strip width<br />
range. With <str<strong>on</strong>g>the</str<strong>on</strong>g> help <str<strong>on</strong>g>of</str<strong>on</strong>g> this combined drive<br />
c<strong>on</strong>cept, different and highly sensitive materials<br />
can be run <strong>on</strong> <strong>on</strong>e single-slitter at c<strong>on</strong>tinuous<br />
winding tightness.<br />
By using slitting cassettes or an automatic<br />
knife shaft c<strong>on</strong>trol <str<strong>on</strong>g>the</str<strong>on</strong>g> handling times as well<br />
shortened. Auxiliary devices, which simplify<br />
and automate <str<strong>on</strong>g>the</str<strong>on</strong>g> core positi<strong>on</strong>ing, finally<br />
round <str<strong>on</strong>g>of</str<strong>on</strong>g>f <str<strong>on</strong>g>the</str<strong>on</strong>g> range <str<strong>on</strong>g>of</str<strong>on</strong>g> products for shortening<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> set-up times.<br />
(5) Custom-built machinery<br />
In order to optimally support <str<strong>on</strong>g>the</str<strong>on</strong>g> customers in<br />
meeting <str<strong>on</strong>g>the</str<strong>on</strong>g>ir special needs, it is important to<br />
resp<strong>on</strong>d to <str<strong>on</strong>g>the</str<strong>on</strong>g> customers’ desires. By <str<strong>on</strong>g>the</str<strong>on</strong>g> way,<br />
some custom-built comp<strong>on</strong>ents has been later<br />
taken as basic design:<br />
• Energy-recovering unwinder (hybrid winding):<br />
While <str<strong>on</strong>g>the</str<strong>on</strong>g> braking power was, for example,<br />
formerly dissipated via braking resistors,<br />
this power is today directly resupplied into<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> winding drives and <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> energy<br />
c<strong>on</strong>sumpti<strong>on</strong> is reduced.<br />
• X-frames for material fine adjustment: Ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
custom-built design is <str<strong>on</strong>g>the</str<strong>on</strong>g> fine adjustment<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material web by a X-frame additi<strong>on</strong>ally<br />
installed in fr<strong>on</strong>t <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting unit.<br />
With its quick reacti<strong>on</strong> to material waste,<br />
as <str<strong>on</strong>g>the</str<strong>on</strong>g> set-up time for material change are Optifoil Heavyslit with automatic slitting gap setting<br />
such a X-frame supports <str<strong>on</strong>g>the</str<strong>on</strong>g> normal side edge<br />
c<strong>on</strong>trol by an absolutely precise material web<br />
alignment directly at <str<strong>on</strong>g>the</str<strong>on</strong>g> cutting knife. This<br />
auxiliary device is recommended especially<br />
for sensitive materials.<br />
• Oil applicator: The opti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> additi<strong>on</strong>ally<br />
installing an oil applicator is just <strong>on</strong>e example<br />
for an ‘added value’ in slitting technology.<br />
During <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting process, <str<strong>on</strong>g>the</str<strong>on</strong>g> material web is<br />
covered with oil, which is required when <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
slitting process is followed by a deep-drawing<br />
process.<br />
• Double-face strip inspecti<strong>on</strong>: The doubleface<br />
strip inspecti<strong>on</strong> is <strong>on</strong>e fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r custombuilt<br />
comp<strong>on</strong>ent. This system scans <str<strong>on</strong>g>the</str<strong>on</strong>g> surface<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> coil and analyses its data. Thus, faults<br />
can be specifically and quickly eliminated for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> inspected coil. As a preventative measure,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong> process can be optimized <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> basis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> inspecti<strong>on</strong> data.<br />
(6) L<strong>on</strong>g-term partnership<br />
Traditi<strong>on</strong>ally, Achenbach c<strong>on</strong>siders itself to be<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> partner <str<strong>on</strong>g>of</str<strong>on</strong>g> its customers. Being a partner<br />
means establishing and maintaining l<strong>on</strong>g-term<br />
business relati<strong>on</strong>s. A product understanding<br />
going bey<strong>on</strong>d <str<strong>on</strong>g>the</str<strong>on</strong>g> delivery <str<strong>on</strong>g>of</str<strong>on</strong>g> first-class machinery<br />
is part <str<strong>on</strong>g>of</str<strong>on</strong>g> this philosophy and comprises<br />
also <str<strong>on</strong>g>the</str<strong>on</strong>g> commitment for maximum<br />
availability throughout <str<strong>on</strong>g>the</str<strong>on</strong>g> whole operati<strong>on</strong>al<br />
period. This is guaranteed by <str<strong>on</strong>g>the</str<strong>on</strong>g> Achenbach<br />
Service & Support for maintaining <str<strong>on</strong>g>the</str<strong>on</strong>g> machine<br />
performance: as immediate measures in<br />
case <str<strong>on</strong>g>of</str<strong>on</strong>g> breakdown, as preventative measures<br />
or as optimizati<strong>on</strong> measures; trusted support<br />
staff is always available.<br />
Rolling mills and foil slitting machines are<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> core parts in our customers’ producti<strong>on</strong>.<br />
Their quality is a decisive factor for our customers’<br />
competitiveness in <str<strong>on</strong>g>the</str<strong>on</strong>g>ir own markets.<br />
For many years, <str<strong>on</strong>g>the</str<strong>on</strong>g> Achenbach brand mark<br />
has already been known for its n<strong>on</strong>-ferrous<br />
rolling mills all over <str<strong>on</strong>g>the</str<strong>on</strong>g> world. This is so<strong>on</strong><br />
to follow for <str<strong>on</strong>g>the</str<strong>on</strong>g> Optifoil foil slitting machines<br />
– for <str<strong>on</strong>g>the</str<strong>on</strong>g> customers’ benefit.<br />
�<br />
8 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
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ROLLING INDUSTRY<br />
Focus <strong>on</strong> rolling mill efficiency: design and c<strong>on</strong>trol<br />
Rainer Neukant, Achenbach Buschhütten GmbH<br />
L<strong>on</strong>g time, <str<strong>on</strong>g>the</str<strong>on</strong>g> challenge in rolling mill<br />
building was to c<strong>on</strong>tinuously increase <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
productivity <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>e hand and <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
o<str<strong>on</strong>g>the</str<strong>on</strong>g>r hand to improve <str<strong>on</strong>g>the</str<strong>on</strong>g> tolerances <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
all kind <str<strong>on</strong>g>of</str<strong>on</strong>g> flat rolled products. Today,<br />
setting <str<strong>on</strong>g>the</str<strong>on</strong>g> course with innovative soluti<strong>on</strong>s<br />
means more and more focusing <strong>on</strong><br />
rolling mill efficiency, with respect to<br />
design and c<strong>on</strong>trol. In this c<strong>on</strong>text it is <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
high importance to particularly aim <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
development work at both, machinery<br />
efficiency and resources efficiency. The<br />
respective fields <str<strong>on</strong>g>of</str<strong>on</strong>g> innovati<strong>on</strong>s are manifold:<br />
simulati<strong>on</strong>, mechatr<strong>on</strong>ics, process<br />
models, use <str<strong>on</strong>g>of</str<strong>on</strong>g> resources and not least<br />
service and support, to menti<strong>on</strong> <strong>on</strong>ly a<br />
few. All <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se innovative search fields<br />
are to be c<strong>on</strong>sidered in an integrative approach,<br />
ensuring at <str<strong>on</strong>g>the</str<strong>on</strong>g> same time high<br />
productivity, best quality and <str<strong>on</strong>g>the</str<strong>on</strong>g> defined<br />
producti<strong>on</strong> flexibility.<br />
1 Machinery efficiency<br />
1.1 Computati<strong>on</strong>al Fluid Dynamics (CDF)<br />
In a rolling mill enormous quantities <str<strong>on</strong>g>of</str<strong>on</strong>g> media<br />
(hydraulic, cooling and lubricati<strong>on</strong> fluids and<br />
exhaust air) must be handled. The fume hood<br />
as an example illustrates that it is possible to<br />
be innovative even with regard to a relatively<br />
simple part <str<strong>on</strong>g>of</str<strong>on</strong>g> machinery. A fume hood is<br />
needed to collect <str<strong>on</strong>g>the</str<strong>on</strong>g> exhaust air loaded with<br />
gaseous rolling oil. There are several reas<strong>on</strong>s<br />
to design this part <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling mill exhaust air<br />
purificati<strong>on</strong> system as efficient as possible:<br />
• guaranteeing best c<strong>on</strong>diti<strong>on</strong>s for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
operators working closely to <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling<br />
mill and to fulfil envir<strong>on</strong>mental, health<br />
and safety requirements<br />
• maximum recovery <str<strong>on</strong>g>of</str<strong>on</strong>g> rolling oil from <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
waste air to comply with ec<strong>on</strong>omic targets.<br />
The classic fume hood design is based <strong>on</strong> both,<br />
experience values and relatively simple geometric<br />
aspects. Today, competitive simulati<strong>on</strong><br />
programs are available allowing more detailed<br />
views into fluid mechanics <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se exhaust air<br />
purificati<strong>on</strong> systems. The knowledge gained<br />
from <str<strong>on</strong>g>the</str<strong>on</strong>g> CFD simulati<strong>on</strong>s results in fluid-optimized<br />
design features to increase <str<strong>on</strong>g>the</str<strong>on</strong>g> exhaust<br />
efficiency and at <str<strong>on</strong>g>the</str<strong>on</strong>g> same time to reduce <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
energy c<strong>on</strong>sumpti<strong>on</strong>.<br />
1.2 Chemical CAD<br />
The applicati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> physical / chemical simulati<strong>on</strong><br />
s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware is a fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r example for advanced<br />
engineering methods to improve <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
efficiency <str<strong>on</strong>g>of</str<strong>on</strong>g> rolling mills. Particularly for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
field <str<strong>on</strong>g>of</str<strong>on</strong>g> exhaust air purificati<strong>on</strong> systems a<br />
physical and chemical process simulati<strong>on</strong> tool<br />
forms <str<strong>on</strong>g>the</str<strong>on</strong>g> basis for <str<strong>on</strong>g>the</str<strong>on</strong>g> optimized design <str<strong>on</strong>g>of</str<strong>on</strong>g> today’s<br />
‘Airpure’ systems.<br />
With <str<strong>on</strong>g>the</str<strong>on</strong>g> help <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se CAD tools, new<br />
Airpure systems can be perfectly designed<br />
while existing systems can be modified for<br />
better performance <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> shortest term. By<br />
means <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> simulati<strong>on</strong> s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware, <str<strong>on</strong>g>the</str<strong>on</strong>g> effects<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> rolling oil comp<strong>on</strong>ents and additives <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
exhaust air can be previously tested and recommendati<strong>on</strong>s<br />
to improve a time-c<strong>on</strong>suming<br />
and expensive exhaust air purificati<strong>on</strong> can be<br />
made at <str<strong>on</strong>g>the</str<strong>on</strong>g> earliest stage.<br />
1.3 Mechatr<strong>on</strong>ics<br />
Setting <str<strong>on</strong>g>the</str<strong>on</strong>g> course for fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r developments<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> customers’ benefit, an integrative approach<br />
is required c<strong>on</strong>sidering at <str<strong>on</strong>g>the</str<strong>on</strong>g> same<br />
time mechanical as well as electr<strong>on</strong>ic aspects<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> engineering. The ‘Win-SprayS’ rolling oil<br />
distributi<strong>on</strong> system is just <strong>on</strong>e example for it<br />
reflected by <str<strong>on</strong>g>the</str<strong>on</strong>g> following soluti<strong>on</strong>s:<br />
• Patented valve design: best reliability is<br />
achieved by eliminating pneumatic comp<strong>on</strong>ents,<br />
i.e. <str<strong>on</strong>g>the</str<strong>on</strong>g> valve is just electrically actuated.<br />
All moving parts that are subject to wear and<br />
tear are integrated in a cartridge that can be<br />
simply replaced from <str<strong>on</strong>g>the</str<strong>on</strong>g> fr<strong>on</strong>t. Before introducti<strong>on</strong><br />
into <str<strong>on</strong>g>the</str<strong>on</strong>g> market, <str<strong>on</strong>g>the</str<strong>on</strong>g> functi<strong>on</strong>ality <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
this valve series was comprehensively verified<br />
in test runs <str<strong>on</strong>g>of</str<strong>on</strong>g> 10,000,000 switching cycles.<br />
• Different valve sizes: two sizes <str<strong>on</strong>g>of</str<strong>on</strong>g> spraying<br />
valves are available to cover <str<strong>on</strong>g>the</str<strong>on</strong>g> range <str<strong>on</strong>g>of</str<strong>on</strong>g> rolling<br />
oil spraying systems from cold strip to foil<br />
rolling mills. The smaller valve is optimized<br />
for narrow 26 mm spacing in <str<strong>on</strong>g>the</str<strong>on</strong>g> spraying bar<br />
and applies 44 l/min, while <str<strong>on</strong>g>the</str<strong>on</strong>g> big valve is suitable<br />
for 52 mm spacing applying 150 l/min<br />
• Valves meeting <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>trol system requirements:<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> aid <str<strong>on</strong>g>of</str<strong>on</strong>g> ‘Matlab’ models <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
spraying geometry is designed for a uniform<br />
cooling effect. The correctness <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se design<br />
models is verified measuring <str<strong>on</strong>g>the</str<strong>on</strong>g> oil distributi<strong>on</strong><br />
for individual nozzles as well as measuring<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> heat transfer. These measurements<br />
are d<strong>on</strong>e <strong>on</strong> a test stand with rolling oil. Both<br />
10 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011<br />
Images: Achenbach
Pulse and Volume (Level) C<strong>on</strong>trol methods<br />
are supported.<br />
• Advanced design tools: toge<str<strong>on</strong>g>the</str<strong>on</strong>g>r with careful<br />
tests in <str<strong>on</strong>g>the</str<strong>on</strong>g> laboratory, today a verificati<strong>on</strong><br />
and optimizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> existing installati<strong>on</strong>s in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> rolling mill is possible. As an example, a<br />
pressure-sensitive film is used to visualize <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
footprint <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> spraying system. This is mainly<br />
d<strong>on</strong>e to identify worn nozzles and to ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
c<strong>on</strong>firm or optimize spraying angles for best<br />
overlapping.<br />
1.4 Process automati<strong>on</strong><br />
In cold rolling mills, particularly in foil rolling<br />
mills, best results have been achieved<br />
with powerful closed-loop c<strong>on</strong>trol systems for<br />
many years. Such systems have been steadily<br />
improved with respect to better measuring<br />
systems (e.g. <str<strong>on</strong>g>the</str<strong>on</strong>g> ‘Optiroll’ flatness measuring<br />
roll), better actuators (e.g. <str<strong>on</strong>g>the</str<strong>on</strong>g> Win-SprayS<br />
rolling oil distributi<strong>on</strong>) and faster c<strong>on</strong>trol systems.<br />
In that way product quality (e.g. thickness<br />
and flatness) as well as productivity (by<br />
higher rolling speeds) could be maximized.<br />
Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r optimizati<strong>on</strong> is now focused <strong>on</strong><br />
meeting <str<strong>on</strong>g>the</str<strong>on</strong>g> high quality requirements already<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g> strip head. This requires a precise presetting<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> mill including for example an<br />
optimum bending force to meet <str<strong>on</strong>g>the</str<strong>on</strong>g> flatness<br />
tolerances even before <str<strong>on</strong>g>the</str<strong>on</strong>g> feedback c<strong>on</strong>troller<br />
is able to compensate for a wr<strong>on</strong>g flatness.<br />
This requires c<strong>on</strong>trol methods, which are not<br />
based <strong>on</strong> measuring <str<strong>on</strong>g>the</str<strong>on</strong>g> parameters to be<br />
c<strong>on</strong>trolled. Here process models are necessary,<br />
which are able to approximate <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling<br />
result. For a l<strong>on</strong>g time, such future-orientated<br />
physical models were available as <str<strong>on</strong>g>of</str<strong>on</strong>g>f-<br />
line models for rolling mill design and layout.<br />
In recent years, <strong>on</strong>line-model applicati<strong>on</strong>s<br />
have been developed.<br />
The integrative Optiroll automati<strong>on</strong> system<br />
comprises both, <strong>on</strong>line process models and<br />
model-based functi<strong>on</strong>s available throughout<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> different levels <str<strong>on</strong>g>of</str<strong>on</strong>g> automati<strong>on</strong> hierarchy.<br />
The Roll Speed Compensati<strong>on</strong> (RSC) is<br />
<strong>on</strong>e example for a model-based functi<strong>on</strong> that<br />
is integrated in <str<strong>on</strong>g>the</str<strong>on</strong>g> Level 1 c<strong>on</strong>trol system for<br />
highest dynamic behaviour, as it compensates<br />
for speed-related tribologic effects in cold<br />
rolling. With RSC, much closer thickness tolerances<br />
are achieved compared to <str<strong>on</strong>g>the</str<strong>on</strong>g> classic<br />
closed loop c<strong>on</strong>trol which is depending <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
slow feedback <str<strong>on</strong>g>of</str<strong>on</strong>g> measured thickness. Without<br />
RSC, <str<strong>on</strong>g>the</str<strong>on</strong>g> changing tribologic c<strong>on</strong>diti<strong>on</strong>s in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
roll gap would result in significant thickness<br />
deviati<strong>on</strong>s during accelerati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling<br />
mill.<br />
Bey<strong>on</strong>d integrated model-based functi<strong>on</strong>s<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Optiroll automati<strong>on</strong> system provides<br />
trendsetting soluti<strong>on</strong>s for dedicated Level 2<br />
process models to comprehensively optimize<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> rolling process. This is particularly required<br />
for both, presetting <str<strong>on</strong>g>the</str<strong>on</strong>g> closed loop c<strong>on</strong>troller<br />
(Level 1) and those c<strong>on</strong>trolling parameters,<br />
which cannot be measured during <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling<br />
process. With regard to Level 2 process models,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>re are two different approaches:<br />
• Before rolling, roll force and roll stack<br />
deflecti<strong>on</strong> are calculated in order to achieve<br />
minimum thickness deviati<strong>on</strong> at <str<strong>on</strong>g>the</str<strong>on</strong>g> strip head<br />
and to reach target pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile /flatness as quick as<br />
possible in order to avoid scrap material. For<br />
this, <str<strong>on</strong>g>the</str<strong>on</strong>g> calculati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> roll force <strong>on</strong> Level<br />
2 provides two opti<strong>on</strong>s: Tribologic models for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> roll gap fricti<strong>on</strong> with l<strong>on</strong>g-term and shortterm<br />
adapti<strong>on</strong>, as far as cold rolling is c<strong>on</strong>cerned.<br />
When it comes to hot rolling, adapti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> flow stress strain curves is applied.<br />
ROLLING INDUSTRY<br />
• During rolling, two different types <str<strong>on</strong>g>of</str<strong>on</strong>g> modeling<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> rolling process are designed:<br />
On <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>e hand, <str<strong>on</strong>g>the</str<strong>on</strong>g> calculati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal<br />
expansi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> work roll to correct <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling<br />
force and <str<strong>on</strong>g>the</str<strong>on</strong>g> mechanical bending in order<br />
to avoid pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile and / or flatness errors and <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r hand, calculati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> strip temperatures<br />
in order to keep <str<strong>on</strong>g>the</str<strong>on</strong>g> material properties<br />
in a certain range.<br />
While all o<str<strong>on</strong>g>the</str<strong>on</strong>g>r functi<strong>on</strong>s are focusing <strong>on</strong><br />
precise pre-setting, <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal models as well<br />
are periodically triggered during rolling, so that<br />
<strong>on</strong>line correcti<strong>on</strong>s with respect to pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile and<br />
flatness or with respect to <str<strong>on</strong>g>the</str<strong>on</strong>g> strip temperature<br />
are possible. Meeting <str<strong>on</strong>g>the</str<strong>on</strong>g> strip temperature<br />
during all passes is not <strong>on</strong>ly required for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> metallurgical quality <str<strong>on</strong>g>of</str<strong>on</strong>g> hot-rolled aircraft<br />
alloys, but also for <str<strong>on</strong>g>the</str<strong>on</strong>g> exact finishing temperature<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> cold-rolled can- stock qualities.<br />
For best performance, <str<strong>on</strong>g>the</str<strong>on</strong>g> integrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
Level 1 and Level 2 functi<strong>on</strong>s is fundamentally<br />
important. Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> modular design, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Optiroll automati<strong>on</strong> system is predestined for<br />
modernizing existing rolling mills. Above that,<br />
especially <str<strong>on</strong>g>the</str<strong>on</strong>g> Level 2 opti<strong>on</strong>s can be customized<br />
to fulfil <str<strong>on</strong>g>the</str<strong>on</strong>g> individual requirements for<br />
improving <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling mill performance.<br />
2 Resources efficiency<br />
2.1 Electrical power<br />
Electrical power and gas are <str<strong>on</strong>g>the</str<strong>on</strong>g> major forms<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> energy that are to be c<strong>on</strong>sidered for <str<strong>on</strong>g>the</str<strong>on</strong>g> efficiency<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a rolled-products producti<strong>on</strong> plant.<br />
Gas is required for heating processes. For <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
rolling mill, however, electrical energy is <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
most important factor.<br />
The first approach to achieve an energy-efficient<br />
rolling mill is <str<strong>on</strong>g>the</str<strong>on</strong>g> identificati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
major energy c<strong>on</strong>sumers. Electrical drives are<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 11
ROLLING INDUSTRY<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> essential c<strong>on</strong>sumers <str<strong>on</strong>g>of</str<strong>on</strong>g> electrical power in<br />
a rolling mill. 60 to 80% <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> electrical power<br />
installed in a foil rolling mill are required<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> main drives, i.e. <str<strong>on</strong>g>the</str<strong>on</strong>g> mill motor and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> coiler drives. Accordingly, top priority to<br />
achieve best energy efficiency is given to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
design <str<strong>on</strong>g>of</str<strong>on</strong>g> drives, motors and c<strong>on</strong>trol systems<br />
main drives <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling mill:<br />
• In cold rolling mills, decoiler and recoiler<br />
drives are c<strong>on</strong>nected to a comm<strong>on</strong> DC link,<br />
which is fed by <str<strong>on</strong>g>the</str<strong>on</strong>g> rectifier unit. So <str<strong>on</strong>g>the</str<strong>on</strong>g> generated<br />
power <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> de-coiler, which is applying<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> tensi<strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> mill, is kept in <str<strong>on</strong>g>the</str<strong>on</strong>g> system<br />
feeding <str<strong>on</strong>g>the</str<strong>on</strong>g> mill motor and re-coiler motor,<br />
which are operated in motoric mode.<br />
• Modern drive systems are additi<strong>on</strong>ally<br />
equipped with an active feeder, which (c<strong>on</strong>trary<br />
to a simple rectifier) is able to feed back<br />
electrical energy into <str<strong>on</strong>g>the</str<strong>on</strong>g> mains supply. Usually,<br />
this is possible whenever <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling mill<br />
is stopped and <str<strong>on</strong>g>the</str<strong>on</strong>g> rotati<strong>on</strong>al energy <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
coils and rolls can be recovered by inverters<br />
that are working in generator mode.<br />
• Saving electrical energy is moreover possible<br />
with efficient motors that c<strong>on</strong>sume fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
1 to 2% less electrical energy compared to<br />
c<strong>on</strong>venti<strong>on</strong>al motors. C<strong>on</strong>sidering that 99% <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> motor cost during its lifetime arises from<br />
energy cost, also such small effects are a valuable<br />
c<strong>on</strong>tributi<strong>on</strong> to an efficient rolling mill.<br />
• Besides <str<strong>on</strong>g>the</str<strong>on</strong>g> installati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> efficient comp<strong>on</strong>ents<br />
also an intelligent automati<strong>on</strong> and c<strong>on</strong>trol<br />
system is a decisive factor for an efficient<br />
rolling mill. Frequency-c<strong>on</strong>trolled pumps and<br />
fans are good examples for such intelligent<br />
and energy-saving c<strong>on</strong>trol systems. Frequency<br />
c<strong>on</strong>trol allows always and c<strong>on</strong>tinuously adjusting<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> power as per <str<strong>on</strong>g>the</str<strong>on</strong>g> actual process<br />
requirements. An ‘Airpure’ fan for example<br />
can be reduced in its rotati<strong>on</strong>s per minute<br />
(and accordingly power c<strong>on</strong>sumpti<strong>on</strong>) when<br />
less air must be moved in case not all rolling<br />
mills <str<strong>on</strong>g>of</str<strong>on</strong>g> a rolling mill line are in operati<strong>on</strong>.<br />
The same applies for pumps <str<strong>on</strong>g>of</str<strong>on</strong>g> a rolling oil<br />
circulati<strong>on</strong> system. Compared to a bypass-c<strong>on</strong>trolled<br />
volume flow, <str<strong>on</strong>g>the</str<strong>on</strong>g> frequency-c<strong>on</strong>trolled<br />
pump is able to save up to 50% <str<strong>on</strong>g>of</str<strong>on</strong>g> electrical<br />
energy with a ‘Superstack’ rolling oil filtrati<strong>on</strong><br />
system.<br />
Intelligent flow-rate c<strong>on</strong>trol and efficient<br />
drives for pumps and fans are good examples<br />
for saving electrical energy with shortest return<br />
<strong>on</strong> investment.<br />
2.2 Rolling oil filtrati<strong>on</strong><br />
Saving electrical energy for fluid circulati<strong>on</strong> is<br />
not <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>ly criteri<strong>on</strong> for efficiency <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling<br />
oil purificati<strong>on</strong> system. The sec<strong>on</strong>d aspect<br />
is maintaining <str<strong>on</strong>g>the</str<strong>on</strong>g> good quality <str<strong>on</strong>g>of</str<strong>on</strong>g> rolling oil<br />
by perfect filtrati<strong>on</strong>. In that way, <str<strong>on</strong>g>the</str<strong>on</strong>g> lifetime<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> rolling oil is maximized and fresh rolling oil<br />
must be added to <str<strong>on</strong>g>the</str<strong>on</strong>g> system less frequently.<br />
In o<str<strong>on</strong>g>the</str<strong>on</strong>g>r words: <str<strong>on</strong>g>the</str<strong>on</strong>g> SuperstackII micr<str<strong>on</strong>g>of</str<strong>on</strong>g>iltrati<strong>on</strong><br />
system preserves a valuable resource –<br />
mineral-oil based rolling oil.<br />
A third aspect <str<strong>on</strong>g>of</str<strong>on</strong>g> efficiency is <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tinuously<br />
c<strong>on</strong>trolled dosage <str<strong>on</strong>g>of</str<strong>on</strong>g> filter aid. Depending<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> differential pressure filter aid is<br />
added, preventing <str<strong>on</strong>g>the</str<strong>on</strong>g> filter cake from getting<br />
clogged. By means <str<strong>on</strong>g>of</str<strong>on</strong>g> this, <str<strong>on</strong>g>the</str<strong>on</strong>g> filtrati<strong>on</strong> cycle is<br />
extended compared to an unc<strong>on</strong>trolled forming<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> filter cake.<br />
Final aspects <str<strong>on</strong>g>of</str<strong>on</strong>g> maintaining <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling oil<br />
quality are in-house developed Achenbach<br />
recipes for filtrati<strong>on</strong> aids and additives. These<br />
recipes are designed specifically to <str<strong>on</strong>g>the</str<strong>on</strong>g> customer’s<br />
rolling processes.<br />
The result <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se features is perfectly<br />
clean rolling oil with extended filtrati<strong>on</strong> cycles,<br />
preserving valuable resources.<br />
2.3 Savings and recovery<br />
For <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> cold rolling process a huge<br />
amount <str<strong>on</strong>g>of</str<strong>on</strong>g> rolling oil is circulated for cooling<br />
and lubricating. As this oil is applied to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
hot work rolls through sprays, a significant<br />
amount <str<strong>on</strong>g>of</str<strong>on</strong>g> rolling oil is taken by <str<strong>on</strong>g>the</str<strong>on</strong>g> exhaust<br />
air <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling mill in form <str<strong>on</strong>g>of</str<strong>on</strong>g> fume and mist.<br />
Recovering that oil from <str<strong>on</strong>g>the</str<strong>on</strong>g> exhaust air is not<br />
<strong>on</strong>ly recovering a valuable resource, but also<br />
recovering energy in form <str<strong>on</strong>g>of</str<strong>on</strong>g> mineral oil. That<br />
oil is fed back into <str<strong>on</strong>g>the</str<strong>on</strong>g> process without any<br />
restricti<strong>on</strong>s.<br />
Today’s high degree <str<strong>on</strong>g>of</str<strong>on</strong>g> rolling oil recovery<br />
is based <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> advanced design feasible by<br />
physical/chemical engineering. Important features<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> this optimizati<strong>on</strong> are:<br />
• recuperators for higher heat recovery<br />
• improved c<strong>on</strong>densers for low-temperature<br />
distillati<strong>on</strong><br />
• reduced pressure losses in air ducts.<br />
Optimized fume hoods and speed-c<strong>on</strong>trolled<br />
fans are fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r criteria <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> highly efficient<br />
Airpure system. The maximized recovery <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
rolling oil and <str<strong>on</strong>g>the</str<strong>on</strong>g> minimum energy c<strong>on</strong>sumpti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Airpure exhaust air purificati<strong>on</strong> is<br />
not <strong>on</strong>ly remarkable with respect to energy<br />
and resources efficiency, but also for reas<strong>on</strong>s<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> envir<strong>on</strong>mental protecti<strong>on</strong>: A rolling mill<br />
with an Airpure system is surpassing <str<strong>on</strong>g>the</str<strong>on</strong>g> strict<br />
European restricti<strong>on</strong>s for VOC emissi<strong>on</strong>s.<br />
The efficiency <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Airpure system in recovering<br />
resources becomes visible comparing<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> amount <str<strong>on</strong>g>of</str<strong>on</strong>g> rolling oil which is recovered<br />
from <str<strong>on</strong>g>the</str<strong>on</strong>g> exhaust air with <str<strong>on</strong>g>the</str<strong>on</strong>g> electrical energy<br />
that is generated by a wind turbine: <str<strong>on</strong>g>the</str<strong>on</strong>g> typical<br />
electrical energy generated by <strong>on</strong>e state<str<strong>on</strong>g>of</str<strong>on</strong>g>-<str<strong>on</strong>g>the</str<strong>on</strong>g>-art<br />
wind turbine for <strong>on</strong>-shore installati<strong>on</strong><br />
is comparable to <str<strong>on</strong>g>the</str<strong>on</strong>g> energy (mineral oil)<br />
recovered from <strong>on</strong>e foil rolling mill.<br />
Saving energy and resources and saving costs<br />
here are in accordance with sustainability and<br />
ecology <str<strong>on</strong>g>of</str<strong>on</strong>g> a modern <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> cold rolling<br />
mill. These benefits are multiplied in rolling<br />
mill lines with three or even more rolling<br />
mills.<br />
3 Service and support<br />
A crucial aspect for any pr<str<strong>on</strong>g>of</str<strong>on</strong>g>essi<strong>on</strong>al service<br />
and support package for rolling mill machinery<br />
is an integrative modular c<strong>on</strong>cept that<br />
aims at maintaining and even increasing <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
machinery performance by taking <str<strong>on</strong>g>the</str<strong>on</strong>g> following<br />
measures:<br />
• Restoring by immediate measures in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
case <str<strong>on</strong>g>of</str<strong>on</strong>g> breakdown<br />
• Preserving by remote and <strong>on</strong>-site<br />
maintenance<br />
• Improving by optimizati<strong>on</strong> measures.<br />
Optimizati<strong>on</strong> measures in <str<strong>on</strong>g>the</str<strong>on</strong>g> sense <str<strong>on</strong>g>of</str<strong>on</strong>g> Achenbach<br />
Service and Support comprise:<br />
• inspecti<strong>on</strong> with ‘Quick Wins’<br />
• analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> process data<br />
• opti<strong>on</strong>s for system modernizati<strong>on</strong><br />
• sustainability measures including tele-<br />
service.<br />
Offering three support packages – Optiroll<br />
check, resources and efficiency check, and<br />
productivity check – Achenbach act as a pr<str<strong>on</strong>g>of</str<strong>on</strong>g>essi<strong>on</strong>al<br />
partner to guarantee high efficiency<br />
and availability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>ir rolling mills all over<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> world. In order to support <str<strong>on</strong>g>the</str<strong>on</strong>g>ir customers<br />
in maintaining competitive advantages in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>ir markets, Achenbach developed a c<strong>on</strong>cept<br />
to ascertain fields with potential for systems’<br />
optimizati<strong>on</strong> and / or c<strong>on</strong>versi<strong>on</strong> respectively<br />
modernizati<strong>on</strong> by installing particular new<br />
individual comp<strong>on</strong>ents. In any case, this c<strong>on</strong>cept<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> supporting <str<strong>on</strong>g>the</str<strong>on</strong>g>ir customers include special<br />
training units.<br />
In c<strong>on</strong>crete terms and in view <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> important<br />
issue <str<strong>on</strong>g>of</str<strong>on</strong>g> resources efficiency, this can<br />
mean:<br />
• new vacuum pumps for better perform-<br />
ance <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Airpure system<br />
• new drives for higher speed and thus<br />
improved productivity<br />
• new automati<strong>on</strong> systems for better<br />
product quality<br />
• new comp<strong>on</strong>ents for c<strong>on</strong>tinuous availabil-<br />
ity and maintainability.<br />
All <str<strong>on</strong>g>the</str<strong>on</strong>g> aforementi<strong>on</strong>ed facts classify Achenbach<br />
as leaders in technology and quality<br />
delivering everything from a single source<br />
– mechanical engineering, machinery, and<br />
service and support – always keeping <strong>on</strong>e eye<br />
<strong>on</strong> rolling mill efficiency in both, installati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> new machinery, modernizati<strong>on</strong> and supporting<br />
high performance in <str<strong>on</strong>g>the</str<strong>on</strong>g> l<strong>on</strong>g run. �<br />
12 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Batch-type and c<strong>on</strong>tinuous floater<br />
furnace facilities for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloy strip<br />
Carl-August Preimesberger, Ebner Industrie<str<strong>on</strong>g>of</str<strong>on</strong>g>enbau GmbH<br />
The producti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> and <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
alloy strips – starting at <str<strong>on</strong>g>the</str<strong>on</strong>g> hot<br />
rolling mill or a c<strong>on</strong>tinuous casting plant<br />
through to sellable strips for <str<strong>on</strong>g>the</str<strong>on</strong>g> widest<br />
range <str<strong>on</strong>g>of</str<strong>on</strong>g> applicati<strong>on</strong>s – involves <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
passing through several stages <str<strong>on</strong>g>of</str<strong>on</strong>g> heat<br />
treatment. Depending <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> starting<br />
material and <str<strong>on</strong>g>the</str<strong>on</strong>g> technological specificati<strong>on</strong>s<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> final product, <str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment<br />
processes may involve annealing,<br />
homogenizing, soluti<strong>on</strong> heat treatment,<br />
recrystallizing, aging or temper annealing.<br />
Basically, all <str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment processes<br />
can be performed during c<strong>on</strong>tinuous annealing<br />
with a floater furnace. However,<br />
cost effective operati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> such a facility<br />
is <strong>on</strong>ly possible if it used predominately<br />
to soluti<strong>on</strong> heat-treat strips. On <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
hand, it is not technically possible to<br />
soluti<strong>on</strong> heat-treat strips in a batch-type<br />
furnace. From an ec<strong>on</strong>omical point <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
view, this kind <str<strong>on</strong>g>of</str<strong>on</strong>g> furnace is ideal for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
remaining heat treatment processes.<br />
The Ebner product range includes proven<br />
designs for both types <str<strong>on</strong>g>of</str<strong>on</strong>g> furnace<br />
The Hic<strong>on</strong> floater furnace manufactured by<br />
Ebner Industrie<str<strong>on</strong>g>of</str<strong>on</strong>g>enbau in Le<strong>on</strong>ding, Austria,<br />
features <str<strong>on</strong>g>the</str<strong>on</strong>g>ir proven design c<strong>on</strong>cept for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
c<strong>on</strong>tinuous heat treatment <str<strong>on</strong>g>of</str<strong>on</strong>g> cold-rolled <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
strip, dramatically improving <str<strong>on</strong>g>the</str<strong>on</strong>g> performance<br />
and quality achieved in c<strong>on</strong>venti<strong>on</strong>al<br />
c<strong>on</strong>tinuous furnaces. Floater furnace facilities<br />
have been built to process strip with a thickness<br />
between 0.3 and 6.35 mm and a width up<br />
to 2,400 mm. Heating up times <str<strong>on</strong>g>of</str<strong>on</strong>g> 1 min/mm<br />
have been achieved at setpoint temperatures<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 560°C and a Δt <str<strong>on</strong>g>of</str<strong>on</strong>g> +0/-3°C.<br />
The combinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> most precise temperature<br />
uniformity and a perfect strip surface<br />
finish specified by end users in <str<strong>on</strong>g>the</str<strong>on</strong>g> automotive<br />
and aerospace industries prompted Ebner to<br />
develop <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>cept <str<strong>on</strong>g>of</str<strong>on</strong>g> a floater furnace in<br />
cooperati<strong>on</strong> with renowned manufacturers <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> products. It is possible to achieve<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> required surface properties because <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> strip is transported totally c<strong>on</strong>tactfree<br />
through <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace facility during <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
entire heating up and cooling process. The<br />
properties apply to <str<strong>on</strong>g>the</str<strong>on</strong>g> deep drawing characteristics<br />
and corrosi<strong>on</strong> resistance.<br />
The Ebner research and development department<br />
advanced nozzle systems which<br />
Photos: Ebner<br />
were <str<strong>on</strong>g>the</str<strong>on</strong>g>n c<strong>on</strong>tinually improved in a test facility.<br />
Powerful Hic<strong>on</strong> high c<strong>on</strong>vecti<strong>on</strong> recirculati<strong>on</strong><br />
technology provides <str<strong>on</strong>g>the</str<strong>on</strong>g> support and<br />
stability required for both thick and thin <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
strip, while achieving <str<strong>on</strong>g>the</str<strong>on</strong>g> best possible<br />
heat transfer rates. Each furnace z<strong>on</strong>e has two<br />
opposing fan units c<strong>on</strong>trolled by frequency<br />
c<strong>on</strong>verters. These atmosphere recirculati<strong>on</strong><br />
fans were also developed by Ebner. The highperformance<br />
impellers, mounted directly <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> fan motor shaft, have underg<strong>on</strong>e extensive<br />
l<strong>on</strong>g-term testing in order to optimize <str<strong>on</strong>g>the</str<strong>on</strong>g>m<br />
for l<strong>on</strong>g service life. Modern automated welding<br />
technology is used to produce impellers <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
optimal and reproducible quality to operate<br />
under extreme <str<strong>on</strong>g>the</str<strong>on</strong>g>rmo-mechanical stress.<br />
The specially developed nozzle system<br />
delivers a uniform transfer <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal energy<br />
across <str<strong>on</strong>g>the</str<strong>on</strong>g> entire width <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> strip during <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
heating up phase. This helps to even improve<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> temperature uniformity throughout <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
soaking phase, in order to meet <str<strong>on</strong>g>the</str<strong>on</strong>g> required<br />
technological specificati<strong>on</strong>s. This furnace secti<strong>on</strong><br />
fulfils <str<strong>on</strong>g>the</str<strong>on</strong>g> strict AMS 2750 D aerospace<br />
standard, applicable worldwide, specifying<br />
that a furnace used for supplying plate to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
aircraft industry (Furnace Class 1) must maintain<br />
a maximum deviati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> ±3K from <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
temperature setpoint in <str<strong>on</strong>g>the</str<strong>on</strong>g> entire workload<br />
space during <str<strong>on</strong>g>the</str<strong>on</strong>g> soaking time. In most cases<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> final deviati<strong>on</strong> form <str<strong>on</strong>g>the</str<strong>on</strong>g> setpoint is down<br />
to around 1.5°C.<br />
Although <str<strong>on</strong>g>the</str<strong>on</strong>g> Hic<strong>on</strong> floater furnaces are<br />
made up <str<strong>on</strong>g>of</str<strong>on</strong>g> individual furnace z<strong>on</strong>es, a distincti<strong>on</strong><br />
is made between heating-up and soaking<br />
z<strong>on</strong>es. The direct gas-fired heating-up z<strong>on</strong>es<br />
C<strong>on</strong>tinuous floater furnace facility<br />
ROLLING INDUSTRY<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace are each equipped with four<br />
low-Nox, tow-stage, all-metall burners. The<br />
combusti<strong>on</strong> air is preheated in a recuperator<br />
to approx. 400°C. The soaking z<strong>on</strong>es are fitted<br />
with two burners which are turndown c<strong>on</strong>trolled<br />
c<strong>on</strong>tinuously. This system, which has been<br />
tried and proven in many facilities, makes<br />
it possible to keep well below <str<strong>on</strong>g>the</str<strong>on</strong>g> threshold<br />
specified in <str<strong>on</strong>g>the</str<strong>on</strong>g> stringent TA-Luft standard.<br />
Once <str<strong>on</strong>g>the</str<strong>on</strong>g> strip leaves <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace secti<strong>on</strong>, it<br />
passes through a combined air/water quench.<br />
This quench, developed by Ebner, makes<br />
possible to implement a special quenching<br />
program designed for each individual alloy,<br />
in order to achieve optimal material properties<br />
at minimal distorti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> strip. Typical<br />
cooling gradients specified for aerospace al-<br />
loy strip exceed 300°C/s. The automati<strong>on</strong><br />
systems s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware developed by Ebner, automatically<br />
selects from a database <str<strong>on</strong>g>the</str<strong>on</strong>g> correct<br />
quenching program suitable for <str<strong>on</strong>g>the</str<strong>on</strong>g> alloy and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> dimensi<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> strip furnace facility.<br />
If quenching need not be that rapid, cooling<br />
can also be effected by air cooling <strong>on</strong>ly. The<br />
water cooling system is <str<strong>on</strong>g>the</str<strong>on</strong>g>n switched <str<strong>on</strong>g>of</str<strong>on</strong>g>f and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> charge is merely cooled by air in <str<strong>on</strong>g>the</str<strong>on</strong>g> highperformance<br />
air cooling secti<strong>on</strong>. By virtue <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
this high degree <str<strong>on</strong>g>of</str<strong>on</strong>g> flexibility, Hic<strong>on</strong> floater<br />
furnace facilities fulfil all requirements placed<br />
<strong>on</strong> heat treatment and quenching <str<strong>on</strong>g>of</str<strong>on</strong>g> a wide<br />
variety <str<strong>on</strong>g>of</str<strong>on</strong>g> alloys.<br />
The Ebner automati<strong>on</strong> system is based <strong>on</strong><br />
a Simatic Step7 system with object-oriented<br />
programming incorporating WINCC and HMI<br />
Faceplates. These faceplates combine operati<strong>on</strong><br />
and supervisi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> facility with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
visualizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> each<br />
device incorporated in<br />
that facility, while at<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> same time, keeping<br />
an <strong>on</strong>line maintenance<br />
log book.<br />
Apart form this, an<br />
operating hours counter<br />
is provided for each<br />
peripheral device. The<br />
integrated diagnostics<br />
system simplifies maintenance<br />
and servicing<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> facility, keeping<br />
downtimes to a minimum.<br />
Hardware and<br />
s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware documentati<strong>on</strong><br />
with comprehen-<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 13
ROLLING INDUSTRY<br />
Gas-fired radiant tube heated batch-type furnace facility<br />
sive annotati<strong>on</strong>s provides <str<strong>on</strong>g>the</str<strong>on</strong>g> user with excellent<br />
support for carrying out maintenance.<br />
By means <str<strong>on</strong>g>of</str<strong>on</strong>g> remote maintenance via modem<br />
Ebner specialists can provide support whenever<br />
needed. Apart from <str<strong>on</strong>g>the</str<strong>on</strong>g> process c<strong>on</strong>trol<br />
system terminal, touch pads c<strong>on</strong>nected via<br />
WLAN are provided, for facilitating remote<br />
adjustments and service work for <str<strong>on</strong>g>the</str<strong>on</strong>g> entire<br />
facility.<br />
In additi<strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> technical and technological<br />
advantages, <str<strong>on</strong>g>the</str<strong>on</strong>g> durable design <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> key<br />
comp<strong>on</strong>ents and service-friendly implementati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> facility has led to well-known<br />
companies investing in Hic<strong>on</strong> floater furnaces.<br />
Apart from floater furnace facilities that have<br />
already been handed over to AMAG in Austria,<br />
Aleris Aluminium in Duffel, Belgium,<br />
and Southwest Aluminium in China, <str<strong>on</strong>g>the</str<strong>on</strong>g> most<br />
recently-placed orders have also been received<br />
by Ebner.<br />
For more than 40 years Ebner has been<br />
building batch-type furnaces for a wide range<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> annealing processes in air or protective atmosphere.<br />
This kind <str<strong>on</strong>g>of</str<strong>on</strong>g> batch-type furnace can<br />
process coils with an outer diameter <str<strong>on</strong>g>of</str<strong>on</strong>g> up to<br />
2,650 mm, coil width <str<strong>on</strong>g>of</str<strong>on</strong>g> up to 2,800 mm and<br />
a net coil weight <str<strong>on</strong>g>of</str<strong>on</strong>g> 25 t<strong>on</strong>nes, accommodating<br />
up to 12 coils in each furnace with <str<strong>on</strong>g>the</str<strong>on</strong>g> charge<br />
c<strong>on</strong>figured in two lanes.<br />
The key requirements for a modern batchtype<br />
furnace are:<br />
• high rate <str<strong>on</strong>g>of</str<strong>on</strong>g> heat transfer<br />
• uniform temperature distributi<strong>on</strong><br />
• low specific energy c<strong>on</strong>sumpti<strong>on</strong><br />
• low maintenance costs<br />
• high degree <str<strong>on</strong>g>of</str<strong>on</strong>g> operati<strong>on</strong>al safety<br />
• low envir<strong>on</strong>mental impact.<br />
The furnace atmosphere is recirculated using<br />
speed-c<strong>on</strong>trolled direct drive fan units.<br />
The process atmosphere is drawn in by fans<br />
mounted in <str<strong>on</strong>g>the</str<strong>on</strong>g> ro<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace and <str<strong>on</strong>g>the</str<strong>on</strong>g>n<br />
passed through a baffle system over radiant<br />
tubes suspended in left and right-hand side<br />
walls <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace. The temperature inside<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> furnace is c<strong>on</strong>trolled by <str<strong>on</strong>g>the</str<strong>on</strong>g>rmocouples located<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> baffle system in <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace ro<str<strong>on</strong>g>of</str<strong>on</strong>g><br />
as well as <str<strong>on</strong>g>the</str<strong>on</strong>g>rmocouples mounted in <str<strong>on</strong>g>the</str<strong>on</strong>g> side<br />
walls ahead <str<strong>on</strong>g>of</str<strong>on</strong>g> and bey<strong>on</strong>d <str<strong>on</strong>g>the</str<strong>on</strong>g> charge.<br />
The latest design <str<strong>on</strong>g>of</str<strong>on</strong>g> single-lane batch-type<br />
furnaces feature a jet-flow system for directing<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> furnace wind at <str<strong>on</strong>g>the</str<strong>on</strong>g> coils. Ebner batch-type<br />
furnaces with dual-lane charge c<strong>on</strong>figurati<strong>on</strong>s<br />
use a combined jet/mass flow system. The<br />
advantage is that <str<strong>on</strong>g>the</str<strong>on</strong>g> temperature difference<br />
between <str<strong>on</strong>g>the</str<strong>on</strong>g> gas flowing out <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> nozzles<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> gas flowing past <str<strong>on</strong>g>the</str<strong>on</strong>g> centerline <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
furnace is negligible so that all <str<strong>on</strong>g>the</str<strong>on</strong>g> coils in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
furnace are heated through more evenly. Ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
advantage is that <str<strong>on</strong>g>the</str<strong>on</strong>g> coils in <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace<br />
can always be charged in <str<strong>on</strong>g>the</str<strong>on</strong>g> same place. This<br />
means that an applicati<strong>on</strong>-specific jet nozzle<br />
system can be used to target each coil. If each<br />
coil can be assigned to a separate furnace z<strong>on</strong>e,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>n it is also possible to trim back <str<strong>on</strong>g>the</str<strong>on</strong>g> overshoot<br />
temperature for each coil individually.<br />
Hic<strong>on</strong> singlecoil<br />
overhead<br />
furnaces are a<br />
special type <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
batch furnace.<br />
The special<br />
feature <str<strong>on</strong>g>of</str<strong>on</strong>g> this<br />
kind <str<strong>on</strong>g>of</str<strong>on</strong>g> singlecoil<br />
overhead<br />
furnace facility<br />
is that each<br />
individual furnace<br />
chamber<br />
is supported <strong>on</strong><br />
a steel structure<br />
and each<br />
furnace cham-<br />
Gas-fired radiant tube single-coil overhead furnace facility<br />
ber holds just <strong>on</strong>e coil. The coil is placed <strong>on</strong><br />
a charging frame integrated into <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace<br />
plug, which is <str<strong>on</strong>g>the</str<strong>on</strong>g>n raised into <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace<br />
chamber.<br />
The individual chambers are served by <strong>on</strong>e<br />
charger that transports <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace plugs plus<br />
coils between <str<strong>on</strong>g>the</str<strong>on</strong>g> charging area and <str<strong>on</strong>g>the</str<strong>on</strong>g> overhead<br />
furnace units.<br />
The charging area al<strong>on</strong>gside <str<strong>on</strong>g>the</str<strong>on</strong>g> facility is<br />
used to charge and remove <str<strong>on</strong>g>the</str<strong>on</strong>g> coils. By defining<br />
a precise positi<strong>on</strong> for <str<strong>on</strong>g>the</str<strong>on</strong>g> charging area, it<br />
can be entered into a coordinates system to be<br />
served automatically by <str<strong>on</strong>g>the</str<strong>on</strong>g> overhead crane.<br />
Because even charging and discharging can be<br />
performed automatically with <str<strong>on</strong>g>the</str<strong>on</strong>g> charger, it<br />
is possible to implement <str<strong>on</strong>g>the</str<strong>on</strong>g>se furnaces as<br />
fully-automated systems.<br />
A Hic<strong>on</strong> single-coil overhead furnace facility<br />
delivers <str<strong>on</strong>g>the</str<strong>on</strong>g> shortest possible heating up<br />
time with a temperature difference as low as<br />
5°C throughout <str<strong>on</strong>g>the</str<strong>on</strong>g> whole coil at <str<strong>on</strong>g>the</str<strong>on</strong>g> end <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
heating.<br />
In additi<strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> high flexibility and<br />
throughput <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se facilities, <str<strong>on</strong>g>the</str<strong>on</strong>g> main advantages<br />
include <str<strong>on</strong>g>the</str<strong>on</strong>g> high as-annealed quality <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> material since <str<strong>on</strong>g>the</str<strong>on</strong>g> anneal process can be<br />
matched to a specific coil. These facilities are<br />
also equipped with an annealing time calculati<strong>on</strong><br />
program featuring an <str<strong>on</strong>g>of</str<strong>on</strong>g>fline model that<br />
pre-calculates processing times in advance <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> anneal and an <strong>on</strong>line model that supervises<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> anneal process in real time and optimizes<br />
it if necessary. This calculati<strong>on</strong> model is also<br />
available for standard multi-coil batch-type<br />
furnace facilities.<br />
Ebner has supplied more than 120 batchtype<br />
furnaces to numerous customers worldwide,<br />
each designed specifically for <strong>on</strong>e or<br />
more <str<strong>on</strong>g>of</str<strong>on</strong>g> a wide range <str<strong>on</strong>g>of</str<strong>on</strong>g> applicati<strong>on</strong>s. Am<strong>on</strong>g<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>se customers are <str<strong>on</strong>g>the</str<strong>on</strong>g> world‘s largest and<br />
most well-known producers <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> and<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloy strip.<br />
�<br />
14 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
ROLLING INDUSTRY<br />
Addressing market requirements in <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> flat products<br />
Sean Carter and Detlef Neumann, Danieli Fröhling<br />
In order to succeed in today’s very competitive<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> plate, strip / sheet and<br />
foil markets, it is not sufficient to <strong>on</strong>ly<br />
fulfil <str<strong>on</strong>g>the</str<strong>on</strong>g> standard basic requirements<br />
when developing plant c<strong>on</strong>cepts for both<br />
rolling mills and downstream cutting lines<br />
but to define and deliver enhanced soluti<strong>on</strong>s<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> future. Particularly, when<br />
c<strong>on</strong>sidering developments in <str<strong>on</strong>g>the</str<strong>on</strong>g> processing<br />
industry with demands for increased<br />
producti<strong>on</strong> levels, larger coil densities,<br />
thinner finished products and increased<br />
material quality <str<strong>on</strong>g>the</str<strong>on</strong>g>se factors have to<br />
be taken into c<strong>on</strong>siderati<strong>on</strong>. Danieli is a<br />
100% metals focused company with over<br />
8,700 employees, with in-house manufacturing<br />
in Italy, Germany, Thailand<br />
and China; al<strong>on</strong>g with its process partner<br />
Innoval Technology, Danieli supplies <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
rolling and processing soluti<strong>on</strong>s<br />
as well as plate stretchers and turnkey<br />
(including FSTK) projects.<br />
General market c<strong>on</strong>siderati<strong>on</strong><br />
Generally, <str<strong>on</strong>g>the</str<strong>on</strong>g> world-wide market for technology<br />
to produce downstream <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> products,<br />
for example rolled products, is quite different<br />
when looking for <str<strong>on</strong>g>the</str<strong>on</strong>g> expected investments<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> near to mid future. Europe’s and<br />
North America’s strategy will be to maintain<br />
and build up<strong>on</strong> its leading positi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> efficien-<br />
cy, quality and service but without significant<br />
expansi<strong>on</strong> into new capacities while realising<br />
maximum pay-back <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> existing assets.<br />
The well-established producti<strong>on</strong> companies<br />
will c<strong>on</strong>centrate <strong>on</strong>:<br />
• Process and yield increase<br />
• Relocati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> facilities and /or c<strong>on</strong>solidate<br />
producti<strong>on</strong> capacities at cen tral points<br />
• Investing in modernisati<strong>on</strong>s and revamps<br />
to maximise current potential as well as<br />
increasing coil density, processing speeds<br />
and product quality<br />
• Improving finished strip quality<br />
• C<strong>on</strong>centrating <strong>on</strong> high-end products such<br />
as foil, lithography, etc.<br />
• Customer service (reduced lead times,<br />
just-in-time producti<strong>on</strong>)<br />
Danieli Wean United Hot Finishing Mill Photos: Danieli Fröhling<br />
• Development <str<strong>on</strong>g>of</str<strong>on</strong>g> new niche high value<br />
products such as clad material, sub 6 μm<br />
foil, bright finished stock, etc.<br />
• Development into new uses for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
rolled products.<br />
These measures will be increasingly important<br />
when c<strong>on</strong>sidering <str<strong>on</strong>g>the</str<strong>on</strong>g> competiti<strong>on</strong> that comes<br />
from <str<strong>on</strong>g>the</str<strong>on</strong>g> large new investments and producti<strong>on</strong><br />
capacity currently being implemented in<br />
Asia and also partly in South America and<br />
Russia. In <str<strong>on</strong>g>the</str<strong>on</strong>g> near future Asia will emerge as<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> dominant market for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> flat rolled<br />
products in <str<strong>on</strong>g>the</str<strong>on</strong>g> world and Asian producers<br />
will try to supply into traditi<strong>on</strong>al markets that<br />
are still occupied by European and American<br />
suppliers. Here, both quality and quantity as<br />
well as supply lead time will be <str<strong>on</strong>g>the</str<strong>on</strong>g> key issues<br />
that purchasers <str<strong>on</strong>g>of</str<strong>on</strong>g> rolled materials will<br />
look for.<br />
An example <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> development <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
products is in aerospace industry that<br />
is c<strong>on</strong>stantly pushing <str<strong>on</strong>g>the</str<strong>on</strong>g> design barriers with<br />
increasingly complex metallic or hybrid aircraft<br />
fuselage skin and structures. This includes<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> development <str<strong>on</strong>g>of</str<strong>on</strong>g> new alloys, for example<br />
damage tolerant Al-Cu-Li fuselage sheet and<br />
high strength alloys c<strong>on</strong>taining Scandium (Sc),<br />
Aluminium-Glare composite material and<br />
ever larger very heavy gauge plates for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
manufacture <str<strong>on</strong>g>of</str<strong>on</strong>g> aircraft spars and ribs.<br />
With <str<strong>on</strong>g>the</str<strong>on</strong>g> increasing word-wide demand for<br />
automotive, aerospace, and canstock products<br />
this paper focuses <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> latest developments<br />
in cold rolling technology and strip processing.<br />
Modern <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> rolling<br />
technology and market trends<br />
In general, <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> rolling market can<br />
be c<strong>on</strong>sidered in three broad sectors relating<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> flat finished products and <str<strong>on</strong>g>the</str<strong>on</strong>g> associated<br />
equipment to produce <str<strong>on</strong>g>the</str<strong>on</strong>g> rolled material:<br />
• Hot rolling – plates, shate and coiled<br />
feedstock for cold and foil rolling<br />
• Cold rolling – sheet for automotive, aero-<br />
space, canstock, lithographic, foil feed-<br />
stock and general applicati<strong>on</strong>s<br />
• Foil rolling – foil for food, cosmetics,<br />
tobacco and pharmaceutical packaging;<br />
technical applicati<strong>on</strong>s such as heat<br />
exchangers and cable wrap; household<br />
applicati<strong>on</strong>s.<br />
Danieli has expertise in all <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> above-menti<strong>on</strong>ed<br />
technologies.<br />
The majority <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> cold mills rolling<br />
sheet products today are a 4-high singlestand<br />
type, which in many cases produces a<br />
quality product meeting end-user requirements.<br />
However, such c<strong>on</strong>venti<strong>on</strong>al mills are<br />
now approaching or have reached <str<strong>on</strong>g>the</str<strong>on</strong>g> technical<br />
limits <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> latest market requirements<br />
that can include:<br />
1. Increasing coil dimensi<strong>on</strong>s including wide<br />
strip width ranges <str<strong>on</strong>g>of</str<strong>on</strong>g> less than 1 metre to 2.7<br />
metre or greater<br />
2. Achievement <str<strong>on</strong>g>of</str<strong>on</strong>g> excellent levels <str<strong>on</strong>g>of</str<strong>on</strong>g> strip<br />
quality including flatness, thickness, surface<br />
finish, dryness, coil build-up, etc across an<br />
ever increasing wide range <str<strong>on</strong>g>of</str<strong>on</strong>g> products with<br />
16 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Danieli Fröhling 6-high Diam<strong>on</strong>d Mill<br />
rolling speeds up to 1,800 m/min<br />
4. Wide entry to exit thickness range, typical-<br />
ly from 10 mm to less than 1 mm<br />
3. Ability to handle and roll coil weights up to<br />
or greater than 35 t<strong>on</strong>nes without a compromise<br />
in rolling dimensi<strong>on</strong>ally smaller coils<br />
4. Large rolling load range to cater for hard<br />
alloys to Electrical Discharge Texturing (EDT)<br />
and skin-passes <strong>on</strong> a single stand<br />
5. Operati<strong>on</strong>al efficiency by reducti<strong>on</strong> in coilto-coil<br />
times and mill stop-time<br />
6. Greater producti<strong>on</strong> flexibility by a wide<br />
mill c<strong>on</strong>trol range thus having <str<strong>on</strong>g>the</str<strong>on</strong>g> ability to<br />
react to future market demands for new strip<br />
products or requirements, i.e. a ‘future pro<str<strong>on</strong>g>of</str<strong>on</strong>g>’<br />
mill<br />
7. Envir<strong>on</strong>mental c<strong>on</strong>siderati<strong>on</strong>s such as electrical<br />
power efficiency and fume recovery with<br />
coolant re-generati<strong>on</strong><br />
8. Improved working envir<strong>on</strong>ment and practices<br />
for mill operators.<br />
Some existing cold mills can be modernised<br />
to include some <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> above latest requirements<br />
and that a new 4-high single stand cold<br />
mill <str<strong>on</strong>g>of</str<strong>on</strong>g> an advanced design may exactly meet<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> specific market and commercial requirements<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a client, for example in <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Danieli Fröhling a ‘4-high Diam<strong>on</strong>d Mill’<br />
being supplied to Nikkei Siam Aluminium<br />
(NSA), Thailand, to roll primarily fin-stock<br />
material. However, <str<strong>on</strong>g>the</str<strong>on</strong>g> majority <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> latest<br />
market requirements require an advanced<br />
6-high mill stand soluti<strong>on</strong> ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r as a single<br />
stand or tandem mill c<strong>on</strong>figurati<strong>on</strong>.<br />
The Danieli Fröhling ‘6-High Diam<strong>on</strong>d<br />
Mill’ in a single stand c<strong>on</strong>figurati<strong>on</strong> being<br />
supplied to Aleris Europe is <str<strong>on</strong>g>the</str<strong>on</strong>g> latest generati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> state-<str<strong>on</strong>g>of</str<strong>on</strong>g>-<str<strong>on</strong>g>the</str<strong>on</strong>g>-art cold rolling mills and is<br />
designed from incepti<strong>on</strong> to meet <str<strong>on</strong>g>the</str<strong>on</strong>g> current<br />
and future market requirements. The superior<br />
technology selected by Aleris and provided<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> Diam<strong>on</strong>d Mill includes <str<strong>on</strong>g>the</str<strong>on</strong>g> following:<br />
• 6-high roll stack c<strong>on</strong>figurati<strong>on</strong> to ensure<br />
mill stack stability with optimum sized<br />
workrolls for <str<strong>on</strong>g>the</str<strong>on</strong>g> specified thickness range<br />
whilst providing <str<strong>on</strong>g>the</str<strong>on</strong>g> highest level <str<strong>on</strong>g>of</str<strong>on</strong>g> strip flatness<br />
performance across a wide strip range<br />
that has a max / min width ratio <str<strong>on</strong>g>of</str<strong>on</strong>g> greater than<br />
two. This c<strong>on</strong>figurati<strong>on</strong> ensures flexibility <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
scheduling current rolling products as well as<br />
future products. The parallel roll design delivers<br />
a practical operati<strong>on</strong>al soluti<strong>on</strong> with a<br />
simple roll grind regime and has an effective<br />
actuator c<strong>on</strong>trol range to guarantee high qual-<br />
Danieli Fröhling Advanced Slitter<br />
ROLLING INDUSTRY<br />
ity strip flatness.<br />
• Hydraulic roll-gap adjustment, utilising<br />
bottom mounted double-acting roll load cylinders<br />
designed for a roll separati<strong>on</strong> force with<br />
an operati<strong>on</strong>al range that covers low load EDT<br />
passes as well as high rolling load capability<br />
for AA5xxx series hard alloys<br />
• The Danieli Fröhling ‘Hi-Res’ coolant spray<br />
c<strong>on</strong>cept with Hot Edge Sprays (HES) providing<br />
precise <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal c<strong>on</strong>trol <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> workrolls that<br />
coupled with <str<strong>on</strong>g>the</str<strong>on</strong>g> dynamic work-roll and intermediate<br />
roll bending and intermediate roll<br />
side-shifting in order to meet Aleris’s stringent<br />
product performance criteria<br />
• Close attenti<strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> design <str<strong>on</strong>g>of</str<strong>on</strong>g> all rolls in<br />
c<strong>on</strong>tact with <str<strong>on</strong>g>the</str<strong>on</strong>g> strip and <str<strong>on</strong>g>the</str<strong>on</strong>g> coil handling to<br />
maintain a defect free material surface finish<br />
• DAN-ECO 2 fume cleaning and rolling oil<br />
recovery system to meet <str<strong>on</strong>g>the</str<strong>on</strong>g> highest European<br />
emissi<strong>on</strong> standards for <str<strong>on</strong>g>the</str<strong>on</strong>g> separati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
Volatile Organic Compounds (VOC) as well as<br />
recovering <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling oil to be fully re-used for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> rolling process<br />
• DANPurity rolling oil filtrati<strong>on</strong> system to<br />
maintain <str<strong>on</strong>g>the</str<strong>on</strong>g> original design specificati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> rolling oil by <str<strong>on</strong>g>the</str<strong>on</strong>g> filtrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>tainments<br />
thus ensuring high strip surface quality.<br />
When <str<strong>on</strong>g>the</str<strong>on</strong>g> Aleris Diam<strong>on</strong>d Mill starts producing<br />
quality material at <str<strong>on</strong>g>the</str<strong>on</strong>g> end <str<strong>on</strong>g>of</str<strong>on</strong>g> 2012, it<br />
will be <strong>on</strong>e <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> most advanced cold mills in<br />
operati<strong>on</strong> around <str<strong>on</strong>g>the</str<strong>on</strong>g> world.<br />
Modern slitting and trimming technology<br />
As <str<strong>on</strong>g>the</str<strong>on</strong>g> requirements for ‘totally’ flat material<br />
with tight tolerances exists not <strong>on</strong>ly for fin-<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 17
ROLLING INDUSTRY<br />
ished rolled material but also for <str<strong>on</strong>g>the</str<strong>on</strong>g> slit strip,<br />
development <str<strong>on</strong>g>of</str<strong>on</strong>g> even more precise and rigid<br />
slitting machines is <str<strong>on</strong>g>of</str<strong>on</strong>g> highest importance.<br />
Shearing stresses have a big influence<br />
<strong>on</strong> subsequent workability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> strip. Single<br />
strips may curl or even jump out <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
stamping die if stresses induced during slit-<br />
ting are too high. Width deviati<strong>on</strong>s could result<br />
in imperfect shapes due to <str<strong>on</strong>g>the</str<strong>on</strong>g> very narrow<br />
trim web at <str<strong>on</strong>g>the</str<strong>on</strong>g> edge <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> strip before<br />
pressing.<br />
With highly accurate adjustment devices,<br />
modern slitting shears provide <str<strong>on</strong>g>the</str<strong>on</strong>g> best chance<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> an exact and repeatable knife shaft adjustment.<br />
It can be seen that <str<strong>on</strong>g>the</str<strong>on</strong>g> slitting shear must<br />
be able to be adjusted as closely as possible<br />
to certain parameters (immersi<strong>on</strong> and cutting<br />
gap) according to <str<strong>on</strong>g>the</str<strong>on</strong>g> material c<strong>on</strong>diti<strong>on</strong>s, this<br />
being essential for thinner strip gauges in particular<br />
Danieli Fröhling accommodates all <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>se through a high standard <str<strong>on</strong>g>of</str<strong>on</strong>g> design and<br />
manufacturing:<br />
• Pre-tensi<strong>on</strong>ed elements giving backlash-<br />
free movement <str<strong>on</strong>g>of</str<strong>on</strong>g> machine parts.<br />
• High accuracy measuring systems to<br />
provide <str<strong>on</strong>g>the</str<strong>on</strong>g> adjustment system with<br />
necessary data. Rigid and solid design to<br />
prevent vibrati<strong>on</strong>.<br />
• Data bases store recipes for different<br />
slitting programmes<br />
• Tool clamping systems to ensure reliable<br />
clamping automatically actuated.<br />
Following <str<strong>on</strong>g>the</str<strong>on</strong>g>se demands, Danieli Fröhling<br />
developed a new generati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> slitting heads.<br />
One <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> main parameters for <str<strong>on</strong>g>the</str<strong>on</strong>g> strip edge<br />
quality is <str<strong>on</strong>g>the</str<strong>on</strong>g> knives’ immersi<strong>on</strong> into <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
to be cut. The optimal immersi<strong>on</strong> depends<br />
<strong>on</strong> material grade, c<strong>on</strong>diti<strong>on</strong> and strip<br />
thickness. The real immersi<strong>on</strong> is a functi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
cutting force and machine rigidity. Part <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
machine rigidity is <str<strong>on</strong>g>the</str<strong>on</strong>g> deflecti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> knife<br />
shaft.<br />
By reducing <str<strong>on</strong>g>the</str<strong>on</strong>g> bearing distance and<br />
optimisati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> whole bearing system,<br />
a reducti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> deflecti<strong>on</strong> by 44 percent is<br />
achieved.<br />
For subscribers<br />
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Even faster – your<br />
added PLUS to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> print medium<br />
The stiffness <str<strong>on</strong>g>of</str<strong>on</strong>g> a knife shaft could be increased<br />
by more than 130 percent.<br />
All <str<strong>on</strong>g>of</str<strong>on</strong>g> this results in even better, reproducible<br />
cutting edge quality and a lower transfer<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> cutting stress to <str<strong>on</strong>g>the</str<strong>on</strong>g> strip.<br />
In l<strong>on</strong>gitudinal slitting lines, a looping pit<br />
is applied for compensati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> different<br />
recoiler diameters <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> single strips – caused<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> differences <str<strong>on</strong>g>of</str<strong>on</strong>g> single strip cross secti<strong>on</strong><br />
due to <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling process. Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> downgauging<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> finished products nowadays and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> request <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> finishing industry for larger<br />
recoiler diameters, tensi<strong>on</strong>ing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> strip with<br />
advanced braking units becomes ever more<br />
important.<br />
Danieli Fröhling has developed <str<strong>on</strong>g>the</str<strong>on</strong>g> vacuum<br />
braking roll in order to avoid or minimise <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
aforementi<strong>on</strong>ed disadvantages. Around 27<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se units have been supplied to industry<br />
to date, and experiences have been ga<str<strong>on</strong>g>the</str<strong>on</strong>g>red<br />
over <str<strong>on</strong>g>the</str<strong>on</strong>g> past about 17 years.<br />
Advantage compared to <str<strong>on</strong>g>the</str<strong>on</strong>g> strip surface:<br />
• Very low surface pressure during braking<br />
• No damage <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> strip surface<br />
• No fricti<strong>on</strong> between upper surface <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
strip and braking means<br />
• Lowest possible fricti<strong>on</strong> at <str<strong>on</strong>g>the</str<strong>on</strong>g> lower side<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> strip<br />
• Same specific strip tensi<strong>on</strong> at all strips,<br />
independent <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile over<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> strip width.<br />
The internati<strong>on</strong>al top level <str<strong>on</strong>g>of</str<strong>on</strong>g> trimming lines<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> industry process coils with<br />
weight <str<strong>on</strong>g>of</str<strong>on</strong>g> around 30 t<strong>on</strong>nes at speeds <str<strong>on</strong>g>of</str<strong>on</strong>g> more<br />
that 1,200 m/min. Danieli Fröhling trimming<br />
lines, having proven <str<strong>on</strong>g>the</str<strong>on</strong>g>ir reliability at stable<br />
operati<strong>on</strong> speeds <str<strong>on</strong>g>of</str<strong>on</strong>g> up to 1,500 m/min since<br />
years, are equipped with special features to<br />
provide precise products at maximum pro-<br />
ducti<strong>on</strong>, such as:<br />
• High-speed cropping<br />
• High precisi<strong>on</strong> electrostatic oiler<br />
• Edge trimming shear with automatic<br />
adjustment<br />
• Scrap sucti<strong>on</strong> devices for high-speed<br />
applicati<strong>on</strong>s<br />
• Dedicated design <str<strong>on</strong>g>of</str<strong>on</strong>g> exit guide unit.<br />
Product services and support<br />
Vital to any organisati<strong>on</strong> is <str<strong>on</strong>g>the</str<strong>on</strong>g> services pro-<br />
vided with both a new project and future support.<br />
This can range from training, process<br />
studies right through to major FSTK projects.<br />
Danieli with its partner Innoval has <str<strong>on</strong>g>the</str<strong>on</strong>g> organisati<strong>on</strong>al<br />
structure to provide <str<strong>on</strong>g>the</str<strong>on</strong>g>se services to<br />
our clients.<br />
Summary<br />
It is evident that <str<strong>on</strong>g>the</str<strong>on</strong>g> end-users <str<strong>on</strong>g>of</str<strong>on</strong>g> high-end<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> products in particular in <str<strong>on</strong>g>the</str<strong>on</strong>g> automotive,<br />
beverage and aerospace markets<br />
are c<strong>on</strong>tinuously innovating to maintain <str<strong>on</strong>g>the</str<strong>on</strong>g>ir<br />
competitiveness, develop new products and<br />
increase <str<strong>on</strong>g>the</str<strong>on</strong>g>ir efficiency and added-value.<br />
C<strong>on</strong>sequently, rolling and processing companies<br />
must resp<strong>on</strong>d to <str<strong>on</strong>g>the</str<strong>on</strong>g>se developments and<br />
also implement similar philosophies encompassing<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> efficient producti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> high quality<br />
end-products.<br />
The result <str<strong>on</strong>g>of</str<strong>on</strong>g> this market and product<br />
advancement requires companies such as<br />
Danieli to react and supply advanced high<br />
quality equipment and process soluti<strong>on</strong>s to<br />
meet <str<strong>on</strong>g>the</str<strong>on</strong>g>se evolving challenges by reacting to<br />
market requirements and providing a spectrum<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> enhanced soluti<strong>on</strong>s for <str<strong>on</strong>g>the</str<strong>on</strong>g> future.<br />
Danieli can do this!<br />
�<br />
18 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
L<strong>on</strong>ger campaigns with improved m<strong>on</strong>olithics<br />
for lining <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> melt-hold furnaces<br />
Andy Wynn, John Coppack and Tom Steele, Thermal Ceramics UK Ltd.<br />
To remain competitive, <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> producers<br />
c<strong>on</strong>tinue to increase productivity<br />
through <str<strong>on</strong>g>the</str<strong>on</strong>g>ir melt-hold furnaces. Increasing<br />
heat input to <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace using more<br />
powerful burners is comm<strong>on</strong> practice.<br />
But faster melting leads to increased<br />
metal losses from surface oxidati<strong>on</strong> and<br />
to segregati<strong>on</strong> from large heat gradients.<br />
These effects are countered by increased<br />
use <str<strong>on</strong>g>of</str<strong>on</strong>g> fluxes and increased stirring. Given<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> increasingly challenging envir<strong>on</strong>ment<br />
within which <str<strong>on</strong>g>the</str<strong>on</strong>g> refractory lining has to<br />
work, traditi<strong>on</strong>al lining soluti<strong>on</strong>s can no<br />
l<strong>on</strong>ger be relied up<strong>on</strong> to provide <str<strong>on</strong>g>the</str<strong>on</strong>g> service<br />
lives that were previously achieved.<br />
Therefore, a new generati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> furnace<br />
lining materials is required to cope with<br />
today’s <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> furnace. This work<br />
reports <strong>on</strong> a new m<strong>on</strong>olithic material<br />
with improved performance, compared to<br />
existing materials, designed for use in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ramp/hearth area <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> furnaces.<br />
Improved behaviour against <str<strong>on</strong>g>the</str<strong>on</strong>g> critical<br />
performance criteria in this furnace regi<strong>on</strong><br />
are dem<strong>on</strong>strated in <str<strong>on</strong>g>the</str<strong>on</strong>g> laboratory<br />
using industry standard test methods.<br />
The refractory lining <str<strong>on</strong>g>of</str<strong>on</strong>g> a typical furnace<br />
used for holding and melting <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> has<br />
to withstand a wide variety <str<strong>on</strong>g>of</str<strong>on</strong>g> physical and<br />
chemical envir<strong>on</strong>ments. Each <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> different<br />
areas within <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace (Fig. 1) presents a different<br />
set <str<strong>on</strong>g>of</str<strong>on</strong>g> operating c<strong>on</strong>diti<strong>on</strong>s, in terms <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
peak temperature, metal c<strong>on</strong>tact, salt c<strong>on</strong>tact,<br />
etc. Therefore, in order for a m<strong>on</strong>olithic material<br />
to perform in a particular area <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
furnace, it needs to cope with <str<strong>on</strong>g>the</str<strong>on</strong>g> specific<br />
envir<strong>on</strong>mental c<strong>on</strong>diti<strong>on</strong>s in that regi<strong>on</strong>. This<br />
is why furnace linings are complex arrangements,<br />
with different materials installed in different<br />
locati<strong>on</strong>s [1].<br />
Background: In <str<strong>on</strong>g>the</str<strong>on</strong>g> last 30 years, a group <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
m<strong>on</strong>olithic technologies has emerged, specifically<br />
designed to perform within <str<strong>on</strong>g>the</str<strong>on</strong>g> unique<br />
envir<strong>on</strong>ment <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> melt-hold fur-<br />
naces. These Al-resistant grades <str<strong>on</strong>g>of</str<strong>on</strong>g>ten c<strong>on</strong>tain<br />
‘n<strong>on</strong>-wetting’ additives, particularly in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
metal c<strong>on</strong>tact areas, to minimize interacti<strong>on</strong><br />
between <str<strong>on</strong>g>the</str<strong>on</strong>g> refractory and <str<strong>on</strong>g>the</str<strong>on</strong>g> melt to suppress<br />
damage from ‘corundum growth’ [2].<br />
As <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> producers strive to increase<br />
productivity, <str<strong>on</strong>g>the</str<strong>on</strong>g> envir<strong>on</strong>ment within <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace<br />
is becoming more arduous. Chamber<br />
temperatures are increasing and more aggressive<br />
fluxes are being used, necessitating more<br />
frequent and severe cleaning operati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> furnace walls. To maintain high productivity,<br />
it is necessary to minimize <str<strong>on</strong>g>the</str<strong>on</strong>g> frequency<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> furnace downtime. The more aggressive<br />
c<strong>on</strong>diti<strong>on</strong>s today mean that lining materials<br />
developed in <str<strong>on</strong>g>the</str<strong>on</strong>g> past are now being used be-<br />
y<strong>on</strong>d <str<strong>on</strong>g>the</str<strong>on</strong>g>ir original intended design boundaries<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g>ir service performance is under threat,<br />
leading to more frequent lining repairs.<br />
Aluminium producers take a furnace <str<strong>on</strong>g>of</str<strong>on</strong>g>fline<br />
for repair <strong>on</strong>ce a critical lining area has degraded<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> point <str<strong>on</strong>g>of</str<strong>on</strong>g> affecting <str<strong>on</strong>g>the</str<strong>on</strong>g> efficiency<br />
and/or safety <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> operati<strong>on</strong>. At this stage,<br />
not all <str<strong>on</strong>g>the</str<strong>on</strong>g> lining will have degraded to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
point that it is in need <str<strong>on</strong>g>of</str<strong>on</strong>g> replacement or repair.<br />
Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> frequency <str<strong>on</strong>g>of</str<strong>on</strong>g> furnace down-<br />
time is determined by <str<strong>on</strong>g>the</str<strong>on</strong>g> area <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace<br />
most quickly and frequently degraded during<br />
operati<strong>on</strong>. In order to increase campaign<br />
times and decrease frequency <str<strong>on</strong>g>of</str<strong>on</strong>g> stoppages,<br />
we need to improve <str<strong>on</strong>g>the</str<strong>on</strong>g> service life <str<strong>on</strong>g>of</str<strong>on</strong>g> this<br />
weak link in <str<strong>on</strong>g>the</str<strong>on</strong>g> lining. To identify <str<strong>on</strong>g>the</str<strong>on</strong>g> regi<strong>on</strong><br />
most frequently and quickly degraded, we<br />
worked with several <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> producers.<br />
Their feedback suggested that <str<strong>on</strong>g>the</str<strong>on</strong>g> most comm<strong>on</strong><br />
area that was <str<strong>on</strong>g>the</str<strong>on</strong>g> cause <str<strong>on</strong>g>of</str<strong>on</strong>g> repair downtime<br />
was <str<strong>on</strong>g>the</str<strong>on</strong>g> ramp / hearth area.<br />
The failure mechanisms within <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace<br />
envir<strong>on</strong>ment, that limit refractory service life,<br />
are listed in [1]. Since our target is to improve<br />
refractory performance in <str<strong>on</strong>g>the</str<strong>on</strong>g> ramp / hearth<br />
regi<strong>on</strong>, we need to understand which <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se<br />
failure modes are most critical to lining performance<br />
in this regi<strong>on</strong>.<br />
Performance targets: A study <str<strong>on</strong>g>of</str<strong>on</strong>g> working<br />
practices and furnace operating c<strong>on</strong>diti<strong>on</strong>s at<br />
MEASURING & CONTROL<br />
a number <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> producers revealed<br />
that <str<strong>on</strong>g>the</str<strong>on</strong>g> ramp / hearth regi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> an <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
melt-hold furnace is subjected to severe mechanical<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal stress during <str<strong>on</strong>g>the</str<strong>on</strong>g> loading<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> large ingot down <str<strong>on</strong>g>the</str<strong>on</strong>g> ramp. Frequent loading<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> heavy ingot to feed <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace, <str<strong>on</strong>g>of</str<strong>on</strong>g>ten<br />
by fork lift truck, subjects <str<strong>on</strong>g>the</str<strong>on</strong>g> ramp to severe<br />
abrasive forces. As <str<strong>on</strong>g>the</str<strong>on</strong>g> ingot is usually at room<br />
temperature, <str<strong>on</strong>g>the</str<strong>on</strong>g>re is also c<strong>on</strong>siderable <str<strong>on</strong>g>the</str<strong>on</strong>g>r-<br />
mal shock <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> ramp / hearth refractory,<br />
which is at furnace operating temperature.<br />
As <str<strong>on</strong>g>the</str<strong>on</strong>g> bottom <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> ramp and <str<strong>on</strong>g>the</str<strong>on</strong>g> complete<br />
hearth are in c<strong>on</strong>tact with molten metal, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
refractory is also subject to chemical attack<br />
from <str<strong>on</strong>g>the</str<strong>on</strong>g> alloy, alloying elements and flux additi<strong>on</strong>s.<br />
A study <str<strong>on</strong>g>of</str<strong>on</strong>g> ramp / hearth degradati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> Al-resistant materials c<strong>on</strong>taining ‘n<strong>on</strong>-wetting’<br />
additives suggested that damage leading<br />
to furnace downtime is mostly due to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
mechanical acti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> erosi<strong>on</strong> and <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal<br />
shock from ingot loading. We <str<strong>on</strong>g>the</str<strong>on</strong>g>refore focused<br />
our work <strong>on</strong> developing a new Al-resistant<br />
material with improved abrasi<strong>on</strong> and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>rmal shock resistance. To achieve significant<br />
improvements in performance we set out<br />
to increase abrasi<strong>on</strong> and <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal shock resistance<br />
by 20% compared to existing materials.<br />
As metal and alkali resistance are sec<strong>on</strong>dary<br />
performance parameters in this furnace regi<strong>on</strong>,<br />
we also had to ensure that any changes<br />
we made to <str<strong>on</strong>g>the</str<strong>on</strong>g> materials did not degrade<br />
chemical resistance.<br />
EXPERIMENTAL<br />
Fig. 1: Furnace<br />
lining z<strong>on</strong>es in a<br />
typical <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
melt-hold furnace<br />
Two existing, industry leading Al-resistant<br />
m<strong>on</strong>olithic materials used by many <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
producers in <str<strong>on</strong>g>the</str<strong>on</strong>g> ramp / hearth area <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 19<br />
Images: Thermal Ceramics
MEASURING & CONTROL<br />
Standard<br />
1<br />
Standard<br />
2<br />
melt-hold furnaces were selected as baseline<br />
materials for <str<strong>on</strong>g>the</str<strong>on</strong>g> study. Detailed analysis was<br />
undertaken in order to identify those aspects<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> materials technology that were c<strong>on</strong>sidered<br />
to be c<strong>on</strong>straining performance, leading<br />
to mechanical failure. The b<strong>on</strong>d chemistry<br />
and aggregate granulometry were <str<strong>on</strong>g>the</str<strong>on</strong>g>n re-engineered<br />
to find <str<strong>on</strong>g>the</str<strong>on</strong>g> optimum balance <str<strong>on</strong>g>of</str<strong>on</strong>g> material<br />
types and grain size, shape and distribu-<br />
ti<strong>on</strong> that produced <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum improvement<br />
in abrasi<strong>on</strong> and <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal shock performance<br />
without negatively affecting o<str<strong>on</strong>g>the</str<strong>on</strong>g>r important<br />
properties. This paper presents <str<strong>on</strong>g>the</str<strong>on</strong>g> results<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> performance and property measurements<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> final, optimized development compositi<strong>on</strong><br />
compared to <str<strong>on</strong>g>the</str<strong>on</strong>g> baseline standards. All<br />
materials in <str<strong>on</strong>g>the</str<strong>on</strong>g> study were tested against <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
four key performance parameters.<br />
Primary performance parameters<br />
New<br />
material<br />
Water (%) 5.5-6.5 5.7 5.3<br />
Bulk<br />
density<br />
(kg/m 3 )<br />
PLC<br />
(%)<br />
CCS<br />
(MPa)<br />
110°C 2840 2630 2640<br />
815°C 2800 2590<br />
1000°C 2790 2580<br />
1300°C 2570 2510<br />
815°C -0.29 -0.43<br />
1000°C -0.32 -0.26<br />
1300°C -0.35 0.38 0.95<br />
110°C 128 122 147<br />
815°C 163 99<br />
1000°C 129 95<br />
1300°C 138 119 144<br />
Table 1: Physical properties <str<strong>on</strong>g>of</str<strong>on</strong>g> materials studied<br />
Standard<br />
1<br />
Standard<br />
2<br />
New<br />
material<br />
% Al 2 O 3 80.6 65.8 66.6<br />
% SiO 2 11.2 26.7 25.6<br />
% CaO 1.8 3.6 3.2<br />
% TiO 2 2.0 2.1 2.2<br />
% Fe 2 O 3 1.2 1.0 1.0<br />
% MgO 0.2 0.1 0.2<br />
% Alkalis 0.2 0.2 0.2<br />
Table 2: Chemical analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> materials studied<br />
1. Abrasi<strong>on</strong> Resistance Test (ASTM C704);<br />
pre-fired samples are blasted with a stream <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
SiC grit <str<strong>on</strong>g>of</str<strong>on</strong>g> specified grain size for a set time.<br />
Samples are cross-secti<strong>on</strong>ed and <str<strong>on</strong>g>the</str<strong>on</strong>g> amount<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> material abraded across <str<strong>on</strong>g>the</str<strong>on</strong>g> secti<strong>on</strong> is<br />
measured in cm 3 .<br />
2. Thermal Shock Resistance Test (ASTM<br />
C1100 – Ribb<strong>on</strong> Test); pre-fired samples are<br />
subjected to alternating heating and cooling<br />
cycles <strong>on</strong> <strong>on</strong>e face using a ribb<strong>on</strong> burner. The<br />
modulus <str<strong>on</strong>g>of</str<strong>on</strong>g> elasticity (E-modulus) <str<strong>on</strong>g>of</str<strong>on</strong>g> samples<br />
is measured n<strong>on</strong>-destructively by ultras<strong>on</strong>ics<br />
before and after testing. The percentage<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> retained E-modulus is used as a measure<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> retained strength.<br />
Sec<strong>on</strong>dary performance parameters<br />
1. Aluminium Resistance ‘Cup’ Test;<br />
Cup samples are prepared and filled<br />
with 7075 alloy. Samples are ramped up<br />
to 1,000°C and held for 100 hours. After<br />
cooling, <str<strong>on</strong>g>the</str<strong>on</strong>g> samples are secti<strong>on</strong>ed vertically<br />
and visually assessed for <str<strong>on</strong>g>the</str<strong>on</strong>g> degree<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> metal penetrati<strong>on</strong> and corundum<br />
growth [3].<br />
2. Alkali Resistance ‘Cup’ Test; sample<br />
preparati<strong>on</strong> is <str<strong>on</strong>g>the</str<strong>on</strong>g> same as for <str<strong>on</strong>g>the</str<strong>on</strong>g> Al resistance<br />
cup test. Instead <str<strong>on</strong>g>of</str<strong>on</strong>g> Al, <str<strong>on</strong>g>the</str<strong>on</strong>g> samples<br />
are filled with mixtures <str<strong>on</strong>g>of</str<strong>on</strong>g> K 2CO 3<br />
and Na 2CO 3 and fired to 900, 1,000 or<br />
1,100°C for five hours. After secti<strong>on</strong>ing,<br />
samples are analyzed by visual inspecti<strong>on</strong><br />
for cracks, bulges, depth <str<strong>on</strong>g>of</str<strong>on</strong>g> penetrati<strong>on</strong><br />
and colour change.<br />
RESULTS AND DISCUSSION<br />
The characteristics <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> optimized new<br />
material compared to <str<strong>on</strong>g>the</str<strong>on</strong>g> two standard<br />
baseline materials are displayed in Tables 1<br />
and 2. Both baseline materials are low cement,<br />
vibrocast grades. The optimized new material<br />
in Table 1 could be cast at 5.3% water, lower<br />
than <str<strong>on</strong>g>the</str<strong>on</strong>g> baseline grades, and gave free flow<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 125 mm and tapped flow <str<strong>on</strong>g>of</str<strong>on</strong>g> 160 mm.<br />
Primary performance parameters<br />
Abrasi<strong>on</strong> resistance test results <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> mate-<br />
rials are presented in Fig. 2. As dried, <str<strong>on</strong>g>the</str<strong>on</strong>g> new<br />
optimized material delivered 16% better resistance<br />
to abrasi<strong>on</strong> compared to Standard<br />
1 and 20% compared to Standard 2. When<br />
pre-fired, <str<strong>on</strong>g>the</str<strong>on</strong>g> new material delivered 30%<br />
improvement <strong>on</strong> abrasi<strong>on</strong> resistance compared<br />
to Standard 1 and 20% compared to<br />
Standard 2.<br />
Thermal shock resistance test results <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> materials are presented in Fig. 3. After 5<br />
cycles, Standard 1 lost 42% <str<strong>on</strong>g>of</str<strong>on</strong>g> its E-modulus<br />
and Standard 2 lost 32%, compared to <strong>on</strong>ly<br />
20% loss for <str<strong>on</strong>g>the</str<strong>on</strong>g> new material. These results<br />
suggest <str<strong>on</strong>g>the</str<strong>on</strong>g> new material can deliver 52% improvement<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal shock resistance compared<br />
to Standard 1 and 38% compared to<br />
Standard 2.<br />
Sec<strong>on</strong>dary performance parameters<br />
As baseline materials 1 and 2 are comm<strong>on</strong>ly<br />
used in service, we fully expected <str<strong>on</strong>g>the</str<strong>on</strong>g>m to<br />
Fig. 2: Abrasi<strong>on</strong> loss resistance <str<strong>on</strong>g>of</str<strong>on</strong>g> test materials<br />
Fig. 3: Thermal shock resistance <str<strong>on</strong>g>of</str<strong>on</strong>g> test materials<br />
pass <str<strong>on</strong>g>the</str<strong>on</strong>g> Al resistance ‘cup’ testing. Both materials,<br />
and all <str<strong>on</strong>g>of</str<strong>on</strong>g> our new development formulati<strong>on</strong>s,<br />
c<strong>on</strong>tain well proven ‘n<strong>on</strong>-wetting’<br />
additives. Our optimized new compositi<strong>on</strong><br />
passed all Al c<strong>on</strong>tact testing and performed<br />
identically to Standards 1 and 2 in <str<strong>on</strong>g>the</str<strong>on</strong>g> visual<br />
assessment <str<strong>on</strong>g>of</str<strong>on</strong>g> Al ‘cup’ test samples (Fig. 4).<br />
Analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> alloy after testing revealed<br />
that although all materials pass <str<strong>on</strong>g>the</str<strong>on</strong>g> test (target<br />
pick up < 0.5% Si, < 0.1% Fe), Si pick up is<br />
much reduced in <str<strong>on</strong>g>the</str<strong>on</strong>g> new material compared<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> two standards. Since ‘Cup’ test failures<br />
are normally accompanied by increased<br />
c<strong>on</strong>centrati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> Si and Fe in <str<strong>on</strong>g>the</str<strong>on</strong>g> alloy after<br />
testing, this result suggests a much reduced<br />
interacti<strong>on</strong> between <str<strong>on</strong>g>the</str<strong>on</strong>g> new material and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
test alloy compared to <str<strong>on</strong>g>the</str<strong>on</strong>g> standards, indicating<br />
superior ‘n<strong>on</strong>-wetting’ behaviour.<br />
For <str<strong>on</strong>g>the</str<strong>on</strong>g> alkali resistance testing, we expected<br />
Standards 1 and 2 to possess good resistance<br />
to alkalis as <str<strong>on</strong>g>the</str<strong>on</strong>g>y are used comm<strong>on</strong>ly<br />
in service. Our final, optimized new composi-<br />
ti<strong>on</strong> passed all Alkali c<strong>on</strong>tact testing with<br />
K 2CO 3 and Na 2CO 3 and performed identically<br />
to Standards 1 and 2 in <str<strong>on</strong>g>the</str<strong>on</strong>g> visual assessment<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> Alkali ‘cup’ test samples after testing, at all<br />
test temperatures.<br />
CONCLUSIONS<br />
1. By working closely with alumin-<br />
20 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Standard<br />
1<br />
Standard<br />
2<br />
New<br />
material<br />
% Si pick up 0.314 0.093 0.011<br />
% Fe pick up 0.052 0.04 0.04<br />
Table 3: Alloy analysis after Al ‘Cup’ testing<br />
ium producers, <str<strong>on</strong>g>the</str<strong>on</strong>g> most frequent cause <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
melt-hold furnace downtime has been identified<br />
as mechanical damage in <str<strong>on</strong>g>the</str<strong>on</strong>g> ramp / hearth<br />
regi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> refractory lining.<br />
2. The main factors leading to mechanical<br />
damage in this regi<strong>on</strong> have been identified as<br />
severe abrasi<strong>on</strong> and <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal shock from <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
frequent loading <str<strong>on</strong>g>of</str<strong>on</strong>g> heavy, cold ingot.<br />
3. Through re-engineering <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> b<strong>on</strong>d chemistry<br />
and aggregate granulometry, significant<br />
improvements have been achieved in abrasi<strong>on</strong><br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal shock resistance for material in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> ramp / hearth regi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> melthold<br />
furnaces.<br />
4. An optimized formulati<strong>on</strong> has been shown<br />
to deliver 20-30% improvement in abrasi<strong>on</strong><br />
resistance and 40-50% improvement in <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal<br />
shock resistance compared to existing<br />
materials.<br />
5. The new material has been shown to pass<br />
MEASURING & CONTROL<br />
Fig. 4: Al ‘Cup’ testing – Standard 2 (left) and New material (right) – dried samples<br />
industry standard <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> c<strong>on</strong>tact and<br />
alkali resistance tests. More detailed investigati<strong>on</strong><br />
indicates <str<strong>on</strong>g>the</str<strong>on</strong>g> new material possesses<br />
superior ‘n<strong>on</strong>-wetting’ characteristics compared<br />
to existing materials.<br />
6. These results suggest that <str<strong>on</strong>g>the</str<strong>on</strong>g> new material<br />
should extend service life in <str<strong>on</strong>g>the</str<strong>on</strong>g> ramp / hearth<br />
area and is thus expected to reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> frequency<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> furnace downtime and allow <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
producers to run l<strong>on</strong>ger producti<strong>on</strong><br />
campaigns, increasing productivity and minimizing<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> need for expensive repairs.<br />
7. This new material is now <strong>on</strong> trial in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ramp/hearth area <str<strong>on</strong>g>of</str<strong>on</strong>g> melt-hold furnaces at several<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> producers around <str<strong>on</strong>g>the</str<strong>on</strong>g> world.<br />
Aluminium am laufenden Band<br />
�����������������<br />
���<br />
REFERENCES<br />
1. A.M. Wynn, T.J. Coppack, T. Steele, K.J. Moody,<br />
and L. Caspersen, M<strong>on</strong>olithic Material Selecti<strong>on</strong> for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Lining <str<strong>on</strong>g>of</str<strong>on</strong>g> Aluminum Holding & Melting Furnaces,<br />
TMS 2010, Seattle, USA, Feb. 14-18, 2010.<br />
2. D. J<strong>on</strong>es, A.M. Wynn, and T.J. Coppack, The Development<br />
and Applicati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> an Aluminium Resistant<br />
Castable, UNITECR ’93, Sao Paulo, Brasil, Oct<br />
31-Nov 3, 1993.<br />
3. A.M. Wynn, T.J. Coppack, and T. Steele, Methods<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> Assessing M<strong>on</strong>olithic Refractories for Material<br />
Selecti<strong>on</strong> in Aluminium Melt-Hold Furnaces, 53rd Internati<strong>on</strong>al Refractories Colloquium, Aachen,<br />
Germany, Sept. 8-9, 2010.<br />
������������������������������������<br />
������������������������������������<br />
����������������������������������������<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 21<br />
�
MEASURING & CONTROL<br />
Optimizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> an <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> rolling<br />
mill with a high speed X-ray thickness gauge<br />
Chr. Burnett, A. Quick and J. Olschewski; Thermo Fisher Scientific<br />
The high speed producti<strong>on</strong> achieved by<br />
modern <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> rolling mills requires<br />
reliable and robust thickness sensors.<br />
The Automatic Gauge C<strong>on</strong>trol (AGC)<br />
systems and hydraulic actuators in place<br />
today are capable <str<strong>on</strong>g>of</str<strong>on</strong>g> reacting to strip<br />
changes within just a few millisec<strong>on</strong>ds so<br />
accurate measurements must be supplied<br />
with comparable speed. In order to aide<br />
process c<strong>on</strong>trol engineers as <str<strong>on</strong>g>the</str<strong>on</strong>g>y optimize<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> throughput <str<strong>on</strong>g>of</str<strong>on</strong>g> a given mill, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Internati<strong>on</strong>al Electrical Commissi<strong>on</strong> (IEC)<br />
has produced Standard 61336 defining<br />
specific terms associated with thickness<br />
measurement equipment and <str<strong>on</strong>g>the</str<strong>on</strong>g> testing<br />
protocol associated with verifying gauge<br />
performance. This paper describes a new<br />
Thermo Scientific sensor that provides<br />
high speed measurements allowing faster<br />
feedback loops and tighter c<strong>on</strong>trol <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
flat sheet <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> and its alloys. For<br />
direct feedback, various communicati<strong>on</strong><br />
protocols are available such as analogue<br />
signals, Pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ibus or E<str<strong>on</strong>g>the</str<strong>on</strong>g>rnet. In additi<strong>on</strong><br />
to using <str<strong>on</strong>g>the</str<strong>on</strong>g> measurement values for direct<br />
feedback, single 1 ms measurement<br />
values can be archived using iba analyzer<br />
allowing efficient post-rolling analysis for<br />
mill optimizati<strong>on</strong> and product improvement<br />
resulting in fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r cost savings.<br />
Rolled <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> strip is used in a wide variety<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> industrial and c<strong>on</strong>sumer applicati<strong>on</strong>s<br />
around <str<strong>on</strong>g>the</str<strong>on</strong>g> world. With <str<strong>on</strong>g>the</str<strong>on</strong>g> ever-growing<br />
c<strong>on</strong>cern for energy efficiency and sustainability,<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> producers strive to provide<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> world class quality strip <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> first coil<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a campaign, maximizing mill yield and<br />
minimizing scrap material. Aluminium sheet<br />
producers and <str<strong>on</strong>g>the</str<strong>on</strong>g>ir customers have agreed<br />
up<strong>on</strong> standards to describe various physical<br />
parameters for <str<strong>on</strong>g>the</str<strong>on</strong>g> material traded. Thickness,<br />
width, hardness, strength, are am<strong>on</strong>g <str<strong>on</strong>g>the</str<strong>on</strong>g> key<br />
variables defined in a simple product code.<br />
Both parties fully understand <str<strong>on</strong>g>the</str<strong>on</strong>g> standards<br />
and any disputes are governed by <str<strong>on</strong>g>the</str<strong>on</strong>g> scope<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> actual standard definiti<strong>on</strong> produced by<br />
<strong>on</strong>e <str<strong>on</strong>g>of</str<strong>on</strong>g> a few <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> industry associati<strong>on</strong>s.<br />
Thickness gauge manufactures are also expected<br />
to produce and test <str<strong>on</strong>g>the</str<strong>on</strong>g>ir equipment<br />
in accordance with an internati<strong>on</strong>al standard<br />
known as IEC 61336. Unfortunately, <str<strong>on</strong>g>the</str<strong>on</strong>g>se<br />
standards are not as well known by <str<strong>on</strong>g>the</str<strong>on</strong>g>ir customers,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> sheet producers. This<br />
can result in c<strong>on</strong>fusi<strong>on</strong> during <str<strong>on</strong>g>the</str<strong>on</strong>g> gauge selecti<strong>on</strong><br />
process, and unmet expectati<strong>on</strong>s for new<br />
mills and mill upgrade projects. This paper<br />
will review <str<strong>on</strong>g>the</str<strong>on</strong>g> role <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> thickness gauge in<br />
a mill, present an overview <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> standards to<br />
which all gauging systems should be held and<br />
present how a modern high speed X-ray thickness<br />
gauge can be used as a tool to optimize<br />
an <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> rolling mill.<br />
Aluminium rolling mills<br />
The evoluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> rolling mills<br />
has accelerated as <str<strong>on</strong>g>the</str<strong>on</strong>g> speed <str<strong>on</strong>g>of</str<strong>on</strong>g> processors<br />
and digital c<strong>on</strong>trols have grown by orders <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
magnitude. The capital cost in a rolling mill is<br />
substantial and investors understand that in<br />
order to achieve <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum ROI and shortest<br />
payback time, <str<strong>on</strong>g>the</str<strong>on</strong>g> mill needs to produce<br />
high quality sheet at <str<strong>on</strong>g>the</str<strong>on</strong>g> fastest possible mill<br />
speeds. Diligent plant managers are always<br />
focused <strong>on</strong> safely maximizing mill output. To<br />
accomplish this, mills are operated 24 hours a<br />
day, seven days a week. When a mill is down<br />
for any reas<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g> accountants not <strong>on</strong>ly c<strong>on</strong>sider<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> energy and labour c<strong>on</strong>sumed while<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> mill is idle, but <str<strong>on</strong>g>the</str<strong>on</strong>g> value <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> product<br />
that could have been made during that ‘lost<br />
time’. It is no surprise to hear that mills operate<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g> highest speeds allowed by <str<strong>on</strong>g>the</str<strong>on</strong>g>ir motors<br />
and drives. However, raw producti<strong>on</strong> in t<strong>on</strong>nes<br />
means nothing if <str<strong>on</strong>g>the</str<strong>on</strong>g> material produced does<br />
not meet quality standards.<br />
Many believe that strip quality begins in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
meltshop, and that is not far from <str<strong>on</strong>g>the</str<strong>on</strong>g> truth.<br />
C<strong>on</strong>trolling <str<strong>on</strong>g>the</str<strong>on</strong>g> chemistry <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> molten <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
not <strong>on</strong>ly assures <str<strong>on</strong>g>the</str<strong>on</strong>g> alloy produced<br />
will meet <str<strong>on</strong>g>the</str<strong>on</strong>g> mechanical properties desired <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> final product, but that <str<strong>on</strong>g>the</str<strong>on</strong>g> strip will handle<br />
Hot roughing mill Hot finish mill Cold rolling mill Foil mill<br />
Max. thickness > 400 mm 20-30 mm 2-6 mm 0.6 mm<br />
Min. thickness 20-30 mm 2-10 mm 0.150 mm 0.006 (x2) mm<br />
Rolling speeds<br />
(metres per min)<br />
~ 100 ~1000 ~2000 ~2000<br />
Table 1: Overview <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> rolling mill parameters<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> t<strong>on</strong>nes <str<strong>on</strong>g>of</str<strong>on</strong>g> pressure and tensi<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> high<br />
speed rolling process. Table 1 summarizes <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
typical thicknesses and rolling speeds for each<br />
mill type. Not surprisingly, as <str<strong>on</strong>g>the</str<strong>on</strong>g> material gets<br />
thinner, <str<strong>on</strong>g>the</str<strong>on</strong>g> speeds increase dramatically.<br />
Automatic Gauge C<strong>on</strong>trol (AGC)<br />
The average human resp<strong>on</strong>se time is <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
order <str<strong>on</strong>g>of</str<strong>on</strong>g> a quarter <str<strong>on</strong>g>of</str<strong>on</strong>g> a sec<strong>on</strong>d, at <str<strong>on</strong>g>the</str<strong>on</strong>g> maximum<br />
rolling speed <str<strong>on</strong>g>of</str<strong>on</strong>g> a cold or foil mill, 8<br />
metres <str<strong>on</strong>g>of</str<strong>on</strong>g> strip is produced. It is easy to see<br />
why AGC is an essential comp<strong>on</strong>ent <str<strong>on</strong>g>of</str<strong>on</strong>g> modern<br />
rolling mills. Comprehensive AGC algorithms<br />
incorporate readings from dozens <str<strong>on</strong>g>of</str<strong>on</strong>g> sensors<br />
around <str<strong>on</strong>g>the</str<strong>on</strong>g> mill.<br />
Some <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> key AGC input parameters<br />
are speed and tensi<strong>on</strong> (Fig. 1). C<strong>on</strong>servati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
mass dictates that <str<strong>on</strong>g>the</str<strong>on</strong>g> mass per unit time entering<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> mill must equal <str<strong>on</strong>g>the</str<strong>on</strong>g> mass per unit time<br />
exiting <str<strong>on</strong>g>the</str<strong>on</strong>g> mill. So as <str<strong>on</strong>g>the</str<strong>on</strong>g> material is rolled<br />
thinner, <str<strong>on</strong>g>the</str<strong>on</strong>g> speeds must increase. If <str<strong>on</strong>g>the</str<strong>on</strong>g> drive<br />
motors are <str<strong>on</strong>g>of</str<strong>on</strong>g>f, even by a few centimetres per<br />
minute, <str<strong>on</strong>g>the</str<strong>on</strong>g> strip may break. There is a delicate<br />
balance between <str<strong>on</strong>g>the</str<strong>on</strong>g> reducti<strong>on</strong> caused by<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> mill force, and <str<strong>on</strong>g>the</str<strong>on</strong>g> reducti<strong>on</strong> caused by<br />
drawing (extruding) <str<strong>on</strong>g>the</str<strong>on</strong>g> material through <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
gap.<br />
The thickness gauges are primarily used<br />
to look for dramatic deviati<strong>on</strong>s in thickness,<br />
o<str<strong>on</strong>g>the</str<strong>on</strong>g>r than that, <str<strong>on</strong>g>the</str<strong>on</strong>g>ir feedback is used to check<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> predicti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> mass flow models. Small<br />
changes are corrected by slight adjustments in<br />
speed and tensi<strong>on</strong>, as <str<strong>on</strong>g>the</str<strong>on</strong>g> motor power can<br />
be c<strong>on</strong>trolled very quickly. Larger changes<br />
are compensated by <str<strong>on</strong>g>the</str<strong>on</strong>g> hydraulic cylinders in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> mill stand, which can react in a matter <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
millisec<strong>on</strong>ds.<br />
When a mill is operating at 1,800 m/min,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> material moves 3 cm every millisec<strong>on</strong>d.<br />
If <str<strong>on</strong>g>the</str<strong>on</strong>g> mill is using 0.5 metre diameter rolls,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> circumference <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> roll would be roughly<br />
equivalent to 50 millisec<strong>on</strong>ds. In order to see<br />
any eccentricity or periodic event related to a<br />
roll <str<strong>on</strong>g>of</str<strong>on</strong>g> this diameter, <strong>on</strong>e would need to have a<br />
thickness sensor not <strong>on</strong>ly capable <str<strong>on</strong>g>of</str<strong>on</strong>g> operating<br />
at 5 ms, but being able to provide measurements<br />
with manageable signal to noise values.<br />
For cable shielding applicati<strong>on</strong>s where electrical<br />
signals are carried at 1 GHz or higher, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ability to see thickness variati<strong>on</strong>s over a distance<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 30 cm is essential to avoid unwanted<br />
electrical harm<strong>on</strong>ics by <str<strong>on</strong>g>the</str<strong>on</strong>g> end c<strong>on</strong>sumer.<br />
22 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Fig. 1: Selected AGC input variables<br />
Thickness gauge selecti<strong>on</strong><br />
While <str<strong>on</strong>g>the</str<strong>on</strong>g>re are several choices in thickness<br />
gauge technology, <str<strong>on</strong>g>the</str<strong>on</strong>g>re really is <strong>on</strong>ly <strong>on</strong>e<br />
choice for <str<strong>on</strong>g>the</str<strong>on</strong>g> speed and accuracy requirements<br />
demanded in optimizing a rolling mill:<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> X-ray gauge.<br />
Direct c<strong>on</strong>tact gauges have <str<strong>on</strong>g>the</str<strong>on</strong>g> advantage<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> being insensitive to alloy, <str<strong>on</strong>g>the</str<strong>on</strong>g> measurement<br />
stylus marks <str<strong>on</strong>g>the</str<strong>on</strong>g> strip, and <str<strong>on</strong>g>the</str<strong>on</strong>g> mechanical tolerances<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> frame prevent measurement<br />
near <str<strong>on</strong>g>the</str<strong>on</strong>g> centreline <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> strip. Additi<strong>on</strong>ally,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> small measurement spot size <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> stylus<br />
translates microvariati<strong>on</strong>s in <str<strong>on</strong>g>the</str<strong>on</strong>g> strip surface<br />
into a noisy signal. While <str<strong>on</strong>g>the</str<strong>on</strong>g>se variati<strong>on</strong>s may<br />
actually be in <str<strong>on</strong>g>the</str<strong>on</strong>g> strip, <str<strong>on</strong>g>the</str<strong>on</strong>g> signal needs to be<br />
filtered to reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> noise, and <str<strong>on</strong>g>the</str<strong>on</strong>g> filtering<br />
will delay resp<strong>on</strong>ses to actual l<strong>on</strong>ger term<br />
changes. Therefore, high speed AGC is not<br />
practical with c<strong>on</strong>tact gauges.<br />
There are o<str<strong>on</strong>g>the</str<strong>on</strong>g>r n<strong>on</strong>-c<strong>on</strong>tact, n<strong>on</strong>-radiati<strong>on</strong><br />
based sensors available, some that use eddy<br />
current and o<str<strong>on</strong>g>the</str<strong>on</strong>g>rs that use laser, but each also<br />
has <str<strong>on</strong>g>the</str<strong>on</strong>g>ir drawbacks, <str<strong>on</strong>g>the</str<strong>on</strong>g> eddy current sensors<br />
have an extremely narrow gap between<br />
emitter and receiver which can turn this n<strong>on</strong>-<br />
c<strong>on</strong>tact gauge into a c<strong>on</strong>tact gauge should <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
strip vary by as little as 12 mm. Additi<strong>on</strong>ally,<br />
like <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tact gauge, <str<strong>on</strong>g>the</str<strong>on</strong>g> sensor frame<br />
mechanics limit <str<strong>on</strong>g>the</str<strong>on</strong>g> measurement locati<strong>on</strong> to<br />
<strong>on</strong>ly a few centimetres from <str<strong>on</strong>g>the</str<strong>on</strong>g> edge. La-<br />
Fig. 2: Simulated sensor resp<strong>on</strong>ses to a 250 ms, 1.0% deviati<strong>on</strong> from target<br />
ser gauges do<br />
benefit from a<br />
larger air gap,<br />
but <str<strong>on</strong>g>the</str<strong>on</strong>g>y can be<br />
sensitive to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
high amount <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
steam and mist<br />
that occurs in<br />
a rolling mill.<br />
Additi<strong>on</strong>ally<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> laser camera<br />
technology<br />
limits <str<strong>on</strong>g>the</str<strong>on</strong>g> resoluti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> measurement<br />
to a few micr<strong>on</strong>s. While this may be<br />
acceptable in certain applicati<strong>on</strong>s, it does not<br />
meet <str<strong>on</strong>g>the</str<strong>on</strong>g> needs <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> thinner faster mills.<br />
N<strong>on</strong>-c<strong>on</strong>tact radiati<strong>on</strong> based thickness<br />
gauges can use ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r radioisotope or X-ray<br />
sources. However in <str<strong>on</strong>g>the</str<strong>on</strong>g> case where <str<strong>on</strong>g>the</str<strong>on</strong>g> gauge<br />
measurement is to be used in a closed loop<br />
c<strong>on</strong>trol or AGC system, <str<strong>on</strong>g>the</str<strong>on</strong>g>re is really <strong>on</strong>ly<br />
<strong>on</strong>e soluti<strong>on</strong>: X-rays. The number <str<strong>on</strong>g>of</str<strong>on</strong>g> phot<strong>on</strong>s<br />
emitted from an X-ray source is approx.<br />
1,000 times that <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> commercially available<br />
isotopes. Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> statistical nature <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
radiati<strong>on</strong> detecti<strong>on</strong>, measurements made with<br />
more phot<strong>on</strong>s have a better signal to noise<br />
ratio, and c<strong>on</strong>sequently a more true measurement.<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> X-ray versus isotope, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
noise level for an isotope is <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> order <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
20 to 30 times worse than that <str<strong>on</strong>g>of</str<strong>on</strong>g> an X-ray<br />
based sensor when <str<strong>on</strong>g>the</str<strong>on</strong>g> same averaging time<br />
is used. Statistical noise at that level creates<br />
a situati<strong>on</strong> where small changes in thickness<br />
are lost in <str<strong>on</strong>g>the</str<strong>on</strong>g> noise <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> signal. While multiple<br />
isotope pellets might be used in an effort<br />
to increase <str<strong>on</strong>g>the</str<strong>on</strong>g> signal, <str<strong>on</strong>g>the</str<strong>on</strong>g> regulatory and safety<br />
c<strong>on</strong>siderati<strong>on</strong>s make this opti<strong>on</strong> prohibitive.<br />
Ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r approach to improve <str<strong>on</strong>g>the</str<strong>on</strong>g> noise <strong>on</strong><br />
isotope based systems is to increase <str<strong>on</strong>g>the</str<strong>on</strong>g> averaging,<br />
or resp<strong>on</strong>se time. However, when this<br />
is d<strong>on</strong>e, small, and instantaneous changes in<br />
product thickness are blurred to <str<strong>on</strong>g>the</str<strong>on</strong>g> point <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
not being seen (Fig. 2).<br />
MEASURING & CONTROL<br />
Just as low signal to noise ratio is a serious<br />
factor in source selecti<strong>on</strong>, <strong>on</strong>e must take care<br />
to select a source <str<strong>on</strong>g>of</str<strong>on</strong>g> a proper energy as to<br />
not have too much signal. While <str<strong>on</strong>g>the</str<strong>on</strong>g> density<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> and its alloys is a tremendous<br />
advantage in aerospace and o<str<strong>on</strong>g>the</str<strong>on</strong>g>r applicati<strong>on</strong>s,<br />
it presents unique challenges in n<strong>on</strong>-c<strong>on</strong>tact<br />
radiati<strong>on</strong> gauging. At typical X-ray energies,<br />
it is nearly thirteen times less absorbing compared<br />
to steel. When compounded by <str<strong>on</strong>g>the</str<strong>on</strong>g> thin<br />
dimensi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a foil mill, <str<strong>on</strong>g>the</str<strong>on</strong>g> X-ray energies<br />
must be reduced to <str<strong>on</strong>g>the</str<strong>on</strong>g> point where measuring<br />
and compensating for envir<strong>on</strong>mental factors<br />
such as air temperature and pressure become<br />
essential. If an X-ray gauge is operated at too<br />
high <str<strong>on</strong>g>of</str<strong>on</strong>g> an energy, <str<strong>on</strong>g>the</str<strong>on</strong>g> dynamic range <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
detector output is reduced, limiting <str<strong>on</strong>g>the</str<strong>on</strong>g> measurement<br />
resoluti<strong>on</strong> and precisi<strong>on</strong>. In <str<strong>on</strong>g>the</str<strong>on</strong>g> case<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> can stock producti<strong>on</strong> at around<br />
250 micr<strong>on</strong>s, a 10 micr<strong>on</strong> change in thickness<br />
results in a signal change <str<strong>on</strong>g>of</str<strong>on</strong>g> less than 0.075%<br />
at a phot<strong>on</strong> energy <str<strong>on</strong>g>of</str<strong>on</strong>g> 60 keV, where as <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
same thickness change at a phot<strong>on</strong> energy <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
10 keV will produce a signal change <str<strong>on</strong>g>of</str<strong>on</strong>g> over<br />
7% (Fig. 3). When <str<strong>on</strong>g>the</str<strong>on</strong>g> statistical noise <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
measurement is ±0.1%, it is easy to see that<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> 60 keV source is just too much for <str<strong>on</strong>g>the</str<strong>on</strong>g> can<br />
stock applicati<strong>on</strong>.<br />
X-ray gauge compensati<strong>on</strong><br />
for alloys and clads<br />
Commercially pure <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> has almost no<br />
practical applicati<strong>on</strong>s due to its weak mechanical<br />
properties. In order for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> to be<br />
useful to industry, small amounts <str<strong>on</strong>g>of</str<strong>on</strong>g> copper,<br />
manganese, magnesium and o<str<strong>on</strong>g>the</str<strong>on</strong>g>r elements<br />
are added. While <str<strong>on</strong>g>the</str<strong>on</strong>g>se elements add strength<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> sheet, <str<strong>on</strong>g>the</str<strong>on</strong>g>ir radiati<strong>on</strong> absorpti<strong>on</strong><br />
properties vary dramatically making<br />
alloy compensati<strong>on</strong> complex for X-ray gauges.<br />
For example, <str<strong>on</strong>g>the</str<strong>on</strong>g> AA5000 series <str<strong>on</strong>g>of</str<strong>on</strong>g> alloys<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g>ir small amount magnesium actually<br />
absorb less radiati<strong>on</strong> than pure <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>, but<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> AA 7000 series can absorb twice as much<br />
radiati<strong>on</strong>, depending <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> amount <str<strong>on</strong>g>of</str<strong>on</strong>g> zinc<br />
and copper present.<br />
While physics can used to predict a <str<strong>on</strong>g>the</str<strong>on</strong>g>oretical<br />
absorpti<strong>on</strong> for any alloy combinati<strong>on</strong>,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> actual density can vary by several percent<br />
when compared to <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>oretical density. It<br />
is this density difference that makes physical<br />
measurement <str<strong>on</strong>g>of</str<strong>on</strong>g> alloys necessary. More<br />
advanced alloy compensati<strong>on</strong> algorithms can<br />
extend this ‘density correcti<strong>on</strong>’ from <strong>on</strong>e alloy<br />
to similar alloys, but many <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
gauge manufacturers require <str<strong>on</strong>g>the</str<strong>on</strong>g> producer<br />
to provide a library <str<strong>on</strong>g>of</str<strong>on</strong>g> samples across a variety<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> thicknesses and alloys to cover <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
whole producti<strong>on</strong> range. This is not possible<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 23
MEASURING & CONTROL<br />
Fig. 3: Sensor resp<strong>on</strong>se as a functi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> thickness for different phot<strong>on</strong> energies<br />
for some producers so <str<strong>on</strong>g>the</str<strong>on</strong>g>y must resort to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
‘stop-and-measure’ technique. A single correcti<strong>on</strong><br />
factor is calculated by comparing <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
uncorrected gauge measurement to a physical<br />
c<strong>on</strong>tact measurement made while <str<strong>on</strong>g>the</str<strong>on</strong>g> strip is<br />
stopped. While simple, it limits <str<strong>on</strong>g>the</str<strong>on</strong>g> accuracy<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> gauge to <str<strong>on</strong>g>the</str<strong>on</strong>g> accuracy <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tact<br />
measurements which not <strong>on</strong>ly slow producti<strong>on</strong><br />
down, but are known to be operator dependent.<br />
The challenges <str<strong>on</strong>g>of</str<strong>on</strong>g> alloy compensati<strong>on</strong> are<br />
fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r complicated when <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> producer<br />
rolls clad products. The alloy <str<strong>on</strong>g>layer</str<strong>on</strong>g>s have<br />
different equivalent absorpti<strong>on</strong>s which by<br />
means <str<strong>on</strong>g>of</str<strong>on</strong>g> proprietary s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware can be c<strong>on</strong>verted<br />
to a single correcti<strong>on</strong> factor for that product.<br />
Without an alloy/clad compensati<strong>on</strong> algorithm,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> compensati<strong>on</strong> approach based <strong>on</strong> sample<br />
sets for each alloy becomes a logistical headache<br />
for storage and quality assurance checks.<br />
Internati<strong>on</strong>al standards<br />
Internati<strong>on</strong>al organizati<strong>on</strong>s like <str<strong>on</strong>g>the</str<strong>on</strong>g> Aluminum<br />
Associati<strong>on</strong>, ASTM, Japanese Standards<br />
Associati<strong>on</strong> and o<str<strong>on</strong>g>the</str<strong>on</strong>g>rs provide guidance <strong>on</strong><br />
not <strong>on</strong>ly alloy chemistry tolerances, but sheet<br />
dimensi<strong>on</strong>al tolerances as well. For instrument<br />
suppliers, <str<strong>on</strong>g>the</str<strong>on</strong>g> Internati<strong>on</strong>al Electrotechnical<br />
Commissi<strong>on</strong> (IEC) has produced standards to<br />
provide guidance and definiti<strong>on</strong> for specific<br />
terms and tests used. The standards act as a<br />
c<strong>on</strong>sistent scale to compare <strong>on</strong>e instrument to<br />
ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r without c<strong>on</strong>fusing nomenclature obscuring<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> true performance <str<strong>on</strong>g>of</str<strong>on</strong>g> each.<br />
The Nuclear Instrumentati<strong>on</strong> Technical<br />
Committee (IEC Technical Committee 45)<br />
produced IEC 61336 ‘Thickness measurement<br />
systems utilizing i<strong>on</strong>izing radiati<strong>on</strong> – Definiti<strong>on</strong>s<br />
and test methods’. The first committee<br />
release was in 1983, and an update was<br />
drafted in 1996. The document is available<br />
for purchase from <str<strong>on</strong>g>the</str<strong>on</strong>g> IEC at http://webstore.<br />
iec.ch/webstore/webstore.nsf/ArtNum_PK/<br />
21703?OpenDocument, as such we cannot<br />
reproduce it here. The standard first defines<br />
comm<strong>on</strong> terms in order to clarify what specific<br />
words mean. For example <str<strong>on</strong>g>the</str<strong>on</strong>g> ‘mean resp<strong>on</strong>se<br />
time’ may be called <str<strong>on</strong>g>the</str<strong>on</strong>g> ‘first time c<strong>on</strong>stant’ by<br />
some, and something else by o<str<strong>on</strong>g>the</str<strong>on</strong>g>rs. (Fig. 4)<br />
The fixed definiti<strong>on</strong>s avoid any ambiguity in<br />
interpretati<strong>on</strong>. They additi<strong>on</strong>ally provide guidance<br />
in setting up and carrying out <str<strong>on</strong>g>the</str<strong>on</strong>g> tests<br />
defined in <str<strong>on</strong>g>the</str<strong>on</strong>g> sec<strong>on</strong>d part <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> standard.<br />
The standard dedicates no less than nine<br />
terms to clarify time based parameters. Some<br />
are related to defining <str<strong>on</strong>g>the</str<strong>on</strong>g> time associated with<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> time taken to resp<strong>on</strong>d to a change, while<br />
o<str<strong>on</strong>g>the</str<strong>on</strong>g>rs are related to <str<strong>on</strong>g>the</str<strong>on</strong>g> digital processing <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
signals. This is particularly critical with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
advent <str<strong>on</strong>g>of</str<strong>on</strong>g> high speed data processors. Incoming<br />
data can be manipulated and processed by<br />
advanced filters to mask or hide true statistical<br />
variati<strong>on</strong>s. As depicted in Fig. 2 above, radiati<strong>on</strong><br />
measurements are statistical by <str<strong>on</strong>g>the</str<strong>on</strong>g>ir very<br />
nature. All noise figures should be quoted with<br />
a reference to <str<strong>on</strong>g>the</str<strong>on</strong>g> number <str<strong>on</strong>g>of</str<strong>on</strong>g> Sigmas, or c<strong>on</strong>fidence<br />
levels (CL). Most gauge manufactures<br />
present 2 sigma (95% CL) noise figures, but<br />
not all. Straightforward data processing provides<br />
for predictable results and a better representati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> process dynamics. If a change<br />
occurs in <str<strong>on</strong>g>the</str<strong>on</strong>g> process, advanced filtering may<br />
portray a porti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> change, but not <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
full change. Process engineers and <str<strong>on</strong>g>the</str<strong>on</strong>g>ir AGC<br />
algorithms may over react, or under correct<br />
thanks to <str<strong>on</strong>g>the</str<strong>on</strong>g> manipulated<br />
data.<br />
In order<br />
to ethically<br />
improve <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
speed <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> sensor resp<strong>on</strong>se<br />
to change, without<br />
increasing <str<strong>on</strong>g>the</str<strong>on</strong>g> statistical<br />
noise <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> measurement,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> physical characteristics<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> sensor<br />
need to be optimized for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> applicati<strong>on</strong>. The raw<br />
signal; must be shielded to remove as much<br />
electrical noise as possible. The ideal approach<br />
for this is represented in <str<strong>on</strong>g>the</str<strong>on</strong>g> Thermo Scientific<br />
RM 210 AS X-ray thickness gauge. In this versatile<br />
instrument, <str<strong>on</strong>g>the</str<strong>on</strong>g> radiati<strong>on</strong> detector output<br />
is digitized right away. The analog detector signal<br />
is c<strong>on</strong>verted to a digital number within a<br />
few millimeters <str<strong>on</strong>g>of</str<strong>on</strong>g> its origin. This practically<br />
eliminates <str<strong>on</strong>g>the</str<strong>on</strong>g> possibility <str<strong>on</strong>g>of</str<strong>on</strong>g> electrical noise<br />
impinging <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> signal. In comparis<strong>on</strong> tests,<br />
following <str<strong>on</strong>g>the</str<strong>on</strong>g> IEC 61336 guide, <str<strong>on</strong>g>the</str<strong>on</strong>g> noise <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> new designed detector improved by a factor<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 30%. Additi<strong>on</strong>ally, users <str<strong>on</strong>g>of</str<strong>on</strong>g> this system<br />
can benefit fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r by taking advantage <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
detector’s ability to operate at a 1 ms mean<br />
resp<strong>on</strong>se time. At this speed, and with <str<strong>on</strong>g>the</str<strong>on</strong>g> reduced<br />
noise, process engineers have <str<strong>on</strong>g>the</str<strong>on</strong>g> tools<br />
to analyze data at high speeds, revealing mill<br />
chatter and o<str<strong>on</strong>g>the</str<strong>on</strong>g>r higher frequency anomalies.<br />
In a typical rolling mill that produces can<br />
stock <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> at 250 um, <str<strong>on</strong>g>the</str<strong>on</strong>g> noise at a 10<br />
ms mean resp<strong>on</strong>se time might be <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> order<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> ±0.20% (2 sigma). With <str<strong>on</strong>g>the</str<strong>on</strong>g> improved<br />
signal processing <str<strong>on</strong>g>of</str<strong>on</strong>g> this system <str<strong>on</strong>g>the</str<strong>on</strong>g> noise will<br />
drop to ±0.15% (2-sigma). For a mill that produces<br />
200,000 t<strong>on</strong>nes a year, that translates<br />
to a savings <str<strong>on</strong>g>of</str<strong>on</strong>g> almost $200,000 in <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
material al<strong>on</strong>e (using <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> price at $1<br />
per pound).<br />
An additi<strong>on</strong>al benefit to digitizing <str<strong>on</strong>g>the</str<strong>on</strong>g> signal<br />
so early in its journey to <str<strong>on</strong>g>the</str<strong>on</strong>g> AGC system,<br />
is speed. Once digitized, <str<strong>on</strong>g>the</str<strong>on</strong>g> data can be processed<br />
with out <str<strong>on</strong>g>the</str<strong>on</strong>g> time c<strong>on</strong>suming ADC/DAC<br />
c<strong>on</strong>versi<strong>on</strong>s. The reducti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a few millisec<strong>on</strong>ds<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> process delay time can assure <str<strong>on</strong>g>the</str<strong>on</strong>g> AGC<br />
has time to fully correct any strip thickness<br />
deviati<strong>on</strong>s. This can result in higher quality<br />
product.<br />
Data archiving<br />
A final benefit is realized in <str<strong>on</strong>g>the</str<strong>on</strong>g> powerful tool<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> data archiving. This ideal system is available<br />
with a s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware feature that stores any<br />
gauge data stream in <str<strong>on</strong>g>the</str<strong>on</strong>g> iba ‘.dat’ format. This<br />
format is gaining popularity as <str<strong>on</strong>g>the</str<strong>on</strong>g> iba PDA<br />
data analysis tool also grows in popularity.<br />
Fig. 4: Graphical representati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> gauge resp<strong>on</strong>se<br />
to an instantaneous thickness change<br />
24 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
���<br />
The flexibility <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> iba visualizati<strong>on</strong> tool<br />
is its real strength. As simple example <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
flexibility is depicted in Fig. 5 showing a coil<br />
report with <str<strong>on</strong>g>the</str<strong>on</strong>g> thickness data presented as a<br />
functi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> length, with tolerances and coil<br />
statistics. Easy to use features allow for time<br />
based, and length based data analysis. Built in<br />
ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical tools such FFT can point process<br />
engineers to mill comp<strong>on</strong>ents that might need<br />
maintenance. In this situati<strong>on</strong>, mill downtime<br />
can be best managed, and unplanned downtime<br />
dramatically reduced.<br />
The data archiving feature can also be c<strong>on</strong>-<br />
figured to accept and record data from o<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
sensors with in <str<strong>on</strong>g>the</str<strong>on</strong>g> mill. Any data point that<br />
is available to <str<strong>on</strong>g>the</str<strong>on</strong>g> mill computer through an<br />
E<str<strong>on</strong>g>the</str<strong>on</strong>g>rnet c<strong>on</strong>necti<strong>on</strong> can be collected by <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
system to allow for comprehensive data analysis.<br />
Thus permitting <str<strong>on</strong>g>the</str<strong>on</strong>g> pairing <str<strong>on</strong>g>of</str<strong>on</strong>g> thickness<br />
measurement output to mill tensi<strong>on</strong>s and<br />
speeds in such a way that complies with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
IEC 61336 testing standards. The IEC 61336<br />
Annex B defines appropriate test points for<br />
data collecti<strong>on</strong> and analysis. While traditi<strong>on</strong>al<br />
analog outputs are typically used for gauge<br />
validati<strong>on</strong>, it is equally acceptable to use <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
data transferred via E<str<strong>on</strong>g>the</str<strong>on</strong>g>rnet, or<br />
o<str<strong>on</strong>g>the</str<strong>on</strong>g>r means to a data archive.<br />
Summary<br />
Advances in <strong>on</strong>line measurement <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
flat sheet have culminated in a state<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> art X-ray based sensor system<br />
that provides high speed/low noise<br />
measurements permitting <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
producers to realize material<br />
savings and quality improvements<br />
not previously achievable. This sen-<br />
MEASURING & CONTROL<br />
sor incorporates alloy and clad compensati<strong>on</strong><br />
based <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> fundamental principles <str<strong>on</strong>g>of</str<strong>on</strong>g> radiati<strong>on</strong><br />
physics. It is housed in a robust frame designed<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> rigors <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> rolling<br />
mill. The complete package is manufactured<br />
and tested following IEC 61336 definiti<strong>on</strong>s<br />
which assure process engineers receive clear<br />
thickness data with out ambiguity. Thus allowing<br />
for mill optimizati<strong>on</strong> to achieve world<br />
class quality and strip uniformity at <str<strong>on</strong>g>the</str<strong>on</strong>g> highest<br />
rolling speeds. This results in maximizing <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
return for <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> rolling mill owners<br />
and investors.<br />
Acknowledgement<br />
The author thanks <str<strong>on</strong>g>the</str<strong>on</strong>g> Internati<strong>on</strong>al Electrotechnical<br />
Commissi<strong>on</strong> (IEC) for permissi<strong>on</strong> to reproduce<br />
Informati<strong>on</strong> from its Internati<strong>on</strong>al Standard IEC<br />
61336 ed.1.0 (1996). All such extracts are copyright<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> IEC, Geneva, Switzerland. All rights reserved.<br />
Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r informati<strong>on</strong> <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> IEC is available<br />
from www.iec.ch. IEC has no resp<strong>on</strong>sibility for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
placement and c<strong>on</strong>text in which <str<strong>on</strong>g>the</str<strong>on</strong>g> extracts and<br />
c<strong>on</strong>tents are reproduced by <str<strong>on</strong>g>the</str<strong>on</strong>g> author, nor is IEC<br />
in any way resp<strong>on</strong>sible for <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r c<strong>on</strong>tent or accuracy<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>rein.<br />
Fig. 5: Typical coil report using iba data archiving tools �<br />
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MEASURING & CONTROL<br />
Optimized raw material usage driven by dynamic alloying<br />
State-<str<strong>on</strong>g>of</str<strong>on</strong>g>-<str<strong>on</strong>g>the</str<strong>on</strong>g>-art casthouse producti<strong>on</strong> management<br />
Dieter Deutz, PSI Metals N<strong>on</strong> Ferrous GmbH<br />
Increasing raw material and scrap prices<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> n<strong>on</strong>-ferrous industry are leading<br />
to a c<strong>on</strong>tinually rising porti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> material<br />
costs in overall producti<strong>on</strong> costs. The<br />
effect <str<strong>on</strong>g>of</str<strong>on</strong>g> optimized raw material usage<br />
is getting more and more important to<br />
manage producti<strong>on</strong> costs and to ensure<br />
competitive advantages. PSImetals, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
producti<strong>on</strong> management soluti<strong>on</strong> specialized<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> needs <str<strong>on</strong>g>of</str<strong>on</strong>g> n<strong>on</strong> ferrous metals<br />
producers, takes this into account by recalculating<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> charging for all scheduled<br />
melt batches giving an overall optimized<br />
decisi<strong>on</strong> support for <str<strong>on</strong>g>the</str<strong>on</strong>g> resp<strong>on</strong>sible pers<strong>on</strong>s.<br />
The PSI system supports all aspects <str<strong>on</strong>g>of</str<strong>on</strong>g> producti<strong>on</strong><br />
management. This includes a knowledge<br />
based order dressing comp<strong>on</strong>ent to manage<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> highest value <str<strong>on</strong>g>of</str<strong>on</strong>g> producti<strong>on</strong> know-how.<br />
The sales and operati<strong>on</strong>al planning, due date<br />
quoting and order related producti<strong>on</strong> planning<br />
processes are covered as well as scheduling<br />
and executi<strong>on</strong>. All comp<strong>on</strong>ents are directly<br />
integrated in <strong>on</strong>e comm<strong>on</strong> factory model. This<br />
makes it possible to combine <str<strong>on</strong>g>the</str<strong>on</strong>g> as-is-situati<strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> short term and even <str<strong>on</strong>g>the</str<strong>on</strong>g> l<strong>on</strong>g term<br />
decisi<strong>on</strong> model.<br />
On executing level starting with <str<strong>on</strong>g>the</str<strong>on</strong>g> goods<br />
receipt, all material flows are not <strong>on</strong>ly tracked<br />
but c<strong>on</strong>trolled. Excavators, wheel loaders<br />
and fork-lift trucks and its weighing systems<br />
are integrated by mobile computers. Melting,<br />
holding, casting and all o<str<strong>on</strong>g>the</str<strong>on</strong>g>r equipments are<br />
directly c<strong>on</strong>ducted by level 2 integrati<strong>on</strong> and<br />
pdc terminals. So all producti<strong>on</strong> processes are<br />
guided and every time <strong>on</strong>line transparent.<br />
PSImetals with its simple and intuitive human<br />
interface is leading to short term implementati<strong>on</strong><br />
and direct acceptance. The real time c<strong>on</strong>necti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> actual analysis measurement<br />
during melting for <str<strong>on</strong>g>the</str<strong>on</strong>g> optimizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
batch compositi<strong>on</strong> and <str<strong>on</strong>g>the</str<strong>on</strong>g> subsequent alloy<br />
takes into account <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace sump, lumpiness<br />
and many o<str<strong>on</strong>g>the</str<strong>on</strong>g>r aspects leads to highest<br />
quality with lowest material costs. Each material<br />
unit is tracked from <str<strong>on</strong>g>the</str<strong>on</strong>g> ingredients to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
final product.<br />
The PSI System delivers <str<strong>on</strong>g>the</str<strong>on</strong>g> current stocks,<br />
and knows <str<strong>on</strong>g>the</str<strong>on</strong>g> planned scrap inflow. The<br />
proactive c<strong>on</strong>trol <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> compositi<strong>on</strong> optimizati<strong>on</strong><br />
uses this knowledge to form follow-up<br />
charges, and thus achieve significantly lower<br />
usage <str<strong>on</strong>g>of</str<strong>on</strong>g> new material and at <str<strong>on</strong>g>the</str<strong>on</strong>g> same time<br />
lower scrap stocks at lower costs.<br />
The tracking and optimizing <str<strong>on</strong>g>of</str<strong>on</strong>g> energy c<strong>on</strong>sumpti<strong>on</strong><br />
as basis for smarter energy procurement<br />
is also already possible.<br />
This text gives an overview <str<strong>on</strong>g>of</str<strong>on</strong>g> how to optimize<br />
material flows within <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> casthouses<br />
by using a holistic producti<strong>on</strong> management<br />
system.<br />
Casthouse producti<strong>on</strong> management<br />
Main cost drivers <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong> costs in<br />
an <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> casthouse are raw material and<br />
energy costs. Both topics are addressed by<br />
PSImetals Producti<strong>on</strong> Management System<br />
(PMS).<br />
To reach targets like<br />
Minimize material and energy costs<br />
• Optimize scrap usage by integrated<br />
alloying<br />
• C<strong>on</strong>trol number <str<strong>on</strong>g>of</str<strong>on</strong>g> alloying steps<br />
• Track and plan energy c<strong>on</strong>sumpti<strong>on</strong><br />
Secure and optimize producti<strong>on</strong> processes,<br />
especially alloying<br />
• Integrated testing device and alloying<br />
recalculati<strong>on</strong><br />
• C<strong>on</strong>trol deviati<strong>on</strong> handling by customer<br />
managed workflows<br />
• Tool management<br />
Real time transparency & material genealogy<br />
• Tracking <str<strong>on</strong>g>of</str<strong>on</strong>g> all relevant events<br />
• Tracking <str<strong>on</strong>g>of</str<strong>on</strong>g> all material items<br />
• Tracking <str<strong>on</strong>g>of</str<strong>on</strong>g> material genealogy<br />
first <str<strong>on</strong>g>of</str<strong>on</strong>g> all real time transparency is needed by<br />
driving and supporting <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong> processes.<br />
Step 1 – material management<br />
and material flow c<strong>on</strong>trol<br />
The fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r approaches are explained based<br />
<strong>on</strong> a casthouse example which is shown in<br />
Fig. 1:<br />
Fig. 1: Areas <str<strong>on</strong>g>of</str<strong>on</strong>g> producti<strong>on</strong> within a casthouse<br />
Beginning with a scrap and metal stockyard<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> casthouse examples c<strong>on</strong>sist <str<strong>on</strong>g>of</str<strong>on</strong>g> melting<br />
furnaces, casting, sawing, homogenizati<strong>on</strong> and<br />
scalping devices. PSImetals covers all types<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> casthouses. The example should point out<br />
high complexity in different alloys and dimensi<strong>on</strong>s<br />
especially when casting ingots and billets<br />
is not limited.<br />
Tracking <str<strong>on</strong>g>of</str<strong>on</strong>g> all types <str<strong>on</strong>g>of</str<strong>on</strong>g> materials is essential<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r steps. The starting point is<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> material input in <str<strong>on</strong>g>the</str<strong>on</strong>g> factory. On basis <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
notificati<strong>on</strong>s and purchase orders <str<strong>on</strong>g>the</str<strong>on</strong>g> input is<br />
booked and <str<strong>on</strong>g>the</str<strong>on</strong>g> material is ready for fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
qualificati<strong>on</strong> and/or preparati<strong>on</strong> steps. Each<br />
movement is driven by PSImetals to ensure<br />
that every material is a <str<strong>on</strong>g>the</str<strong>on</strong>g> right positi<strong>on</strong> in<br />
accordance to <str<strong>on</strong>g>the</str<strong>on</strong>g> schedules. At each workplace<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> corresp<strong>on</strong>ding schedule gives <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
workers <str<strong>on</strong>g>the</str<strong>on</strong>g>ir program for <str<strong>on</strong>g>the</str<strong>on</strong>g> shift. By activating<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> next task related transport orders<br />
for forklifts, cranes or fully automatic handling<br />
devices are generated.<br />
This principle <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>trolling and driving<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> material movements, tracking <str<strong>on</strong>g>the</str<strong>on</strong>g> locati<strong>on</strong><br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> as-is values <str<strong>on</strong>g>of</str<strong>on</strong>g> each material unit is<br />
not <strong>on</strong>ly valid for raw materials (RM), but<br />
also for work in process (WIP), semi-finished<br />
goods (SFG) and finished goods (FG).<br />
PSImetals provides all needed customizing<br />
functi<strong>on</strong>ality to make all adopti<strong>on</strong>s to <str<strong>on</strong>g>the</str<strong>on</strong>g> customer<br />
situati<strong>on</strong> as easy as possible. As an example<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> built in editor for <str<strong>on</strong>g>the</str<strong>on</strong>g> yard topology<br />
is menti<strong>on</strong>ed. With this editor <str<strong>on</strong>g>the</str<strong>on</strong>g> customer<br />
can change his structure directly without any<br />
programming. This is in <str<strong>on</strong>g>the</str<strong>on</strong>g> casthouse area<br />
used to change <str<strong>on</strong>g>the</str<strong>on</strong>g> structure <str<strong>on</strong>g>of</str<strong>on</strong>g> boxes in according<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> product mix and <str<strong>on</strong>g>the</str<strong>on</strong>g> procurement<br />
strategy.<br />
Step 2 – integrated dynamic alloying<br />
Based <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> sufficient transparency <str<strong>on</strong>g>the</str<strong>on</strong>g> real<br />
benefits are achieved by using <str<strong>on</strong>g>the</str<strong>on</strong>g> built-in al-<br />
26 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Fig. 2: Optimized raw material calculati<strong>on</strong> using a LP solver always c<strong>on</strong>sidering given restricti<strong>on</strong>s and<br />
optimizati<strong>on</strong> targets<br />
loying module which can be used by <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong><br />
planning, scheduling or executi<strong>on</strong>. For<br />
calculating <str<strong>on</strong>g>the</str<strong>on</strong>g> optimized raw material supply<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> actual situati<strong>on</strong>, all scheduled batches or<br />
producti<strong>on</strong> orders are taking into account.<br />
The calculating is down by feeding a LP (linear<br />
programming) solver. Fig. 2 shows <str<strong>on</strong>g>the</str<strong>on</strong>g> schedule<br />
generati<strong>on</strong> inclusive material supply. In<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> first stage <str<strong>on</strong>g>the</str<strong>on</strong>g> melting and casting batches<br />
are built up and sequenced for each device.<br />
With <str<strong>on</strong>g>the</str<strong>on</strong>g> sec<strong>on</strong>d stage <str<strong>on</strong>g>the</str<strong>on</strong>g> material supply for<br />
every scheduled batch is calculated.<br />
Managing energy<br />
The energy costs are getting more and more<br />
into <str<strong>on</strong>g>the</str<strong>on</strong>g> focus. The complexity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> regi<strong>on</strong>ally<br />
different influences and restricti<strong>on</strong>s makes<br />
it difficult to manage. The forecasting and procurement<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> energy and even <str<strong>on</strong>g>the</str<strong>on</strong>g> reactivity in<br />
adopting <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong> <strong>on</strong> a short term notice<br />
to a different energy situati<strong>on</strong> are <str<strong>on</strong>g>the</str<strong>on</strong>g> challenges<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> future.<br />
PSImetals provides <str<strong>on</strong>g>the</str<strong>on</strong>g> functi<strong>on</strong>ality for<br />
c<strong>on</strong>sider <str<strong>on</strong>g>the</str<strong>on</strong>g> various aspects <str<strong>on</strong>g>of</str<strong>on</strong>g> increasing<br />
energy efficiency, forecasting and producti<strong>on</strong><br />
c<strong>on</strong>trol:<br />
Tracking and short term c<strong>on</strong>trol<br />
• High level <str<strong>on</strong>g>of</str<strong>on</strong>g> transparency in energy<br />
Fig. 3: Energy management to track and c<strong>on</strong>trol<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> energy c<strong>on</strong>sumpti<strong>on</strong> in producti<strong>on</strong><br />
c<strong>on</strong>sumpti<strong>on</strong><br />
• Early warning system to avoid violati<strong>on</strong>s<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>tractual limited peak loads<br />
• Predicted overall energy c<strong>on</strong>sumpti<strong>on</strong> for<br />
operati<strong>on</strong>al decisi<strong>on</strong> support<br />
Energy c<strong>on</strong>sumpti<strong>on</strong> in planning<br />
and scheduling<br />
• Energy c<strong>on</strong>sumpti<strong>on</strong> values – part <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
producti<strong>on</strong> order routings<br />
• C<strong>on</strong>sumpti<strong>on</strong> forecast for different<br />
time-frames<br />
• Support for c<strong>on</strong>tract negotiati<strong>on</strong> with<br />
energy supplier<br />
Summary<br />
Potential benefits are summarized in <str<strong>on</strong>g>the</str<strong>on</strong>g> following<br />
overview:<br />
Transparency and <strong>on</strong>line material genealogy<br />
• Decrease <str<strong>on</strong>g>of</str<strong>on</strong>g> reacti<strong>on</strong> time and efforts<br />
• Integrated alloying<br />
• Optimized material supply <str<strong>on</strong>g>of</str<strong>on</strong>g> all<br />
scheduled batches<br />
• Decrease in producti<strong>on</strong> costs<br />
• Secured alloying process<br />
• Reduced alloying adjustment steps<br />
(~ 1,1 steps in average)<br />
• Support in deviati<strong>on</strong> handling<br />
• Decrease in material costs by over 10%<br />
Fig. 4: Managing <str<strong>on</strong>g>the</str<strong>on</strong>g> load peaks <str<strong>on</strong>g>of</str<strong>on</strong>g> your energy<br />
demand to avoid limit violati<strong>on</strong> costs<br />
MEASURING & CONTROL<br />
• Additi<strong>on</strong>al benefits by adopted<br />
procurement strategies<br />
Integrated energy management<br />
• Minimizing energy costs<br />
• Basis for new business model ‘selling<br />
c<strong>on</strong>trol power’<br />
Next steps<br />
For fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r improvements in adopting <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical models to <str<strong>on</strong>g>the</str<strong>on</strong>g> real world ‘Qualicisi<strong>on</strong>’<br />
will be used. Qualicisi<strong>on</strong> is an extended<br />
fuzzy logic based optimizing module which<br />
leads to more human way <str<strong>on</strong>g>of</str<strong>on</strong>g> decisi<strong>on</strong> by recalculating<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> different parameters <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> linear<br />
programming model. With <str<strong>on</strong>g>the</str<strong>on</strong>g> Qualicisi<strong>on</strong><br />
module shows how this level as a qualitative<br />
decisi<strong>on</strong> level will be integrated into <str<strong>on</strong>g>the</str<strong>on</strong>g> system<br />
structure:<br />
About PSI Metals<br />
PSI is <str<strong>on</strong>g>the</str<strong>on</strong>g> leading IT supplier for producti<strong>on</strong><br />
management soluti<strong>on</strong>s in <str<strong>on</strong>g>the</str<strong>on</strong>g> metals industry<br />
combining supply chain management,<br />
advanced planning and scheduling, producti<strong>on</strong><br />
executi<strong>on</strong> and logistics optimizati<strong>on</strong>.<br />
For more than 40 years, we have been delivering<br />
added-value soluti<strong>on</strong>s to maximize <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
plant performances <str<strong>on</strong>g>of</str<strong>on</strong>g> numerous metals producers<br />
around <str<strong>on</strong>g>the</str<strong>on</strong>g> globe. PSImetals s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware<br />
soluti<strong>on</strong>s enable producers <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>,<br />
steel and copper products to ensure <str<strong>on</strong>g>the</str<strong>on</strong>g>ir competitive<br />
edge by delivering products as agreed<br />
in quantity, quality and time whilst c<strong>on</strong>sidering<br />
inventory, productivity and performance<br />
targets.<br />
The PSImetals soluti<strong>on</strong> line is an end-toend<br />
approach for <str<strong>on</strong>g>the</str<strong>on</strong>g> overall supply chain caring<br />
for all <str<strong>on</strong>g>the</str<strong>on</strong>g> needs <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> metals industry.<br />
From your supplier to your customer, PSImetals<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g>fers powerful and tailor-made products<br />
to support all processes from planning to<br />
executi<strong>on</strong> within your supply chain always<br />
c<strong>on</strong>sidering <str<strong>on</strong>g>the</str<strong>on</strong>g> complexity <str<strong>on</strong>g>of</str<strong>on</strong>g> metals producti<strong>on</strong>:<br />
• Planning level to support all planning processes<br />
from Business Planning via Producti<strong>on</strong><br />
Planning to Detailed Scheduling<br />
• Executi<strong>on</strong> level to m<strong>on</strong>itor and c<strong>on</strong>trol producti<strong>on</strong><br />
activities as well as to assure quality<br />
• Level <str<strong>on</strong>g>of</str<strong>on</strong>g> material- and transport logistic to<br />
optimise all transports requested to keep producti<strong>on</strong><br />
running<br />
• Energy management level<br />
• Cross-applicati<strong>on</strong> KPI and producti<strong>on</strong><br />
m<strong>on</strong>itoring functi<strong>on</strong>s.<br />
All informati<strong>on</strong> is based <strong>on</strong> an integrated<br />
factory model for c<strong>on</strong>sistent real time plant<br />
status informati<strong>on</strong>.<br />
�<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 27
MEASURING & CONTROL<br />
M<strong>on</strong>itoring <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> extrusi<strong>on</strong> dies<br />
cleaning process by an optic sensor<br />
A. Pascual Formoso 1 ; E. Piñeiro Ben 1 ; L. Herrero Castilla 1 ; C. Domínguez 2 , A. Llobera 2<br />
1 2 Aimen Technology Center, P<strong>on</strong>tevedra, Centro Naci<strong>on</strong>al de Microelectrónica (IMB-CNM, CSIC),<br />
Barcel<strong>on</strong>a, Universidad Autónoma de Barcel<strong>on</strong>a, Bellaterra (Barcel<strong>on</strong>a)<br />
The aim <str<strong>on</strong>g>of</str<strong>on</strong>g> this work has been <str<strong>on</strong>g>the</str<strong>on</strong>g> assessment<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> a multiple internal<br />
reflecti<strong>on</strong> sensor in order to m<strong>on</strong>itor <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
advance <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> extrusi<strong>on</strong> dies<br />
cleaning process. The main goal <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
sensor is that it is able to measure different<br />
initial c<strong>on</strong>centrati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> NaOH and it<br />
shows <str<strong>on</strong>g>the</str<strong>on</strong>g> point in which <str<strong>on</strong>g>the</str<strong>on</strong>g> aluminate<br />
starts to precipitate allowing to distinguish<br />
states <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> bath <strong>on</strong> c<strong>on</strong>centrati<strong>on</strong><br />
ratios <str<strong>on</strong>g>of</str<strong>on</strong>g> [Al] / [NaOH] = 0.1.<br />
The <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> extrusi<strong>on</strong> industry has a significant<br />
ec<strong>on</strong>omic importance all over Europe.<br />
The process is carried out using extrusi<strong>on</strong> dies,<br />
steel disks with an opening cut through <str<strong>on</strong>g>the</str<strong>on</strong>g>m,<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> size and shape <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> intended crosssecti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> final extruded product. An <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
billet pre-heated (500ºC) is forced<br />
to flow through <str<strong>on</strong>g>the</str<strong>on</strong>g> die in order to get <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
required pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile. At <str<strong>on</strong>g>the</str<strong>on</strong>g> end <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> cycle, it is<br />
necessary to remove all <str<strong>on</strong>g>the</str<strong>on</strong>g> remaining metal<br />
inside <str<strong>on</strong>g>the</str<strong>on</strong>g> cavities <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> die to reuse it in new<br />
pieces producti<strong>on</strong>. In fact, <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> dies<br />
are resp<strong>on</strong>sible for quality and process performance<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g>ir cost is between 35-50% <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> cost <str<strong>on</strong>g>of</str<strong>on</strong>g> manufacture (Guía Tecnológica).<br />
The ordinary cleaning method c<strong>on</strong>sists <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
loading <str<strong>on</strong>g>the</str<strong>on</strong>g> dies into open tanks, c<strong>on</strong>taining a<br />
soluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> NaOH (caustic soda) at high c<strong>on</strong>centrati<strong>on</strong><br />
and temperature near <str<strong>on</strong>g>the</str<strong>on</strong>g> boiling<br />
point. The cleaning process may even exceed<br />
10 hours, depending <strong>on</strong> die size and <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
quantity adhered to its surface. Generally,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> baths are changed after each use without<br />
making a preliminary analysis to determine<br />
if <str<strong>on</strong>g>the</str<strong>on</strong>g> bath still retains its cleaning properties.<br />
Daily bath emptying (which can exceed 3,000<br />
litre per day) causes a high cost due to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
new formulati<strong>on</strong> reagents (water and sodium<br />
hydr<str<strong>on</strong>g>oxide</str<strong>on</strong>g>) and energy. In additi<strong>on</strong>, it generates<br />
a large amount <str<strong>on</strong>g>of</str<strong>on</strong>g> hazardous waste (with<br />
high basicity and high c<strong>on</strong>tent <str<strong>on</strong>g>of</str<strong>on</strong>g> dissolved<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g>) (Guía Tecnológica).<br />
Several studies (Li et al, 2005a) have shown<br />
that <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> in a caustic soluti<strong>on</strong> at a temperature<br />
approaching to boiling point leads<br />
to sodium aluminate (NaAlO 2), resulting in<br />
hydrogen gas (H 2 (g)). Sodium aluminate so-<br />
luti<strong>on</strong>s begin to run out, since a mesoscopic<br />
point <str<strong>on</strong>g>of</str<strong>on</strong>g> view, due to presence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
hydr<str<strong>on</strong>g>oxide</str<strong>on</strong>g>s like gibbsite and bayerite (Harris<br />
et al, 1999). Optical scattering techniques, like<br />
Dynamic Light Scattering (DLS), have been<br />
proven its feasibility to characterize <str<strong>on</strong>g>the</str<strong>on</strong>g> nucleati<strong>on</strong><br />
and growth <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se species.<br />
The growing interest <str<strong>on</strong>g>of</str<strong>on</strong>g> industry for c<strong>on</strong>trol<br />
and m<strong>on</strong>itoring <str<strong>on</strong>g>of</str<strong>on</strong>g> producti<strong>on</strong> process<br />
motivates research in <str<strong>on</strong>g>the</str<strong>on</strong>g> development <str<strong>on</strong>g>of</str<strong>on</strong>g> new<br />
optical devices that allow <str<strong>on</strong>g>the</str<strong>on</strong>g>ir integrati<strong>on</strong> into<br />
producti<strong>on</strong> lines (Harris et al, 1999). These<br />
systems provide real-time informati<strong>on</strong> about<br />
a process. One <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se labs <strong>on</strong> a chip device<br />
are <str<strong>on</strong>g>the</str<strong>on</strong>g> multiple internal reflecti<strong>on</strong> (MIR) systems.<br />
(Llobera et al, 2007).<br />
The aim <str<strong>on</strong>g>of</str<strong>on</strong>g> this work has been <str<strong>on</strong>g>the</str<strong>on</strong>g> assessment<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> a low cost MIR sensor<br />
fabricated in PDMS in order to m<strong>on</strong>itor<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> advance <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> extrusi<strong>on</strong> dies<br />
cleaning process.<br />
Method<br />
Soluti<strong>on</strong> preparati<strong>on</strong>: Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> impossibility<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> working with real extrusi<strong>on</strong> dies at laboratory<br />
scale, small pieces <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> have<br />
been used for <str<strong>on</strong>g>the</str<strong>on</strong>g> simulati<strong>on</strong>s. Cleaning baths<br />
are prepared using NaOH soluti<strong>on</strong> in a benchscale.<br />
This bath is heated to <str<strong>on</strong>g>the</str<strong>on</strong>g> temperature<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> work and <str<strong>on</strong>g>the</str<strong>on</strong>g> fragment <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> is put<br />
into <str<strong>on</strong>g>the</str<strong>on</strong>g> bath. Once treatment time is completed,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> attacked <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> piece is removed.<br />
When <str<strong>on</strong>g>the</str<strong>on</strong>g> bath is cool<br />
a dark gelatinous compounds<br />
start to precipitate<br />
(<str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
hydr<str<strong>on</strong>g>oxide</str<strong>on</strong>g> and aluminates).<br />
The <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
c<strong>on</strong>centrati<strong>on</strong> in soluti<strong>on</strong><br />
and free sodium<br />
hydr<str<strong>on</strong>g>oxide</str<strong>on</strong>g> c<strong>on</strong>centrati<strong>on</strong><br />
are determined in<br />
each test <str<strong>on</strong>g>of</str<strong>on</strong>g> experimental<br />
set-up. The ratio <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
free sodium hydr<str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
and <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> in so-<br />
luti<strong>on</strong> gives an idea <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
bath exhausti<strong>on</strong>.<br />
Optical characterizati<strong>on</strong>: This work has been<br />
carried out to characterize <str<strong>on</strong>g>the</str<strong>on</strong>g> optical properties<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> samples such as refractive index, transmittance<br />
spectral resp<strong>on</strong>se and scattering.<br />
The size distributi<strong>on</strong> has been analyzed by<br />
dynamic light scattering, from samples prepared<br />
according to <str<strong>on</strong>g>the</str<strong>on</strong>g> procedure menti<strong>on</strong>ed<br />
previously (to 95ºC from a soluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> initial<br />
NaOH c<strong>on</strong>centrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> 19%). The size <str<strong>on</strong>g>of</str<strong>on</strong>g> particles<br />
suspended in <str<strong>on</strong>g>the</str<strong>on</strong>g> bath has been determined<br />
using a Spectrometer Autosizer 4800<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> Malvern Instruments (PCS technique). The<br />
refractive index has been measured at different<br />
times (with a refractometer ABBEMAT-<br />
HP) for so what‘s <str<strong>on</strong>g>the</str<strong>on</strong>g> bath depleti<strong>on</strong> point.<br />
Reference measurement system: Experiments<br />
with laboratory samples have been<br />
c<strong>on</strong>ducted to evaluate <str<strong>on</strong>g>the</str<strong>on</strong>g> behaviour <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
samples measured by <str<strong>on</strong>g>the</str<strong>on</strong>g> sensor and verify<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> feasibility <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> proposed detecti<strong>on</strong><br />
methods, as well as <str<strong>on</strong>g>the</str<strong>on</strong>g> needs and tolerances<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> coupling and sealing systems. For <str<strong>on</strong>g>the</str<strong>on</strong>g>se<br />
tests, a setup similar to <str<strong>on</strong>g>the</str<strong>on</strong>g> proposed sensor<br />
has been used, but discrete optical elements<br />
were used instead <str<strong>on</strong>g>of</str<strong>on</strong>g> waveguides, as a reference<br />
measurement system. This assembly allows<br />
to develop transmissi<strong>on</strong> and dispersi<strong>on</strong><br />
measurements at 90° simultaneously. The light<br />
is injected through a multimode optical fibre<br />
and collected with plastic optical fibres <str<strong>on</strong>g>of</str<strong>on</strong>g> 1<br />
mm in diameter.<br />
In order to improve <str<strong>on</strong>g>the</str<strong>on</strong>g> signal to noise ratio<br />
and eliminate <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tributi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> light which is<br />
Fig. 1: Attenuati<strong>on</strong> and dispersi<strong>on</strong> at 90° for soluti<strong>on</strong>s caustic soda with different<br />
c<strong>on</strong>centrati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> Images: Aimen<br />
28 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
necessary in <str<strong>on</strong>g>the</str<strong>on</strong>g> specific case <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> measurement<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> dispersi<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g> laser is modulated to<br />
low frequencies (721 Hz) and <str<strong>on</strong>g>the</str<strong>on</strong>g> resp<strong>on</strong>se <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
both detectors is processed via a synchr<strong>on</strong>ic<br />
detecti<strong>on</strong> algorithm or lock-in.<br />
To perform <str<strong>on</strong>g>the</str<strong>on</strong>g>se tests, aliquots <str<strong>on</strong>g>of</str<strong>on</strong>g> soda/<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> soluti<strong>on</strong> are sampled at different<br />
reacti<strong>on</strong> times. The measurements made<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> reference system allow observing <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
dependence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> transmissi<strong>on</strong> and optical<br />
dispersi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> sample with reacti<strong>on</strong> time.<br />
Fig. 1 show <str<strong>on</strong>g>the</str<strong>on</strong>g> measurements obtained in dB<br />
relative to <str<strong>on</strong>g>the</str<strong>on</strong>g> power transmitted to <str<strong>on</strong>g>the</str<strong>on</strong>g> sample<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> NaOH (blank) and correlati<strong>on</strong> coefficients<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a linear fit.<br />
MIR based sensor: From a fluidic point <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
view, <str<strong>on</strong>g>the</str<strong>on</strong>g> proposed system c<strong>on</strong>sist <str<strong>on</strong>g>of</str<strong>on</strong>g> a MIR<br />
structure directly c<strong>on</strong>nected to fluidic input/<br />
output reservoirs. The sensor operati<strong>on</strong> is<br />
based <strong>on</strong> circulating fluid through <str<strong>on</strong>g>the</str<strong>on</strong>g> guide<br />
MIR. The light is injected through optical fibres<br />
and light is collected after travelling part<br />
way through <str<strong>on</strong>g>the</str<strong>on</strong>g> fluid (Fig. 2) (Llobera et al,<br />
2007). The measured magnitude is <str<strong>on</strong>g>the</str<strong>on</strong>g> loss<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> irradiance associated with <str<strong>on</strong>g>the</str<strong>on</strong>g> presence <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
particles relevant process in questi<strong>on</strong>, which<br />
in this particular case are compounds <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
(<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> particles and <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
hydr<str<strong>on</strong>g>oxide</str<strong>on</strong>g>).<br />
In order to study <str<strong>on</strong>g>the</str<strong>on</strong>g> process that takes<br />
place in <str<strong>on</strong>g>the</str<strong>on</strong>g> cleaning bath, <str<strong>on</strong>g>the</str<strong>on</strong>g> alkaline soluti<strong>on</strong><br />
should be circulated through <str<strong>on</strong>g>the</str<strong>on</strong>g> interior<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> guide MIR.<br />
Fig. 2: Experimental setup<br />
Results<br />
The experimental tests performed to validate<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> optical sensor at <str<strong>on</strong>g>the</str<strong>on</strong>g> laboratory, dem<strong>on</strong>strate<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> capacity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> device to determine<br />
optimal initial c<strong>on</strong>diti<strong>on</strong>s and <str<strong>on</strong>g>the</str<strong>on</strong>g> point <str<strong>on</strong>g>of</str<strong>on</strong>g> depleti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> bath, allowing <str<strong>on</strong>g>the</str<strong>on</strong>g> optimizati<strong>on</strong><br />
process.<br />
Resistance testing: Some experiments have<br />
been c<strong>on</strong>ducted in order to test <str<strong>on</strong>g>the</str<strong>on</strong>g> resistance<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> materials <str<strong>on</strong>g>of</str<strong>on</strong>g> MIR guide. The device is immersed<br />
in a bath (19% [NaOH], 95ºC) during<br />
a time <str<strong>on</strong>g>of</str<strong>on</strong>g> 8 hours. Fig. 3, shows <str<strong>on</strong>g>the</str<strong>on</strong>g> resp<strong>on</strong>se<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> MIR guide after <str<strong>on</strong>g>the</str<strong>on</strong>g> resistance test <strong>on</strong> a several<br />
samples. The curve for <str<strong>on</strong>g>the</str<strong>on</strong>g> soda soluti<strong>on</strong> is<br />
similar to <str<strong>on</strong>g>the</str<strong>on</strong>g> curve produced by <str<strong>on</strong>g>the</str<strong>on</strong>g> transmissi<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> water, while <str<strong>on</strong>g>the</str<strong>on</strong>g> signal associated with<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> sample with <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> is an<br />
order <str<strong>on</strong>g>of</str<strong>on</strong>g> magnitude lower than <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
previous <strong>on</strong>e. The presence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
particles lead to losses to<br />
reduce light scattering coupled to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> output fibre. The sensor is not<br />
damaged in its functi<strong>on</strong>al capacity.<br />
The materials used for m<strong>on</strong>itoring<br />
purposes are feasible for at least<br />
<strong>on</strong>e cycle <str<strong>on</strong>g>of</str<strong>on</strong>g> industrial process.<br />
Process m<strong>on</strong>itoring: The aim<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> this study has been <str<strong>on</strong>g>the</str<strong>on</strong>g> assessment<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> an optic sensor<br />
in order to m<strong>on</strong>itor <str<strong>on</strong>g>the</str<strong>on</strong>g> advance<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> extrusi<strong>on</strong> dies<br />
cleaning process, and estimate <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
end point <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> bath. Aliquots <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
caustic soda (NaOH 14%, 95°C) /<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> soluti<strong>on</strong> are sampled<br />
at different reacti<strong>on</strong> times have<br />
been injected into <str<strong>on</strong>g>the</str<strong>on</strong>g> guide MIR.<br />
Fig. 4 illustrates <str<strong>on</strong>g>the</str<strong>on</strong>g> signal decay<br />
with increasing time <str<strong>on</strong>g>of</str<strong>on</strong>g> reacti<strong>on</strong><br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g>refore decreases as <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ratio [NaOH] / [Al]. These variati<strong>on</strong>s<br />
are due to <str<strong>on</strong>g>the</str<strong>on</strong>g> formati<strong>on</strong> and<br />
growth <str<strong>on</strong>g>of</str<strong>on</strong>g> particles in <str<strong>on</strong>g>the</str<strong>on</strong>g> sample.<br />
In Fig. 5 (see next<br />
page) two characteristic<br />
regi<strong>on</strong>s can be distinguished.<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> regi<strong>on</strong><br />
between 10 and 60 min<br />
a rapid decrease <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ratio [NaOH]/[Al] is observed toge<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
with a low sensitivity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
signal <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> device (0.4 ±0.06 dB/<br />
(M/M)). The sec<strong>on</strong>d regi<strong>on</strong> is located<br />
above 60 min. Here <str<strong>on</strong>g>the</str<strong>on</strong>g> change is<br />
less pr<strong>on</strong>ounced but device sensitivity<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> device is higher (3.7 ±0.5<br />
dB/(M/M)) for ratios <str<strong>on</strong>g>of</str<strong>on</strong>g> [NaOH]/<br />
[Al] inferior to 3. Starting from this<br />
point <str<strong>on</strong>g>the</str<strong>on</strong>g> values c<strong>on</strong>verge to bath<br />
saturati<strong>on</strong> <strong>on</strong>es. In <str<strong>on</strong>g>the</str<strong>on</strong>g> first regi<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>centrati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> dissolved <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> increases<br />
but <str<strong>on</strong>g>the</str<strong>on</strong>g> particle size is below <str<strong>on</strong>g>the</str<strong>on</strong>g> wavelength<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> emitted light so that no signal <str<strong>on</strong>g>of</str<strong>on</strong>g> scattering<br />
is recorded. This explains <str<strong>on</strong>g>the</str<strong>on</strong>g> low intensity<br />
measured by <str<strong>on</strong>g>the</str<strong>on</strong>g> device. However, in <str<strong>on</strong>g>the</str<strong>on</strong>g> sec<strong>on</strong>d<br />
regi<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> particle size is superior to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
selected wavelength and <str<strong>on</strong>g>the</str<strong>on</strong>g> sensitivity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
device increases. These results are in accordance<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> observati<strong>on</strong>s made by Harris et<br />
MEASURING & CONTROL<br />
al, 1999, regarding <str<strong>on</strong>g>the</str<strong>on</strong>g> measurement <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
inducti<strong>on</strong> period, from where a linear growth<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> particles present in <str<strong>on</strong>g>the</str<strong>on</strong>g> saturated soluti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> Al in NaOH at high temperature is<br />
observed.<br />
The maximum sensitivity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> sensor for<br />
process m<strong>on</strong>itoring is achieved with a wave-<br />
Fig. 3: Device resp<strong>on</strong>se for a sample <str<strong>on</strong>g>of</str<strong>on</strong>g> distilled water, [NaOH]<br />
5.94 M and [NaOH]/[Al] 0.78<br />
Fig. 4: Spectral resp<strong>on</strong>se <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> measurand for each time <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
bath<br />
length <str<strong>on</strong>g>of</str<strong>on</strong>g> 577 nm with a linear slope <str<strong>on</strong>g>of</str<strong>on</strong>g> 0.041<br />
±0.004 dB / min. This allows to distinguish<br />
states <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> bath <strong>on</strong> c<strong>on</strong>centrati<strong>on</strong> ratios <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
[Al] / [NaOH] = 0.1.<br />
Initial c<strong>on</strong>diti<strong>on</strong>s: Laboratory scale assays to<br />
measure <str<strong>on</strong>g>the</str<strong>on</strong>g> transducer resp<strong>on</strong>se for different<br />
initial c<strong>on</strong>diti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> baths show that <str<strong>on</strong>g>the</str<strong>on</strong>g> device<br />
has <str<strong>on</strong>g>the</str<strong>on</strong>g> capacity to distinguish different<br />
initial c<strong>on</strong>centrati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> caustic soda. Different<br />
samples <str<strong>on</strong>g>of</str<strong>on</strong>g> NaOH soluti<strong>on</strong> (10%, 14% and<br />
19% c<strong>on</strong>centrati<strong>on</strong>) have been injected into<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> device. C<strong>on</strong>sidering <str<strong>on</strong>g>the</str<strong>on</strong>g> dissoluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
10% as blank, an increasing to 19% NaOH<br />
c<strong>on</strong>centrati<strong>on</strong> represents an increase in <str<strong>on</strong>g>the</str<strong>on</strong>g> signal<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 1.04 dB (Fig. 6). These increases in signal<br />
are due to changes in <str<strong>on</strong>g>the</str<strong>on</strong>g> refractive index <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> different soluti<strong>on</strong>s: 1.360 (NaOH 10%)<br />
1.367 (NaOH 14%) 1.379 (19% NaOH).<br />
The sensitivity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> device to scattering<br />
losses and refractive index changes enable to<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 29
MEASURING & CONTROL<br />
Fig. 5: Evoluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> intensity losses and ratio [NaOH]/[Al] in functi<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> time at laboratory c<strong>on</strong>diti<strong>on</strong>s<br />
determine as <str<strong>on</strong>g>the</str<strong>on</strong>g> optimal initial c<strong>on</strong>diti<strong>on</strong>s as<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> exhausti<strong>on</strong> point <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> reacti<strong>on</strong>.<br />
C<strong>on</strong>clusi<strong>on</strong>s<br />
This work aims <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>trol and analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
industrial process <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> extrusi<strong>on</strong> die<br />
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<str<strong>on</strong>g>aluminium</str<strong>on</strong>g>ePaper.com<br />
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cleaning using optical sensors. An integrated<br />
optical technology, with capacity for m<strong>on</strong>itoring<br />
industrial processes in c<strong>on</strong>diti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> very<br />
extreme temperature and pH has been developed.<br />
The results show that <str<strong>on</strong>g>the</str<strong>on</strong>g> prototype exceeds<br />
all critical requirements.<br />
The data obtained after <str<strong>on</strong>g>the</str<strong>on</strong>g> validati<strong>on</strong><br />
dem<strong>on</strong>strate <str<strong>on</strong>g>the</str<strong>on</strong>g> applicability<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> optical<br />
sensors for m<strong>on</strong>itoring<br />
bath dedicated<br />
to <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> dissoluti<strong>on</strong>.<br />
Absorpti<strong>on</strong><br />
and scattering losses,<br />
related to <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
particles present in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> cleaning soluti<strong>on</strong>s,<br />
have been correlated<br />
with initial<br />
caustic soluti<strong>on</strong> c<strong>on</strong>diti<strong>on</strong>s.<br />
Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>rmore,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> degradati<strong>on</strong> study<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> sensor reflects<br />
after use for an industrial<br />
bath, <str<strong>on</strong>g>the</str<strong>on</strong>g> device<br />
does not suffer<br />
damage affecting <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
proper operati<strong>on</strong>.<br />
The results <str<strong>on</strong>g>of</str<strong>on</strong>g> this<br />
research indicate that<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> applicati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
this optic sensor as a<br />
m<strong>on</strong>itoring technique<br />
in <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> caustic<br />
soluti<strong>on</strong>s is feasible.<br />
The industrial applicati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> this sensor<br />
would help <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
companies to<br />
select <str<strong>on</strong>g>the</str<strong>on</strong>g> most suitable<br />
cleaning opera-<br />
Fig. 6: Spectral resp<strong>on</strong>se <str<strong>on</strong>g>of</str<strong>on</strong>g> different soluti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> NaOH<br />
according to its requirements. By stating <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
amount <str<strong>on</strong>g>of</str<strong>on</strong>g> dissolved <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>, <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
industry could work under different c<strong>on</strong>diti<strong>on</strong>s<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> sodium hydr<str<strong>on</strong>g>oxide</str<strong>on</strong>g> c<strong>on</strong>cen trati<strong>on</strong>, temperature<br />
and time. This would mean a decrease<br />
in c<strong>on</strong>sumpti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> raw materials (caustic soda<br />
and water), energy and a reducti<strong>on</strong> in effluents<br />
and waste management. M<strong>on</strong>itoring is a useful<br />
investment with wide practical benefits.<br />
Acknowledgements<br />
This work was supported by project <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Ministerio de Industria, Turismo y Comercio.<br />
Secretaría de Estado de Telecomunicaci<strong>on</strong>es y<br />
para la Sociedad de la Información Dirección<br />
General para el Desarrollo de la Sociedad de<br />
la Información, TSI-020301-2008-11. The assistance<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> Iñigo Salinas and David Izquierdo<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> University <str<strong>on</strong>g>of</str<strong>on</strong>g> Zaragoza for design and<br />
measurement implementati<strong>on</strong> with reference<br />
system is gratefully acknowledged.<br />
Bibliography<br />
Guía Tecnológica. Directiva 96/61 relativa a la prevención<br />
y c<strong>on</strong>trol integrados a la prevención y c<strong>on</strong>trol<br />
integrados de la c<strong>on</strong>taminación. Epígrafe 2.5.<br />
Metalurgia de aluminio.<br />
Harris D.R., Keir R.I., Prestidge C.A., Thomas J.C.,<br />
1999. A dynamic light scattering investigati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
nucleati<strong>on</strong> and growth in supersaturated alkaline<br />
sodium aluminate soluti<strong>on</strong>s (syn<str<strong>on</strong>g>the</str<strong>on</strong>g>tic Bayer liquors),<br />
Colloids and Surfaces A, p. 154 343-352.<br />
Li H.; Addai-Mensah J.; Thomasb J. C.; Gers<strong>on</strong>a A.<br />
R. 2005a. The influence <str<strong>on</strong>g>of</str<strong>on</strong>g> Al(III) supersaturati<strong>on</strong><br />
and NaOH c<strong>on</strong>centrati<strong>on</strong> <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> rate <str<strong>on</strong>g>of</str<strong>on</strong>g> crystallizati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> Al(OH)3 precursor particles from sodium<br />
aluminate soluti<strong>on</strong>s. Journal <str<strong>on</strong>g>of</str<strong>on</strong>g> Colloid and Interface<br />
Science 286, p. 511-519.<br />
Llobera A. Demming S.; Wilkea R. and Bu¨ttgenbacha<br />
S.; 2007. Multiple internal reflecti<strong>on</strong> poly (dimethylsiloxane)<br />
systems for optical sensing. Advance Article<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> www.rsc.org/loc | Lab <strong>on</strong> a Chip.<br />
ti<strong>on</strong> c<strong>on</strong>diti<strong>on</strong>s and �<br />
30 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
<str<strong>on</strong>g>Influence</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> raw material c<strong>on</strong>stituti<strong>on</strong> <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> quality <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
gloss alloy-type extrusi<strong>on</strong> billets – a report from practice<br />
Klaus H<str<strong>on</strong>g>of</str<strong>on</strong>g>fmann, Ralf Munk, Marcel Rosefort and Dietmar Bramh<str<strong>on</strong>g>of</str<strong>on</strong>g>f, Trimet Aluminium AG<br />
The Trimet group provides <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
processing industry with primary metal,<br />
alloys, semi-finished products, castings<br />
and recycling. The competences <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
business unit Primary Products are electrolysis<br />
and c<strong>on</strong>tinuous casting. Products<br />
are rolling slabs, extrusi<strong>on</strong> and forging<br />
billets, hot dip-coating alloys, initial products<br />
for safety parts and liquid <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>.<br />
Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> demand for high quality<br />
and services regarding <str<strong>on</strong>g>the</str<strong>on</strong>g>se products in<br />
particular <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> automotive industry it<br />
is essential to enforce and secure quality<br />
c<strong>on</strong>trol. All <str<strong>on</strong>g>the</str<strong>on</strong>g>se high quality products<br />
from Trimet, especially <str<strong>on</strong>g>the</str<strong>on</strong>g> safety parts,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> gloss alloys and parts with functi<strong>on</strong>al<br />
surfaces for automotive applicati<strong>on</strong>s, are<br />
characterized by an extremely homogenous<br />
microstructure without<br />
internal defects or inclusi<strong>on</strong>s.<br />
Within our permanent quality<br />
improvement programme an examinati<strong>on</strong><br />
has been carried out to<br />
measure <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> raw material<br />
c<strong>on</strong>stituti<strong>on</strong> <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> product<br />
quality. Therefore <str<strong>on</strong>g>the</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> liquid<br />
metal, ingot metal and mixtures <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>se has been tested. The paper<br />
covers <str<strong>on</strong>g>the</str<strong>on</strong>g> essential producti<strong>on</strong><br />
steps for such challenging high<br />
quality billets. It gives a report<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> quality requirements, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
qualifying <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> alloying material and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
process parameters. Especially <str<strong>on</strong>g>the</str<strong>on</strong>g> methods<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> analysis, like PoDFa and inclusi<strong>on</strong><br />
identificati<strong>on</strong>, and <str<strong>on</strong>g>the</str<strong>on</strong>g> correlati<strong>on</strong>s between<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> process parameters, <str<strong>on</strong>g>the</str<strong>on</strong>g> feedstock<br />
and metal quality are described.<br />
The market for extrusi<strong>on</strong> billets for bright surface<br />
products in Europe is bigger than 15,000<br />
t<strong>on</strong>nes a year. The highest demand for this<br />
special material comes from <str<strong>on</strong>g>the</str<strong>on</strong>g> automotive<br />
industry. There it is used for trim parts, ro<str<strong>on</strong>g>of</str<strong>on</strong>g><br />
racks and cover plates. But <str<strong>on</strong>g>the</str<strong>on</strong>g>re is also a<br />
market for this material in <str<strong>on</strong>g>the</str<strong>on</strong>g> lighting and audio<br />
industry. One can say that <str<strong>on</strong>g>the</str<strong>on</strong>g> time <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
black coated trims is over – for <str<strong>on</strong>g>the</str<strong>on</strong>g> moment.<br />
To fulfil <str<strong>on</strong>g>the</str<strong>on</strong>g> very challenging specificati<strong>on</strong>s<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> final parts, <str<strong>on</strong>g>the</str<strong>on</strong>g> whole process from <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
alumina for <str<strong>on</strong>g>the</str<strong>on</strong>g> electrolyses up to <str<strong>on</strong>g>the</str<strong>on</strong>g> anodising<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> final part has to be fully tuned and<br />
straight designed. All changes in this process<br />
chain have to be scrutinised, and all changes<br />
have to be discussed and well co-ordinated<br />
between <str<strong>on</strong>g>the</str<strong>on</strong>g> partners <str<strong>on</strong>g>of</str<strong>on</strong>g> this sensitive process<br />
chain.<br />
So, why change such a sensitive process?<br />
If we want to improve <str<strong>on</strong>g>the</str<strong>on</strong>g> quality <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> end<br />
product, we will have to change <str<strong>on</strong>g>the</str<strong>on</strong>g> process<br />
from time to time, or <str<strong>on</strong>g>the</str<strong>on</strong>g>re are technical needs<br />
to change a step in <str<strong>on</strong>g>the</str<strong>on</strong>g> process. This paper discusses<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> solid/liquid metal<br />
ratio.<br />
The trimal BQ process<br />
Trimet developed a special process named BQ<br />
(Brilliant Quality) to fulfil all <str<strong>on</strong>g>the</str<strong>on</strong>g>se requirements<br />
for a brilliant end product.<br />
The trimal BQ process is a special process<br />
for producing extrusi<strong>on</strong> billets, to fulfil high<br />
requirements and to cover all <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong><br />
steps and parameters that are adjusted for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
end product: <str<strong>on</strong>g>the</str<strong>on</strong>g> alumina, melting, casting, homogenizing,<br />
testing.<br />
This process includes all parts <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> pro-<br />
Producti<strong>on</strong> flow in <str<strong>on</strong>g>the</str<strong>on</strong>g> casthouse<br />
Images: Trimet<br />
EXTRUSION<br />
ducti<strong>on</strong> chain starting with <str<strong>on</strong>g>the</str<strong>on</strong>g> alumina and<br />
anodes for <str<strong>on</strong>g>the</str<strong>on</strong>g> electrolysis at <str<strong>on</strong>g>the</str<strong>on</strong>g> Essen or<br />
Hamburg smelter to produce <str<strong>on</strong>g>the</str<strong>on</strong>g> liquid and<br />
solid raw material. Followed by alloying, metal<br />
treatment, grain refining and casting, finished<br />
up with <str<strong>on</strong>g>the</str<strong>on</strong>g> customised homogenizing process<br />
unique for <str<strong>on</strong>g>the</str<strong>on</strong>g>se billets.<br />
The electrolysis process<br />
At <str<strong>on</strong>g>the</str<strong>on</strong>g> electrolysis <str<strong>on</strong>g>the</str<strong>on</strong>g>re are several pots operated<br />
as high purity pots. For <str<strong>on</strong>g>the</str<strong>on</strong>g>se pots <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
alumina is not used in <str<strong>on</strong>g>the</str<strong>on</strong>g> waste gas purificati<strong>on</strong><br />
process to avoid <str<strong>on</strong>g>the</str<strong>on</strong>g> enrichment <str<strong>on</strong>g>of</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
elements. The anodes are hand selected according<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g>ir metal c<strong>on</strong>tent and <str<strong>on</strong>g>the</str<strong>on</strong>g>ir operating<br />
life in <str<strong>on</strong>g>the</str<strong>on</strong>g> cells is shorter than in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
standard pots.<br />
The c<strong>on</strong>trol <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> pots is d<strong>on</strong>e by<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Trimet 9-box matrix model [1]. This<br />
is increasing current efficiency and reducing<br />
energy c<strong>on</strong>sumpti<strong>on</strong>. After <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
transport, crucible with <str<strong>on</strong>g>the</str<strong>on</strong>g> pot room<br />
metal is arriving at <str<strong>on</strong>g>the</str<strong>on</strong>g> casthouse <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
dross is accurately removed from <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
metal surface. Now <str<strong>on</strong>g>the</str<strong>on</strong>g> metal is transferred<br />
to <strong>on</strong>e <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> melting furnaces or<br />
casted into sow forms.<br />
Melting and casting<br />
The process in <str<strong>on</strong>g>the</str<strong>on</strong>g> casthouse (see flow<br />
chart) starts with <str<strong>on</strong>g>the</str<strong>on</strong>g> loading <str<strong>on</strong>g>of</str<strong>on</strong>g> solid metal into<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> gas fired melting furnace. When <str<strong>on</strong>g>the</str<strong>on</strong>g> solid<br />
metal is heated up to <str<strong>on</strong>g>the</str<strong>on</strong>g> required temperature<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> hot pot room metal (approx. 930°C)<br />
is added to <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace. In this step we use <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
energy which is stored in <str<strong>on</strong>g>the</str<strong>on</strong>g> pot room metal<br />
to bring <str<strong>on</strong>g>the</str<strong>on</strong>g> sows into <str<strong>on</strong>g>the</str<strong>on</strong>g> liquid state. The liq-<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 31
EXTRUSION<br />
Grain refiner rod (AlTixBx )<br />
• Chemical analysis<br />
• Efficiency<br />
• Metallography<br />
Oxide, <str<strong>on</strong>g>oxide</str<strong>on</strong>g> lines<br />
TiB2 agglomerate<br />
Al3Ti - phases<br />
Grain refiner input [2]<br />
uid metal will <str<strong>on</strong>g>the</str<strong>on</strong>g>n be mixed thoroughly.<br />
For <str<strong>on</strong>g>the</str<strong>on</strong>g> quality <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> end product <str<strong>on</strong>g>the</str<strong>on</strong>g> quality<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> metal input is essentially important. If<br />
low quality base material is used, <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a clean melt will be impossible. At Trimet<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> hot metal is analysed and melt-dross<br />
is skimmed <str<strong>on</strong>g>of</str<strong>on</strong>g>f; when cold metal is used, <strong>on</strong>ly<br />
ingots from in-house producti<strong>on</strong> are added to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> pot room metal.<br />
After skimming <str<strong>on</strong>g>the</str<strong>on</strong>g> surface <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> bath,<br />
a sample will be taken and <str<strong>on</strong>g>the</str<strong>on</strong>g> required elements<br />
will be brought into <str<strong>on</strong>g>the</str<strong>on</strong>g> batch. This<br />
additi<strong>on</strong> will be d<strong>on</strong>e in <str<strong>on</strong>g>the</str<strong>on</strong>g> appropriate sequence<br />
and at <str<strong>on</strong>g>the</str<strong>on</strong>g> needed temperature. For <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
alloying we use master alloys from certified<br />
suppliers. The melt will be stirred, skimmed<br />
and a sample will be taken. If <str<strong>on</strong>g>the</str<strong>on</strong>g> analysis is<br />
Filter box for <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tinuous casting [3]<br />
Unacceptable <str<strong>on</strong>g>oxide</str<strong>on</strong>g> lines and TiB 2<br />
agglomerates in a grain refiner rod<br />
within <str<strong>on</strong>g>the</str<strong>on</strong>g> range given by <str<strong>on</strong>g>the</str<strong>on</strong>g> customer and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> temperature at <str<strong>on</strong>g>the</str<strong>on</strong>g> demanded level, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
melt will be transferred into <str<strong>on</strong>g>the</str<strong>on</strong>g> inductive<br />
heated casting furnace. From this point <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>re is no fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r additi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> any alloying<br />
agent. The <strong>on</strong>ly excepti<strong>on</strong> is <str<strong>on</strong>g>the</str<strong>on</strong>g> grain refiner<br />
rod, which is added process-related during <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
casting. All delivered batches <str<strong>on</strong>g>of</str<strong>on</strong>g> grain refiner<br />
are tested for chemical analysis, <str<strong>on</strong>g>oxide</str<strong>on</strong>g> lines,<br />
TiB 2 agglomerates and Al 3Ti particle size.<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> following it is very important to prevent<br />
any turbulence to avoid <str<strong>on</strong>g>the</str<strong>on</strong>g> forming <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
dross in <str<strong>on</strong>g>the</str<strong>on</strong>g> melt. The melt cleaning process is<br />
divided into three separate steps.<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> casting furnace <str<strong>on</strong>g>the</str<strong>on</strong>g> first step <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
metal cleaning is<br />
d<strong>on</strong>e. The melt is<br />
cleaned by a mixture<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> Ar and Cl,<br />
this is dispersed<br />
by a rotary gas<br />
injector into <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
melt. During this<br />
step sodium, calcium,<br />
hydrogen<br />
and n<strong>on</strong>-metallic<br />
inclusi<strong>on</strong>s are removed.<br />
After <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
sec<strong>on</strong>d step, a suf-<br />
Automated casting using <str<strong>on</strong>g>the</str<strong>on</strong>g> spout and floater technique at <str<strong>on</strong>g>the</str<strong>on</strong>g> Trimet plant in Essen [4]<br />
ficient holding time, <str<strong>on</strong>g>the</str<strong>on</strong>g> casting is started and<br />
during casting <str<strong>on</strong>g>the</str<strong>on</strong>g> third step <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> metal cleaning<br />
is operated in-line by a CFF (see Fig. 3).<br />
Usually we use 40 ppi CCFs for <str<strong>on</strong>g>the</str<strong>on</strong>g> trimal BQ<br />
process. For <str<strong>on</strong>g>the</str<strong>on</strong>g> automated casting we use <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
spout and floater technique, which has some<br />
advantages c<strong>on</strong>cerning <str<strong>on</strong>g>the</str<strong>on</strong>g> inclusi<strong>on</strong> c<strong>on</strong>tent.<br />
With this technique we are able to cast all our<br />
alloys in <str<strong>on</strong>g>the</str<strong>on</strong>g> desired quality.<br />
Quality c<strong>on</strong>trol<br />
First a short overview <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> inspecti<strong>on</strong>s and<br />
tests which have to be d<strong>on</strong>e before, during and<br />
after <str<strong>on</strong>g>the</str<strong>on</strong>g> BQ process to secure <str<strong>on</strong>g>the</str<strong>on</strong>g> expected<br />
brilliant quality.<br />
Melting: analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> hot and cold metal and <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
master alloys.<br />
Metal treatment: analysis, quantities, times,<br />
filter.<br />
Casting: H 2 measurement, analysis at casting<br />
start, casting parameter, analysis at end casting,<br />
PoDFA samples.<br />
First inspecti<strong>on</strong>: ultras<strong>on</strong>ic test, length, shape,<br />
surface defects.<br />
Homogenizati<strong>on</strong>: recipe, temperature, time,<br />
cooling.<br />
Structure: cracks, inclusi<strong>on</strong>s, porosity, coarse<br />
grain, surface defects.<br />
Of particular importance during quality<br />
c<strong>on</strong>trol in <str<strong>on</strong>g>the</str<strong>on</strong>g> cast shop are <str<strong>on</strong>g>the</str<strong>on</strong>g> melt analysis<br />
c<strong>on</strong>cerning H 2 and inclusi<strong>on</strong>s (PoDFA-measurements),<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tinuous c<strong>on</strong>trol <str<strong>on</strong>g>of</str<strong>on</strong>g> all casting<br />
parameters and <str<strong>on</strong>g>the</str<strong>on</strong>g> ultras<strong>on</strong>ic testing after<br />
casting.<br />
These checks are supplemented by metallographic<br />
quality c<strong>on</strong>trol in <str<strong>on</strong>g>the</str<strong>on</strong>g> Trimet laboratory.<br />
This means detailed c<strong>on</strong>trolling <str<strong>on</strong>g>of</str<strong>on</strong>g> possible<br />
cracks, inclusi<strong>on</strong>s, porosity, grain structure,<br />
etc.<br />
Trials about <str<strong>on</strong>g>the</str<strong>on</strong>g> solid / liquid ratio<br />
So why should we change a stable and successful<br />
process? One <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> reas<strong>on</strong>s was <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
crisis that started in 2009. Trimet had to reduce<br />
its output <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> casthouse and to switch<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g>f around two thirds <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> electrolyses capacity.<br />
This implied that <str<strong>on</strong>g>the</str<strong>on</strong>g> number <str<strong>on</strong>g>of</str<strong>on</strong>g> high<br />
purity pots was decreased, too. This resulted<br />
in a lack <str<strong>on</strong>g>of</str<strong>on</strong>g> high purity metal for a trimal BQ<br />
campaign.<br />
The trials were supposed to answer <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
questi<strong>on</strong> whe<str<strong>on</strong>g>the</str<strong>on</strong>g>r <str<strong>on</strong>g>the</str<strong>on</strong>g>re is a difference in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
quality <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> billets when <str<strong>on</strong>g>the</str<strong>on</strong>g>y are produced<br />
from 100% solid metal or 100% liquid metal<br />
or 50/50%.<br />
The melt quality was checked with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
PoDFA method. The Porous Disc Filtrati<strong>on</strong><br />
Apparatus is a method by which liquid metal<br />
32 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Principle <str<strong>on</strong>g>of</str<strong>on</strong>g> taking PoDFA-samples [5]<br />
from <str<strong>on</strong>g>the</str<strong>on</strong>g> melt is pressed by pressed air or<br />
sucked by vacuum through a ceramic filter<br />
disc (see Fig. 5). Inclusi<strong>on</strong>s are c<strong>on</strong>centrated<br />
by filtrati<strong>on</strong> in fr<strong>on</strong>t <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> filter disc. This area<br />
has to be prepared with metallographic techniques<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> microscopic examinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
sample and <str<strong>on</strong>g>the</str<strong>on</strong>g> identificati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> inclusi<strong>on</strong><br />
types. The evaluati<strong>on</strong> has to be d<strong>on</strong>e by an<br />
experienced metallographer who is counting<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> covered area <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> single inclusi<strong>on</strong>s. The<br />
c<strong>on</strong>centrati<strong>on</strong> is given for each type <str<strong>on</strong>g>of</str<strong>on</strong>g> inclusi<strong>on</strong><br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> covered area in mm 2 /kg filtered<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g>. The inclusi<strong>on</strong>s are identified by<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>ir colour and shape with <str<strong>on</strong>g>the</str<strong>on</strong>g> assistance <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> PoDFA-catalogue.<br />
For <str<strong>on</strong>g>the</str<strong>on</strong>g> identificati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> unknown inclu-<br />
Typical inclusi<strong>on</strong>s in <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> melt [5]<br />
si<strong>on</strong>s a scanning electr<strong>on</strong><br />
microscope with<br />
energy dispersive Xray<br />
is helpful.<br />
The advantage <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> PoDFA method<br />
is <str<strong>on</strong>g>the</str<strong>on</strong>g> possibility to<br />
identify <str<strong>on</strong>g>the</str<strong>on</strong>g> nature <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> inclusi<strong>on</strong>s and to<br />
count <str<strong>on</strong>g>the</str<strong>on</strong>g>ir frequency.<br />
A handicap <str<strong>on</strong>g>of</str<strong>on</strong>g> this<br />
technique is that <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
result <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> test is a<br />
snap-shot <str<strong>on</strong>g>of</str<strong>on</strong>g> just <strong>on</strong>e<br />
moment. This is <str<strong>on</strong>g>the</str<strong>on</strong>g> reas<strong>on</strong> why <str<strong>on</strong>g>the</str<strong>on</strong>g> sampling<br />
has to be d<strong>on</strong>e very carefully and well planned<br />
to get repeatable results. It has to be scheduled<br />
where <str<strong>on</strong>g>the</str<strong>on</strong>g> sampling will be d<strong>on</strong>e, when and<br />
how <str<strong>on</strong>g>of</str<strong>on</strong>g>ten it has to be d<strong>on</strong>e.<br />
As metal input for <str<strong>on</strong>g>the</str<strong>on</strong>g>se tests we used liquid<br />
pot room metal and cold pot room metal as <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
solid raw material. For <str<strong>on</strong>g>the</str<strong>on</strong>g> tests we produced<br />
a 6,000 series with approx. 0,5% silic<strong>on</strong> and<br />
magnesium, which is usually used for automotive<br />
applicati<strong>on</strong>s. The PoDFA samples were<br />
taken at <str<strong>on</strong>g>the</str<strong>on</strong>g> beginning and at <str<strong>on</strong>g>the</str<strong>on</strong>g> end <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
castings. One sample was taken in fr<strong>on</strong>t <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
filter and <strong>on</strong>e after <str<strong>on</strong>g>the</str<strong>on</strong>g> filter.<br />
These tests were also used to verify <str<strong>on</strong>g>the</str<strong>on</strong>g> performance<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> ceramic foam filter system.<br />
The results <str<strong>on</strong>g>of</str<strong>on</strong>g> both parameters for six casting<br />
heats are shown in <str<strong>on</strong>g>the</str<strong>on</strong>g> figure. There is no significant<br />
difference in <str<strong>on</strong>g>the</str<strong>on</strong>g> inclusi<strong>on</strong> c<strong>on</strong>centrati<strong>on</strong><br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> product whe<str<strong>on</strong>g>the</str<strong>on</strong>g>r 100% liquid pot<br />
room metal is used as metal input or 100%<br />
solid potroom metal or 50% <str<strong>on</strong>g>of</str<strong>on</strong>g> each is used as<br />
metal input. The comparis<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> PoDFA results<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g> beginning <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> casting and at <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
end <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> casting shows that <str<strong>on</strong>g>the</str<strong>on</strong>g> filter system<br />
is capable to reduce all kind <str<strong>on</strong>g>of</str<strong>on</strong>g> inclusi<strong>on</strong>s.<br />
The comparis<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> PoDFA results<br />
shows that <str<strong>on</strong>g>the</str<strong>on</strong>g> filter system is working effec-<br />
PoDFA measurements to compare inclusi<strong>on</strong> amount using hot metal and cold metal (50%), before and after <str<strong>on</strong>g>the</str<strong>on</strong>g> ceramic foam filter-system<br />
SESSION EXTRUSION<br />
tively and is reducing <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tent <str<strong>on</strong>g>of</str<strong>on</strong>g> all types<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> inclusi<strong>on</strong>s in <str<strong>on</strong>g>the</str<strong>on</strong>g> melt. The filter system is<br />
working solid during <str<strong>on</strong>g>the</str<strong>on</strong>g> whole casting run.<br />
C<strong>on</strong>clusi<strong>on</strong><br />
The exceedingly sophisticated standard <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
producti<strong>on</strong> process <str<strong>on</strong>g>of</str<strong>on</strong>g> Trimet Aluminium as<br />
well as <str<strong>on</strong>g>the</str<strong>on</strong>g> intensive fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r development <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
a product will also satisfy <str<strong>on</strong>g>the</str<strong>on</strong>g> growing quality<br />
requirements in <str<strong>on</strong>g>the</str<strong>on</strong>g> future. The sum <str<strong>on</strong>g>of</str<strong>on</strong>g> process<br />
steps, quality c<strong>on</strong>trol and quality management<br />
is <str<strong>on</strong>g>the</str<strong>on</strong>g> basis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> high standard <str<strong>on</strong>g>of</str<strong>on</strong>g> Trimet<br />
quality.<br />
In additi<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> metal input is essential for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> product quality. The advantage <str<strong>on</strong>g>of</str<strong>on</strong>g> Trimet<br />
is <str<strong>on</strong>g>the</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> own liquid and solid metal for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong>. Trials have shown that <str<strong>on</strong>g>the</str<strong>on</strong>g>re<br />
is no significant difference between 100%<br />
liquid pot room metal and 100% solid pot<br />
room metal or any mixture as metal input for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> product quality <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> trimal BQ process.<br />
Due to this great variability c<strong>on</strong>cerning <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
metal input, ec<strong>on</strong>omic fluctuati<strong>on</strong>s, such as <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
above menti<strong>on</strong>ed crisis, induce no quality variati<strong>on</strong>s<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> producti<strong>on</strong> at Trimet.<br />
References<br />
[1] Light Metals 2003: Increased Current Efficiency<br />
And Reduced Energy C<strong>on</strong>sumti<strong>on</strong> At The Trimet<br />
Smelter Essen Using 9 Box Matrix C<strong>on</strong>trol, [pp.<br />
449ff] T.Rieck, M. Iffert, P. White, R. Rodrigo and<br />
P. Kelchtermans<br />
[2] Light Metals 2008: Producing Bright Shining<br />
Products For Special Applicati<strong>on</strong>s – Experience<br />
from Practice”, J. Dressler, D. Bramh<str<strong>on</strong>g>of</str<strong>on</strong>g>f, C. Deiters,<br />
H. Koch<br />
[3] Fa. Drache Umwelttechnik<br />
[4] C. Kammer: Aluminium Taschenbuch, Aluminium<br />
Verlag Düsseldorf<br />
[5] ABB: PoDFA – Inclusi<strong>on</strong> Identificati<strong>on</strong> And<br />
Quantificati<strong>on</strong> Analysis. �<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 33
EXTRUSION<br />
Heavy duty extrusi<strong>on</strong> presses for large pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile applicati<strong>on</strong>s<br />
Axel Bauer, SMS Meer GmbH<br />
SMS Meer, a member <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> SMS group,<br />
is currently building several heavy extrusi<strong>on</strong><br />
presses for large pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile applicati<strong>on</strong>s.<br />
Two <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se presses have a nominal<br />
pressing force <str<strong>on</strong>g>of</str<strong>on</strong>g> 150 MN and are c<strong>on</strong>sidered<br />
as <str<strong>on</strong>g>the</str<strong>on</strong>g> largest state-<str<strong>on</strong>g>of</str<strong>on</strong>g>-<str<strong>on</strong>g>the</str<strong>on</strong>g>-art fr<strong>on</strong>tloading<br />
presses in <str<strong>on</strong>g>the</str<strong>on</strong>g> world. Typical applicati<strong>on</strong>s<br />
for those presses for large pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles<br />
are am<strong>on</strong>g o<str<strong>on</strong>g>the</str<strong>on</strong>g>rs railway pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles.<br />
Looking at <str<strong>on</strong>g>the</str<strong>on</strong>g> market for railway pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles, it is<br />
clearly seen that it is a tight market with <strong>on</strong>ly<br />
few global p<str<strong>on</strong>g>layer</str<strong>on</strong>g>s, e. g. C<strong>on</strong>stellium (formerly<br />
Alcan Engineered Products) or Aleris, but also<br />
some growing competitors from Far East like<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Jilin Midas Group.<br />
The global distributi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> railway<br />
applicati<strong>on</strong>s shows regi<strong>on</strong>al differences:<br />
in North America <str<strong>on</strong>g>the</str<strong>on</strong>g> passenger transportati<strong>on</strong><br />
system is more or less limited to commuter<br />
service within <str<strong>on</strong>g>the</str<strong>on</strong>g> great metropolitan areas<br />
<strong>on</strong>ly, while in Europe in general <str<strong>on</strong>g>the</str<strong>on</strong>g> passenger<br />
volume is very high. On <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r hand freight<br />
transportati<strong>on</strong> by rail is very comm<strong>on</strong> in North<br />
America, whereas in Europe we have mainly<br />
freight transportati<strong>on</strong> by road. For China,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> most populous territorial state, passenger<br />
transportati<strong>on</strong> by train is getting more and<br />
more important.<br />
All <str<strong>on</strong>g>the</str<strong>on</strong>g> fast developing countries like China,<br />
Russia, India or Brazil <str<strong>on</strong>g>the</str<strong>on</strong>g>se days do have<br />
infrastructural programmes which include<br />
new railway lines. These projects comprise<br />
high-speed lines for <str<strong>on</strong>g>the</str<strong>on</strong>g> l<strong>on</strong>g distance c<strong>on</strong>necti<strong>on</strong>s<br />
as well as investments in Intercity<br />
c<strong>on</strong>necti<strong>on</strong>s, commuter trains or metros. China’s<br />
aim is to build 20.000 km <str<strong>on</strong>g>of</str<strong>on</strong>g> high-speed<br />
tracks until 2020 while in Russia an investment<br />
programme <str<strong>on</strong>g>of</str<strong>on</strong>g> 7,5 billi<strong>on</strong> euros for <str<strong>on</strong>g>the</str<strong>on</strong>g> erecti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 11.000 km <str<strong>on</strong>g>of</str<strong>on</strong>g> high-speed rail tracks<br />
has started recently. Also India, which has <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
world’s largest railway network, is looking for<br />
fundamental modernizati<strong>on</strong>.<br />
Even in those projects where normally <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
big p<str<strong>on</strong>g>layer</str<strong>on</strong>g>s like Siemens, Bombardier or Alstom<br />
are in involved, <str<strong>on</strong>g>the</str<strong>on</strong>g>re is always a certain<br />
percentage <str<strong>on</strong>g>of</str<strong>on</strong>g> local c<strong>on</strong>tent in <str<strong>on</strong>g>the</str<strong>on</strong>g> supplies,<br />
i. e. <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> extrusi<strong>on</strong>s are produced<br />
locally.<br />
This is <strong>on</strong>e explanati<strong>on</strong> for <str<strong>on</strong>g>the</str<strong>on</strong>g> big invest-<br />
View <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> manipulator for loose dummy block handling and <str<strong>on</strong>g>the</str<strong>on</strong>g> 52,000-litre hydraulic tank<br />
ments in large extrusi<strong>on</strong> presses in China.<br />
The Internati<strong>on</strong>al Uni<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> Railways (UIC)<br />
is expecting that <str<strong>on</strong>g>the</str<strong>on</strong>g> global high-speed network<br />
will triple within <str<strong>on</strong>g>the</str<strong>on</strong>g> next 15 years.<br />
Taking into account that this is <strong>on</strong>ly an outlook<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> high-speed network, a huge demand for<br />
railway extrusi<strong>on</strong>s is expected.<br />
Aluminium is not <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>ly material railway<br />
cars can be built with. Steel is a permanent<br />
competitor. There are even some ideas to use<br />
composite material for certain areas <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> car<br />
body. But <str<strong>on</strong>g>the</str<strong>on</strong>g> comparis<strong>on</strong> between <str<strong>on</strong>g>the</str<strong>on</strong>g> integrated<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> design and <str<strong>on</strong>g>the</str<strong>on</strong>g> steel structure<br />
design clearly shows a weight reducti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> more than 20 percent <strong>on</strong> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> design.<br />
This is resulting in an estimated energy saving<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> five percent for every ten percent <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
weight reducti<strong>on</strong>. The limited axle load <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
European railway network <strong>on</strong>ly allows for<br />
higher pay loads if <str<strong>on</strong>g>the</str<strong>on</strong>g> net weight <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> train<br />
is reduced.<br />
Additi<strong>on</strong>ally <str<strong>on</strong>g>the</str<strong>on</strong>g>re are o<str<strong>on</strong>g>the</str<strong>on</strong>g>r known advantages<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> like nearly 100 percent<br />
recyclability, good corrosi<strong>on</strong> resistance, high<br />
strength to weight ratio or <str<strong>on</strong>g>the</str<strong>on</strong>g> decorative as-<br />
34 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011<br />
Photos: SMS Meer
Counter platen with fixed tie rods<br />
EXTRUSION<br />
pect <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>. Looking at <str<strong>on</strong>g>the</str<strong>on</strong>g> global greenhouse gas emissi<strong>on</strong>s,<br />
27 percent <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se emissi<strong>on</strong>s are caused by transportati<strong>on</strong><br />
and 73 percent are caused by road transportati<strong>on</strong>, while<br />
<strong>on</strong>ly 2 percent arise due to rail transportati<strong>on</strong>. Rail transportati<strong>on</strong><br />
is a ‘green soluti<strong>on</strong>’ to move people or goods and a low<br />
carb<strong>on</strong> technology. A slogan <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> railway manufacturer Bombardier<br />
is pointing out, that ‘<str<strong>on</strong>g>the</str<strong>on</strong>g> climate is right for trains!’<br />
Eventually all this leads to an increasing market for large<br />
pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles and since <str<strong>on</strong>g>the</str<strong>on</strong>g> numbers <str<strong>on</strong>g>of</str<strong>on</strong>g> operative heavy presses were<br />
limited, now big investments in extrusi<strong>on</strong> plants for heavy duty<br />
and large secti<strong>on</strong>s are being made, especially in China.<br />
But it is not <strong>on</strong>ly <str<strong>on</strong>g>the</str<strong>on</strong>g> number <str<strong>on</strong>g>of</str<strong>on</strong>g> presses; it is also <str<strong>on</strong>g>the</str<strong>on</strong>g> size<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> presses that is c<strong>on</strong>stantly increasing over <str<strong>on</strong>g>the</str<strong>on</strong>g> last years.<br />
While a 65 MN press was c<strong>on</strong>sidered as a huge press a few years<br />
ago, today some people would call it ‘medium size’ <strong>on</strong>ly.<br />
C<strong>on</strong>sidering <str<strong>on</strong>g>the</str<strong>on</strong>g> recent orders <str<strong>on</strong>g>of</str<strong>on</strong>g> SMS…<br />
• 70 MN fr<strong>on</strong>tloading press for Nanshan Aluminium<br />
• 82 MN fr<strong>on</strong>tloading press for Nanshan Aluminium<br />
• 82 MN fr<strong>on</strong>tloading press for Yankuang Aluminium<br />
• 82 MN fr<strong>on</strong>tloading press for Nanshan USA<br />
• 100 MN fr<strong>on</strong>tloading press for Jilin Lijuan<br />
• 150 MN fr<strong>on</strong>tloading tube press for Yankuang Aluminium<br />
• 150 MN fr<strong>on</strong>tloading press for Nanshan Aluminium<br />
…we see a high potential <strong>on</strong> this market regarding also o<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
press manufacturers from Europe or Asia who are getting significant<br />
orders <strong>on</strong> big presses, too.<br />
�<br />
ETS<br />
Extrusi<strong>on</strong> Tooling Soluti<strong>on</strong>s<br />
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EXTRUSION<br />
Gerhardi Alutechnik and GIA Clecim – a European partnership<br />
Extrusi<strong>on</strong> line from a single source for intelligent pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles (I)<br />
Christoph Deiters, Gerhardi AluTechnik GmbH<br />
The German Gerhardi Alutechnik, founded<br />
in 1796 and even today owned by <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
founder family, c<strong>on</strong>sequently transfers<br />
values like reliability, l<strong>on</strong>g term thinking<br />
and traditi<strong>on</strong>, but also innovati<strong>on</strong><br />
and willingness to invest. The latter has<br />
carried <str<strong>on</strong>g>the</str<strong>on</strong>g> company through more than<br />
two centuries and was <strong>on</strong>ce more proved<br />
during <str<strong>on</strong>g>the</str<strong>on</strong>g> last three years: management<br />
and owners decided for a sec<strong>on</strong>d extrusi<strong>on</strong><br />
line with <str<strong>on</strong>g>the</str<strong>on</strong>g> necessary mechanical<br />
periphery and a c<strong>on</strong>siderable expansi<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> factory. This investment lead to an<br />
augmentati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> capacity from 6, 000 to<br />
16.000 t<strong>on</strong>nes a year.<br />
Today <str<strong>on</strong>g>the</str<strong>on</strong>g>re are 125 employees who develop,<br />
produce and market 10,000 to 11,000 t<strong>on</strong>nes<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles. These are sold to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
building industry (‘Gerac<strong>on</strong>struct’ including<br />
‘Gerasolar’ – shutters pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles and guide rails,<br />
shading technique, room-dividing elements,<br />
sanitary equipment, skirting boards, solar<br />
industry), <str<strong>on</strong>g>the</str<strong>on</strong>g> automotive industry (‘Geramotive’<br />
– window frames, guide rails, decorative<br />
parts, ro<str<strong>on</strong>g>of</str<strong>on</strong>g> rail systems), <str<strong>on</strong>g>the</str<strong>on</strong>g> electr<strong>on</strong>ic industry<br />
(‘Geratr<strong>on</strong>ics’ – pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles for cooling elements)<br />
and industrial technique (‘Geratechnics’ – machine<br />
building, lighting industry, furniture).<br />
Gerhardi is a state<str<strong>on</strong>g>of</str<strong>on</strong>g>-<str<strong>on</strong>g>the</str<strong>on</strong>g>-art<br />
manufacturer<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> semi-finished <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
products and – also due to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> new 33 MN extrusi<strong>on</strong> line –<br />
in a positi<strong>on</strong> to meet <str<strong>on</strong>g>the</str<strong>on</strong>g> market’s high<br />
requirements as to technical and organizati<strong>on</strong>al<br />
quality.<br />
The Spanish partner, GIA Clecim Press,<br />
has become <strong>on</strong>e <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> leaders in <str<strong>on</strong>g>the</str<strong>on</strong>g> metal<br />
extrusi<strong>on</strong> market during <str<strong>on</strong>g>the</str<strong>on</strong>g> past years. The<br />
company was established in <str<strong>on</strong>g>the</str<strong>on</strong>g> early eighties<br />
by Gaspar Fernández in Albacete, Spain. This<br />
is nowadays <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>ly manufacturing plant with<br />
300 employees exclusively working for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
field <str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> metals and special alloys.<br />
GIA took its positi<strong>on</strong> as a complete plant<br />
supplier throughout <str<strong>on</strong>g>the</str<strong>on</strong>g> years. The company<br />
got <str<strong>on</strong>g>the</str<strong>on</strong>g> vast majority <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Spanish market as<br />
well as presence in many o<str<strong>on</strong>g>the</str<strong>on</strong>g>r countries. In<br />
2006, GIA Clecim Press purchased <str<strong>on</strong>g>the</str<strong>on</strong>g> knowhow<br />
and all activities <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Presses divisi<strong>on</strong><br />
from Siemens. After this acquisiti<strong>on</strong>, GIA<br />
Clecim Press became <str<strong>on</strong>g>the</str<strong>on</strong>g> press manufacturer<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> largest number <str<strong>on</strong>g>of</str<strong>on</strong>g> references in Europe.<br />
Why did Gerhardi invest<br />
in a new extrusi<strong>on</strong> press?<br />
Gerhardi installed <str<strong>on</strong>g>the</str<strong>on</strong>g> first extrusi<strong>on</strong> line in<br />
1945. Up to 2009 <str<strong>on</strong>g>the</str<strong>on</strong>g> company produced with<br />
a 2,000-t<strong>on</strong>ne extrusi<strong>on</strong> press <str<strong>on</strong>g>of</str<strong>on</strong>g> 1979. From<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> management’s viewpoint this meant a<br />
risk – for <str<strong>on</strong>g>the</str<strong>on</strong>g> customers as well as for <str<strong>on</strong>g>the</str<strong>on</strong>g> enterprise,<br />
which bears <str<strong>on</strong>g>the</str<strong>on</strong>g> resp<strong>on</strong>sibility for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
employees and for which <str<strong>on</strong>g>the</str<strong>on</strong>g> subject ‘future’<br />
traditi<strong>on</strong>ally was and still is <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>siderable<br />
importance according to <str<strong>on</strong>g>the</str<strong>on</strong>g> company’s philosophy<br />
‘Comm<strong>on</strong> Future in Pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile’.<br />
As a c<strong>on</strong>sequence – after thorough c<strong>on</strong>siderati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> all strategic alternatives – owners<br />
and management decided to invest in a sec<strong>on</strong>d<br />
extrusi<strong>on</strong> line in order to be a reliable supplier<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> semi-finished <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> products.<br />
As <str<strong>on</strong>g>the</str<strong>on</strong>g> market forecast for semi-finished<br />
products in <str<strong>on</strong>g>the</str<strong>on</strong>g> alu-minium sector is positive<br />
and even shows c<strong>on</strong>siderable<br />
growth rates, <str<strong>on</strong>g>the</str<strong>on</strong>g> company<br />
acts in a<br />
developable<br />
and growing<br />
market.<br />
This could<br />
already be<br />
observed<br />
and had<br />
major influence<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
time <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
investment<br />
decisi<strong>on</strong> – a very courageous decisi<strong>on</strong>:<br />
Regarding <str<strong>on</strong>g>the</str<strong>on</strong>g> market potential <str<strong>on</strong>g>of</str<strong>on</strong>g> about<br />
800.000 tpy in Germany, <str<strong>on</strong>g>the</str<strong>on</strong>g> decisi<strong>on</strong> makers,<br />
however, came to <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>clusi<strong>on</strong> that <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
accumulated maximum producti<strong>on</strong> capacity<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 16.000 tpy <str<strong>on</strong>g>of</str<strong>on</strong>g> two Gerhardi presses<br />
might be a reas<strong>on</strong>able and realizable target.<br />
The investment would be suitable to secure<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> existence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> company by providing<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> technical prerequisites for an expanded<br />
product range and adapting <str<strong>on</strong>g>the</str<strong>on</strong>g>m<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> company’s high innovati<strong>on</strong> potential.<br />
Installati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> line<br />
New products like pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles <str<strong>on</strong>g>of</str<strong>on</strong>g> glossy and<br />
crash-relevant <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloys for automotive<br />
applicati<strong>on</strong>s, resulting from <str<strong>on</strong>g>the</str<strong>on</strong>g> close<br />
cooperati<strong>on</strong> especially with Gerhardi’s raw<br />
material supplier, required more flexibility <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong> process.<br />
What did Gerhardi buy?<br />
Gerhardi has invested in a sec<strong>on</strong>d extrusi<strong>on</strong><br />
line with many technical opti<strong>on</strong>s. It was important<br />
to run <str<strong>on</strong>g>the</str<strong>on</strong>g> press with <str<strong>on</strong>g>the</str<strong>on</strong>g> same billet<br />
diameter (8 inch) as <str<strong>on</strong>g>the</str<strong>on</strong>g> existing press. This<br />
guarantees that <str<strong>on</strong>g>the</str<strong>on</strong>g> matrices <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> older device<br />
can also be used in <str<strong>on</strong>g>the</str<strong>on</strong>g> new press. The<br />
dialog with GIA resulted in <str<strong>on</strong>g>the</str<strong>on</strong>g> decisi<strong>on</strong> for a<br />
press with a power <str<strong>on</strong>g>of</str<strong>on</strong>g> 33 MN in order to be<br />
later able to apply a 9 inch or maybe also a<br />
10 inch billet.<br />
In order to reach a c<strong>on</strong>stant quality, which<br />
is especially important for <str<strong>on</strong>g>the</str<strong>on</strong>g> decorative parts<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> functi<strong>on</strong>al parts, Gerhardi bought a<br />
combined billet heating: pre-heating with gas<br />
and complementary inducti<strong>on</strong> heating, which<br />
allows an even temperature for <str<strong>on</strong>g>the</str<strong>on</strong>g> pressing<br />
process at <str<strong>on</strong>g>the</str<strong>on</strong>g> point <str<strong>on</strong>g>of</str<strong>on</strong>g> matrix. Special attenti<strong>on</strong><br />
is given to <str<strong>on</strong>g>the</str<strong>on</strong>g> cooling process.<br />
GIA installed a pr<strong>on</strong>ounced cooling tunnel<br />
with air- / air-water- and water-cooling.<br />
These cooling mechanisms allow <str<strong>on</strong>g>the</str<strong>on</strong>g> extru-<br />
si<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> higher strength material – also an<br />
36 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011<br />
Gerhardi
opti<strong>on</strong> for <str<strong>on</strong>g>the</str<strong>on</strong>g> future.<br />
As Gerhardi wanted to use its building’s<br />
full size <str<strong>on</strong>g>of</str<strong>on</strong>g> 120 metres for <str<strong>on</strong>g>the</str<strong>on</strong>g> line, <str<strong>on</strong>g>the</str<strong>on</strong>g> length<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> run-out-system is c<strong>on</strong>siderable. The<br />
60-metre pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles are stacked and <str<strong>on</strong>g>the</str<strong>on</strong>g>n sewed<br />
to customized size from 2,000 mm upwards.<br />
Press, stacker and saw are followed by a fully<br />
automatic assembly line which guarantees that<br />
no worker touches <str<strong>on</strong>g>the</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles until reaching<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> packing unit.<br />
The building c<strong>on</strong>cept over two floors prescribes<br />
a stringent material flow. Oven storage,<br />
packaging and processing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles are<br />
effected <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> upper floor.<br />
All <str<strong>on</strong>g>the</str<strong>on</strong>g>se requirements were laid down in a<br />
specificati<strong>on</strong> sheet. The Gerhardi project team<br />
travelled a lot, visited various extrusi<strong>on</strong> companies<br />
and as many suppliers as possible. The<br />
managing director and his team went through<br />
all <str<strong>on</strong>g>of</str<strong>on</strong>g> Europe to get to know <str<strong>on</strong>g>the</str<strong>on</strong>g> relevant companies,<br />
to talk to <str<strong>on</strong>g>the</str<strong>on</strong>g>m and to see reference<br />
lines.<br />
Whom did Gerhardi choose?<br />
After an intensive analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> all <str<strong>on</strong>g>of</str<strong>on</strong>g>fers as to<br />
ec<strong>on</strong>omic aspects, but also as to <str<strong>on</strong>g>the</str<strong>on</strong>g> product<br />
availability and <str<strong>on</strong>g>the</str<strong>on</strong>g> vertical range <str<strong>on</strong>g>of</str<strong>on</strong>g> manufacture,<br />
Gerhardi decided to buy an extrusi<strong>on</strong><br />
line made by <str<strong>on</strong>g>the</str<strong>on</strong>g> Spanish company GIA Clecim.<br />
The core business for GIA is <str<strong>on</strong>g>the</str<strong>on</strong>g> manufacturing<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong> plants and 95% <str<strong>on</strong>g>of</str<strong>on</strong>g> jobs<br />
are turnkey projects. The strategies <str<strong>on</strong>g>of</str<strong>on</strong>g> n<strong>on</strong>subc<strong>on</strong>tracting<br />
lets GIA get <str<strong>on</strong>g>the</str<strong>on</strong>g> highest quality<br />
for such equipment. GIA holds a manufacturing<br />
ratio <str<strong>on</strong>g>of</str<strong>on</strong>g> 80%, which means that all equipment<br />
is manufactured, assembled and tested<br />
in its facilities.<br />
For Gerhardi <str<strong>on</strong>g>the</str<strong>on</strong>g> most important criteria<br />
in favour <str<strong>on</strong>g>of</str<strong>on</strong>g> GIA were <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
following:<br />
• Under an ec<strong>on</strong>omic<br />
point <str<strong>on</strong>g>of</str<strong>on</strong>g> view <str<strong>on</strong>g>the</str<strong>on</strong>g> GIA<br />
Clecim <str<strong>on</strong>g>of</str<strong>on</strong>g>fer was persuading<br />
in comparis<strong>on</strong><br />
to all <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r suppliers<br />
• Gerhardi got a good<br />
impressi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> technical<br />
aspects <str<strong>on</strong>g>of</str<strong>on</strong>g> a GIA press<br />
– especially <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> solid<br />
machine c<strong>on</strong>structi<strong>on</strong>,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> extremely effective<br />
and good hydraulic system,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> interacti<strong>on</strong> in a<br />
completely coordinated<br />
system<br />
• All from a single<br />
source – GIA is <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>ly<br />
producer <str<strong>on</strong>g>of</str<strong>on</strong>g> complete extrusi<strong>on</strong><br />
systems from <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
billet store over <str<strong>on</strong>g>the</str<strong>on</strong>g> billet heating to <str<strong>on</strong>g>the</str<strong>on</strong>g> press,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> saw and <str<strong>on</strong>g>the</str<strong>on</strong>g> assembling device<br />
• GIA has an enormous in-house producti<strong>on</strong><br />
depth. All mechanical parts are manufactured<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> company itself and even <str<strong>on</strong>g>the</str<strong>on</strong>g> hydraulic<br />
system is developed in Albacete and produced<br />
by GIA<br />
• GIA is a family enterprise like Gerhardi and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> customer negotiates with <str<strong>on</strong>g>the</str<strong>on</strong>g> owner himself<br />
• GIA very much wanted to install a reference<br />
extrusi<strong>on</strong> line in Germany so that Gerhardi<br />
could take it for granted that <str<strong>on</strong>g>the</str<strong>on</strong>g> Spanish<br />
partner would make c<strong>on</strong>siderable efforts in<br />
this project.<br />
How was <str<strong>on</strong>g>the</str<strong>on</strong>g> installati<strong>on</strong><br />
process effected?<br />
33 MN GIA extrusi<strong>on</strong> press for Gerhardi<br />
After signing <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tract both parties formed<br />
project teams who communicated directly<br />
with each o<str<strong>on</strong>g>the</str<strong>on</strong>g>r. GIA employed a German<br />
speaking coordinator for <str<strong>on</strong>g>the</str<strong>on</strong>g> German market,<br />
so that <str<strong>on</strong>g>the</str<strong>on</strong>g> communicati<strong>on</strong> could take place<br />
in German. Innumerable plans were exchanged.<br />
In interacti<strong>on</strong> between architects,<br />
c<strong>on</strong>structi<strong>on</strong> companies and o<str<strong>on</strong>g>the</str<strong>on</strong>g>r project<br />
partners <str<strong>on</strong>g>the</str<strong>on</strong>g> prerequisites for <str<strong>on</strong>g>the</str<strong>on</strong>g> installati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> line were created. Various<br />
journeys from Germany to Spain and vice<br />
versa were necessary to realize <str<strong>on</strong>g>the</str<strong>on</strong>g> planned<br />
targets.<br />
After <str<strong>on</strong>g>the</str<strong>on</strong>g> preparing activities <str<strong>on</strong>g>the</str<strong>on</strong>g> actual installati<strong>on</strong><br />
was effected by a competent team <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
technical assemblers and s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware engineers.<br />
Highlights <str<strong>on</strong>g>of</str<strong>on</strong>g> this phase were certainly <str<strong>on</strong>g>the</str<strong>on</strong>g> socalled<br />
marriage, <str<strong>on</strong>g>the</str<strong>on</strong>g> merging <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> first part<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> press with <str<strong>on</strong>g>the</str<strong>on</strong>g> building, and <str<strong>on</strong>g>the</str<strong>on</strong>g> first<br />
warm billet.<br />
Summary<br />
EXTRUSION<br />
The installati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a technologically sophisticated<br />
extrusi<strong>on</strong> line is always a great challenge<br />
– especially if it is a European line like in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
case <str<strong>on</strong>g>of</str<strong>on</strong>g> Gerhardi, where <str<strong>on</strong>g>the</str<strong>on</strong>g> devices came primarily<br />
from Spain, but also from <str<strong>on</strong>g>the</str<strong>on</strong>g> Ne<str<strong>on</strong>g>the</str<strong>on</strong>g>rlands,<br />
from Italy and Germany.<br />
Gerhardi – after a careful choice <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
suppliers – was very satisfied that all partners<br />
were eager to c<strong>on</strong>structively accompany <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
investment. All companies involved learnt a<br />
lot in <str<strong>on</strong>g>the</str<strong>on</strong>g> project – like <str<strong>on</strong>g>the</str<strong>on</strong>g> adequate estimati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a permanent dialogue, <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> quality<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> exchanged informati<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g> presence and<br />
otivati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> own team within <str<strong>on</strong>g>the</str<strong>on</strong>g> planning<br />
and installati<strong>on</strong> process and <str<strong>on</strong>g>the</str<strong>on</strong>g> anticipatory<br />
understanding for <str<strong>on</strong>g>the</str<strong>on</strong>g> partner’s different<br />
mentality. Gerhardi is aware <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> special<br />
challenge <str<strong>on</strong>g>of</str<strong>on</strong>g> a European extrusi<strong>on</strong> line, but<br />
is at <str<strong>on</strong>g>the</str<strong>on</strong>g> same time c<strong>on</strong>vinced to have placed<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> GIA Clecim press <str<strong>on</strong>g>the</str<strong>on</strong>g> right investment<br />
following its philosophy ‘Comm<strong>on</strong> future<br />
in Pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile’. ‘Comm<strong>on</strong>’ not <strong>on</strong>ly with customers<br />
and employees, but also, as it was laid<br />
down in <str<strong>on</strong>g>the</str<strong>on</strong>g> corporate presentati<strong>on</strong> many<br />
years ago, also with <str<strong>on</strong>g>the</str<strong>on</strong>g> suppliers.<br />
Especially with <str<strong>on</strong>g>the</str<strong>on</strong>g> Spanish partners Gerhardi<br />
developed a business relati<strong>on</strong>ship, which<br />
also lead to comm<strong>on</strong> private activities. Visits<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> Mr Gaspar Roldan or his fa<str<strong>on</strong>g>the</str<strong>on</strong>g>r Gaspar<br />
Fernandez were remarkable events as well as<br />
visits <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Gerhardi owners in Spain.<br />
Gerhardi and GIA – this is not <strong>on</strong>ly a partnership<br />
resulting from <str<strong>on</strong>g>the</str<strong>on</strong>g> purchase <str<strong>on</strong>g>of</str<strong>on</strong>g> an<br />
extrusi<strong>on</strong> press for intelligent Gerhardi <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles, but also a European friendship.<br />
�<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 37
EXTRUSION<br />
Gerhardi and GIA Clecim – an European partnership<br />
Extrusi<strong>on</strong> line from a single source for intelligent pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles (II)<br />
Gaspar Fernandez Roldán, GIA Clecim Press<br />
GIA Clecim Press would like use this<br />
unique opportunity at <str<strong>on</strong>g>the</str<strong>on</strong>g> GDA c<strong>on</strong>ference<br />
to introduce itself as a company able<br />
to attend <str<strong>on</strong>g>the</str<strong>on</strong>g> existing <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> extrusi<strong>on</strong><br />
demands. GIA Clecim Press is a dynamic<br />
company which has become, during<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> past years, <strong>on</strong>e <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> leaders in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> metal extrusi<strong>on</strong> market in <str<strong>on</strong>g>the</str<strong>on</strong>g> world.<br />
At <str<strong>on</strong>g>the</str<strong>on</strong>g> beginning <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 1980s, when GIA in<br />
Albacete, Spain, began producing extrusi<strong>on</strong><br />
dies, <str<strong>on</strong>g>the</str<strong>on</strong>g>re was a boom in Spain’s building<br />
industry which provided huge market opportunities<br />
for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> window and structural<br />
secti<strong>on</strong>s. Good starting c<strong>on</strong>diti<strong>on</strong>s, which encouraged<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> young company to extend<br />
its engineering performance besides<br />
die manufacturing to o<str<strong>on</strong>g>the</str<strong>on</strong>g>r applicati<strong>on</strong>s<br />
in extrusi<strong>on</strong> plants. So GIA became an<br />
equipment manufacturer which <str<strong>on</strong>g>of</str<strong>on</strong>g>fered<br />
handling and processing equipment for<br />
extruded secti<strong>on</strong>s to <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>n growing<br />
Spanish market.<br />
A substantial gap was filled when,<br />
towards <str<strong>on</strong>g>the</str<strong>on</strong>g> end <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 1980s, <str<strong>on</strong>g>the</str<strong>on</strong>g> technical<br />
staff at GIA ventured to attempt<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> centrepiece <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> plants: <str<strong>on</strong>g>the</str<strong>on</strong>g> first<br />
extrusi<strong>on</strong> press designed by <str<strong>on</strong>g>the</str<strong>on</strong>g> company<br />
itself and made by it in 1990 was<br />
a 14 MN press <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>venti<strong>on</strong>al, backloading<br />
c<strong>on</strong>figurati<strong>on</strong>, which began<br />
operating as part <str<strong>on</strong>g>of</str<strong>on</strong>g> a complete plant<br />
supplied by GIA to a Spanish extruder<br />
in Albacete.<br />
Following <str<strong>on</strong>g>the</str<strong>on</strong>g> company policy to<br />
become a supplier <str<strong>on</strong>g>of</str<strong>on</strong>g> turn-key projects<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> business, GIA developed<br />
and introduced to <str<strong>on</strong>g>the</str<strong>on</strong>g> market <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
short-stroke back loading design <str<strong>on</strong>g>of</str<strong>on</strong>g> 18<br />
to 22 MN. Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> factory locati<strong>on</strong><br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> great growth <str<strong>on</strong>g>of</str<strong>on</strong>g> extruded <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
c<strong>on</strong>sumpti<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g> main approached market at<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> time was Spain where <str<strong>on</strong>g>the</str<strong>on</strong>g> equipment had<br />
a huge demand and customer acceptance.<br />
At <str<strong>on</strong>g>the</str<strong>on</strong>g> end <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> 1990s <str<strong>on</strong>g>the</str<strong>on</strong>g> leap to trading<br />
overseas took place. After orders from <str<strong>on</strong>g>the</str<strong>on</strong>g> Dominican<br />
Republic o<str<strong>on</strong>g>the</str<strong>on</strong>g>rs followed from Mexico<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> Sou<str<strong>on</strong>g>the</str<strong>on</strong>g>rn states <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> USA. By<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> end <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> millennium, that is within about<br />
ten years, GIA had supplied 45 new extrusi<strong>on</strong><br />
plants equipped with 18 and 35 MN presses<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> its own. Changed c<strong>on</strong>diti<strong>on</strong>s in <str<strong>on</strong>g>the</str<strong>on</strong>g> extru-<br />
si<strong>on</strong> market and also <str<strong>on</strong>g>the</str<strong>on</strong>g> advance into new<br />
markets such as <str<strong>on</strong>g>the</str<strong>on</strong>g> gulf regi<strong>on</strong> demanded <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
development <str<strong>on</strong>g>of</str<strong>on</strong>g> larger presses from <str<strong>on</strong>g>the</str<strong>on</strong>g> beginning<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> new millennium. Thus, <str<strong>on</strong>g>the</str<strong>on</strong>g> range<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> short stroke back-loading presses was extended<br />
up to 45 MN. As before, <str<strong>on</strong>g>the</str<strong>on</strong>g>se formed<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> centrepiece <str<strong>on</strong>g>of</str<strong>on</strong>g> complete GIA plants.<br />
The decisi<strong>on</strong> by Siemens VAI in 2006 to<br />
break away from <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> press c<strong>on</strong>structi<strong>on</strong><br />
activities <str<strong>on</strong>g>of</str<strong>on</strong>g> its French traditi<strong>on</strong>al trademark<br />
Clecim opened up new perspectives for<br />
GIA. It was so<strong>on</strong> decided to acquire <str<strong>on</strong>g>the</str<strong>on</strong>g> rights<br />
to and designs <str<strong>on</strong>g>of</str<strong>on</strong>g> Clecim presses and, toge<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> company’s own press programme, to<br />
market ‘GIA Clecim’ presses. For GIA, Clecim’s<br />
technology was a milest<strong>on</strong>e for <str<strong>on</strong>g>the</str<strong>on</strong>g> company’s<br />
fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r development. At <str<strong>on</strong>g>the</str<strong>on</strong>g> time <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
sale Clecim still had a proud reference list <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
more than 100 extrusi<strong>on</strong> presses built since<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> early 1970s.<br />
GIA Clecim Press became <str<strong>on</strong>g>the</str<strong>on</strong>g>n <str<strong>on</strong>g>the</str<strong>on</strong>g> press<br />
manufacturer with <str<strong>on</strong>g>the</str<strong>on</strong>g> largest number <str<strong>on</strong>g>of</str<strong>on</strong>g> references<br />
in Europe. This transfer <str<strong>on</strong>g>of</str<strong>on</strong>g> property<br />
c<strong>on</strong>gregated technology and know-how from<br />
all companies which have merged to Clecim<br />
al<strong>on</strong>g <str<strong>on</strong>g>the</str<strong>on</strong>g> time. GIA Clecim Press also took<br />
advantage <str<strong>on</strong>g>of</str<strong>on</strong>g> this transfer by hiring expert engineers<br />
from former Clecim Presses Divisi<strong>on</strong>.<br />
Therefore, GIA Clecim Press became <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
successor <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> companies Loewy, Davy, Morane,<br />
Somu, Loire, Secim, Clesid and finally<br />
Clecim, since <str<strong>on</strong>g>the</str<strong>on</strong>g> foundati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> Chavanne<br />
Brun in M<strong>on</strong>tbris<strong>on</strong> (France) in 1857. All <str<strong>on</strong>g>the</str<strong>on</strong>g>se<br />
company were extraordinary press builders<br />
al<strong>on</strong>g <str<strong>on</strong>g>the</str<strong>on</strong>g> time, and have dem<strong>on</strong>strated outstanding<br />
designs for <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> field.<br />
GIA Clecim Press has in its archive all <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
informati<strong>on</strong>, calculati<strong>on</strong>s and drawings <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
presses designed by <str<strong>on</strong>g>the</str<strong>on</strong>g>se manufacturers during<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>ir activity. Our company maintains <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
willing <str<strong>on</strong>g>of</str<strong>on</strong>g> keeping c<strong>on</strong>tact with all users <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>se equipments as well as c<strong>on</strong>tinues increasing<br />
this reference list.<br />
Particularly important in <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> extrusi<strong>on</strong><br />
field, GIA acquired an established <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
range <str<strong>on</strong>g>of</str<strong>on</strong>g> modern short-stroke presses. Since<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>n, al<strong>on</strong>g with its own back loading<br />
presses <str<strong>on</strong>g>the</str<strong>on</strong>g> company has been able<br />
to react flexibly to <str<strong>on</strong>g>the</str<strong>on</strong>g> various needs<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> market and <str<strong>on</strong>g>of</str<strong>on</strong>g>fer <str<strong>on</strong>g>the</str<strong>on</strong>g> optimum<br />
press c<strong>on</strong>figurati<strong>on</strong> for each individual<br />
case as <str<strong>on</strong>g>the</str<strong>on</strong>g> market de-mands. Ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
benefit for GIA is <str<strong>on</strong>g>the</str<strong>on</strong>g> fact that Clecim<br />
extrusi<strong>on</strong> presses were not built for<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> al<strong>on</strong>e. Through Clecim<br />
GIA also acquired technologies and<br />
references for <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
materials, such as stainless steel, copper,<br />
special alloys as well as particular<br />
projects. In that c<strong>on</strong>necti<strong>on</strong> it is worth<br />
menti<strong>on</strong>ing that GIA Clecim Press has<br />
just commissi<strong>on</strong>ed 22 MN press for a<br />
stainless steel plant in Austria and has<br />
been awarded for o<str<strong>on</strong>g>the</str<strong>on</strong>g>r interesting<br />
projects as <str<strong>on</strong>g>the</str<strong>on</strong>g> 42 MN extrusi<strong>on</strong> press<br />
for stainless also in Sweden and a 35<br />
MN complete extrusi<strong>on</strong> plant for copper<br />
alloys in China.<br />
The meanwhile c<strong>on</strong>solidated engineering<br />
programme that originated<br />
from GIA and Clecim today includes<br />
presses <str<strong>on</strong>g>of</str<strong>on</strong>g> any load and type including direct<br />
and indirect extrusi<strong>on</strong> with or without piercer,<br />
opti<strong>on</strong>ally in fr<strong>on</strong>t-loading or back-loading<br />
versi<strong>on</strong>s. In <str<strong>on</strong>g>the</str<strong>on</strong>g> recent past several complete<br />
plants have been commissi<strong>on</strong>ed all over <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
world such as a 14 MN line in Bosnia, 18 MN<br />
in Ireland, a 30 MN fr<strong>on</strong>t loading press plant<br />
in Bahrain, a 22 MN press line in Saudi Arabia,<br />
a 65 MN fr<strong>on</strong>t loading press to Japan.<br />
All <str<strong>on</strong>g>the</str<strong>on</strong>g> plants are developed, designed, produced,<br />
assembled and tested at <str<strong>on</strong>g>the</str<strong>on</strong>g> company’s<br />
own works in Spain. In <str<strong>on</strong>g>the</str<strong>on</strong>g> mechanical workshop<br />
parts weighing up to 100 t<strong>on</strong>nes can be<br />
machined.<br />
38 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Photos: GIA<br />
In autumn 2009 Gerhardi Alutechnik in<br />
Lüdenscheid, Germany, began operating its<br />
sec<strong>on</strong>d extrusi<strong>on</strong> line which was supplied by<br />
GIA. Its centrepiece is a 35 MN short-stroke,<br />
fr<strong>on</strong>t-loading press <str<strong>on</strong>g>of</str<strong>on</strong>g> GIA Clecim Press design.<br />
The press enables short extrusi<strong>on</strong> cycle<br />
times and so achieves corresp<strong>on</strong>dingly high<br />
productivity.<br />
To understand and appreciate <str<strong>on</strong>g>the</str<strong>on</strong>g> big step<br />
this project was for GIA Clecim Press, it is<br />
worth menti<strong>on</strong>ing <str<strong>on</strong>g>the</str<strong>on</strong>g> challenges and <str<strong>on</strong>g>the</str<strong>on</strong>g> importance<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> this c<strong>on</strong>tract. It should be known<br />
that Gerhardi’s producti<strong>on</strong> programme is not<br />
c<strong>on</strong>cerned with mass goods but c<strong>on</strong>tains many<br />
special products for niche markets, some <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>m made in relatively small quantities to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> highest quality standards, e. g. stretch-bent<br />
decorative trim strips <str<strong>on</strong>g>of</str<strong>on</strong>g> a high-gloss alloy can<br />
be menti<strong>on</strong>ed here. The Gerhardi c<strong>on</strong>tract is<br />
<strong>on</strong>e <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> projects where GIA engineering<br />
shows state-<str<strong>on</strong>g>of</str<strong>on</strong>g>-<str<strong>on</strong>g>the</str<strong>on</strong>g>-art technological developments,<br />
which <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> industry in highlydeveloped<br />
industrialised countries now demands<br />
from extrusi<strong>on</strong> plant manufacturers.<br />
Gerhardi is <strong>on</strong>e <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> companies<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> highest level <str<strong>on</strong>g>of</str<strong>on</strong>g> flexibility without giving<br />
away any productivity ratios. This extrusi<strong>on</strong><br />
plant meant a great step forward for Gerhardi<br />
but for GIA also as it shows <str<strong>on</strong>g>the</str<strong>on</strong>g> Spanish<br />
company is at <str<strong>on</strong>g>the</str<strong>on</strong>g> level <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> most demanding<br />
extruders.<br />
The more than 100 extrusi<strong>on</strong> presses built<br />
so far by GIA are almost without excepti<strong>on</strong><br />
used in extrusi<strong>on</strong> lines which, from <str<strong>on</strong>g>the</str<strong>on</strong>g> log<br />
store to <str<strong>on</strong>g>the</str<strong>on</strong>g> finishing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> secti<strong>on</strong>s, were<br />
designed and c<strong>on</strong>structed by <str<strong>on</strong>g>the</str<strong>on</strong>g> company.<br />
GIA group is divided in several business units<br />
coordinated to provide complete soluti<strong>on</strong>s to<br />
extruders. GIA Matriceria, as ever, produces<br />
extrusi<strong>on</strong> dies and all kind <str<strong>on</strong>g>of</str<strong>on</strong>g> tooling for extrusi<strong>on</strong>.<br />
Log stores, shears, billet saws, billet loader,<br />
extrusi<strong>on</strong> presses, handling and puller systems<br />
are all designed and made by <str<strong>on</strong>g>the</str<strong>on</strong>g> core<br />
unit GIA. Special positi<strong>on</strong>ing devices for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
secti<strong>on</strong> saws ensure precise lengths and rapid<br />
material flow. The fully automatic stackers<br />
developed by GIA not <strong>on</strong>ly ensure a rapid<br />
and reliable producti<strong>on</strong> sequence, but are so<br />
c<strong>on</strong>structed as to protect <str<strong>on</strong>g>the</str<strong>on</strong>g> finished secti<strong>on</strong>s<br />
from damage.<br />
Besides pure extrusi<strong>on</strong> lines, under <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
trade name ‘GIA Aplicaci<strong>on</strong>es’ GIA supplies<br />
units for heating and heat treatment within<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> line which include log furnaces,<br />
die heaters, ageing ovens and die nitriding<br />
furnaces. In additi<strong>on</strong>, o<str<strong>on</strong>g>the</str<strong>on</strong>g>r units developed,<br />
designed and manufactured by <str<strong>on</strong>g>the</str<strong>on</strong>g> company<br />
itself are <str<strong>on</strong>g>of</str<strong>on</strong>g>fered, which are important for finishing<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> secti<strong>on</strong>s, namely units for powder<br />
coating and anodising. Thus, <str<strong>on</strong>g>the</str<strong>on</strong>g> company can<br />
supply complete extrusi<strong>on</strong> plants, from <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
EXTRUSION<br />
log store right up to <str<strong>on</strong>g>the</str<strong>on</strong>g> surface finishing <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> ready secti<strong>on</strong>s.<br />
Ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r company <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> group, GIA Hidraulica,<br />
not <strong>on</strong>ly builds hydraulic power units<br />
for various applicati<strong>on</strong>s in general mechanical<br />
engineering, especially in combinati<strong>on</strong> with<br />
GIA’s own extrusi<strong>on</strong> machines. This unit also<br />
specialises in electrical and electr<strong>on</strong>ic equipment<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>trol and automati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong><br />
plants and is, moreover, resp<strong>on</strong>sible for<br />
commissi<strong>on</strong>ing <str<strong>on</strong>g>the</str<strong>on</strong>g> plants supplied by GIA.<br />
There is a fifth business unit, GIA Suministros,<br />
in charge <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> service and supply <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
spare parts for GIA Clecim Press extrusi<strong>on</strong><br />
equipment. This unit keeps a great number <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
parts in stock in order to provide a perfect<br />
service to its customers.<br />
GIA Clecim Press is located, as ever, in<br />
Albacete, Spain, which is nowadays <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>ly<br />
manufacturing plant with 35.000 m2 <str<strong>on</strong>g>of</str<strong>on</strong>g> bays<br />
and where counts with 275 employees exclusively<br />
working in <str<strong>on</strong>g>the</str<strong>on</strong>g> field <str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong>.<br />
Core business for GIA Clecim Press is <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
manufacturing <str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong> and surface treatment<br />
plants and 90% <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> jobs are turnkey<br />
projects. Its strategy <str<strong>on</strong>g>of</str<strong>on</strong>g> n<strong>on</strong>-subc<strong>on</strong>tracting let<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>m get <str<strong>on</strong>g>the</str<strong>on</strong>g> highest quality for such equipment.<br />
GIA Clecim Press holds a manufacturing<br />
ratio <str<strong>on</strong>g>of</str<strong>on</strong>g> 80%, which means that all equipment<br />
is manufactured, assembled and tested<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g>ir own facilities.<br />
�<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 39
EXTRUSION<br />
Integrated processing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles subsequent to hot extrusi<strong>on</strong><br />
A. Jäger, N. Ben Khalifa, A.E. Tekkaya, Institute <str<strong>on</strong>g>of</str<strong>on</strong>g> Forming Technology<br />
and Lightweight C<strong>on</strong>structi<strong>on</strong>, TU Dortmund University, Dortmund, Germany<br />
Strategies <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmo-mechanical processing<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles subsequent to<br />
hot extrusi<strong>on</strong> were developed and tested.<br />
By using <str<strong>on</strong>g>the</str<strong>on</strong>g> process heat <str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong> for<br />
subsequent forming and heat treatment<br />
steps, process chains for <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> graded <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles were developed<br />
and realized <strong>on</strong> an experimental<br />
scale. Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> geometric limitati<strong>on</strong>s,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> technology <str<strong>on</strong>g>of</str<strong>on</strong>g> realizing a grading in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> geometry <str<strong>on</strong>g>of</str<strong>on</strong>g> open and hollow pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles<br />
is different. Therefore, two innovative<br />
c<strong>on</strong>cepts for <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmo-mechanical<br />
processing <str<strong>on</strong>g>of</str<strong>on</strong>g> open and hollow secti<strong>on</strong>s<br />
were developed, allowing electromagnetic<br />
compressi<strong>on</strong> and rolling to become<br />
integrated within <str<strong>on</strong>g>the</str<strong>on</strong>g> process chains. Possible<br />
applicati<strong>on</strong>s are seen in producing<br />
functi<strong>on</strong>ally graded products with locally<br />
adapted properties.<br />
C<strong>on</strong>venti<strong>on</strong>al hot metal extrusi<strong>on</strong> is used to<br />
produce straight, semi-finished products in<br />
mass producti<strong>on</strong> (Laue and Stenger, 1976) with<br />
a c<strong>on</strong>stant cross secti<strong>on</strong> over <str<strong>on</strong>g>the</str<strong>on</strong>g> length and<br />
homogeneous mechanical and micro-structural<br />
properties (Hall and Mudawar, 1996).<br />
Aluminium secti<strong>on</strong>s are frequently used as<br />
c<strong>on</strong>structi<strong>on</strong> elements. Generally, <str<strong>on</strong>g>the</str<strong>on</strong>g> loading<br />
c<strong>on</strong>diti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> structure elements in technical<br />
c<strong>on</strong>structi<strong>on</strong>s differ locally. The c<strong>on</strong>stant cross<br />
Fig. 2: C<strong>on</strong>cept <str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong> and subsequent forming by rollers (schematic)<br />
Fig. 1: C<strong>on</strong>cept <str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong> with in-line electromagnetic compressi<strong>on</strong> (l<strong>on</strong>gitudinal secti<strong>on</strong>, schematic)<br />
secti<strong>on</strong>, which is attributed to <str<strong>on</strong>g>the</str<strong>on</strong>g> peculiarity<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> process itself, mostly represents<br />
a compromise between <str<strong>on</strong>g>the</str<strong>on</strong>g> functi<strong>on</strong>ality<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> comp<strong>on</strong>ent design, which e. g. involves<br />
a local oversizing and thus an excessive use<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> resources. Here, a local adapti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
geometry could be suitable in order to meet<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> locally specific demands <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> structure<br />
properties. For this reas<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g> development<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> innovative forming technologies is indispensable<br />
in order to manufacture products<br />
with graded, locally adapted structural properties<br />
as well as varying geometric shapes.<br />
The increase <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> formability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
can be enhanced by heat treatment<br />
between <str<strong>on</strong>g>the</str<strong>on</strong>g> single forming steps. The integrati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmo-mechanical processing after<br />
extrusi<strong>on</strong> is a desirable<br />
substitute for additi<strong>on</strong>al<br />
heat treatment processes<br />
for several reas<strong>on</strong>s:<br />
additi<strong>on</strong>al producti<strong>on</strong><br />
steps lead to increased<br />
producti<strong>on</strong> time, energy<br />
c<strong>on</strong>sumpti<strong>on</strong> and producti<strong>on</strong><br />
costs. Incorporating<str<strong>on</strong>g>the</str<strong>on</strong>g>rmo-mechanical<br />
processing immediately<br />
after extrusi<strong>on</strong><br />
will save <str<strong>on</strong>g>the</str<strong>on</strong>g> time and<br />
energy needed to reheat<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles for o<str<strong>on</strong>g>the</str<strong>on</strong>g>r hot<br />
forming steps.<br />
In this paper, strategies<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmo-mechanical<br />
processing <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles by<br />
hot forming subsequent to hot extrusi<strong>on</strong> for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> manufacturing <str<strong>on</strong>g>of</str<strong>on</strong>g> geometrically graded<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles are given. Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> geometric<br />
limitati<strong>on</strong>s, <str<strong>on</strong>g>the</str<strong>on</strong>g> technology <str<strong>on</strong>g>of</str<strong>on</strong>g> subsequent<br />
processing <str<strong>on</strong>g>the</str<strong>on</strong>g> geometry <str<strong>on</strong>g>of</str<strong>on</strong>g> open and<br />
hollow pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles is different. Two c<strong>on</strong>cepts for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> processing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles by applying<br />
hot extrusi<strong>on</strong> combined with subsequent<br />
hot electromagnetic compressi<strong>on</strong> and alternatively<br />
combined with an integrated hot rolling<br />
c<strong>on</strong>cept were developed and tested <strong>on</strong> an<br />
experimental scale. By process integrati<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
process heat <str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong> is used for <str<strong>on</strong>g>the</str<strong>on</strong>g> successive<br />
forming operati<strong>on</strong>.<br />
Descripti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> new c<strong>on</strong>cepts<br />
For <str<strong>on</strong>g>the</str<strong>on</strong>g> processing <str<strong>on</strong>g>of</str<strong>on</strong>g> hollow pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles a combinati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> hot extrusi<strong>on</strong> and electromagnetic<br />
compressi<strong>on</strong> was developed. Hot metal extrusi<strong>on</strong><br />
is used to produce tubular semi-finished<br />
products c<strong>on</strong>tinuously by pushing a billet<br />
through a die (DIN 8583-6, 2003). In typical<br />
industrial hot <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> extrusi<strong>on</strong>, pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile<br />
exiting speeds <str<strong>on</strong>g>of</str<strong>on</strong>g> up to 50 m/min are comm<strong>on</strong><br />
(Ostermann, 2007). In c<strong>on</strong>trast to this,<br />
electromagnetic compressi<strong>on</strong> is used to reduce<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> cross secti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a workpiece locally (Harvey<br />
and Brower, 1961). The applied magnetic<br />
pressure can achieve values <str<strong>on</strong>g>of</str<strong>on</strong>g> up to several<br />
hundred MPa and accelerates <str<strong>on</strong>g>the</str<strong>on</strong>g> workpiece<br />
to typical strain rates <str<strong>on</strong>g>of</str<strong>on</strong>g> about 10 4 s -1 completing<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> entire forming process in approximately<br />
50 to 200 μs. Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> favourable<br />
relati<strong>on</strong> between resulting exit speed in extrusi<strong>on</strong><br />
and processing time in electromagnetic<br />
compressi<strong>on</strong>, a l<strong>on</strong>gitudinal translati<strong>on</strong> be-<br />
40 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011<br />
Images: IUL
Fig. 3: Experimental setup for extrusi<strong>on</strong> with subsequent electromagnetic compressi<strong>on</strong><br />
tween <str<strong>on</strong>g>the</str<strong>on</strong>g> workpiece and <str<strong>on</strong>g>the</str<strong>on</strong>g> tool coil during<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> compressi<strong>on</strong> process can be neglected. For<br />
example, with an exiting speed <str<strong>on</strong>g>of</str<strong>on</strong>g> 50 m/min,<br />
and 100 μs for <str<strong>on</strong>g>the</str<strong>on</strong>g> electromagnetic forming<br />
process, a relative movement between <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
extrudate pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile and <str<strong>on</strong>g>the</str<strong>on</strong>g> tool coil <str<strong>on</strong>g>of</str<strong>on</strong>g> about<br />
160 μm results, which meets <str<strong>on</strong>g>the</str<strong>on</strong>g> geometrical<br />
tolerance field <str<strong>on</strong>g>of</str<strong>on</strong>g> macroscopic forming processes.<br />
Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> applicati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> electromagnetic<br />
compressi<strong>on</strong> subsequent to extrusi<strong>on</strong><br />
is possible without a compensati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
relative speed between <str<strong>on</strong>g>the</str<strong>on</strong>g> workpiece and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
tooling.<br />
To integrate both processes, a tool coil for<br />
compressi<strong>on</strong> was positi<strong>on</strong>ed behind <str<strong>on</strong>g>the</str<strong>on</strong>g> die<br />
exit and coaxial to <str<strong>on</strong>g>the</str<strong>on</strong>g> extrudate in order to<br />
reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> workpiece cross secti<strong>on</strong> locally<br />
(Fig. 1). Additi<strong>on</strong>ally, a counter die in <str<strong>on</strong>g>the</str<strong>on</strong>g> shape<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a mandrel can be mounted to <str<strong>on</strong>g>the</str<strong>on</strong>g> mandrel<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a porthole extrusi<strong>on</strong> die, which extended<br />
into <str<strong>on</strong>g>the</str<strong>on</strong>g> tool coil (Jäger et al., 2009). By this,<br />
besides achieving a more defined geometry in<br />
comparis<strong>on</strong> to a free forming operati<strong>on</strong>, an<br />
increase <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> geometrical complexity <str<strong>on</strong>g>of</str<strong>on</strong>g> locally<br />
compressed areas can be achieved.<br />
For processing open secti<strong>on</strong>s, like L-, T<br />
and double-T-shaped pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles, a rolling pro-<br />
cess was developed. By executing <str<strong>on</strong>g>the</str<strong>on</strong>g> subsequent<br />
forming operati<strong>on</strong> as a rolling process,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tinuous run out <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile can be<br />
taken into account.<br />
Fig. 4: Dimensi<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> mandrel for electromagnetic forming<br />
A special rolling stand was developed and<br />
mounted behind <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> platen <str<strong>on</strong>g>of</str<strong>on</strong>g> an<br />
extrusi<strong>on</strong> press, allowing <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tinuous forming<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> outgoing extrusi<strong>on</strong> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles. The<br />
rollers mesh toge<str<strong>on</strong>g>the</str<strong>on</strong>g>r with sinusoidal teeth,<br />
creating a corrugated c<strong>on</strong>tour <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> web <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
a c<strong>on</strong>tinuously fed I-beam-shaped pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile. The<br />
c<strong>on</strong>tour <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> forming dies stores <str<strong>on</strong>g>the</str<strong>on</strong>g> desired<br />
geometry <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> workpiece. As <str<strong>on</strong>g>the</str<strong>on</strong>g> exit speed <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> extrudate varies, compensati<strong>on</strong> strategies<br />
have to be provided. For this, <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling stand<br />
was swivel-mounted and <str<strong>on</strong>g>the</str<strong>on</strong>g> rotati<strong>on</strong>al speed<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rollers was adapted permanently (Fig. 2).<br />
Extrusi<strong>on</strong> and electromagnetic forming<br />
A test rig for evaluating <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>cept <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
integrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> an electromagnetic compressi<strong>on</strong><br />
step subsequent to extrusi<strong>on</strong> was built (Fig. 3).<br />
A tool coil was positi<strong>on</strong>ed behind <str<strong>on</strong>g>the</str<strong>on</strong>g> die exit<br />
in order to reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> workpiece cross secti<strong>on</strong><br />
locally. To adapt <str<strong>on</strong>g>the</str<strong>on</strong>g> tool coil and <str<strong>on</strong>g>the</str<strong>on</strong>g> extrudate<br />
geometry, a field shaper made out <str<strong>on</strong>g>of</str<strong>on</strong>g> a<br />
CuCrZr-alloy, electrically insulated with a<br />
polyimide foil, is used. Bey<strong>on</strong>d shaping and<br />
c<strong>on</strong>centrating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> electromagnetic field, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
field shaper also prevents an overheating <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> tool coil by <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal radiati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> processed<br />
hot extrudate. To assure a uniform air<br />
gap between <str<strong>on</strong>g>the</str<strong>on</strong>g> field shaper and <str<strong>on</strong>g>the</str<strong>on</strong>g> workpiece<br />
guiding rollers made out <str<strong>on</strong>g>of</str<strong>on</strong>g> brass are ar-<br />
EXTRUSION<br />
ranged pairwise at <str<strong>on</strong>g>the</str<strong>on</strong>g> inlet and run-out side<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> tool coil. For heat treating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> extruded<br />
and subsequently hot deformed workpieces<br />
made <str<strong>on</strong>g>of</str<strong>on</strong>g> heat treatable alloys, an additi<strong>on</strong>al<br />
quenching setup was positi<strong>on</strong>ed behind<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> tool coil. Atomizing nozzles are located<br />
around <str<strong>on</strong>g>the</str<strong>on</strong>g> press axis providing air atomized<br />
water mist streams. To use <str<strong>on</strong>g>the</str<strong>on</strong>g> press heat <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
extrusi<strong>on</strong> for <str<strong>on</strong>g>the</str<strong>on</strong>g> subsequent <str<strong>on</strong>g>the</str<strong>on</strong>g>rmo-mechanical<br />
processing steps efficiently, <str<strong>on</strong>g>the</str<strong>on</strong>g> whole<br />
setup is designed compactly. From <str<strong>on</strong>g>the</str<strong>on</strong>g> die exit<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> quenching, <str<strong>on</strong>g>the</str<strong>on</strong>g> whole setup has a length<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> less than <strong>on</strong>e meter.<br />
Experimental trials were performed using<br />
a 250-t<strong>on</strong> direct extrusi<strong>on</strong> press (Collin<br />
PLA250t) and a pulse power generator (Maxwell-Magneform<br />
series 7000). Solenoid coils<br />
fabricated from copper and embedded in a<br />
fibre-reinforced resin were used as tool coils<br />
(Poynting GmbH). Using an EN AW-6082 <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
alloy, a porthole extrusi<strong>on</strong> die and a<br />
squared field shaper, a squared hollow pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile<br />
(30 x 30 x 1.8 mm) was extruded with an exiting<br />
speed <str<strong>on</strong>g>of</str<strong>on</strong>g> about 16 mm/s while compressi<strong>on</strong><br />
by electromagnetic forming was applied<br />
periodically in intervals <str<strong>on</strong>g>of</str<strong>on</strong>g> approximately<br />
10s. Semi-finished products with local bulges<br />
arranged around <str<strong>on</strong>g>the</str<strong>on</strong>g> circumference <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
squared tube can be produced.<br />
In order to expand <str<strong>on</strong>g>the</str<strong>on</strong>g> range <str<strong>on</strong>g>of</str<strong>on</strong>g> geometrical<br />
shapes with cross-secti<strong>on</strong>s o<str<strong>on</strong>g>the</str<strong>on</strong>g>r than that<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> extruded <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>, a mandrel can be<br />
used to define <str<strong>on</strong>g>the</str<strong>on</strong>g> cross secti<strong>on</strong> geometry. A<br />
squared mandrel for <str<strong>on</strong>g>the</str<strong>on</strong>g> processing <str<strong>on</strong>g>of</str<strong>on</strong>g> a round<br />
tube was chosen and specially designed to prevent<br />
force fit between <str<strong>on</strong>g>the</str<strong>on</strong>g> workpiece and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
die (Fig. 4). By using a squared field shaper,<br />
with an aperture <str<strong>on</strong>g>of</str<strong>on</strong>g> 43.4 x 43.4 mm and a<br />
length <str<strong>on</strong>g>of</str<strong>on</strong>g> 27 mm <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>centrator, in combinati<strong>on</strong><br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a round tube<br />
(Ø 40 x 2 mm) fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r trials were performed.<br />
In this combinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> field shaper, workpiece<br />
and mandrel an adapted air gap and<br />
pressure distributi<strong>on</strong> al<strong>on</strong>g <str<strong>on</strong>g>the</str<strong>on</strong>g> workpiece<br />
circumference can be achieved which helps<br />
to prevent a force fit between <str<strong>on</strong>g>the</str<strong>on</strong>g> extrudate<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> mandrel. In order to character-<br />
ize <str<strong>on</strong>g>the</str<strong>on</strong>g> forming results when a mandrel was<br />
used as a form defining tool, an experimental<br />
study was performed at charging energies<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 6.4 kJ, 8 kJ and 8.8 kJ. To measure <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
high speed current pulse in <str<strong>on</strong>g>the</str<strong>on</strong>g> tool coil a<br />
Rogowski coil was used. The best forming result/geometrical<br />
accuracy could be achieved at<br />
a charging energy <str<strong>on</strong>g>of</str<strong>on</strong>g> 8 kJ. For this a maximum<br />
coil current amplitude <str<strong>on</strong>g>of</str<strong>on</strong>g> 62 kA and frequency<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> discharging current <str<strong>on</strong>g>of</str<strong>on</strong>g> 4.5 kHz were detected.<br />
To prevent damage by overheating <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> tool coil and <str<strong>on</strong>g>the</str<strong>on</strong>g> electrical isolati<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
field shaper was cooled by compressed air<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 41
EXTRUSION<br />
Fig. 5: (a) tubular product, (b) positi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> mandrel (l<strong>on</strong>gitudinal secti<strong>on</strong>), (c) applicati<strong>on</strong> ‘crashbox’<br />
during stops, e. g. due to billet loading. In an<br />
industrial applicati<strong>on</strong> a water-cooling <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
field shaper by integrated cooling channels<br />
would be useful. Strategies for cooling <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
coil or <str<strong>on</strong>g>the</str<strong>on</strong>g> field shaper in electromagnetic<br />
forming are suggested e. g. by Golovashchenko<br />
et al. (2006) or Hahn (2006).<br />
Fig. 5 a shows a locally geometrically graded<br />
pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile manufactured by <str<strong>on</strong>g>the</str<strong>on</strong>g> introduced<br />
process chain processing <str<strong>on</strong>g>of</str<strong>on</strong>g> a round tube in<br />
combinati<strong>on</strong> with a squared mandrel (Fig. 5 b).<br />
The distance between <str<strong>on</strong>g>the</str<strong>on</strong>g> local bulges is determined<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile’s exit speed and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
discharging frequency <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> electromagnetic<br />
forming machine, which is limited by <str<strong>on</strong>g>the</str<strong>on</strong>g> capacitor<br />
charging time. The general feasibility<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> this technological c<strong>on</strong>cept could be proven.<br />
Details about <str<strong>on</strong>g>the</str<strong>on</strong>g> geometric accuracy, <str<strong>on</strong>g>the</str<strong>on</strong>g> process<br />
limits and defects are provided in Jäger et<br />
al. (2011a).<br />
A possible applicati<strong>on</strong> might be <str<strong>on</strong>g>the</str<strong>on</strong>g> use as<br />
a ‘crashbox’, as a crash absorbing element in<br />
a car bumper system, with an adapted forcedisplacement<br />
characteristic (Fig. 5 c), e. g. designed<br />
as a telescoping tube or inversi<strong>on</strong> tube.<br />
The inversi<strong>on</strong> process involves <str<strong>on</strong>g>the</str<strong>on</strong>g> turning<br />
inside out <str<strong>on</strong>g>of</str<strong>on</strong>g> a tube under axial compressive<br />
load, characterized by a c<strong>on</strong>stant load level<br />
(Guist, L.R. and Marble, D.P., 1966.).<br />
Extrusi<strong>on</strong> and rolling<br />
A roll stand for <str<strong>on</strong>g>the</str<strong>on</strong>g> corrugating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles subsequent to hot extrusi<strong>on</strong> was developed<br />
and aligned to <str<strong>on</strong>g>the</str<strong>on</strong>g> press axis <str<strong>on</strong>g>of</str<strong>on</strong>g> an<br />
extrusi<strong>on</strong> press (Fig. 7). The roll stand c<strong>on</strong>sists<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> two, e. g. sinusoidal shaped, counter<br />
rotating rollers driven by a gear motor. For<br />
adjusting <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling gap, <strong>on</strong>e <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rollers<br />
can be moved laterally by a manually driven<br />
threaded spindle.<br />
As <str<strong>on</strong>g>the</str<strong>on</strong>g> exit speed <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> extrudate varies,<br />
in particular when extrusi<strong>on</strong> is initiated<br />
or restarted after billet loading, <str<strong>on</strong>g>the</str<strong>on</strong>g> roll<br />
stand is swivelling-mounted at <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong><br />
platen <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> press. By this, a clearance for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> compensati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a varying exit speed <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> extrudate is given. Additi<strong>on</strong>ally, excessive<br />
reacti<strong>on</strong> forces between <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> process are prevented. To adapt<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> circumferential speed <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rollers to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> speed, <str<strong>on</strong>g>the</str<strong>on</strong>g> deflecti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> roll<br />
stand is measured by a potentiometer which is<br />
mounted in <str<strong>on</strong>g>the</str<strong>on</strong>g> swivelling axis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling<br />
stand. The obtained signal is used for a closed<br />
Fig. 6: Experimental setup for extrusi<strong>on</strong> and rolling<br />
loop process c<strong>on</strong>trol <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling speed.<br />
This allows <str<strong>on</strong>g>the</str<strong>on</strong>g> rolling stand to be kept parallel<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> platen. Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r details<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> process c<strong>on</strong>trol are given in Jäger et<br />
al. (2011b). For damping <str<strong>on</strong>g>of</str<strong>on</strong>g> possible vibrati<strong>on</strong>s,<br />
a hydraulic shock absorber is mounted<br />
between <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> press and <str<strong>on</strong>g>the</str<strong>on</strong>g> free end<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> roll stand.<br />
Experimental trials were performed extruding<br />
a double-T-shaped pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile <str<strong>on</strong>g>of</str<strong>on</strong>g> an EN AW-<br />
6082 <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloy using a 1,000-t<strong>on</strong>ne<br />
direct extrusi<strong>on</strong> press (SMS Meer) and two<br />
sets <str<strong>on</strong>g>of</str<strong>on</strong>g> sinusoidal shaped rollers, pairwise.<br />
Corrugated web beams with partial corrugati<strong>on</strong><br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> web <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> beam secti<strong>on</strong> could be<br />
produced quasi c<strong>on</strong>tinuously (Figs. 7 a & 7 b).<br />
As an alternative to produce regularly<br />
deformed pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles, irregularly shaped rollers<br />
with e. g. varying amplitude and phase and<br />
even with secti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> a c<strong>on</strong>stant radius can<br />
be used to manufacture geometrical graded<br />
products with e. g. locally adapted torsi<strong>on</strong> rigidity<br />
or bending stiffness.<br />
For <str<strong>on</strong>g>the</str<strong>on</strong>g> first trials two sets composed <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
two sinusoidally shaped rollers were manufac-<br />
tured out <str<strong>on</strong>g>of</str<strong>on</strong>g> sheet metal blanks with a thickness<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 10 mm by laser cutting. Geometrical<br />
details <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> corrugati<strong>on</strong> and <str<strong>on</strong>g>the</str<strong>on</strong>g> positi<strong>on</strong>ing<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> rollers are given in Figs. 7 a) and 7 b).<br />
To prevent shear cutting in <str<strong>on</strong>g>the</str<strong>on</strong>g> transiti<strong>on</strong><br />
area between <str<strong>on</strong>g>the</str<strong>on</strong>g> flange and <str<strong>on</strong>g>the</str<strong>on</strong>g> web, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
rollers were positi<strong>on</strong>ed at a distance <str<strong>on</strong>g>of</str<strong>on</strong>g> 5 mm<br />
parallel to <str<strong>on</strong>g>the</str<strong>on</strong>g> flanges. The metal forming operati<strong>on</strong><br />
processes comprise elements <str<strong>on</strong>g>of</str<strong>on</strong>g> bending<br />
and stretch bending, partially performed<br />
as a free forming and a tool-bounded operati<strong>on</strong>.<br />
Microscopic analysis revealed a crack<br />
42 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
initiati<strong>on</strong> at <str<strong>on</strong>g>the</str<strong>on</strong>g> pole <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> corrugati<strong>on</strong> in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
transiti<strong>on</strong> between <str<strong>on</strong>g>the</str<strong>on</strong>g> flange and <str<strong>on</strong>g>the</str<strong>on</strong>g> web for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> tested c<strong>on</strong>figurati<strong>on</strong> (Fig. 7 c). To prevent<br />
excessive shear, especially in <str<strong>on</strong>g>the</str<strong>on</strong>g> transiti<strong>on</strong><br />
area between <str<strong>on</strong>g>the</str<strong>on</strong>g> flange and <str<strong>on</strong>g>the</str<strong>on</strong>g> web, a redesign<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> geometry and <str<strong>on</strong>g>the</str<strong>on</strong>g> rollers is necessary.<br />
Possible applicati<strong>on</strong>s are seen in <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> lightweight c<strong>on</strong>structi<strong>on</strong> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles<br />
(Fig. 8 a) with reduced web thickness. Bey<strong>on</strong>d<br />
that, pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles with a varying or even a partial<br />
corrugati<strong>on</strong> geometry are c<strong>on</strong>ceivable (Fig.<br />
8 b), which would result in graded bending<br />
rigidity or torsi<strong>on</strong>al stiffness properties.<br />
C<strong>on</strong>clusi<strong>on</strong><br />
Two strategies for <str<strong>on</strong>g>the</str<strong>on</strong>g> manufacturing <str<strong>on</strong>g>of</str<strong>on</strong>g> products,<br />
or ra<str<strong>on</strong>g>the</str<strong>on</strong>g>r semi-finished products, with<br />
locally adapted geometrical properties were<br />
developed. Due to geometric limitati<strong>on</strong>s and<br />
accessibilities <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> cross secti<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> technology<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> integrated processing <str<strong>on</strong>g>of</str<strong>on</strong>g> open and hollow<br />
pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles by forming is different.<br />
For open secti<strong>on</strong>s a rolling setup for corrugating<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> web <str<strong>on</strong>g>of</str<strong>on</strong>g> an I-beam secti<strong>on</strong> subsequent<br />
to hot extrusi<strong>on</strong> was developed and<br />
tested. Future work will focus <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> extensi<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> geometrical complexity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> products<br />
and <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> geometrical, mechanical<br />
and resulting structural properties.<br />
Experiments were c<strong>on</strong>ducted <strong>on</strong> hollow<br />
pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles which were compressed by electromagnetic<br />
forming subsequent to extrusi<strong>on</strong>.<br />
Due to an extremely short processing time <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> high speed forming process, a compensati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> relative speed between <str<strong>on</strong>g>the</str<strong>on</strong>g> workpiece<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> tooling can be ignored. By <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
c<strong>on</strong>tactless force inducti<strong>on</strong>, an additi<strong>on</strong>al benefit<br />
is given for <str<strong>on</strong>g>the</str<strong>on</strong>g> heat balance. To fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
understand this process, analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> process<br />
dependencies in <str<strong>on</strong>g>the</str<strong>on</strong>g> system workpiece, field<br />
shaper and mandrel is necessary.<br />
Fig. 7: (a) L<strong>on</strong>gitudinal cut, (b) cross secti<strong>on</strong>, (c) crack<br />
Acknowledgement<br />
This work was carried out in <str<strong>on</strong>g>the</str<strong>on</strong>g> subproject<br />
TPA2 within <str<strong>on</strong>g>the</str<strong>on</strong>g> Transregi<strong>on</strong>al Collaborative<br />
Research Centre SFB/TR30, funded by <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
German Research Foundati<strong>on</strong> (DFG).<br />
References<br />
Fig. 8: Corrugated web beam, a) c<strong>on</strong>tinuously corrugate, b) partly corrugated<br />
DIN 8583-6, 2003. Manufacturing processes forming<br />
under compressive c<strong>on</strong>diti<strong>on</strong>s – Part 6: Extrusi<strong>on</strong>;<br />
Classificati<strong>on</strong>, subdivisi<strong>on</strong>, terms and definiti<strong>on</strong>s,<br />
Beuth, Berlin.<br />
Guist, L.R., Marble, D.P., 1966. Predicti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
inversi<strong>on</strong> load. NASA<br />
Technical Note 3622.<br />
Golovashchenko, S.,<br />
Dmitriev, V., Canfield,<br />
P., Krause, A., Maranville,<br />
C., 2006. Patent<br />
applicati<strong>on</strong> US<br />
2006/0086165A1.<br />
Apparatus for electromagnetic<br />
forming with<br />
durability and efficiency<br />
enhancement.<br />
Hahn, R., 2004.<br />
Werkzeuge zum impulsmagnetischenWarmfügen<br />
v<strong>on</strong> Pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ilen aus<br />
Aluminium- und Magnesiumlegierungen,doctoral<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>sis, Technische<br />
Universität Berlin.<br />
Hall, D. D., Mudawar, I.,<br />
EXTRUSION<br />
1996. Optimizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> quench history <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
parts for superior mechanical properties, Internati<strong>on</strong>al<br />
Journal <str<strong>on</strong>g>of</str<strong>on</strong>g> Heat and Mass Transfer 39 (1),<br />
p. 81-95.<br />
Harvey, G. W., Brower, D. F., 1961. US patent 2 976<br />
907. Metal forming device and method, 28 March.<br />
Jäger, A., Risch, D., Tekkaya, A. E., 2009. Patent<br />
applicati<strong>on</strong> <strong>DE</strong> 10 2009 039 759 A1. Verfahren und<br />
Vorrichtung zum Strangpressen und nachfolgender<br />
elektromagnetischer Umformung, 31 August.<br />
Jäger, A., Risch, D., Tekkaya, A. E., 2011a. Thermomechanical<br />
processing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles by<br />
integrated electromagnetic compressi<strong>on</strong> subsequent<br />
to hot extrusi<strong>on</strong>, Journal <str<strong>on</strong>g>of</str<strong>on</strong>g> Materials Processing<br />
Technology 211 (5), Special Issue: Impulse Forming,<br />
p. 936-943.<br />
Jäger, A., Ben Khalifa, N., Psyk, V., Tekkaya, A.<br />
E. 2011b. Thermo-mechanical processing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles subsequent to hot extrusi<strong>on</strong>, steel<br />
research internati<strong>on</strong>al, Special editi<strong>on</strong>: Internati<strong>on</strong>al<br />
C<strong>on</strong>ference <strong>on</strong> Technology <str<strong>on</strong>g>of</str<strong>on</strong>g> Plasticity,<br />
ICTP, 2011, Aachen, Germany<br />
Laue, K. Stenger, H., 1976. Strangpressen, Aluminium<br />
Verlag, Düsseldorf, p. 1. Ostermann, F.,<br />
2007. Anwendungstechnologie Aluminium, 2nd<br />
Editi<strong>on</strong>. Springer, Berlin, p. 440-441.<br />
Authors<br />
Dipl.-Ing. Andreas Jäger is head <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> department<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> bulk metal forming at <str<strong>on</strong>g>the</str<strong>on</strong>g> Institute <str<strong>on</strong>g>of</str<strong>on</strong>g> Forming<br />
Technology and Lightweight C<strong>on</strong>structi<strong>on</strong> (IUL).<br />
Dipl.-Ing. Nooman Ben Khalifa is chief engineer for<br />
research at <str<strong>on</strong>g>the</str<strong>on</strong>g> IUL.<br />
Pr<str<strong>on</strong>g>of</str<strong>on</strong>g>. Dr.-Ing. A. Erman Tekkaya is head <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> IUL.<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 43
EXTRUSION<br />
Flexible automated material flow in extrusi<strong>on</strong> operati<strong>on</strong>s<br />
Georg Papadopoulos, H+H Herrmann + Hieber GmbH<br />
The logistics specialist H+H Herrmann +<br />
Hieber based in Denkendorf near Stuttgart<br />
has worked for more than 20 years<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> special field <str<strong>on</strong>g>of</str<strong>on</strong>g> in-house transport<br />
in extrusi<strong>on</strong> plants. Since 1989 H+H has<br />
planned and supplied machinery and<br />
equipment for almost every major extrusi<strong>on</strong><br />
plants in Germany and for many<br />
elsewhere in Europe.<br />
The fact that material flow automati<strong>on</strong> in this<br />
sector has become so successfully established,<br />
can be attributed <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>e hand to <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tinual<br />
growth <str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong> producti<strong>on</strong> in Germany,<br />
but in additi<strong>on</strong> ec<strong>on</strong>omic c<strong>on</strong>diti<strong>on</strong>s in<br />
Europe after <str<strong>on</strong>g>the</str<strong>on</strong>g> fall <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Ir<strong>on</strong> Curtain have<br />
played a part not to be underestimated. The<br />
ec<strong>on</strong>omic opening has created opportunities,<br />
but has at <str<strong>on</strong>g>the</str<strong>on</strong>g> same time brought Germany, as<br />
an established industrial locati<strong>on</strong>, under str<strong>on</strong>g<br />
pressure. Faced with <str<strong>on</strong>g>the</str<strong>on</strong>g> choice between relocating<br />
to regi<strong>on</strong>s with lower labour costs<br />
and embarking up<strong>on</strong> rati<strong>on</strong>alisati<strong>on</strong> efforts,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> industry solved <str<strong>on</strong>g>the</str<strong>on</strong>g> dilemma by<br />
opting for <str<strong>on</strong>g>the</str<strong>on</strong>g> sec<strong>on</strong>d alternative. This set in<br />
moti<strong>on</strong> unprecedented rati<strong>on</strong>alisati<strong>on</strong> initiatives,<br />
which have brought extrusi<strong>on</strong> plants in<br />
Germany to a worldwide peak positi<strong>on</strong> from<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> technological standpoint.<br />
Numerous technical and organisati<strong>on</strong>al innovati<strong>on</strong>s<br />
have c<strong>on</strong>tributed to this successful<br />
development. And in this it is certain that, not<br />
least, <str<strong>on</strong>g>the</str<strong>on</strong>g> step by step automati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> material<br />
flow through <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> plant has been an<br />
important factor. It can now be stated with<br />
some c<strong>on</strong>fidence that <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> plants<br />
which operate most successfully are those<br />
which paid attenti<strong>on</strong> to that aspect in good<br />
time. Since <str<strong>on</strong>g>the</str<strong>on</strong>g>re is unanimous c<strong>on</strong>victi<strong>on</strong><br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> branch that in times to come competitive<br />
pressure will not get any less severe, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
compulsi<strong>on</strong> to rati<strong>on</strong>alise and automate is becoming<br />
still more urgent – and thus too, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
demand for automated internal logistics.<br />
Analysis and planning – <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
starting point <str<strong>on</strong>g>of</str<strong>on</strong>g> any project<br />
At H+H Herrmann + Hieber every project<br />
begins with analysis and comprehensive, forward-looking<br />
planning. This demands specialists<br />
who not <strong>on</strong>ly have mastery over <str<strong>on</strong>g>the</str<strong>on</strong>g> tools<br />
for material flow planning, but in additi<strong>on</strong><br />
possess comprehensive knowledge about <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
processes involved in extrusi<strong>on</strong> operati<strong>on</strong>s.<br />
Automated material flow at Pandolfo Alluminio<br />
In every case <str<strong>on</strong>g>the</str<strong>on</strong>g> planning is based <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
individual circumstances <str<strong>on</strong>g>of</str<strong>on</strong>g> a project and <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> planning figures <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong> operati<strong>on</strong>.<br />
As dem<strong>on</strong>strated for H+H in well over<br />
50 successfully completed extrusi<strong>on</strong> projects,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> specificati<strong>on</strong>s and requirements to be met<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> planning are always different. In practice<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>re is no standard soluti<strong>on</strong>.<br />
Planning starts with observati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
current situati<strong>on</strong>, for which all <str<strong>on</strong>g>the</str<strong>on</strong>g> data are<br />
collected. The quantitative framework (press<br />
capacity, ageing capacity, etc.) is specified by<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong> department. For <str<strong>on</strong>g>the</str<strong>on</strong>g> definiti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> target situati<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g> planning must generally<br />
take into account that what is involved<br />
is not static values, but a dynamic, variable<br />
operating situati<strong>on</strong>. This means that <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong><br />
plant must by capable <str<strong>on</strong>g>of</str<strong>on</strong>g> resp<strong>on</strong>ding flexibly<br />
to changing market needs. The associated<br />
material flow variati<strong>on</strong>s necessarily have to be<br />
based <strong>on</strong> forward-looking planning c<strong>on</strong>siderati<strong>on</strong>s.<br />
In this c<strong>on</strong>text overall planning takes into<br />
account not just <str<strong>on</strong>g>the</str<strong>on</strong>g> transport <str<strong>on</strong>g>of</str<strong>on</strong>g> extruded secti<strong>on</strong>s,<br />
but also that <str<strong>on</strong>g>of</str<strong>on</strong>g> all auxiliary materials<br />
required for <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong> process. This includes<br />
in particular <str<strong>on</strong>g>the</str<strong>on</strong>g> transport <str<strong>on</strong>g>of</str<strong>on</strong>g> spacers<br />
and packing materials, as well as <str<strong>on</strong>g>the</str<strong>on</strong>g> transport<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> scrap.<br />
When <str<strong>on</strong>g>the</str<strong>on</strong>g> individual material flows have<br />
been defined and <str<strong>on</strong>g>the</str<strong>on</strong>g> necessary areas calculated,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> next step is to implement <str<strong>on</strong>g>the</str<strong>on</strong>g> soluti<strong>on</strong><br />
in design and structural terms. For this,<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> first instance tried and tested basic<br />
modules are available – manually c<strong>on</strong>trolled<br />
trolleys, automatic cranes and o<str<strong>on</strong>g>the</str<strong>on</strong>g>rs – whose<br />
dimensi<strong>on</strong>s and capacities can be adapted to<br />
suit <str<strong>on</strong>g>the</str<strong>on</strong>g> requirements in each case. During this<br />
planning phase it is found in many cases that<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> planned material flow cannot be achieved<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> standard comp<strong>on</strong>ents available – or<br />
<strong>on</strong>ly insufficiently so. At that point <str<strong>on</strong>g>the</str<strong>on</strong>g> innovative<br />
ability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> planning team is called<br />
into play.<br />
Generally, in projects <str<strong>on</strong>g>of</str<strong>on</strong>g> this type <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
changes to be made have to be carried out<br />
while interfering as little as possible with<br />
<strong>on</strong>-going extrusi<strong>on</strong> operati<strong>on</strong>s. If this is not<br />
achieved <str<strong>on</strong>g>the</str<strong>on</strong>g> investment project is doomed to<br />
failure already from <str<strong>on</strong>g>the</str<strong>on</strong>g> start, since it is <str<strong>on</strong>g>the</str<strong>on</strong>g>n<br />
no l<strong>on</strong>ger viable.<br />
Pandolfo Alluminio – an<br />
example <str<strong>on</strong>g>of</str<strong>on</strong>g> a successful project<br />
How to set about implementing such a project,<br />
and what its effects can be, is shown here by<br />
c<strong>on</strong>sidering <str<strong>on</strong>g>the</str<strong>on</strong>g> example <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Italian extrusi<strong>on</strong><br />
plant Pandolfo Alluminio in Padua in<br />
nor<str<strong>on</strong>g>the</str<strong>on</strong>g>rn Italy.<br />
“Please supply us with a detailed material<br />
flow plan, to include all structural changes for<br />
automating <str<strong>on</strong>g>the</str<strong>on</strong>g> pallet transport with a view<br />
to increasing output in <str<strong>on</strong>g>the</str<strong>on</strong>g> medium term by<br />
about a third, up to 32,000 t<strong>on</strong>nes per year!”<br />
With this request, made by Gianfranco Pandolfo,<br />
chairman <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> board and CEO <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Italian extrusi<strong>on</strong> plant Pandolfo Alluminio to<br />
H+H, a comprehensive modernisati<strong>on</strong> and<br />
extensi<strong>on</strong> programme worth some 15 milli<strong>on</strong><br />
euros began in 2003. The result sets new standards<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> sector.<br />
44 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011<br />
Images: H + H
The medium-sized, family-run company was<br />
at that time producing up to 23,000 tpy at its<br />
Plant 1, with around 400 employees and four<br />
extrusi<strong>on</strong> lines. In Plant 2, about five kilometres<br />
from <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> plant, <str<strong>on</strong>g>the</str<strong>on</strong>g> Pandolfo<br />
group also operates efficient secti<strong>on</strong> machining<br />
and surface finishing facilities.<br />
At <str<strong>on</strong>g>the</str<strong>on</strong>g> start <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> project, toge<str<strong>on</strong>g>the</str<strong>on</strong>g>r with<br />
Pandolfo H+H worked out a general plan<br />
which – after approval by <str<strong>on</strong>g>the</str<strong>on</strong>g> customer – was<br />
implemented in several steps, and this in such<br />
a way that secti<strong>on</strong> producti<strong>on</strong> was affected as<br />
little as possible. The fourth and for <str<strong>on</strong>g>the</str<strong>on</strong>g> time<br />
being <str<strong>on</strong>g>the</str<strong>on</strong>g> last step <str<strong>on</strong>g>of</str<strong>on</strong>g> this comprehensive<br />
project was completed according to plan in<br />
2008.<br />
The project starts at <str<strong>on</strong>g>the</str<strong>on</strong>g> point where <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
sawn secti<strong>on</strong> lengths, stacked in racks, are<br />
available. At this point <str<strong>on</strong>g>the</str<strong>on</strong>g> previously fixed<br />
material flow has now been replaced by flexible<br />
handling. This flexible automati<strong>on</strong> makes<br />
special demands. At Pandolfo <str<strong>on</strong>g>the</str<strong>on</strong>g> number <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
logistical opti<strong>on</strong>s available was drastically increased<br />
by free allocati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material to<br />
furnaces, storage positi<strong>on</strong>s and packing stati<strong>on</strong>s<br />
and by partial sorting out for fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
processing.<br />
At <str<strong>on</strong>g>the</str<strong>on</strong>g> start <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> project, according to plan<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment<br />
capacities were extended<br />
and modernised.<br />
Two older heat<br />
treatment furnaces<br />
were dismantled and<br />
replaced by new units.<br />
In additi<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> heat<br />
treatment capacity<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> plant was also<br />
massively increased<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> commissi<strong>on</strong>ing<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r, large<br />
furnace unit. The final<br />
result is that <str<strong>on</strong>g>the</str<strong>on</strong>g> plant<br />
now has a total <str<strong>on</strong>g>of</str<strong>on</strong>g> seven<br />
furnace units.<br />
In accordance with works specificati<strong>on</strong>s <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
total producti<strong>on</strong> from all four presses can be<br />
allocated arbitrarily to any <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> total <str<strong>on</strong>g>of</str<strong>on</strong>g> seven<br />
heat treatment furnaces. Operati<strong>on</strong> is <str<strong>on</strong>g>the</str<strong>on</strong>g>refore<br />
free and individual charges, made up in<br />
accordance with various criteria, can be distributed<br />
between <str<strong>on</strong>g>the</str<strong>on</strong>g> existing furnaces without<br />
any restricti<strong>on</strong>. Besides, <str<strong>on</strong>g>the</str<strong>on</strong>g>re is <str<strong>on</strong>g>of</str<strong>on</strong>g> course<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> opti<strong>on</strong> to omit heat treatment entirely.<br />
All <str<strong>on</strong>g>the</str<strong>on</strong>g> furnaces are charged by a central<br />
automatic crane which moves over <str<strong>on</strong>g>the</str<strong>on</strong>g> full<br />
EXTRUSION<br />
Interim storage <str<strong>on</strong>g>of</str<strong>on</strong>g> racks at <str<strong>on</strong>g>the</str<strong>on</strong>g> transfer stati<strong>on</strong> between two automatic cranes<br />
width <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> shed. In this case <str<strong>on</strong>g>the</str<strong>on</strong>g> automatic<br />
crane is, as it were, <str<strong>on</strong>g>the</str<strong>on</strong>g> link between <str<strong>on</strong>g>the</str<strong>on</strong>g> presses<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment. The racks, filled by<br />
stacking machines, are stored intermediately<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> help <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> crane at depositi<strong>on</strong> points<br />
underneath <str<strong>on</strong>g>the</str<strong>on</strong>g> crane track and are <str<strong>on</strong>g>the</str<strong>on</strong>g>n taken<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace c<strong>on</strong>cerned as necessary.<br />
At <str<strong>on</strong>g>the</str<strong>on</strong>g> outlet <str<strong>on</strong>g>of</str<strong>on</strong>g> each furnace <str<strong>on</strong>g>the</str<strong>on</strong>g> heat<br />
treated goods are checked. Special inspecti<strong>on</strong><br />
positi<strong>on</strong>s have been installed for this purpose.<br />
All <str<strong>on</strong>g>the</str<strong>on</strong>g> racks that leave <str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment fur-<br />
TOOL STEEL AND TOOLING<br />
COMPETENCE<br />
FROM<br />
ONE SOURCE<br />
Kind & Co., Edelstahlwerk, KG<br />
Bielsteiner Str. 124 – 130<br />
D-51674 Wiehl<br />
Tel +49 (0) 22 62 / 84-0<br />
Fax +49 (0) 22 62 / 84-175<br />
info@kind-co.de · www.kind-co.de
EXTRUSION<br />
naces pass through this inspecti<strong>on</strong><br />
stage. The heat treatment process<br />
data are recorded by <str<strong>on</strong>g>the</str<strong>on</strong>g> transport<br />
management system (TMS), archived,<br />
and sent <strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> superordinated<br />
operati<strong>on</strong>al computer level<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> plant for charge tracking<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>text <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> QA system.<br />
The checked racks are again<br />
stored intermediately and are <str<strong>on</strong>g>the</str<strong>on</strong>g>n<br />
taken to individual packing positi<strong>on</strong>s<br />
as necessary. In this area too<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>re has to be unrestricted flexibility:<br />
any rack can be assigned to<br />
any packing positi<strong>on</strong>. To be able<br />
to achieve this a hi<str<strong>on</strong>g>the</str<strong>on</strong>g>rto unique<br />
transport and storage system was<br />
developed. Owing to <str<strong>on</strong>g>the</str<strong>on</strong>g> numerous transport<br />
opti<strong>on</strong>s and <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>sequently large storage<br />
area involved, a system comprising several<br />
automatic cranes was provided. The cranes operate<br />
redundantly, i. e. <str<strong>on</strong>g>the</str<strong>on</strong>g>y match <str<strong>on</strong>g>the</str<strong>on</strong>g>ir acti<strong>on</strong>s<br />
to <strong>on</strong>e ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r in a flexible manner. Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>rmore,<br />
as a special feature automatic optimisati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> all transport and storage movements<br />
is provided and this covers all <str<strong>on</strong>g>the</str<strong>on</strong>g> transport<br />
units. In practice this means that for every task<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> optimum procedure (shortest path, smallest<br />
number <str<strong>on</strong>g>of</str<strong>on</strong>g> individual movements, etc.) is<br />
sought. This takes place having regard to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
system as a whole, i.e. <str<strong>on</strong>g>the</str<strong>on</strong>g> rack movements are<br />
co-ordinated automatically in accordance with<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> specified optimum.<br />
A fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r automatic crane is provided for<br />
goods to be separated out, which are taken in<br />
special racks to Plant 2 for fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r processing.<br />
These secti<strong>on</strong>s have to be re-stacked in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
special racks. The same crane provides transport<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> re-stacking stati<strong>on</strong>.<br />
The detailed planning <str<strong>on</strong>g>of</str<strong>on</strong>g> this area had<br />
to ensure that <str<strong>on</strong>g>the</str<strong>on</strong>g> floor <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> shed remains<br />
freely accessible and not obstructed by transport<br />
units. This was achieved by locating <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
rack transport so far as possible around <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
edges. Full racks are transported at floor level<br />
whereas in c<strong>on</strong>trast empty racks are generally<br />
moved three metres above floor level.<br />
The packing positi<strong>on</strong>s are located after <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
store areas. Here too, <str<strong>on</strong>g>the</str<strong>on</strong>g> packing positi<strong>on</strong>s<br />
can receive material automatically from any<br />
part <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> store. For this, <str<strong>on</strong>g>the</str<strong>on</strong>g> racks are placed<br />
by <strong>on</strong>e <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> automatic cranes <strong>on</strong>to <str<strong>on</strong>g>the</str<strong>on</strong>g> appropriate<br />
roller track and taken automatically<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> packing positi<strong>on</strong> intended. At present a<br />
total <str<strong>on</strong>g>of</str<strong>on</strong>g> seven packing positi<strong>on</strong>s are available.<br />
Each <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>m is equipped with accessories<br />
which facilitate <str<strong>on</strong>g>the</str<strong>on</strong>g> work <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> packers and<br />
help to increase packing output.<br />
The system as a whole is c<strong>on</strong>trolled by a<br />
central transport management system. This<br />
Automatic crane No 4 with overhead roller track for empty racks at <str<strong>on</strong>g>the</str<strong>on</strong>g> back<br />
system, which also assists producti<strong>on</strong> planning,<br />
was developed by H+H toge<str<strong>on</strong>g>the</str<strong>on</strong>g>r with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
company Aberle Steuerungstechnik in Leingarten.<br />
At Pandolfo <str<strong>on</strong>g>the</str<strong>on</strong>g> new system was installed<br />
already during <str<strong>on</strong>g>the</str<strong>on</strong>g> first phase <str<strong>on</strong>g>of</str<strong>on</strong>g> project<br />
implementati<strong>on</strong>, so that <str<strong>on</strong>g>the</str<strong>on</strong>g> areas completed<br />
<strong>on</strong>e after ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r could be integrated into<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> system step by step. The central transport<br />
management system records all <str<strong>on</strong>g>the</str<strong>on</strong>g> secti<strong>on</strong><br />
racks by means <str<strong>on</strong>g>of</str<strong>on</strong>g> barcodes and c<strong>on</strong>trols <str<strong>on</strong>g>the</str<strong>on</strong>g>ir<br />
movements up to <str<strong>on</strong>g>the</str<strong>on</strong>g> storage <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> packed<br />
goods. It is c<strong>on</strong>sequently in a positi<strong>on</strong> at anytime<br />
to provide informati<strong>on</strong> about <str<strong>on</strong>g>the</str<strong>on</strong>g> current<br />
positi<strong>on</strong> and processing status <str<strong>on</strong>g>of</str<strong>on</strong>g> each and<br />
every rack. This ability makes <str<strong>on</strong>g>the</str<strong>on</strong>g> transport<br />
management system a valuable aid to producti<strong>on</strong><br />
planning.<br />
Moreover, it was decided at Pandolfo<br />
to integrate scrap transport as well into <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
automatic system. Any scrap produced in or<br />
arriving at <str<strong>on</strong>g>the</str<strong>on</strong>g> packing area, which has to be<br />
returned to <str<strong>on</strong>g>the</str<strong>on</strong>g> foundry, is taken <str<strong>on</strong>g>the</str<strong>on</strong>g>re fully<br />
automatically by a central transport system.<br />
To maximise value recovery, this even takes<br />
place after sorting into distinct alloys.<br />
Success factors: flexibility<br />
and low operating costs<br />
Already at <str<strong>on</strong>g>the</str<strong>on</strong>g> beginning it was stated that automated<br />
secti<strong>on</strong> transport through <str<strong>on</strong>g>the</str<strong>on</strong>g> plant<br />
– under <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>diti<strong>on</strong>s prevailing in <str<strong>on</strong>g>the</str<strong>on</strong>g> work<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> central-European extrusi<strong>on</strong> plants – has<br />
ec<strong>on</strong>omic advantages and substantially improves<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> competitiveness <str<strong>on</strong>g>of</str<strong>on</strong>g> an appropriately<br />
equipped extrusi<strong>on</strong> plant.<br />
The prerequisite for this is, firstly, that operati<strong>on</strong>s<br />
must take place absolutely faultlessly.<br />
For that reas<strong>on</strong> particular attenti<strong>on</strong> is paid to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> aim <str<strong>on</strong>g>of</str<strong>on</strong>g> ‘maximum availability’. At Pandolfo,<br />
for example, <str<strong>on</strong>g>the</str<strong>on</strong>g> design <str<strong>on</strong>g>of</str<strong>on</strong>g> a new rack<br />
type adapted to <str<strong>on</strong>g>the</str<strong>on</strong>g> system has proved to be a<br />
decisive factor. Before being fed into <str<strong>on</strong>g>the</str<strong>on</strong>g> trans-<br />
port system each rack is checked<br />
for damage. In this way and with<br />
a series <str<strong>on</strong>g>of</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r measures, a total<br />
availability <str<strong>on</strong>g>of</str<strong>on</strong>g> 98.5 percent over<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> year, and for some parts <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
plant even more than 99 percent,<br />
is achieved.<br />
The end result is that <str<strong>on</strong>g>the</str<strong>on</strong>g> logistical<br />
objectives <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> project have<br />
been fully implemented:<br />
• automated material transport<br />
• absolute flexibility, i. e. all aggregates<br />
can freely be called into<br />
acti<strong>on</strong><br />
• linking <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material flow to<br />
and from Plant 2<br />
• automatic return transport to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
central scrap collecti<strong>on</strong> point and <str<strong>on</strong>g>the</str<strong>on</strong>g> foundry,<br />
etc.<br />
The c<strong>on</strong>diti<strong>on</strong>s set by <str<strong>on</strong>g>the</str<strong>on</strong>g> customer:<br />
• maximum availability <str<strong>on</strong>g>of</str<strong>on</strong>g> all units<br />
• no damage during transport<br />
• implementati<strong>on</strong> without interfering with<br />
operati<strong>on</strong>s<br />
• high safety standards<br />
• unobstructed shed floor surface<br />
have also been met in full. Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>rmore, at<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>clusi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> project it emerged that<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> forecast planning figures are in some cases<br />
being substantially exceeded.<br />
The extrusi<strong>on</strong> enterprise is benefiting from<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> automati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> its mat flow in many ways.<br />
The rati<strong>on</strong>alisati<strong>on</strong> effect is directly visible in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> reduced pers<strong>on</strong>nel needs and <str<strong>on</strong>g>the</str<strong>on</strong>g> troublefree<br />
operati<strong>on</strong>. Transport-generated scrap, a<br />
not negligible cost factor during <str<strong>on</strong>g>the</str<strong>on</strong>g> operati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a c<strong>on</strong>venti<strong>on</strong>ally equipped extrusi<strong>on</strong> plant,<br />
has never yet been produced so far!<br />
Above all, however, <str<strong>on</strong>g>the</str<strong>on</strong>g> company is in a<br />
positi<strong>on</strong> to resp<strong>on</strong>d, with <str<strong>on</strong>g>the</str<strong>on</strong>g> same staff, to<br />
changing market circumstances. In <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
Pandolfo Alluminio it has proved possible in<br />
this way to increase <str<strong>on</strong>g>the</str<strong>on</strong>g> plant’s capacity by<br />
more than <str<strong>on</strong>g>the</str<strong>on</strong>g> promised 35 percent. If necessary<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> company is now capable <str<strong>on</strong>g>of</str<strong>on</strong>g> producing<br />
35,000 t<strong>on</strong>nes a year. Should <str<strong>on</strong>g>the</str<strong>on</strong>g> market<br />
weaken, however, as it did unexpectedly for<br />
extrusi<strong>on</strong> plants at <str<strong>on</strong>g>the</str<strong>on</strong>g> end <str<strong>on</strong>g>of</str<strong>on</strong>g> 2008, producti<strong>on</strong><br />
can be adapted flexibly thanks to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
lower staffing level.<br />
To what extent ec<strong>on</strong>omy and flexibility<br />
can be increased in specific, individual cases<br />
depends <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> initial situati<strong>on</strong> and <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
circumstances <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> case. No generally valid<br />
figure can be given, for that reas<strong>on</strong>. However,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> projects implemented until now show that<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> return <str<strong>on</strong>g>of</str<strong>on</strong>g> investment (ROI) for <str<strong>on</strong>g>the</str<strong>on</strong>g> resources<br />
devoted to extrusi<strong>on</strong> plant automati<strong>on</strong> is<br />
not l<strong>on</strong>ger than four to five years.<br />
�<br />
46 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
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APPLICATION-ORIENTED TECHNOLOGIES<br />
Laser cleaning and surface modificati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> – first step to a green plant<br />
Edwin Büchter, Clean-Lasersysteme GmbH<br />
Advanced industrial lasers have evolved<br />
well bey<strong>on</strong>d simple cutting and welding<br />
applicati<strong>on</strong>s. Laser technology now <str<strong>on</strong>g>of</str<strong>on</strong>g>fers<br />
an industrial de-coating and surface<br />
cleaning soluti<strong>on</strong> that is cost-effective<br />
as well as resp<strong>on</strong>sive to envir<strong>on</strong>mental<br />
c<strong>on</strong>cerns. From <str<strong>on</strong>g>the</str<strong>on</strong>g> automated cleaning<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> moulds to precise de-coating to<br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g> removal, laser surface treatments<br />
are proving to be an attractive opti<strong>on</strong> to<br />
traditi<strong>on</strong>al labour intensive methods. Besides<br />
simple cleaning applicati<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> laser<br />
technology is also capable to apply modificati<strong>on</strong>s<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> substrate surface such as<br />
roughening or changing <str<strong>on</strong>g>the</str<strong>on</strong>g> metallurgical<br />
structure. Using a laser for surface modificati<strong>on</strong><br />
means substituting critical c<strong>on</strong>venti<strong>on</strong>al<br />
chemical media blasting process<br />
by cleaning with laser light.<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> past decade laser cleaning and surface<br />
treatment systems have generated significant<br />
interest as a viable alternative to c<strong>on</strong>venti<strong>on</strong>al<br />
cleaning and paint removal technologies.<br />
Research <str<strong>on</strong>g>of</str<strong>on</strong>g> mobile, reliable, and powerful<br />
laser systems for cleaning and paint removal<br />
operati<strong>on</strong>s began in <str<strong>on</strong>g>the</str<strong>on</strong>g> late eighties with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
modificati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> weld or cutting lasers into laser<br />
systems for surface preparati<strong>on</strong>. This approach<br />
did not meet <str<strong>on</strong>g>the</str<strong>on</strong>g> requirements for a surface<br />
preparati<strong>on</strong> laser, which are significantly different<br />
than for cutting and welding. In <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
early nineties, research took place around <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
world for more efficient, reliable laser systems<br />
for surface preparati<strong>on</strong> work. It took ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
few years to develop <str<strong>on</strong>g>the</str<strong>on</strong>g> technology from a<br />
laboratory system to a system capable for use<br />
in day-to-day industrial operati<strong>on</strong>s. Today, laser<br />
systems are widely used for various surface<br />
preparati<strong>on</strong> tasks in many industries. Those<br />
tasks include: mould cleaning, paint removal,<br />
joining pretreatment, oil and grease removal,<br />
and many more.<br />
Operating principle<br />
The laser generates a directed and m<strong>on</strong>ochromatic<br />
beam <str<strong>on</strong>g>of</str<strong>on</strong>g> light. In order to create a high<br />
power density, <str<strong>on</strong>g>the</str<strong>on</strong>g> laser beam is also typically<br />
tightly focused. In <str<strong>on</strong>g>the</str<strong>on</strong>g> focal point, <str<strong>on</strong>g>the</str<strong>on</strong>g> intense<br />
laser beam is absorbed by <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>taminati<strong>on</strong><br />
or paint and <str<strong>on</strong>g>the</str<strong>on</strong>g>rmally incinerates or sublimates<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> target material, i. e. paint or c<strong>on</strong>-<br />
Operating principle (Nd:YAG): pulsed laser vaporizes <str<strong>on</strong>g>the</str<strong>on</strong>g> absorbing ‘dirt’ <str<strong>on</strong>g>layer</str<strong>on</strong>g>, scanned beam covers and<br />
cleans <str<strong>on</strong>g>the</str<strong>on</strong>g> whole surface until <str<strong>on</strong>g>the</str<strong>on</strong>g> blank substrate reflects <str<strong>on</strong>g>the</str<strong>on</strong>g> laser radiati<strong>on</strong><br />
taminati<strong>on</strong>s. This incinerati<strong>on</strong> or vaporizati<strong>on</strong><br />
will, in combinati<strong>on</strong> with <str<strong>on</strong>g>the</str<strong>on</strong>g> resulting micro<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>rmal shockwave, remove <str<strong>on</strong>g>the</str<strong>on</strong>g> target material<br />
as l<strong>on</strong>g as <str<strong>on</strong>g>the</str<strong>on</strong>g> target material is able to<br />
absorb <str<strong>on</strong>g>the</str<strong>on</strong>g> laser energy. The better <str<strong>on</strong>g>the</str<strong>on</strong>g> target<br />
material absorbs <str<strong>on</strong>g>the</str<strong>on</strong>g> energy, <str<strong>on</strong>g>the</str<strong>on</strong>g> faster it can<br />
be removed.<br />
Colour, chemical compositi<strong>on</strong> and thickness<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> target <str<strong>on</strong>g>layer</str<strong>on</strong>g> all have a direct impact <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> effectiveness <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> process. The removal<br />
process automatically stops <strong>on</strong>ce a metal substrate<br />
is reached since metal surfaces reflect<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> laser beam and do not generally absorb<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> laser energy.<br />
The heat transfer into <str<strong>on</strong>g>the</str<strong>on</strong>g> substrate material<br />
can be a critical factor. To minimize this<br />
effect, many laser equipment manufacturers<br />
use pulsed laser sources.<br />
The laser intensity, known as <str<strong>on</strong>g>the</str<strong>on</strong>g> laser<br />
power per beam spot, is a critical parameter<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> heat transfer into <str<strong>on</strong>g>the</str<strong>on</strong>g> substrate material.<br />
Very short laser pulses with a pulse durati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <strong>on</strong>ly a few nanosec<strong>on</strong>ds (ns) in combinati<strong>on</strong><br />
with a very small focus diameter (less<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>n 500 μm) result in a minimal heat transfer<br />
into <str<strong>on</strong>g>the</str<strong>on</strong>g> substrate material. Under normal operating<br />
c<strong>on</strong>diti<strong>on</strong>s and with <str<strong>on</strong>g>the</str<strong>on</strong>g> right process<br />
parameters, damage to <str<strong>on</strong>g>the</str<strong>on</strong>g> substrate material<br />
can be eliminated. The heat transfer factor <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
c<strong>on</strong>tinuous wave laser systems is much higher<br />
and might result in substrate temperatures that<br />
will damage <str<strong>on</strong>g>the</str<strong>on</strong>g> substrate. Test results with a<br />
Precise automated paint stripping / manual paint stripping for repair applicati<strong>on</strong>s<br />
48 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Surface modificati<strong>on</strong> and de-coating <str<strong>on</strong>g>of</str<strong>on</strong>g> anodized <str<strong>on</strong>g>layer</str<strong>on</strong>g>s for electrical b<strong>on</strong>ding<br />
Laser modificati<strong>on</strong> <strong>on</strong> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> surfaces for adhesive b<strong>on</strong>ding and improved wettability prior to painting<br />
handheld pulsed Nd:YAG laser with an average<br />
laser power <str<strong>on</strong>g>of</str<strong>on</strong>g> 500 W (peak power <str<strong>on</strong>g>of</str<strong>on</strong>g> over<br />
400 kW) <strong>on</strong> an <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> sheet resulted in<br />
maximum substrate temperatures <str<strong>on</strong>g>of</str<strong>on</strong>g> 80°C.<br />
Pulsed laser systems generate laser power<br />
levels well bey<strong>on</strong>d <str<strong>on</strong>g>the</str<strong>on</strong>g> average power <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
laser source. A pulsed 150 W solid-state laser<br />
will generate a peak pulse power <str<strong>on</strong>g>of</str<strong>on</strong>g> over<br />
160 kW. This high peak power and <str<strong>on</strong>g>the</str<strong>on</strong>g> above<br />
menti<strong>on</strong>ed beam parameter results in a power<br />
intensity removing many target materials with<br />
acceptable producti<strong>on</strong> rates.<br />
Currently, <str<strong>on</strong>g>the</str<strong>on</strong>g>re are three different kinds<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> laser sources available for surface preparati<strong>on</strong><br />
works. The main difference is <str<strong>on</strong>g>the</str<strong>on</strong>g> laser<br />
generati<strong>on</strong> and <str<strong>on</strong>g>the</str<strong>on</strong>g> resulting beam delivery<br />
c<strong>on</strong>figurati<strong>on</strong>. Respecting<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> automati<strong>on</strong> and<br />
integrati<strong>on</strong> possibilities,<br />
solid-state Nd:YAG laser<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g>fer special advantages<br />
in industrial, automated<br />
applicati<strong>on</strong>s such adhesive<br />
b<strong>on</strong>ding preparati<strong>on</strong>, pint<br />
stripping, mould cleaning<br />
and pre- / post treatment<br />
for welding and brazing.<br />
The operative wavelength<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 1,064 nanometres<br />
(nm) lies within <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
transmissi<strong>on</strong> bandwidth <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
comm<strong>on</strong> optical glass and<br />
enables <str<strong>on</strong>g>the</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> fibre<br />
optic cables for beam delivery. Fibre optics<br />
dramatically increases <str<strong>on</strong>g>the</str<strong>on</strong>g> flexibility <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
laser system. Nd:YAG lasers can be used for<br />
work <strong>on</strong> hard to reach areas. Currently, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
maximum fibre optic length is 150 ft. Nd:YAG<br />
lasers are nearly maintenance free and very<br />
simple to operate. Pulsed systems for surface<br />
preparati<strong>on</strong> use reach average laser power<br />
levels <str<strong>on</strong>g>of</str<strong>on</strong>g> up to 1,000 W.<br />
Sustainable technology<br />
Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> media free cleaning with light,<br />
cleanLaser <str<strong>on</strong>g>of</str<strong>on</strong>g>fer several advantages. These<br />
advantages, which are leading to sustainable<br />
savings, are:<br />
Laser cleaning <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> car body parts for welding preparati<strong>on</strong><br />
APPLICATION-ORIENTED TECHNOLOGIES<br />
• No media and chemical materials required<br />
• Energy c<strong>on</strong>sumpti<strong>on</strong> far low<br />
(typically 5 kW or less)<br />
• Up to 80% lower running costs and waste<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> resources significant reduced<br />
• No noise and dirt allocati<strong>on</strong> leading to<br />
better and safer workplaces.<br />
This combinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> saving resources an reducti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> costs will have a sustainable l<strong>on</strong>g<br />
term effect in industrial cleaning and surface<br />
applicati<strong>on</strong>s.<br />
In October 2010, <str<strong>on</strong>g>the</str<strong>on</strong>g> founders <str<strong>on</strong>g>of</str<strong>on</strong>g> cleanLA-<br />
SER have been awarded with Europe’s highest<br />
doped envir<strong>on</strong>mental award, <str<strong>on</strong>g>the</str<strong>on</strong>g> German envir<strong>on</strong>mental<br />
award (Deutscher Umweltpreis).<br />
Clean Laser has also been nominated for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Clean Tech Media Award 2011.<br />
Current applicati<strong>on</strong> fields<br />
for cleanLaser technology<br />
Currently, a wide range <str<strong>on</strong>g>of</str<strong>on</strong>g> industrial applicati<strong>on</strong><br />
fields are applicable for cleanLaser surface<br />
treatment and cleaning technology:<br />
• Cleaning <str<strong>on</strong>g>of</str<strong>on</strong>g> metal parts, especially alumin-<br />
ium for following producti<strong>on</strong> steps<br />
• Pre-treatment prior to painting<br />
• Adhesive b<strong>on</strong>ding and pre-treatment <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> for l<strong>on</strong>g term stability<br />
• Welding and brazing preparati<strong>on</strong>s<br />
• (Precise) de-coating and ablati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>s<br />
for joining or electrical b<strong>on</strong>ding <str<strong>on</strong>g>of</str<strong>on</strong>g> plated<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
• Modificati<strong>on</strong> and structuring <str<strong>on</strong>g>of</str<strong>on</strong>g> (metal)<br />
surfaces for enhanced performance.<br />
cleanLaser Systems<br />
Clean-Lasersysteme GmbH, an ISO 9001:<br />
2008 certified laser system manufacturer <str<strong>on</strong>g>of</str<strong>on</strong>g>fers<br />
a wide range <str<strong>on</strong>g>of</str<strong>on</strong>g> powerful laser systems for<br />
surface applicati<strong>on</strong>s. These systems are available<br />
with different end effectors. Laser optics<br />
are available for manual use and as well as for<br />
automated applicati<strong>on</strong>s. Due to cleanLaser’s<br />
fibre coupling technology, <str<strong>on</strong>g>the</str<strong>on</strong>g> compact basic<br />
laser unit can be c<strong>on</strong>nected to a laser optics by<br />
using an up to 50 m l<strong>on</strong>g flexible fibre cable.<br />
The flexibility <str<strong>on</strong>g>of</str<strong>on</strong>g>fers easy integrati<strong>on</strong> as<br />
well as suitable power ranges for applicati<strong>on</strong>s<br />
in an industrial envir<strong>on</strong>ment. Advantages such<br />
as in-line cleaning are evident.<br />
High efficient laser systems mainly based<br />
<strong>on</strong> Q-switched solid state laser sources guaranty<br />
short laser pulse impact times for sensitive<br />
cleaning by nothing else <str<strong>on</strong>g>the</str<strong>on</strong>g>n laser light.<br />
Current laser systems are available in a<br />
power range between 20 to 1,000 Watts, ready<br />
for serving nearly every speed and cycle time<br />
demand.<br />
�<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 49<br />
Audi AG
APPLICATION-ORIENTED TECHNOLOGIES<br />
Corrosi<strong>on</strong> behaviour <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
materials in aqueous cleaning soluti<strong>on</strong>s<br />
Silvio Koehler, Georg Reinhard, Excor Korrosi<strong>on</strong>sforschung GmbH<br />
Especially in <str<strong>on</strong>g>the</str<strong>on</strong>g> car and aviati<strong>on</strong> industry<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> and its alloys are <str<strong>on</strong>g>the</str<strong>on</strong>g> most important<br />
materials. One advantage <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
is <str<strong>on</strong>g>the</str<strong>on</strong>g> generally passive and corrosi<strong>on</strong> resistance<br />
in aqueous soluti<strong>on</strong>s within a defined<br />
pH range except for pitting corrosi<strong>on</strong> due to<br />
some reactive species, such as chloride. While<br />
pure <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> is covered by a homogenous<br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>, <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloys <str<strong>on</strong>g>of</str<strong>on</strong>g>ten c<strong>on</strong>sist <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
several phases (aggregates and mixed phases<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> alloying elements) leading to an inhomogeneous<br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>. The effect <str<strong>on</strong>g>of</str<strong>on</strong>g> alloying elements<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> breakdown <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> passive film<br />
was extensively studied using various grades<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> and different metals [1,2].<br />
At <str<strong>on</strong>g>the</str<strong>on</strong>g> cleaning <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> materials<br />
most <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> problems arise because <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
wr<strong>on</strong>g pH-value <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> respective cleaning<br />
bath. The Pourbaix diagram <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> can<br />
be used for a rough estimati<strong>on</strong>, but it is not valid<br />
by 100% for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloys. The sec<strong>on</strong>d<br />
problem is <str<strong>on</strong>g>the</str<strong>on</strong>g> present <str<strong>on</strong>g>of</str<strong>on</strong>g> corrosi<strong>on</strong> promoting<br />
ani<strong>on</strong>s, not <strong>on</strong>ly chloride. In combinati<strong>on</strong> with<br />
an unsuitable pH-value <str<strong>on</strong>g>the</str<strong>on</strong>g> follows for <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
to clean can be dramatically, also in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
present <str<strong>on</strong>g>of</str<strong>on</strong>g> small quantities.<br />
Before <str<strong>on</strong>g>the</str<strong>on</strong>g> corrosi<strong>on</strong> ability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
materials Al1050 and 2014 was characterized<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> aqueous soluti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> commercial<br />
available cleaning c<strong>on</strong>centrates, <str<strong>on</strong>g>the</str<strong>on</strong>g> effect <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> pH and <str<strong>on</strong>g>the</str<strong>on</strong>g> chloride c<strong>on</strong>centrati<strong>on</strong> were<br />
investigated in model electrolytes with pH<br />
values between 3 and 10 at room temperature.<br />
In ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r set <str<strong>on</strong>g>of</str<strong>on</strong>g> experiments sodium chloride<br />
was added to soluti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> pH8. In all soluti<strong>on</strong>s<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> free corrosi<strong>on</strong> potential as well as time<br />
depending impedance spectra were recorded<br />
using <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> materials as working<br />
electrode in a top part measuring cell.<br />
For pure <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> (Al 1050) <str<strong>on</strong>g>the</str<strong>on</strong>g> results<br />
measured in <str<strong>on</strong>g>the</str<strong>on</strong>g> model electrolytes with<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> different pH values were in accordance<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> Pourbaix diagram. Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r, passive<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> is ra<str<strong>on</strong>g>the</str<strong>on</strong>g>r stable up to high chloride<br />
c<strong>on</strong>tents. But in <str<strong>on</strong>g>the</str<strong>on</strong>g> industrial aqueous<br />
cleaning soluti<strong>on</strong>s Al1050 corrosi<strong>on</strong> attacks<br />
were observed, although <str<strong>on</strong>g>the</str<strong>on</strong>g> pH value <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
cleaning soluti<strong>on</strong> was in <str<strong>on</strong>g>the</str<strong>on</strong>g> passive regi<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>. Surfactants and complexing<br />
agents included in <str<strong>on</strong>g>the</str<strong>on</strong>g> cleaners seem to have<br />
a corrosi<strong>on</strong> promoting effect. In <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloy Al 2014 in all soluti<strong>on</strong>s<br />
(model electrolytes as well as cleaning baths)<br />
a corrosi<strong>on</strong> attack was observed. It could be<br />
shown by means <str<strong>on</strong>g>of</str<strong>on</strong>g> SEM that in <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
Al 2014 <str<strong>on</strong>g>the</str<strong>on</strong>g> selective corrosi<strong>on</strong> around <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
cathodic copper-rich inter-metallic dominates<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> corrosi<strong>on</strong> performance.<br />
The next step was to find suitable inhibitors<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> cleaning soluti<strong>on</strong>, which are able<br />
to protect <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> materials, but <str<strong>on</strong>g>the</str<strong>on</strong>g>y<br />
should not lower <str<strong>on</strong>g>the</str<strong>on</strong>g> pH-value to uphold <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
cleaning effect. Promising results were observed<br />
at combinati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> substances creating<br />
a c<strong>on</strong>verting <str<strong>on</strong>g>layer</str<strong>on</strong>g> <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> basis<br />
material with substances inhibiting <str<strong>on</strong>g>the</str<strong>on</strong>g> copper<br />
rich phases selectively.<br />
1. Introducti<strong>on</strong><br />
Aluminium materials are widely used in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
automotive, aerospace and railways industries<br />
[3]. Therefore, protecti<strong>on</strong> c<strong>on</strong>cepts for semifinished<br />
as well as final products made <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
and its alloys are requested.<br />
One way to protect <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> surfaces<br />
during <str<strong>on</strong>g>the</str<strong>on</strong>g>ir storage into moist air is <str<strong>on</strong>g>the</str<strong>on</strong>g> use<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> volatile corrosi<strong>on</strong> inhibitors. These are inhibiting<br />
substances with a sufficient vapour<br />
pressure, which can be incorporated in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
matrix <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> packaging materials like paper<br />
and films. The VCI can be released by sublimati<strong>on</strong><br />
and/or be transporting by water vapour<br />
into <str<strong>on</strong>g>the</str<strong>on</strong>g> package. In <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> densely closed<br />
packages <str<strong>on</strong>g>the</str<strong>on</strong>g> VCI enrich and saturate <str<strong>on</strong>g>the</str<strong>on</strong>g> inner<br />
atmosphere. Through a reversible adsorpti<strong>on</strong><br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> metal surface <str<strong>on</strong>g>the</str<strong>on</strong>g>y inhibit corrosi<strong>on</strong> as<br />
far as <str<strong>on</strong>g>the</str<strong>on</strong>g> packaging is closed [4,5]. Besides <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
densely closed packages <str<strong>on</strong>g>the</str<strong>on</strong>g> right combinati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> inhibitors has to be used depending <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
compositi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloy [6].<br />
The surfaces to protect have to be accessible<br />
and clean. To install an effective cleaning<br />
process a plenty <str<strong>on</strong>g>of</str<strong>on</strong>g> parameters and requirements<br />
have to take into account especially<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> compatibility <str<strong>on</strong>g>of</str<strong>on</strong>g> cleaner and material [7].<br />
At <str<strong>on</strong>g>the</str<strong>on</strong>g> cleaning <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> materials most<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> problems arise because <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> wr<strong>on</strong>g<br />
pH-value <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> respective cleaning bath. The<br />
sec<strong>on</strong>d problem is <str<strong>on</strong>g>the</str<strong>on</strong>g> present <str<strong>on</strong>g>of</str<strong>on</strong>g> corrosi<strong>on</strong><br />
promoting ani<strong>on</strong>s like chloride, because <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> l<strong>on</strong>g-term use <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> respective cleaning<br />
baths. In combinati<strong>on</strong> with an unsuitable pHvalue<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> follows for <str<strong>on</strong>g>the</str<strong>on</strong>g> material to clean can<br />
be dramatically, also in <str<strong>on</strong>g>the</str<strong>on</strong>g> present <str<strong>on</strong>g>of</str<strong>on</strong>g> small<br />
quantities. It is known that most <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> cleaning<br />
processes take place at temperatures around<br />
60°C. Here, <str<strong>on</strong>g>the</str<strong>on</strong>g> pH value is shifted to more<br />
alkaline values compared to room temperature.<br />
Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r, <str<strong>on</strong>g>the</str<strong>on</strong>g> solubility <str<strong>on</strong>g>of</str<strong>on</strong>g> solids (e. g. surface<br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>s, inorganic particles) as well<br />
as <str<strong>on</strong>g>the</str<strong>on</strong>g> velocity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>ir dissoluti<strong>on</strong> is increased<br />
and intended for good cleaning results with-<br />
in short c<strong>on</strong>tact times [8]. It is not <str<strong>on</strong>g>the</str<strong>on</strong>g> purpose<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> this paper to describe <str<strong>on</strong>g>the</str<strong>on</strong>g> mechanism during<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> cleaning process itself. Especially <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
electrochemical measurements should be presented<br />
as tools to answer questi<strong>on</strong>s about <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
compatibility <str<strong>on</strong>g>of</str<strong>on</strong>g> cleaning bath and material to<br />
clean and to evaluate <str<strong>on</strong>g>the</str<strong>on</strong>g> current ‘corrosiveness’<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a cleaning bath similar to <str<strong>on</strong>g>the</str<strong>on</strong>g> chip/<br />
filter paper test according to DIN 51360 part<br />
2 finally with <str<strong>on</strong>g>the</str<strong>on</strong>g> aim to obtain c<strong>on</strong>diti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> metal surface that <str<strong>on</strong>g>the</str<strong>on</strong>g> applicati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> VCI<br />
is successful.<br />
2. Experimental<br />
Test panels (50 x 100 mm) <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
alloys menti<strong>on</strong>ed in Table 1 were used for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
experiments. At first <str<strong>on</strong>g>the</str<strong>on</strong>g> panels were cleaned<br />
with methanol and acet<strong>on</strong>e assisted by an ultras<strong>on</strong>ic<br />
bath. After this <str<strong>on</strong>g>the</str<strong>on</strong>g>y have been stored<br />
in a desiccator for at least 12 h. So a reproducible<br />
formati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a native <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> was assured.<br />
For <str<strong>on</strong>g>the</str<strong>on</strong>g> electrochemical measurements<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> panels were put in a cylindrical top cell<br />
realizing a circular electrode area <str<strong>on</strong>g>of</str<strong>on</strong>g> 1.76 cm²<br />
acting as working electrode. As counter and<br />
reference electrode a platinum net and saturated<br />
calomel electrode (SCE) were used. All<br />
electrical measurements were performed using<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> impedance measurement system IM6<br />
(Zahner Instruments, Kr<strong>on</strong>ach, Germany) at<br />
room temperature (22°C). In a first set <str<strong>on</strong>g>of</str<strong>on</strong>g> experiments<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> pH value <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
corrosi<strong>on</strong> were investigated. Therefore, aqueous<br />
soluti<strong>on</strong>s (de-i<strong>on</strong>ized water) including<br />
0.01M KNO 3 as supporting electrolyte <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Material Si Fe Cu Mn Mg Cr Zn Ti Zr<br />
1050 0.09 0.25 0.001 0.01 0.01 0 0.01 0.01 0<br />
2014 0.88 0.11 4.85 0.85 0.73 0.004 0.05 0.02 0.01<br />
Table 1: Compositi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> investigated <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloys<br />
50 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
following pH values were prepared: pH 3, pH<br />
5, pH 8 and pH 10. The pH value was adjusted<br />
with HNO 3 and NaOH, respectively. After<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>se experiments 1-3 wt% aqueous soluti<strong>on</strong>s<br />
(de-i<strong>on</strong>ized water) including 0.01M KNO 3 as<br />
supporting electrolyte <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> commercial available<br />
cleaner c<strong>on</strong>centrates menti<strong>on</strong>ed in Table<br />
2 were prepared. In all aerated soluti<strong>on</strong>s <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
free corrosi<strong>on</strong> potential has been measured for<br />
30 min. After this electrochemical impedance<br />
spectra (EIS) were recorded at <str<strong>on</strong>g>the</str<strong>on</strong>g> respective<br />
open circuit potentials in a frequency range <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
100 kHz to 50 MHz after 5, 10, 15 and 30min<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> immersi<strong>on</strong> time. Thereby, <str<strong>on</strong>g>the</str<strong>on</strong>g> impedance<br />
spectra were taken at o<str<strong>on</strong>g>the</str<strong>on</strong>g>r surface areas than<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>se used for <str<strong>on</strong>g>the</str<strong>on</strong>g> recording <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> free corrosi<strong>on</strong><br />
potentials. The EIS curves were fitted using<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Thales s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware (Zahner Instruments,<br />
Kr<strong>on</strong>ach, Germany).<br />
The samples <str<strong>on</strong>g>of</str<strong>on</strong>g> Al 2014 were investigated<br />
by SEM (Scanning Electr<strong>on</strong> Microscopy)<br />
No. kind <str<strong>on</strong>g>of</str<strong>on</strong>g> cleaner suitable for* pH value at 25°C*<br />
1 demulsifying Fe, (Al) 9.1 ± 0.3 (1%)<br />
2 demulsifying Fe, Al, Zn 8.0 ± 0.2 (2%)<br />
3 emulsifying Fe, Al, Zn 8.6 ± 0.3 (1%)<br />
* according to product data sheet<br />
Table 2: List <str<strong>on</strong>g>of</str<strong>on</strong>g> investigated cleaners<br />
coupled with EDX (Energy-dispersive X-ray<br />
spectroscopy). Here, surface regi<strong>on</strong>s affected<br />
and not affected by cleaning soluti<strong>on</strong> 2 were<br />
investigated and compared c<strong>on</strong>cerning <str<strong>on</strong>g>the</str<strong>on</strong>g> ratio<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> elements Al, Cu and O. The SEM<br />
images were recorded with a LEO 440 (STS,<br />
North Billerica, USA) at activati<strong>on</strong> energies<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 5 keV and 20 keV, respectively. The EDX<br />
spectra were recorded by <str<strong>on</strong>g>the</str<strong>on</strong>g> coupled SDD<br />
(Silic<strong>on</strong> Drift Detector) AXAS (Ketek GmbH,<br />
München, Germany).<br />
In ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r set <str<strong>on</strong>g>of</str<strong>on</strong>g> experiments 0.01M benzotriazole<br />
and/or 0.01M sodium di-hydrogen<br />
phosphate was added to a 2 wt% soluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
cleaner 2. The free corrosi<strong>on</strong> potential as well<br />
as electrochemical impedance spectra were<br />
recorded as described above.<br />
3. Results and discussi<strong>on</strong><br />
At first <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> pH value and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
chloride c<strong>on</strong>centrati<strong>on</strong> were investigated <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> alloy 1050, which c<strong>on</strong>sists <str<strong>on</strong>g>of</str<strong>on</strong>g> pure <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
by almost 99.5%. As expected from<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Pourbaix-diagram <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> [9] <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
free corrosi<strong>on</strong> potential E corr measured in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
pH range between 3 and 5 remains in a regi<strong>on</strong>,<br />
where <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> surface is in a passive<br />
state, while at pH 10 <str<strong>on</strong>g>the</str<strong>on</strong>g> free corrosi<strong>on</strong> potential<br />
corresp<strong>on</strong>ds to an active dissoluti<strong>on</strong> (see<br />
Fig. 1).<br />
APPLICATION-ORIENTED TECHNOLOGIES<br />
In alkaline soluti<strong>on</strong>s <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> dissolves<br />
under <str<strong>on</strong>g>the</str<strong>on</strong>g> formati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> [Al(OH) 4 ]- complexes.<br />
The impedance spectra recorded at pH10 (Fig.<br />
2) show an increase <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> C ox combined with<br />
a decreasing resistance in <str<strong>on</strong>g>the</str<strong>on</strong>g> regi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> lower<br />
frequencies. This behaviour is typical for a<br />
uniform dissoluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> [10].<br />
Str<strong>on</strong>g deviati<strong>on</strong>s from <str<strong>on</strong>g>the</str<strong>on</strong>g> Pourbaix-diagram<br />
menti<strong>on</strong>ed above can be observed at <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
investigati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloys. The inter-<br />
Fig. 1: Free corrosi<strong>on</strong> potential E corr <str<strong>on</strong>g>of</str<strong>on</strong>g> Al 1050 in<br />
soluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> different pH value<br />
Fig.2: Impedance spectra <str<strong>on</strong>g>of</str<strong>on</strong>g> Al 1050 at several pH<br />
values after 30 min immersi<strong>on</strong> time<br />
pretati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> free corrosi<strong>on</strong> potentials <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloys is ra<str<strong>on</strong>g>the</str<strong>on</strong>g>r complicated,<br />
because <str<strong>on</strong>g>the</str<strong>on</strong>g>y are mixed potentials with porti<strong>on</strong>s<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> bulk and/or selective corrosi<strong>on</strong> processes.<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> copper-rich Al2014<br />
(Fig. 3) <str<strong>on</strong>g>the</str<strong>on</strong>g> curve in <str<strong>on</strong>g>the</str<strong>on</strong>g> beginning can be<br />
interpreted by a selective corrosi<strong>on</strong> around<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> cathodic copper-rich inter-metallic phases<br />
followed by a stabilizati<strong>on</strong> / passivati<strong>on</strong> at pHvalues<br />
between 3 and 10. In more acid as well<br />
as more alkaline soluti<strong>on</strong>s <str<strong>on</strong>g>the</str<strong>on</strong>g> free corrosi<strong>on</strong><br />
potentials are typical for <str<strong>on</strong>g>the</str<strong>on</strong>g> dissoluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> bulk <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> [11,12]. More details are<br />
available from <str<strong>on</strong>g>the</str<strong>on</strong>g> impedance data. As already<br />
menti<strong>on</strong>ed <str<strong>on</strong>g>the</str<strong>on</strong>g> alloy Al2014 is characterized<br />
by a higher c<strong>on</strong>tent <str<strong>on</strong>g>of</str<strong>on</strong>g> copper, which forms inter-metallic<br />
phases. In <str<strong>on</strong>g>the</str<strong>on</strong>g> impedance spectra<br />
(Fig. 4) <strong>on</strong>e can observe lower resistances in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> low-frequency regi<strong>on</strong> compared to pure<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g>. Taking a look <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> transient behaviour<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>se resistances keep c<strong>on</strong>stant <strong>on</strong> a<br />
low level at pH values below 3 and above 10.<br />
The capacities bel<strong>on</strong>ging to <str<strong>on</strong>g>the</str<strong>on</strong>g>m keep c<strong>on</strong>-<br />
stant, too. Such a behaviour can be explained<br />
by a selective corrosi<strong>on</strong> around <str<strong>on</strong>g>the</str<strong>on</strong>g> copper rich<br />
inter-metallic phases.<br />
Transferring <str<strong>on</strong>g>the</str<strong>on</strong>g> findings to industrial<br />
cleaning baths: Here, soluti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> 3 commercial<br />
available cleaning c<strong>on</strong>centrates were pre-<br />
Fig. 3: Free corrosi<strong>on</strong> potential E corr <str<strong>on</strong>g>of</str<strong>on</strong>g> Al 2014 in<br />
soluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> different pH value<br />
Fig. 4: Impedance spectra <str<strong>on</strong>g>of</str<strong>on</strong>g> Al 2014 at several pH<br />
values after 30min immersi<strong>on</strong> time<br />
pared. All cleaners should be suitable to clean<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> according to <str<strong>on</strong>g>the</str<strong>on</strong>g>ir product data<br />
sheets (see Table 2), however, at higher temperatures<br />
as room temperature. A str<strong>on</strong>g uniform<br />
corrosi<strong>on</strong> was observed already at room<br />
temperature in <str<strong>on</strong>g>the</str<strong>on</strong>g> baths prepared <str<strong>on</strong>g>of</str<strong>on</strong>g> cleaner<br />
1 and 3. This is explainable by <str<strong>on</strong>g>the</str<strong>on</strong>g> pH-value<br />
situated in <str<strong>on</strong>g>the</str<strong>on</strong>g> active regi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>. In<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> cleaner 2 with pH8 <strong>on</strong>ly a moderate attack<br />
was observed (Fig. 5). Maybe <str<strong>on</strong>g>the</str<strong>on</strong>g> bath ingredients<br />
accelerate <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> dissoluti<strong>on</strong><br />
at local defects by complexi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
[13]. For <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloy Al2014 <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
results found in <str<strong>on</strong>g>the</str<strong>on</strong>g> cleaning soluti<strong>on</strong>s were<br />
identical to this in <str<strong>on</strong>g>the</str<strong>on</strong>g> respective pH-model<br />
soluti<strong>on</strong>s. A black-colouring <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> immerged<br />
alloy surfaces as shown in Fig. 6 was observed<br />
every time.<br />
Surface areas <str<strong>on</strong>g>of</str<strong>on</strong>g> Al 2014 affected (Fig. 6,<br />
black coloured area in <str<strong>on</strong>g>the</str<strong>on</strong>g> small picture) and<br />
not affected (Fig. 6, grey coloured area in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
small picture) by cleaner 2 were investigated<br />
by SEM and EDX. According to <str<strong>on</strong>g>the</str<strong>on</strong>g> measured<br />
element ratios (Table 3) <str<strong>on</strong>g>the</str<strong>on</strong>g> selective corrosi<strong>on</strong><br />
and dissoluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> around <str<strong>on</strong>g>the</str<strong>on</strong>g> copper<br />
rich phases could be proved. The black<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 51
APPLICATION-ORIENTED TECHNOLOGIES<br />
Fig. 5: Impedance spectra <str<strong>on</strong>g>of</str<strong>on</strong>g> Al1050 at pH8 and in<br />
soluti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> cleaner 1-3 (Table 2)<br />
Fig. 6: SEM image (5 keV, 200x): Al2014 after immersi<strong>on</strong><br />
in a soluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> cleaner 2<br />
corrosi<strong>on</strong> product is most likely Al(OH) 3,<br />
which <strong>on</strong>ly appears black because <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> small<br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g> thickness.<br />
The next step was to find suitable inhibitors<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> cleaning soluti<strong>on</strong>, which are able to protect<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> materials, but <str<strong>on</strong>g>the</str<strong>on</strong>g>y should<br />
not lower <str<strong>on</strong>g>the</str<strong>on</strong>g> pH-value to uphold <str<strong>on</strong>g>the</str<strong>on</strong>g> cleaning<br />
effect. First experiments were d<strong>on</strong>e with sodium<br />
di-hydrogen phosphate and benzotriazole.<br />
The substances were added to a 2% soluti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> cleaner 2 toge<str<strong>on</strong>g>the</str<strong>on</strong>g>r and each al<strong>on</strong>e. In Fig. 7<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> resistances R ox extracted from <str<strong>on</strong>g>the</str<strong>on</strong>g> impedance<br />
spectra at low frequency regi<strong>on</strong>s (around<br />
100 mHz) are presented. They corresp<strong>on</strong>d to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> quality <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> and <str<strong>on</strong>g>the</str<strong>on</strong>g> corrosi<strong>on</strong><br />
resistance, c<strong>on</strong>sequently. Here, <str<strong>on</strong>g>the</str<strong>on</strong>g> inhibiti<strong>on</strong><br />
effect <str<strong>on</strong>g>of</str<strong>on</strong>g> both substances is obvious,<br />
whereas <str<strong>on</strong>g>the</str<strong>on</strong>g> effect <str<strong>on</strong>g>of</str<strong>on</strong>g> each single substance is<br />
limited. The following mechanism is assumed:<br />
Phosphate is forming insoluble <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
phosphate, inhibiting <str<strong>on</strong>g>the</str<strong>on</strong>g> dissoluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> bulk material. Benzotriazole is<br />
well known as inhibitor for copper. It forms<br />
c<strong>on</strong>versi<strong>on</strong> <str<strong>on</strong>g>layer</str<strong>on</strong>g>s <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> copper rich phases,<br />
blocking <str<strong>on</strong>g>the</str<strong>on</strong>g> reducti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> oxygen. In comparis<strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> dissoluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> bulk material<br />
dominates in <str<strong>on</strong>g>the</str<strong>on</strong>g> soluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> cleaner 2.<br />
Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> single additi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> benzotriazole<br />
Cu Al O<br />
N<strong>on</strong> affected area 5 80 5<br />
Affected area 78 7 10<br />
Table 3: Results <str<strong>on</strong>g>of</str<strong>on</strong>g> EDX measurements, amounts <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> elements Cu, Al and O in wt%<br />
Fig. 7: R OX extracted from <str<strong>on</strong>g>the</str<strong>on</strong>g> impedance spectra<br />
recorded in soluti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> cleaner 2 with and without<br />
benzotriazole and sodium di-hydrogen phosphate<br />
to inhibit <str<strong>on</strong>g>the</str<strong>on</strong>g> inter-crystalline corrosi<strong>on</strong> is insufficient<br />
to stop <str<strong>on</strong>g>the</str<strong>on</strong>g> bulk corrosi<strong>on</strong>, whereas<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> single additi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> phosphate can inhibit<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> bulk corrosi<strong>on</strong>, but not <str<strong>on</strong>g>the</str<strong>on</strong>g> inter-crystalline<br />
corrosi<strong>on</strong>.<br />
Finally, Fig. 8 shows panels <str<strong>on</strong>g>of</str<strong>on</strong>g> Al 2014<br />
completely cleaned (dip-cleaning assisted by<br />
ultrasound for 10 min) with cleaner 2 with and<br />
without <str<strong>on</strong>g>the</str<strong>on</strong>g> additi<strong>on</strong>ally added benzotriazole<br />
and sodium di-hydrogen phosphate. The effect<br />
is obvious [14].<br />
4. C<strong>on</strong>clusi<strong>on</strong>s<br />
Using <str<strong>on</strong>g>the</str<strong>on</strong>g> electrochemical methods <str<strong>on</strong>g>the</str<strong>on</strong>g> different<br />
corrosi<strong>on</strong> mechanisms <str<strong>on</strong>g>of</str<strong>on</strong>g> pure <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
and Al 2014 could be detected. However, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
behaviour <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> free corrosi<strong>on</strong> potentials is<br />
difficult to interpret especially for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
alloys. Here, <str<strong>on</strong>g>the</str<strong>on</strong>g> resulting potential is always<br />
a mixture <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> resp<strong>on</strong>se <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> several inter<br />
metallic phases.<br />
Pure <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> behaved passively in a<br />
pH range between 5 and 8. In <str<strong>on</strong>g>the</str<strong>on</strong>g> recorded<br />
impedance spectra <strong>on</strong>ly <str<strong>on</strong>g>the</str<strong>on</strong>g> resistance <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
electrolyte and <str<strong>on</strong>g>the</str<strong>on</strong>g> capacity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> barrier <str<strong>on</strong>g>layer</str<strong>on</strong>g><br />
were visible. At pH values above 10 a uniform<br />
dissoluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> was observed<br />
characterized by a decreasing <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> resistance<br />
and an increasing surface capacity.<br />
The investigated <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloy Al 2014<br />
is an inhomogeneous alloy and has a relatively<br />
high copper c<strong>on</strong>tent. The surface <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> alloy is also inhomogeneous and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
bulk material c<strong>on</strong>sists <str<strong>on</strong>g>of</str<strong>on</strong>g> several phases. For<br />
this alloy a uniform and/or selective corro-<br />
si<strong>on</strong> was found depending <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> pH value<br />
already at room temperature. Below pH 3<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> alloy showed a uniform corrosi<strong>on</strong>. In <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
pH range between 3 and 8 an increase <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
resistance in <str<strong>on</strong>g>the</str<strong>on</strong>g> lower frequency range combined<br />
with an unchanged capacity at medium<br />
frequencies were detected. This resp<strong>on</strong>se can<br />
be interpreted as selective corrosi<strong>on</strong> around<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> cathodic copper rich phases. This (maybe)<br />
leads to a formati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> corrosi<strong>on</strong> products with<br />
a black visual appearance. They precipitated<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> whole immersed surface. Additi<strong>on</strong>ally<br />
measurements by SEM/EDX proved <str<strong>on</strong>g>the</str<strong>on</strong>g> selective<br />
corrosi<strong>on</strong> and dissoluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
around <str<strong>on</strong>g>the</str<strong>on</strong>g> copper rich phases. At pH values<br />
above 10 a uniform dissoluti<strong>on</strong> was observed<br />
for Al 2014.<br />
Transferred to <str<strong>on</strong>g>the</str<strong>on</strong>g> industrial cleaning <str<strong>on</strong>g>the</str<strong>on</strong>g>se<br />
results reveal <str<strong>on</strong>g>the</str<strong>on</strong>g> importance <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> ‘right<br />
choice’ <str<strong>on</strong>g>of</str<strong>on</strong>g> method and cleaner c<strong>on</strong>centrate (pH<br />
value!) as well as an experienced bath m<strong>on</strong>itoring<br />
(at least pH value and chloride c<strong>on</strong>tent).<br />
Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>rmore, <str<strong>on</strong>g>the</str<strong>on</strong>g> experiments showed that<br />
always <str<strong>on</strong>g>the</str<strong>on</strong>g> compatibility <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> cleaner and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> material has to be tested before <str<strong>on</strong>g>the</str<strong>on</strong>g> applicati<strong>on</strong>.<br />
Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> recording <str<strong>on</strong>g>of</str<strong>on</strong>g> electrochemical<br />
impedance spectra at <str<strong>on</strong>g>the</str<strong>on</strong>g> free corrosi<strong>on</strong><br />
potential is predestinated. A comparis<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> three commercial available cleaners (all<br />
should be suitable for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> according<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g>ir product data sheet) showed, that in<br />
cleaners with <str<strong>on</strong>g>the</str<strong>on</strong>g> pH value above 8.5 pure<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> corroded heavily. But also in cleaners<br />
with a suitable pH-value a moderate at-<br />
tack was observed, caused by a complexi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> by cleaner ingredients.<br />
The additi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> both, sodium di-hydrogen<br />
phosphate and benzotriazole, can prevent<br />
Al2014 in near neutral cleaning soluti<strong>on</strong>s. But<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> single additi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> benzotriazole to inhibit<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> inter-crystalline corrosi<strong>on</strong> is insufficient to<br />
stop <str<strong>on</strong>g>the</str<strong>on</strong>g> bulk corrosi<strong>on</strong>, whereas <str<strong>on</strong>g>the</str<strong>on</strong>g> single additi<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> phosphate can inhibit <str<strong>on</strong>g>the</str<strong>on</strong>g> bulk corrosi<strong>on</strong>,<br />
but not <str<strong>on</strong>g>the</str<strong>on</strong>g> inter-crystalline corrosi<strong>on</strong>.<br />
References<br />
[1] H. Zhan, J. M. C. Mol, F. Hannour, L. Zhuang,<br />
H. Terryn and J. H. W. de Wit; “The influence <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
copper c<strong>on</strong>tent <strong>on</strong> intergranular corrosi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> model<br />
Fig. 8: Al 2014 test panels after dip cleaning in a 2 wt% soluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> cleaner 2; left: without benzotriazole<br />
and sodium di-hydrogen phosphate, right: with benzotriazole and sodium di-hydrogen phosphate<br />
52 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
AlMgSi(Cu) alloys”; Mat. Corr., 2008, 59, 670-675.<br />
[2] B. Zaid, D. Saidi, A. Benzaid, S. Hadji;“ Effects<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> pH and chloride c<strong>on</strong>centrati<strong>on</strong> <strong>on</strong> pitting<br />
corrosi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> AA6061 aluminum alloy“; Corros.<br />
Sci., 2008, 50, 1841-1847.<br />
[3] www.aluinfo.de, 2011.<br />
[4] U. Rammelt, S. Koehler, G. Reinhard; “Use <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
vapour phase corrosi<strong>on</strong> inhibitors in packages for<br />
protecting mild steel against corrosi<strong>on</strong>”; Corros.<br />
Sci., 2009, 51, 921-925.<br />
[5] S. Koehler, G. Reinhard; “Temporärer Korrosi<strong>on</strong>sschutz”,<br />
Maschinenbau, 2008, 7, 34-37.<br />
[6] G. Reinhard, S. Lautner; “Temporärer Korro-<br />
si<strong>on</strong>sschutz v<strong>on</strong> Aluminiumwerkst<str<strong>on</strong>g>of</str<strong>on</strong>g>fen mit flüch-<br />
tigen Korrosi<strong>on</strong>sinhibitoren”; “GfKORR-Jahres-<br />
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APPLICATION-ORIENTED TECHNOLOGIES<br />
tagung 1998”, 1998, 97-108.<br />
[7] H. Thompsen, F.H. Rögner; “Reinigen und Vorbehandeln<br />
– Keine triviale Angelegenheit”; Metalloberfläche,<br />
2007, 61, 44-47.<br />
[8] H. Kollek „Reinigen und Vorbehandeln“, Curt<br />
R. Vincentz Verlag, Hannover, 1996, 13-20.<br />
[9] A. Bart, M.Stratmann (ed.); “Encyclopedia <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
Electrochemistry“ vol. 4 „Corrosi<strong>on</strong> and Oxide<br />
films“; Vol. Editors: M. Stratmann, G.S. Frankel;<br />
Wiley VCH Weinheim 2003; Chapter 2.<br />
[10] Kyung-Keun Lee, Kwang-Bum Kim; “Electrochemical<br />
impedance characteristics <str<strong>on</strong>g>of</str<strong>on</strong>g> pure Al<br />
and Al–Sn alloys in NaOH soluti<strong>on</strong>”; Corros. Sci.,<br />
2001, 43, 561-575.<br />
[11] Y. L. Cheng, Z. Zhang, F. H. Cao, J. F. Li, J. Q.<br />
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Zhang, J. M. Wang and C. N. Cao; “Study <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
potential electrochemical noise during corrosi<strong>on</strong><br />
process <str<strong>on</strong>g>of</str<strong>on</strong>g> aluminum alloys 2024, 7075 and pure<br />
aluminum (pages 601–608)”; Mat. Corr., 2003, 54,<br />
601-608.<br />
[12] F.M. Queiroz, M. Magnani, I. Costa, H.G. de<br />
Melo; “Investigati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> corrosi<strong>on</strong> behaviour <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
AA 2024-T3 in low c<strong>on</strong>centrated chloride media“;<br />
Corros. Sci., 2008, 50, 2646-2657.<br />
[13] D. Mercier, M.-G. Barthés-Labrousse; “The role<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> chelating agents <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> corrosi<strong>on</strong> mechanisms<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> in alkaline aqueous soluti<strong>on</strong>s”; Corros.<br />
Sci., 2009, 51, 339-348.<br />
[14] C.M. v<strong>on</strong> Klingspor, Bachelor-Thesis, HTW-<br />
University <str<strong>on</strong>g>of</str<strong>on</strong>g> Applied Science Dresden, 2011. �<br />
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<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 53
APPLICATION-ORIENTED TECHNOLOGIES<br />
Soldering and brazing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> and its alloys<br />
Christian Eisenbeis, SLV Duisburg<br />
The joining <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> always requires<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> special technologies. In particular,<br />
soldering and brazing techniques<br />
need special experience in order to obtain<br />
joints <str<strong>on</strong>g>of</str<strong>on</strong>g> good quality and sufficient<br />
strength. In additi<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g>re is <str<strong>on</strong>g>of</str<strong>on</strong>g>ten a<br />
good chance to use <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing technologies<br />
for an efficient and highly mechanized<br />
fabricati<strong>on</strong> process. Compared with<br />
welding, soldering and brazing allow<br />
appropriate higher or lower process-temperatures,<br />
depending <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> type <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> base metal. The market <str<strong>on</strong>g>of</str<strong>on</strong>g>fers<br />
new and improved filler metals and fluxes,<br />
and – at <str<strong>on</strong>g>the</str<strong>on</strong>g> same time – <str<strong>on</strong>g>the</str<strong>on</strong>g> demands<br />
<strong>on</strong> quality and strength <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> brazed <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
joints have increased. Traditi<strong>on</strong>al<br />
and highly developed procedures like<br />
flame brazing, resistant brazing, or c<strong>on</strong>trolled-arc-brazing<br />
are available ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
for simple or sophisticated brazed comp<strong>on</strong>ents<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>. In this presentati<strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> basics and <str<strong>on</strong>g>the</str<strong>on</strong>g> technical soluti<strong>on</strong>s will<br />
be explained and illustrated by figures<br />
and practical examples.<br />
1. The brazing process<br />
For soldering and brazing unlike welding an<br />
additi<strong>on</strong>al brazing filler metal is used whose<br />
melting temperature (or melting range) is<br />
below <str<strong>on</strong>g>the</str<strong>on</strong>g> melting temperature <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> parent<br />
metal. The joining surfaces <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> parent metals<br />
are wetted by <str<strong>on</strong>g>the</str<strong>on</strong>g> liquid braze without being<br />
molten <str<strong>on</strong>g>the</str<strong>on</strong>g>mselves.<br />
As a result, <str<strong>on</strong>g>the</str<strong>on</strong>g> following aspects are <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
importance:<br />
• It is possible to join dissimilar metals and<br />
metal alloys, respectively<br />
• Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> relatively low process tempera-<br />
ture <str<strong>on</strong>g>the</str<strong>on</strong>g> comp<strong>on</strong>ent is less <str<strong>on</strong>g>the</str<strong>on</strong>g>rmally<br />
influenced<br />
• The amount <str<strong>on</strong>g>of</str<strong>on</strong>g> filler metal is relatively<br />
small<br />
• The rapid sequence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing process<br />
• Low distorti<strong>on</strong> compared with welding<br />
• Brazing/soldering <str<strong>on</strong>g>of</str<strong>on</strong>g> a variety <str<strong>on</strong>g>of</str<strong>on</strong>g> areas to<br />
be joined at <str<strong>on</strong>g>the</str<strong>on</strong>g> same time.<br />
The joint is built up by <str<strong>on</strong>g>the</str<strong>on</strong>g> exchange <str<strong>on</strong>g>of</str<strong>on</strong>g> diffusi<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> metals within a small z<strong>on</strong>e (Fig.<br />
1). To enable this diffusi<strong>on</strong>-mechanism, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
surface <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> joining area must be free from<br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g>s and be protected against <str<strong>on</strong>g>the</str<strong>on</strong>g> renewed<br />
formati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g>s during soldering/brazing.<br />
Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g>re are two prec<strong>on</strong>diti<strong>on</strong>s to be<br />
fulfilled when brazing, using a flux:<br />
• The melting temperature <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> braze<br />
must be below <str<strong>on</strong>g>the</str<strong>on</strong>g> melting temperature<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> parent metal<br />
• The surface <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material must be<br />
completely free from <str<strong>on</strong>g>oxide</str<strong>on</strong>g>s<br />
• <str<strong>on</strong>g>the</str<strong>on</strong>g> flux must be intensive enough having<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> adequate effective temperature.<br />
2. The process ranges<br />
Brazing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> is classified into brazing<br />
and soldering. At brazing, filler metals with<br />
melting temperatures above 450°C are used.<br />
Solders, having a melting point below 450°C,<br />
are called solder filler metals and <str<strong>on</strong>g>the</str<strong>on</strong>g> process<br />
is called soldering or s<str<strong>on</strong>g>of</str<strong>on</strong>g>t-soldering.<br />
The process temperature can be freely<br />
chosen, but it must be within <str<strong>on</strong>g>the</str<strong>on</strong>g> solidus temperature<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> filler metal and <str<strong>on</strong>g>the</str<strong>on</strong>g> melting<br />
temperature <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> parent metal. The flux will<br />
be chosen matching <str<strong>on</strong>g>the</str<strong>on</strong>g> soldering or brazing<br />
temperature; <str<strong>on</strong>g>the</str<strong>on</strong>g> effective temperature and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> chemical intensity must be coordinated<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> soldering/brazing process.<br />
More generally, <str<strong>on</strong>g>the</str<strong>on</strong>g> higher <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing<br />
temperature, <str<strong>on</strong>g>the</str<strong>on</strong>g> higher is <str<strong>on</strong>g>the</str<strong>on</strong>g> mechanical<br />
strength.<br />
3. Structural requirements <strong>on</strong> brazing<br />
During brazing usually a brazing gap is produced<br />
by a braze drawn into <str<strong>on</strong>g>the</str<strong>on</strong>g> gap due to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> capillary forces (capillary brazing). The<br />
braze displaces <str<strong>on</strong>g>the</str<strong>on</strong>g> flux as so<strong>on</strong> as <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g>s<br />
are dissolved <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> joining surface. A relatively<br />
large-surface joint is produced and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
braze <str<strong>on</strong>g>layer</str<strong>on</strong>g> located in <str<strong>on</strong>g>the</str<strong>on</strong>g> soldering gap will<br />
be mechanically streng<str<strong>on</strong>g>the</str<strong>on</strong>g>ned if a load is exerted<br />
<strong>on</strong> it. By this means c<strong>on</strong>siderable forces<br />
may be exerted that are able to exceed <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
strength <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> parent metal.<br />
4. Properties <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> brazed joints<br />
4.1 Brazed joints: The strength <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
brazed joint <str<strong>on</strong>g>of</str<strong>on</strong>g>ten is <str<strong>on</strong>g>the</str<strong>on</strong>g> same as a<br />
welded joint if <str<strong>on</strong>g>the</str<strong>on</strong>g> ‘joint is suitable for brazing’.<br />
During brazing <str<strong>on</strong>g>of</str<strong>on</strong>g> Al-materials <str<strong>on</strong>g>of</str<strong>on</strong>g> higher<br />
strength as well as <str<strong>on</strong>g>of</str<strong>on</strong>g> Al-cast alloys <str<strong>on</strong>g>the</str<strong>on</strong>g>re is<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> risk <str<strong>on</strong>g>of</str<strong>on</strong>g> a melt down <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> surfaces to be<br />
joined since <str<strong>on</strong>g>the</str<strong>on</strong>g> melting temperature <str<strong>on</strong>g>of</str<strong>on</strong>g> such<br />
type <str<strong>on</strong>g>of</str<strong>on</strong>g> alloys can be near <str<strong>on</strong>g>the</str<strong>on</strong>g> melting point <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> brazing filler metal. The chemical resistance<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a brazed joint <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> comm<strong>on</strong>ly used<br />
braze material Al88Si is not worse than that<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a welded joint. It is true that brazed joints<br />
can be anodized, but in <str<strong>on</strong>g>the</str<strong>on</strong>g> joining area (braze<br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g>) <str<strong>on</strong>g>the</str<strong>on</strong>g>y will get a darker colour.<br />
4.2 Soldered joints: Both, strength and corrosi<strong>on</strong><br />
resistance <str<strong>on</strong>g>of</str<strong>on</strong>g> soldered joints are much<br />
lower. A dry envir<strong>on</strong>ment or corrosi<strong>on</strong> protecti<strong>on</strong><br />
(lacquering, greasing) will <str<strong>on</strong>g>the</str<strong>on</strong>g>n become<br />
necessary. It is nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r possible to<br />
perform anodic oxidati<strong>on</strong> nor to have oper-<br />
ating temperatures c<strong>on</strong>siderably above<br />
100°C.<br />
Fig. 1: Built-up <str<strong>on</strong>g>of</str<strong>on</strong>g> a brazed joint by diffusi<strong>on</strong> (Source: Hydro Aluminium)<br />
54 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Fig. 2: Al-base metal-alloys and AlSi3-brazing filler metal<br />
5. Aluminium brazes and solders<br />
5.1 Brazes: Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> oxidic protective <str<strong>on</strong>g>layer</str<strong>on</strong>g><br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g>fers good corrosi<strong>on</strong> resistance.<br />
Therefore Al-brazes with 5 to 12% silic<strong>on</strong><br />
have proven successful; hence <str<strong>on</strong>g>the</str<strong>on</strong>g> comm<strong>on</strong>ly<br />
used braze is Al 112 (B-Al88Si) ISO 17672<br />
(former AL 104 – EN1044) with a melting<br />
range <str<strong>on</strong>g>of</str<strong>on</strong>g> 575 to 585°C. Hence, at a working<br />
temperature <str<strong>on</strong>g>of</str<strong>on</strong>g> 585°C both, pure <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
and all <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloys can be brazed<br />
that have a melting interval over 640°C (Fig.<br />
2). In practical terms this means that <strong>on</strong>ly pure<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> and AlMn-alloys can be brazed<br />
well.<br />
5.2 Solders: Comm<strong>on</strong> solders are tin-zinc<br />
solders such as SnZn40 or ZnAl5. O<str<strong>on</strong>g>the</str<strong>on</strong>g>r sol-<br />
ders such as Sn96Ag can be used for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>,<br />
too. In general, <str<strong>on</strong>g>the</str<strong>on</strong>g> relatively poor suit-<br />
ability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> to be soldered (stable <str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
skin, poor corrosi<strong>on</strong> resistance <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> soldered<br />
joint) prevent from a more widespread<br />
soldering <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>. On <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r hand,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>re is an increased demand <strong>on</strong> soldering using<br />
a process temperature as low as possible<br />
due to <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloys applied.<br />
6. Fluxes for brazing/soldering <str<strong>on</strong>g>of</str<strong>on</strong>g> Al alloys<br />
Fluxes serve for dissolving <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> and<br />
to avoid a renewed c<strong>on</strong>taminati<strong>on</strong> by oxygen<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> fresh metal surface.<br />
6.1 Fluxes for brazing: Fluxes for light metals<br />
(FL) are stated in DIN EN 1045. The fluxes<br />
actuate above 500°C. A distincti<strong>on</strong> is made<br />
between corrosive and n<strong>on</strong>-corrosive fluxes.<br />
APPLICATION-ORIENTED TECHNOLOGIES<br />
6.2 Fluxes for soldering: These are included<br />
in DIN EN ISO 9453 and <str<strong>on</strong>g>of</str<strong>on</strong>g>ten are based <strong>on</strong><br />
zinc or tin chloride, possibly added by alkaline<br />
chlorides or organic substances.<br />
Destroying <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> and a sufficient<br />
wetting <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> solder is not always successful<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> flux. New fluxes such<br />
as those alloyed with caesium under certain<br />
c<strong>on</strong>diti<strong>on</strong>s may enhance wetting with solder<br />
(like with a slightly higher Mg c<strong>on</strong>tent, too),<br />
which may be very important.<br />
7. Processes for soldering /<br />
brazing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
The possibilities <str<strong>on</strong>g>of</str<strong>on</strong>g> soldering or brazing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
(alloys) are c<strong>on</strong>siderably determined<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> special properties <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> (problem<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>, low melting<br />
temperature, very different wetting properties,<br />
high affinity <str<strong>on</strong>g>of</str<strong>on</strong>g> oxygen, susceptibility to<br />
corrosi<strong>on</strong> if heavy metals are present).<br />
Some <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> frequently used processes are:<br />
7.1 Flame brazing: During flame brazing <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
parts are heated to <str<strong>on</strong>g>the</str<strong>on</strong>g> soldering or brazing<br />
temperature using a torch (Fig. 4); depending<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> temperature required propane, <str<strong>on</strong>g>natural</str<strong>on</strong>g><br />
gas or acetylene are used (toge<str<strong>on</strong>g>the</str<strong>on</strong>g>r with air<br />
or oxygen). When heating up it must be observed<br />
that <str<strong>on</strong>g>the</str<strong>on</strong>g> flame is not always permitted<br />
to have c<strong>on</strong>tact with <str<strong>on</strong>g>the</str<strong>on</strong>g> soldering point, depending<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> type <str<strong>on</strong>g>of</str<strong>on</strong>g> solder/braze.<br />
After reaching <str<strong>on</strong>g>the</str<strong>on</strong>g> working temperature <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
flux is already chemically active. The solder<br />
will become liquid thus wetting <str<strong>on</strong>g>the</str<strong>on</strong>g> surfaces<br />
and being drawn into <str<strong>on</strong>g>the</str<strong>on</strong>g> soldering gap, respec-<br />
tively. At <str<strong>on</strong>g>the</str<strong>on</strong>g> same time <str<strong>on</strong>g>the</str<strong>on</strong>g> flux will<br />
be displaced by <str<strong>on</strong>g>the</str<strong>on</strong>g> solder.<br />
7.2 Inducti<strong>on</strong> brazing: For <str<strong>on</strong>g>the</str<strong>on</strong>g> inductive<br />
heating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> c<strong>on</strong>siderable<br />
inducti<strong>on</strong> power is required<br />
(<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> is not ferromagnetic<br />
and has a high electric c<strong>on</strong>ductivity).<br />
Therefore, <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> is inducti<strong>on</strong><br />
brazed using a deep frequency and a<br />
high power. The main problem is still<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>trol <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> power, in order to<br />
avoid melting up <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material.<br />
7.3 Salt bath brazing: Here, <str<strong>on</strong>g>the</str<strong>on</strong>g> assembled<br />
parts applied with solder/<br />
braze are immersed into a bath <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
molten flux which serves as a medium<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> heat transfer at <str<strong>on</strong>g>the</str<strong>on</strong>g> same time.<br />
This process has several advantages<br />
(no applicati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> flux, good <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal<br />
transfer, no air c<strong>on</strong>tact, tighter<br />
tolerances can be kept and brazing<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> several spots at <str<strong>on</strong>g>the</str<strong>on</strong>g> same time is<br />
possible). Parts that are particularly<br />
thin and <str<strong>on</strong>g>of</str<strong>on</strong>g> a complicated shape can<br />
be securely brazed using this process.<br />
On <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r hand, a large c<strong>on</strong>sumpti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
fluxes is needed that adhere to <str<strong>on</strong>g>the</str<strong>on</strong>g> part and<br />
have to be removed, and disposed <str<strong>on</strong>g>of</str<strong>on</strong>g> using<br />
large amounts <str<strong>on</strong>g>of</str<strong>on</strong>g> rinsing water. Due to this<br />
reas<strong>on</strong> salt bath brazing is used less and less.<br />
7.4 Furnace brazing:<br />
C<strong>on</strong>trolled atmosphere brazing (CAB): brazing<br />
is performed in a c<strong>on</strong>tinuous furnace<br />
using a shielding gas (nitrogen, sometimes<br />
nitrogen/hydrogen). Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> applicati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a n<strong>on</strong>-corrosive and thus milder flux<br />
is sufficient. Porti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> hydrogen are used<br />
if <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> is brazed with CrNi. The flux<br />
can be applied ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r as a suspensi<strong>on</strong>, paste<br />
or dust (electrostatically), whereas <str<strong>on</strong>g>the</str<strong>on</strong>g> braze<br />
is increasingly directly applied to <str<strong>on</strong>g>the</str<strong>on</strong>g> surface<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> manufacturer (Fig. 3). Advantages:<br />
little c<strong>on</strong>sumpti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> flux, <strong>on</strong>ly slight residuals<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> part, cleaning not necessary.<br />
Fluxes from potassium and <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> fluorides<br />
(KAlF4) have proven worldwide that<br />
have a melting range in <str<strong>on</strong>g>the</str<strong>on</strong>g> defined compositi<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 565 to 572°C. Complex parts such as<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> radiators are manufactured by this.<br />
Vacuum brazing (VB): due to heating up in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> furnace <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> material expands<br />
more than <str<strong>on</strong>g>the</str<strong>on</strong>g> adhering <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>; by this <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g> will be separated or solved, respectively.<br />
As this is performed under a vacuum, <str<strong>on</strong>g>the</str<strong>on</strong>g> surface<br />
laid bare remains metallically blank; <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
braze can wet <str<strong>on</strong>g>the</str<strong>on</strong>g> parent metal without <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
additi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a flux. Previously, <str<strong>on</strong>g>the</str<strong>on</strong>g> residual oxygen<br />
has been bound in <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace by glowing<br />
magnesium chips (‘getter material’). Requirements<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> braze gap: <strong>on</strong>ly 0.05 to 1.0 mm.<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 55
APPLICATION-ORIENTED TECHNOLOGIES<br />
Fig. 3: C<strong>on</strong>trolled atmosphere brazing (CAB) <str<strong>on</strong>g>of</str<strong>on</strong>g> an <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> radiator (Source: Solvay)<br />
7.5 Arc and laser beam brazing (braze weld-<br />
ing)<br />
Gas-metal arc brazing: <str<strong>on</strong>g>the</str<strong>on</strong>g> arc is used to break<br />
up <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g>s due to local heating. The braze<br />
melting in <str<strong>on</strong>g>the</str<strong>on</strong>g> arc will flow under <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g>s<br />
thus wetting <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> surface. Newly<br />
developed brazes with a slightly reduced melting<br />
temperature, partly <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> basis <str<strong>on</strong>g>of</str<strong>on</strong>g> Zn, acting<br />
with arcs-very-poor-<str<strong>on</strong>g>of</str<strong>on</strong>g>-energy are used.<br />
Laser beam brazing: (e. g. Al- plates in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
c<strong>on</strong>structi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> car bodies) also makes use <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
a tool (e. g. a separate sec<strong>on</strong>d laser beam or<br />
arc), in order to separate <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g>s. During<br />
laser beam brazing it is intended to use as little<br />
energy as possible and a defocused beam.<br />
There is <str<strong>on</strong>g>the</str<strong>on</strong>g> problem, however, to separate <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g>s <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>e hand and to securely avoid<br />
melting up <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r. Advantage: a flux free<br />
brazing process <str<strong>on</strong>g>of</str<strong>on</strong>g> high process speed.<br />
7.6 Resistance brazing<br />
Resistance spot brazing: <str<strong>on</strong>g>the</str<strong>on</strong>g> high electric c<strong>on</strong>ductivity,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> highly melting <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> as<br />
well as <str<strong>on</strong>g>the</str<strong>on</strong>g> good diffusi<strong>on</strong> behaviour <str<strong>on</strong>g>of</str<strong>on</strong>g> Al-Cu<br />
makes this process c<strong>on</strong>siderably more complicated.<br />
Good results, however, can be obtained<br />
with braze cladded surfaces (e. g. Al88Si, <str<strong>on</strong>g>layer</str<strong>on</strong>g><br />
thickness approx. 60 to 100 μm, plate thicknesses<br />
0.7 to 2 mm) using c<strong>on</strong>venti<strong>on</strong>al spot<br />
welding units (alternating current, without<br />
current and power program).<br />
The advantages <str<strong>on</strong>g>of</str<strong>on</strong>g> this process: almost no deformati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> surface, short welding times,<br />
high process stability, applicati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> simple<br />
welding units.<br />
8. Processes for soldering <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
alloys with reduced melting points<br />
The solders used for soldering <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> (alloys)<br />
were menti<strong>on</strong>ed before. The comm<strong>on</strong>ly<br />
used processes are aimed at a <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal energy<br />
as low as possible, or at joining temperatures<br />
as low as possible. This is necessary with <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
alloys with melting temperatures that<br />
do not permit <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
use <str<strong>on</strong>g>of</str<strong>on</strong>g> brazes (e. g.<br />
Al88Si) any more<br />
if too much process<br />
heat could lead<br />
to s<str<strong>on</strong>g>of</str<strong>on</strong>g>tening <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
material. In general,<br />
1xxx (Al-alloyed),<br />
2xxx (Cualloyed),<br />
3xxx<br />
(Mn-alloyed),<br />
4xxx (Si-alloyed)<br />
and 7xxx (Zn-alloyed)<br />
are more<br />
suitable for soldering,<br />
whereas<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> 5xxx (Mg-alloyed)<br />
and 6xxx<br />
(Si-/Mg-alloyed)<br />
are less suitable for soldering. It is ra<str<strong>on</strong>g>the</str<strong>on</strong>g>r <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
latter <strong>on</strong>es, however, that are <str<strong>on</strong>g>of</str<strong>on</strong>g>ten used in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
automotive industry.<br />
9. Brazed <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> dissimilar joints<br />
During brazing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing temperatures<br />
are limited to approx. 600°C. For<br />
brazing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> to titanium soldering<br />
using special zinc based solders is suitable.<br />
For joining <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> to magnesium solders<br />
based <strong>on</strong> zinc and magnesium are available<br />
with good experience made in ultrasound<br />
based flux free soldering. Aluminium is <str<strong>on</strong>g>of</str<strong>on</strong>g>ten<br />
brazed with Cr-Steel or CrNi steel in a c<strong>on</strong>tinuous<br />
furnace under c<strong>on</strong>trolled atmosphere.<br />
10. Summary<br />
In general, <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> is suitable for soldering<br />
and brazing. There are, however limits due to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> relatively low melting point and <str<strong>on</strong>g>the</str<strong>on</strong>g> influence<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> wettability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> surface depending<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> type <str<strong>on</strong>g>of</str<strong>on</strong>g> alloy. A variety <str<strong>on</strong>g>of</str<strong>on</strong>g> systems<br />
for soldering and brazing as well as types <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
fluxes is available. The most important process<br />
today is c<strong>on</strong>trolled atmosphere furnace<br />
brazing (CAB) with braze-cladded materials<br />
enhancing this very effective processing.<br />
Soldering processes are supported by metal<br />
alloyed fluxes with improved wettability. The<br />
applicati<strong>on</strong> by ultrasound partly enables brazing<br />
without using a flux. Current developments<br />
in soldering and brazing and <strong>on</strong> processes<br />
in particular in <str<strong>on</strong>g>the</str<strong>on</strong>g> field <str<strong>on</strong>g>of</str<strong>on</strong>g> soldering will develop<br />
new technical possibilities <str<strong>on</strong>g>of</str<strong>on</strong>g> processing<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> and <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloys and secure<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>m by new fields <str<strong>on</strong>g>of</str<strong>on</strong>g> manufacture.<br />
11. Standards and regulati<strong>on</strong><br />
DIN EN ISO 9453 (2006) • S<str<strong>on</strong>g>of</str<strong>on</strong>g>t solder alloys –<br />
Chemical compositi<strong>on</strong>s and forms; supersedes<br />
DIN EN 29454 (1994)<br />
DIN EN ISO 17672 (2010) • Brazing – Filler<br />
metals; supersedes DIN EN 1044 (2006)<br />
DIN 1707-100 (2011) • S<str<strong>on</strong>g>of</str<strong>on</strong>g>t solder alloys –<br />
Chemical compositi<strong>on</strong> and forms<br />
DIN EN ISO 3677 (1995) • Filler metals for soldering,<br />
brazing and braze welding – designati<strong>on</strong>s<br />
DIN EN 1045 (1997) • Fluxes for brazing<br />
DIN EN 13133 (2000) • Brazing / Brazer approval<br />
DIN EN 13134 (2000) • Brazing / Procedure<br />
approval<br />
DIN EN 12799 (2000) • Brazing / N<strong>on</strong>-destructive<br />
examinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> brazed joints<br />
DIN EN 12797 (2000) • Brazing / Destructive<br />
examinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> brazed joints<br />
DIN EN ISO 18279 (2004) • Imperfecti<strong>on</strong>s<br />
in brazed joints<br />
Fig. 4: Flame brazing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>: dissimilar metals (Source: Everwand & Fell) �<br />
56 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
APPLICATION-ORIENTED TECHNOLOGIES<br />
<str<strong>on</strong>g>Influence</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>natural</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> <strong>on</strong> brazeability<br />
J. Zähr 1 , S. Oswald 2 , M. Türpe 3 , H.-J. Ullrich 1 , U. Füssel 1<br />
1 TU Dresden, Institute <str<strong>on</strong>g>of</str<strong>on</strong>g> Surface and Manufacturing Technology, Joining Technology and Assembly,<br />
Germany • 2 IFW Dresden, Germany • 3 Behr GmbH & Co. KG, Stuttgart, Germany<br />
For brazing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>, <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>natural</str<strong>on</strong>g><br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> has a significant influence.<br />
However, <str<strong>on</strong>g>the</str<strong>on</strong>g> behaviour <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g> before brazing, e. g. due to changing<br />
climate c<strong>on</strong>diti<strong>on</strong>s during <str<strong>on</strong>g>the</str<strong>on</strong>g> storage or<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> transport and during <str<strong>on</strong>g>the</str<strong>on</strong>g> heating process,<br />
are not analysed comprehensively<br />
yet. In this paper, two analysing methods<br />
are explained, which enable <str<strong>on</strong>g>the</str<strong>on</strong>g> analysis<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> increased humidities<br />
and temperatures <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> compositi<strong>on</strong> and<br />
thickness <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>natural</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g>. Additi<strong>on</strong>ally, brazing tests are d<strong>on</strong>e<br />
to get a correlati<strong>on</strong> between <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
before <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing process and <str<strong>on</strong>g>the</str<strong>on</strong>g> brazeability<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material. The brazing tests<br />
are d<strong>on</strong>e in a shielding gas lab furnace<br />
without using flux. The tests have shown<br />
that especially c<strong>on</strong>densati<strong>on</strong> leads to a<br />
growth <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> oxidic <str<strong>on</strong>g>layer</str<strong>on</strong>g> and to a significant<br />
decrease <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> brazeability. So<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> understanding about <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> atmospheric c<strong>on</strong>diti<strong>on</strong>s <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> oxidic<br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g> and also <str<strong>on</strong>g>the</str<strong>on</strong>g> brazeability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
is enhanced.<br />
Aluminium is a material widely used in industry,<br />
due to its good relati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> weight to<br />
strength, good corrosi<strong>on</strong> resistance and formability<br />
[1]. For assembly <str<strong>on</strong>g>of</str<strong>on</strong>g> several parts, a material<br />
joining is <str<strong>on</strong>g>of</str<strong>on</strong>g>ten necessary. For material<br />
joints between <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> materials, a removal<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> is necessary,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> so called <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> surface activati<strong>on</strong>.<br />
The surface activati<strong>on</strong> method used depends<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing technique. For flame brazing<br />
as well as brazing in a shielding gas furnace,<br />
flux is <str<strong>on</strong>g>of</str<strong>on</strong>g>ten used for <str<strong>on</strong>g>the</str<strong>on</strong>g> surface activati<strong>on</strong> [2-<br />
[5]. The task <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> flux is widely discussed in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> literature. On <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>e hand side, <str<strong>on</strong>g>the</str<strong>on</strong>g> flux<br />
shall chemically dissolve <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> [5-<br />
7]. Thereby, <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> is cracked by <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
flux, so <str<strong>on</strong>g>the</str<strong>on</strong>g> flux can flow under <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> particles<br />
and blast <str<strong>on</strong>g>the</str<strong>on</strong>g>m. Additi<strong>on</strong>ally, <str<strong>on</strong>g>the</str<strong>on</strong>g> flux<br />
decreases <str<strong>on</strong>g>the</str<strong>on</strong>g> surface tensi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> solder.<br />
Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> flow ability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> solder is increased<br />
[6].<br />
Ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r comm<strong>on</strong> brazing technique is <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
brazing inside a vacuum chamber. The surface<br />
activati<strong>on</strong> is realized due to <str<strong>on</strong>g>the</str<strong>on</strong>g> Mg-gettering<br />
effect as well as <str<strong>on</strong>g>the</str<strong>on</strong>g> different <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal expansi<strong>on</strong><br />
coefficients <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> base ma-<br />
terial and <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>natural</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g><br />
[8-9]. Most <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> comm<strong>on</strong> research analyses<br />
for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> brazing are discussing <str<strong>on</strong>g>the</str<strong>on</strong>g> fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
development <str<strong>on</strong>g>of</str<strong>on</strong>g> brazing techniques [10-<br />
11], solder systems [12-13] or <str<strong>on</strong>g>the</str<strong>on</strong>g> corrosi<strong>on</strong><br />
behaviour <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> brazed parts [14]. However,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> before brazing<br />
is not characterized yet. There is <strong>on</strong>ly few<br />
informati<strong>on</strong> available in literature c<strong>on</strong>cerning<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> correlati<strong>on</strong> between <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> c<strong>on</strong>diti<strong>on</strong>s<br />
before brazing and <str<strong>on</strong>g>the</str<strong>on</strong>g> brazeability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
material. Gray et. al. [15] menti<strong>on</strong>s, that <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g> thickness influences <str<strong>on</strong>g>the</str<strong>on</strong>g> flow ability <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> solder. Swiderksy [16] specifies this correlati<strong>on</strong>:<br />
with increase <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> thickness<br />
from 4 to 22 nm an increase <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> amount<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> flux from 2 to 5 g/m 2 is necessary. But<br />
it is not clear, how this change <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g> can occur. This paper explains <str<strong>on</strong>g>the</str<strong>on</strong>g> compositi<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>natural</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> as well as<br />
two possibilities for <str<strong>on</strong>g>the</str<strong>on</strong>g> analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> this nm<br />
thick <str<strong>on</strong>g>layer</str<strong>on</strong>g>. Additi<strong>on</strong>ally, <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> typical<br />
envir<strong>on</strong>mental c<strong>on</strong>diti<strong>on</strong>s during storage<br />
and brazing are described. Afterwards, brazing<br />
tests are d<strong>on</strong>e to get a correlati<strong>on</strong> between<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> oxidic <str<strong>on</strong>g>layer</str<strong>on</strong>g> thickness and compositi<strong>on</strong> to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> brazeability.<br />
Natural <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> –<br />
structure, analyzing methods<br />
The <str<strong>on</strong>g>natural</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> c<strong>on</strong>sists <str<strong>on</strong>g>of</str<strong>on</strong>g> exactly two<br />
sheets: an <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> directly <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
(= barrier <str<strong>on</strong>g>layer</str<strong>on</strong>g>) and a hydroxidic <str<strong>on</strong>g>layer</str<strong>on</strong>g><br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g> transiti<strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> atmosphere (= surface<br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g>) [17]. In normal climate c<strong>on</strong>diti<strong>on</strong>s (NC,<br />
20°C, 50% rel. humidity), <str<strong>on</strong>g>the</str<strong>on</strong>g> barrier <str<strong>on</strong>g>layer</str<strong>on</strong>g><br />
has a thickness <str<strong>on</strong>g>of</str<strong>on</strong>g> ca. 2 nm and c<strong>on</strong>sists <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
amorphous Al 2 O 3 . The electrical c<strong>on</strong>ductivity<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> this compact <str<strong>on</strong>g>layer</str<strong>on</strong>g> is very low [17]. Therefore,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> i<strong>on</strong> diffusi<strong>on</strong> is minimized at room<br />
temperature, so this <str<strong>on</strong>g>layer</str<strong>on</strong>g> acts as corrosi<strong>on</strong><br />
protecti<strong>on</strong> for <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> material. Rising<br />
temperatures cause an increased i<strong>on</strong> diffusi<strong>on</strong>,<br />
which leads to a growth <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>.<br />
Additi<strong>on</strong>ally, crystalline Al 2 O 3 -structures are<br />
formed at temperatures above 400°C.<br />
The surface <str<strong>on</strong>g>layer</str<strong>on</strong>g> also has a thickness <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
2-3 nm under normal climate c<strong>on</strong>diti<strong>on</strong>s (NC).<br />
This <str<strong>on</strong>g>layer</str<strong>on</strong>g> c<strong>on</strong>sists <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> hydr<str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
(Al(OH) 3 ) as well as pores and crystalline parts<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> heterogeneous phases <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> base material.<br />
This <str<strong>on</strong>g>layer</str<strong>on</strong>g> is formed by <str<strong>on</strong>g>the</str<strong>on</strong>g> reacti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> barrier<br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g> (Al 2 O 3 ) or metallic <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> with<br />
water. Therefore, this <str<strong>on</strong>g>layer</str<strong>on</strong>g> can grow significantly<br />
due to an increase <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> relative humidity<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> atmosphere or if c<strong>on</strong>densed water is<br />
available at <str<strong>on</strong>g>the</str<strong>on</strong>g> surface.<br />
During transport or storage <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
materials before brazing, relative humidities<br />
above 90% or even c<strong>on</strong>densati<strong>on</strong> can occur at<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> surface <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> base materials. These c<strong>on</strong>diti<strong>on</strong>s<br />
influence <str<strong>on</strong>g>the</str<strong>on</strong>g> thickness <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> surface<br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g>. In c<strong>on</strong>trast to this, <str<strong>on</strong>g>the</str<strong>on</strong>g> heating process<br />
during brazing leads to a change <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> compositi<strong>on</strong><br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> thickness <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> barrier <str<strong>on</strong>g>layer</str<strong>on</strong>g>.<br />
In literature, <str<strong>on</strong>g>the</str<strong>on</strong>g>re are a lot <str<strong>on</strong>g>of</str<strong>on</strong>g> studies available<br />
c<strong>on</strong>cerning <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> different ambient<br />
c<strong>on</strong>diti<strong>on</strong>s <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> and<br />
hydr<str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>. Never<str<strong>on</strong>g>the</str<strong>on</strong>g>less, <str<strong>on</strong>g>the</str<strong>on</strong>g>se analyses<br />
do not correlate with <str<strong>on</strong>g>the</str<strong>on</strong>g> real c<strong>on</strong>diti<strong>on</strong>s for<br />
brazing materials and processes regarding <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
compositi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> materials, <str<strong>on</strong>g>the</str<strong>on</strong>g> temperatures,<br />
humidities, durati<strong>on</strong>s and ambient at-<br />
Fig. 1: XPS-spectra <str<strong>on</strong>g>of</str<strong>on</strong>g> surface <str<strong>on</strong>g>of</str<strong>on</strong>g> Al-material (EN AW-Al Mn1Cu with solder EN AW-Al Si10)<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 57
SESSION APPLICATION-ORIENTED TECHNOLOGIES<br />
Fig. 2: FTIR-Spectra while heating from room temperature to 605°C (left), summary <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> peak area<br />
depending <strong>on</strong> heating temperature for <str<strong>on</strong>g>the</str<strong>on</strong>g> three phases existing at <str<strong>on</strong>g>the</str<strong>on</strong>g> material surface (right)<br />
mospheres. In <str<strong>on</strong>g>the</str<strong>on</strong>g> subsequently described<br />
analyses <str<strong>on</strong>g>the</str<strong>on</strong>g> following materials and atmospheric<br />
c<strong>on</strong>diti<strong>on</strong>s were used:<br />
1. Material: Solder plated (both sides) Alsheets<br />
a. Base material: EN AW-Al Mn1Cu,<br />
thickness: 0.32 mm<br />
b. Solder: EN AW-Al Si10, thickness:<br />
0.04 mm (<strong>on</strong> both sides)<br />
2. Atmospheric c<strong>on</strong>diti<strong>on</strong>s for <str<strong>on</strong>g>the</str<strong>on</strong>g> analysis<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> storage and transport<br />
c<strong>on</strong>diti<strong>on</strong>s<br />
a. Normal climate (NC) – 23°C/ 50%<br />
rel. humidity<br />
b. Humid climate (HC) – 40°C/ 92%<br />
rel. humidity<br />
c. C<strong>on</strong>densati<strong>on</strong> (C) – 23°C/ > 100%<br />
rel. humidity<br />
3. Heating tests for <str<strong>on</strong>g>the</str<strong>on</strong>g> analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> influence<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> increased temperatures<br />
a. Heating temperature: 605°C<br />
b. Ambient atmosphere: Nitrogen<br />
The challenge for <str<strong>on</strong>g>the</str<strong>on</strong>g> analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> influence<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> real c<strong>on</strong>diti<strong>on</strong>s <strong>on</strong> brazing materials is <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
choice <str<strong>on</strong>g>of</str<strong>on</strong>g> suitable methods which are able to<br />
analyse nm-thick <str<strong>on</strong>g>layer</str<strong>on</strong>g>s and to distinguish between<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> and hydr<str<strong>on</strong>g>oxide</str<strong>on</strong>g> phases.<br />
With XPS-measurements, <str<strong>on</strong>g>the</str<strong>on</strong>g> compositi<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> surface can be measured. The spectra<br />
shows <str<strong>on</strong>g>the</str<strong>on</strong>g> intensity depending <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> binding<br />
energy, see Fig. 1. For <str<strong>on</strong>g>natural</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> surfaces<br />
oxygen, carb<strong>on</strong>, magnesium as well as<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> can be measured.<br />
The important phases and <str<strong>on</strong>g>the</str<strong>on</strong>g>ir binding energies<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> present analyses are [18]:<br />
Metallic Al 72,5 – 73 eV<br />
γ-Al 2O 3 73,7 – 74,5 eV<br />
Al(OH) 3 73,4 eV.<br />
Obviously it is not possible to distinguish between<br />
oxidic and hydroxidic phases <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
base <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> binding energy. Ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r possibility<br />
to distinguish between <str<strong>on</strong>g>the</str<strong>on</strong>g>se two phases is<br />
described by Wittenberg et. al. [19]. In this<br />
study, <str<strong>on</strong>g>the</str<strong>on</strong>g> oxidic and hydroxidic phases are<br />
classified by <str<strong>on</strong>g>the</str<strong>on</strong>g> formati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> relati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> atomic c<strong>on</strong>centrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
peak to <str<strong>on</strong>g>the</str<strong>on</strong>g> oxygen peak (Al/O). However,<br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> industrial material used in <str<strong>on</strong>g>the</str<strong>on</strong>g> present<br />
analysis, <str<strong>on</strong>g>the</str<strong>on</strong>g> measured <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> intensity<br />
c<strong>on</strong>sists always <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> oxidic bound <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> metallic <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>. The signal <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> metallic bound <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> originates from<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> metallic <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> base material directly<br />
under <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>. Therefore,<br />
this metallic <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> signal cannot be<br />
taken into account for <str<strong>on</strong>g>the</str<strong>on</strong>g> determinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> surface phases. Hence, <strong>on</strong>ly <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
oxidic bound <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> is set into relati<strong>on</strong> to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> oxygen intensity in <str<strong>on</strong>g>the</str<strong>on</strong>g> present analysis.<br />
For Al 2O 3 <str<strong>on</strong>g>the</str<strong>on</strong>g> ratio <str<strong>on</strong>g>of</str<strong>on</strong>g> Al <str<strong>on</strong>g>oxide</str<strong>on</strong>g> to O is about 2/3,<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> hydroxidic bound <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> Al(OH) 3<br />
this ratio is about 1/3. Additi<strong>on</strong>ally, <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g> thickness can be estimated using <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
ratio <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> intensity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> oxidic to metallic<br />
bound <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> [20].<br />
The XPS-measurement <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>natural</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
surfaces as well as <str<strong>on</strong>g>of</str<strong>on</strong>g> materials stored<br />
under normal climate, humid climate and c<strong>on</strong>densati<strong>on</strong><br />
show, that <str<strong>on</strong>g>the</str<strong>on</strong>g> hydroxidic <str<strong>on</strong>g>layer</str<strong>on</strong>g> is<br />
existent <strong>on</strong> all surfaces, even <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> surface<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>natural</str<strong>on</strong>g> (not stored) <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> materials. In<br />
c<strong>on</strong>trast to this, <str<strong>on</strong>g>the</str<strong>on</strong>g> storage c<strong>on</strong>diti<strong>on</strong>s have a<br />
measurable influence <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> thickness.<br />
Especially, <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>densed water<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> surface causes a significant increase <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>, see Fig. 4.<br />
The temperature increase during <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing<br />
process has ano<str<strong>on</strong>g>the</str<strong>on</strong>g>r significant influence<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> thickness and compositi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>s<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g> surface <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> materials. The<br />
behaviour <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se <str<strong>on</strong>g>layer</str<strong>on</strong>g>s during heating from<br />
room temperature till 605°C (= brazing temperature)<br />
can be analyzed with <str<strong>on</strong>g>the</str<strong>on</strong>g> help <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
FTIR measurements under a N 2-atmosphere<br />
(= brazing atmosphere). All tests were d<strong>on</strong>e<br />
at Innoval Technology Ltd. Banbury, where a<br />
FTIR-spectrometer with an additi<strong>on</strong>al heating<br />
device is available.. A spectrum is taken <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> surface every minute during <str<strong>on</strong>g>the</str<strong>on</strong>g> heating<br />
process. All spectra for <strong>on</strong>e heating cycle are<br />
displayed in Fig. 2.<br />
It is obvious, that <str<strong>on</strong>g>the</str<strong>on</strong>g>re are three phases<br />
existing at <str<strong>on</strong>g>the</str<strong>on</strong>g> surface during <str<strong>on</strong>g>the</str<strong>on</strong>g> heating<br />
process. At room temperature <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
amorphous Al 2O 3-phase dominates<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> surface. With rising temperatures,<br />
especially at temperatures above<br />
400°C, <str<strong>on</strong>g>the</str<strong>on</strong>g> Al/O-signal moves to<br />
lower wave numbers. Unfortunately,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> phase could not be defined until<br />
now. This phase can c<strong>on</strong>sist <str<strong>on</strong>g>of</str<strong>on</strong>g> ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r<br />
crystalline Al 2O 3 or MgAl 2O 4. For a<br />
precise determinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> this phase,<br />
TEM analyses are planned. At temperatures<br />
above 577°C, <str<strong>on</strong>g>the</str<strong>on</strong>g> solidus<br />
temperature <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> solder, MgO is<br />
growing at <str<strong>on</strong>g>the</str<strong>on</strong>g> surface. With <str<strong>on</strong>g>the</str<strong>on</strong>g> help <str<strong>on</strong>g>of</str<strong>on</strong>g> this<br />
analyzing method, <str<strong>on</strong>g>the</str<strong>on</strong>g> behaviour <str<strong>on</strong>g>of</str<strong>on</strong>g> materials,<br />
which were stored under c<strong>on</strong>densed water,<br />
was also analyzed. These materials have<br />
a major growth <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> during <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
heating process.<br />
Correlati<strong>on</strong> between surface<br />
c<strong>on</strong>diti<strong>on</strong> and brazeability<br />
Brazing method for analyzing influence <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> <strong>on</strong> brazeability: The brazing tests<br />
were d<strong>on</strong>e in a laboratory shielding gas furnace.<br />
To see <strong>on</strong>ly <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g> <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> brazeability, a mechanical surface<br />
activati<strong>on</strong> method, see Fig. 3, was used instead<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> a chemical surface activati<strong>on</strong>. To realize <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
cracking <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>, <str<strong>on</strong>g>the</str<strong>on</strong>g> upper joining<br />
partner is pressed inside <str<strong>on</strong>g>the</str<strong>on</strong>g> liquid solder by<br />
applying a weight. Therefore, tensi<strong>on</strong>s are induced<br />
inside <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>, which cause <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
cracking <str<strong>on</strong>g>of</str<strong>on</strong>g> this <str<strong>on</strong>g>layer</str<strong>on</strong>g>. Afterwards <str<strong>on</strong>g>the</str<strong>on</strong>g> liquid<br />
solder can flow to <str<strong>on</strong>g>the</str<strong>on</strong>g> upper joining partner<br />
and wet it.<br />
Brazing results for different surface c<strong>on</strong>diti<strong>on</strong>s:<br />
A storage under humid climate as well<br />
as under c<strong>on</strong>densati<strong>on</strong> for a short period<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> time (3 days) causes a growth <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g>, but does not influence <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing<br />
Fig. 3: Mechanism <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> mechanical surface<br />
activati<strong>on</strong><br />
58 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
level significantly, see Fig. 4. A l<strong>on</strong>ger storage<br />
under c<strong>on</strong>densati<strong>on</strong> suppresses <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing<br />
process completely. However, storage in a normal<br />
climate after <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>densati<strong>on</strong> leads to a<br />
significant improvement <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> brazeability <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> material.<br />
It has to be followed, that <str<strong>on</strong>g>the</str<strong>on</strong>g> water, which<br />
is stored inside <str<strong>on</strong>g>the</str<strong>on</strong>g> pores <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g><br />
due to <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>densati<strong>on</strong>, influences <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing<br />
level. This water leads to an increased<br />
growth <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> during <str<strong>on</strong>g>the</str<strong>on</strong>g> heating.<br />
This thickened <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> cannot be cracked<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> weight <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> upper joining partner.<br />
Hence, <str<strong>on</strong>g>the</str<strong>on</strong>g> flow <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> solder is suppressed<br />
completely. In c<strong>on</strong>trast to this, <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g><br />
thickness has a minor influence <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> brazeability.<br />
C<strong>on</strong>clusi<strong>on</strong>s<br />
The present analysis characterizes <str<strong>on</strong>g>the</str<strong>on</strong>g> influence<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> humidity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> atmosphere as<br />
well as <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>densed water at <str<strong>on</strong>g>the</str<strong>on</strong>g> surface <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> materials <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>natural</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>. With <str<strong>on</strong>g>the</str<strong>on</strong>g> help <str<strong>on</strong>g>of</str<strong>on</strong>g> XPS-measurements,<br />
it has been shown, that storage under<br />
normal or humid climate does not influence<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> thickness significantly. In c<strong>on</strong>trast<br />
to this, <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>densed water<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> surface causes an intense growth <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>. FTIR measurements with an<br />
heating device have also shown that materials,<br />
which were stored under <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>densed<br />
water, have a significant thicker <str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g> at brazing temperature.<br />
Subsequent brazing tests have been d<strong>on</strong>e<br />
in a shielding gas furnace with a mechanical<br />
surface activati<strong>on</strong> to see <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> brazeability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material.<br />
These tests have shown that <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g><br />
thickness before brazing is not <str<strong>on</strong>g>the</str<strong>on</strong>g> critical<br />
parameter for <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing result. In fact, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
water inside <str<strong>on</strong>g>the</str<strong>on</strong>g> pores <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> hydroxidic <str<strong>on</strong>g>layer</str<strong>on</strong>g><br />
causes an increased growth <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g><br />
during <str<strong>on</strong>g>the</str<strong>on</strong>g> heating process. This effect <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
c<strong>on</strong>densed water can be avoided, if <str<strong>on</strong>g>the</str<strong>on</strong>g> materials<br />
are stored under normal climate after having<br />
water present at <str<strong>on</strong>g>the</str<strong>on</strong>g> surface <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
materials.<br />
The analyses showed that not <strong>on</strong>ly <str<strong>on</strong>g>the</str<strong>on</strong>g> solder<br />
or <str<strong>on</strong>g>the</str<strong>on</strong>g> brazing c<strong>on</strong>diti<strong>on</strong>s are important for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> brazing result <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> materials, but<br />
also <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>natural</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>. The<br />
<str<strong>on</strong>g>natural</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g> can be influenced significantly<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> atmospheric c<strong>on</strong>diti<strong>on</strong>s during<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> transport and <str<strong>on</strong>g>the</str<strong>on</strong>g> storage <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> materials.<br />
Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>rmore, it has to be assumed that also<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> surface <str<strong>on</strong>g>of</str<strong>on</strong>g> different brazing partners, e. g.<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> or stainless steels, can influence<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> brazeability.<br />
References<br />
APPLICATION-ORIENTED TECHNOLOGIES<br />
[1] Ostermann, F.: Anwendungstechnologie Aluminium<br />
– ein Werkst<str<strong>on</strong>g>of</str<strong>on</strong>g>fhandbuch. Springer Berlin<br />
Heidelberg; Auflage: 2., 2007.<br />
[2] Kohlweiler, A.: Hartlöten v<strong>on</strong> Aluminium – so<br />
geht es auch. In: Der Praktiker.(1996) Heft 2, S.<br />
40-45.<br />
[3] Meurer, C.; Belt, H.-J.; König, H.: Das Nocolok-<br />
Flux-Hartlötverfahren. In: Die Kälte und Klima-<br />
technik. (1997) Heft 10, S. 802-808.<br />
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<str<strong>on</strong>g>of</str<strong>on</strong>g> brazed <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> heat-exchangers, Part I.<br />
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für die Praxis. Düsseldorf: Deutscher Verlag für<br />
Schweißtechnik DVS-Verlag GmbH, 1995.<br />
[7] Terrill, J. R.; Cochran, C. N.; Stokes, J. J.; Haupin;<br />
W. E.: Understanding <str<strong>on</strong>g>the</str<strong>on</strong>g> Mechanisms <str<strong>on</strong>g>of</str<strong>on</strong>g> Aluminium<br />
Brazing. In: Welding Journal. (1971) S. 833-839.<br />
[8] Ashburn, L. L.: Fluxless Vacuum Furnace Brazing<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> Aluminum particularly Advantageous for<br />
more critical Applicati<strong>on</strong>s: I. In: Industrial Heating.<br />
(1994) S. 47-51.<br />
[9] Byrnes, E. R.: Vacuum Fluxless Brazing <str<strong>on</strong>g>of</str<strong>on</strong>g> Aluminium.<br />
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[10] Füssel, U.; Six, S.: Entwicklung eines NIR-<br />
Lötverfahrens für die Fertigung v<strong>on</strong> Solarabsorbern<br />
aus Aluminium. LÖT, 9. Internati<strong>on</strong>al C<strong>on</strong>ference<br />
Brazing, High Temperature Brazing and Diffusi<strong>on</strong><br />
Welding. In: DVS-Berichte: Band 263 (2010) S.<br />
358-360<br />
[11] Möller, F.; Thomy, C.; Vollertsen, F.: Flussmittelfreies<br />
Hartlöten v<strong>on</strong> Aluminiumlegierungen mit<br />
einem koaxialen Laser-Plasma-Hybridlötprozess.<br />
In: Schweißen und Schneiden 62/5 (2010) 294.<br />
[12] Bach, F.W.; Möhwald, K.; Holländer, U.; Langohr,<br />
A.: Niedrig schmelzende Aluminiumhartlote<br />
aus dem System Al-Si-Zn. 9. Internati<strong>on</strong>al C<strong>on</strong>ference<br />
Brazing, High Temperature Brazing and<br />
Diffusi<strong>on</strong> Welding. In: DVS-Berichte. Düsseldorf:<br />
DVS-Verlag. Band 263 (2010) Seite 117-121.<br />
[13] Tillmann, W.; LIU, C.; Wojarski, L.: Dotierung<br />
v<strong>on</strong> Aluminiumbasisloten zum flussmittelfreien<br />
Hartlöten v<strong>on</strong> Aluminiumlegierungen. 9. Internati<strong>on</strong>al<br />
C<strong>on</strong>ference Brazing, High Temperature<br />
Brazing and Diffusi<strong>on</strong> Welding. In: DVS-Berichte.<br />
Düsseldorf: DVS-Verlag.: Band 263 (2010) Seite<br />
106-112.<br />
[14] Melander, M.; Woods, R.: A corrosi<strong>on</strong> study <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
brazed <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> heat exchangers after field service.<br />
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(2010) Heft 7/8, Seite 56-61.<br />
[15] Gray, A.; Flemming, A. J. E.; Evans, J. M.: Optimising<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Properties <str<strong>on</strong>g>of</str<strong>on</strong>g> L<strong>on</strong>g-life Brazing Sheet<br />
Alloys for Vacuum and Nocolok Brazed Comp<strong>on</strong>ents.<br />
VTMS 4 C<strong>on</strong>ference Proceedings, L<strong>on</strong>d<strong>on</strong>,<br />
May 1999.<br />
[16] Swidersky, H.-W.: Aluminium brazing with<br />
n<strong>on</strong>-corrosive fluxes – state <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> art and trends in<br />
Nocolok flux technology. In: Hart- und Hochtem-<br />
peraturlöten und Diffusi<strong>on</strong>sschweißen DVS-Berichte<br />
Band 212. Düsseldorf: DVS-Verlag, DVS-Berichte<br />
Band 212 (2001), S. 164-169.<br />
[17] Altenpohl, D.: Aluminium und Aluminium-<br />
legierungen. Berlin: Springer Verlag, 1965.<br />
[18] Moulder, J. F.; Stickle, W. F.; Sobol, P. E.;<br />
Bomben, K. D.: Handbook <str<strong>on</strong>g>of</str<strong>on</strong>g> X-Ray Photoelectr<strong>on</strong><br />
Spectroscopy: A Reference Book <str<strong>on</strong>g>of</str<strong>on</strong>g> Standard<br />
Spectra for Identificati<strong>on</strong> and Interpretati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
XPS-Data. Physical Electr<strong>on</strong>ics, 1995. – ISBN-10:<br />
096481241X<br />
[19] Wittenberg, T. N.; Douglas, W. J.; Wang, P. S.:<br />
Aluminium hydr<str<strong>on</strong>g>oxide</str<strong>on</strong>g> growth <strong>on</strong> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> surfaces<br />
exposed to an air/1% NO 2 mixture. In: Journal<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> Materials Science, 23 (1988), S. 1745-1747.<br />
[20] Kozlowska, M.; Reiche, R.; Oswald, S.; Vinzelberg,<br />
H.; Hübner, R.; Wetzig, K.: Quantitative<br />
ARXPS investigati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> systems at ultrathin <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
<str<strong>on</strong>g>oxide</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>s. Surface Interface Anal. 36<br />
(2004) 1600.<br />
�<br />
Fig. 4: <str<strong>on</strong>g>Influence</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> storage c<strong>on</strong>diti<strong>on</strong>s and durati<strong>on</strong> <strong>on</strong> <str<strong>on</strong>g>oxide</str<strong>on</strong>g> thickness and brazing level<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 59
MELTING, RECYCLING & HEAT TREATMENT<br />
The new generati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
heat treatment plants – a vanguard c<strong>on</strong>cept<br />
Markus Belte and Dan Dragulin, Belte AG<br />
The vigorous discussi<strong>on</strong> in <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g><br />
heat treatment community about <str<strong>on</strong>g>the</str<strong>on</strong>g> development<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> appropriate technique<br />
becomes within <str<strong>on</strong>g>the</str<strong>on</strong>g> framework <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
present work a genuine c<strong>on</strong>crete answer.<br />
This paper is completely dedicated to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
presentati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a new generati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> heat<br />
treatment plants; it first introduces <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
fundamentals <str<strong>on</strong>g>of</str<strong>on</strong>g> high speed heat transfer<br />
processes and presents practical results<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g>irs <str<strong>on</strong>g>the</str<strong>on</strong>g>rmodynamical analysis and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>n <str<strong>on</strong>g>of</str<strong>on</strong>g>fers a detailed perspective <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
vanguard c<strong>on</strong>cept <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> new generati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> heat treatment plants. The<br />
present work is based <strong>on</strong> original experiments<br />
and investigati<strong>on</strong>s obtained by <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
authors and will present techniques never<br />
used before in <str<strong>on</strong>g>the</str<strong>on</strong>g> industrial heat treatment<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g>.<br />
Infrared radiati<strong>on</strong> – <str<strong>on</strong>g>the</str<strong>on</strong>g>oretical aspects<br />
The radiati<strong>on</strong> heat transfer process is described<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> law <str<strong>on</strong>g>of</str<strong>on</strong>g> Stefan-Boltzmann:<br />
• ∂Q<br />
Q = ⎯⎯ = εσST 4<br />
∂t (1)<br />
• 4 4<br />
Q = εσS [T O - T U ] (2)<br />
•<br />
Where: Q = heat flow rate; ε = emissivity 1 ;<br />
σ = 5.67 x 10 -8 W/m 2 K 4 Stefan-Boltzmannc<strong>on</strong>stant;<br />
S = surface <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> emitting body;<br />
T = temperature <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> emitting body (Kelvin);<br />
T O = surface temperature; T U = envir<strong>on</strong>ment<br />
temperature 2 .<br />
The heating rate can be calculated using <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
following formula:<br />
mc 100 TWB Ta<br />
τ = ⎯ ⎯⎯ [ ξ´(⎯⎯)- ξ´´ (⎯⎯)]<br />
α T 3<br />
U<br />
TU TU (⎯⎯)<br />
100<br />
(3) 3<br />
Where: m = mass/surface unity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> product<br />
to be heated; c =specific heat; TWB = heat<br />
treatment temperature; TU = envir<strong>on</strong>ment temperature;<br />
ξ = f(TWB/TU) A special case <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> heat transfer process<br />
is <str<strong>on</strong>g>the</str<strong>on</strong>g> infrared heat transfer process.<br />
“Infrared radiati<strong>on</strong>, that porti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
electromagnetic spectrum that extends from<br />
1 ε Є (0,1] ; for <str<strong>on</strong>g>the</str<strong>on</strong>g> ideal black body: ε = 1<br />
2 The envir<strong>on</strong>ment could be <str<strong>on</strong>g>the</str<strong>on</strong>g> interior <str<strong>on</strong>g>of</str<strong>on</strong>g> a furnace.<br />
3 According to [3]<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> l<strong>on</strong>g wavelength, or red, end <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> visiblelight<br />
range to <str<strong>on</strong>g>the</str<strong>on</strong>g> microwave range. Invisible<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> eye, it can be detected as a sensati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> warmth <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> skin. The infrared range<br />
is usually divided into three regi<strong>on</strong>s: near<br />
infrared (nearest <str<strong>on</strong>g>the</str<strong>on</strong>g> visible spectrum), with<br />
wavelengths 0.78 to about 2.5 micrometres (a<br />
micrometre, or micr<strong>on</strong>, is 10 -6 metre); middle<br />
infrared, with wavelengths 2.5 to about 50 micrometres;<br />
and far infrared, with wavelengths<br />
50 to 1,000 micrometres. Most <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> radiati<strong>on</strong><br />
emitted by a moderately heated surface is infrared;<br />
it forms a c<strong>on</strong>tinuous spectrum. Molecular<br />
excitati<strong>on</strong> also produces copious infrared<br />
radiati<strong>on</strong> but in a discrete spectrum <str<strong>on</strong>g>of</str<strong>on</strong>g> lines or<br />
bands.” [Encyclopaedia Britannica [1]]<br />
“Radiant heating has been used in <str<strong>on</strong>g>the</str<strong>on</strong>g> industry<br />
since <str<strong>on</strong>g>the</str<strong>on</strong>g> 1930s, where it was introduced to<br />
bake finishes <strong>on</strong> cars. It took time for <str<strong>on</strong>g>the</str<strong>on</strong>g> new<br />
technology to gain acceptance but today <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
technology is used in most industrialised countries<br />
especially for drying and curing <str<strong>on</strong>g>of</str<strong>on</strong>g> paints<br />
and drying <str<strong>on</strong>g>of</str<strong>on</strong>g> textile, pulp and paper. Infrared<br />
energy is unique because it can heat materials<br />
or objects without heating <str<strong>on</strong>g>the</str<strong>on</strong>g> air around <str<strong>on</strong>g>the</str<strong>on</strong>g>m.<br />
That allows infrared heat to be c<strong>on</strong>centrated<br />
exactly where it is wanted without much loss<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> energy.” [2]<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> an infrared heating <str<strong>on</strong>g>the</str<strong>on</strong>g> maxi-<br />
mum temperature which can be reached depends<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> envir<strong>on</strong>ment temperature:<br />
T - T U = (T max - T U)(1-e -B . τ ) (4) [3]<br />
Where: T = body temperature; τ = durati<strong>on</strong>;<br />
T U = envir<strong>on</strong>ment temperature; T max = maximum<br />
temperature; B = coefficient which takes<br />
into account <str<strong>on</strong>g>the</str<strong>on</strong>g> process c<strong>on</strong>diti<strong>on</strong>s<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> a classic heat transfer process<br />
performed exclusively through air c<strong>on</strong>vecti<strong>on</strong>,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> body temperature can not exceed <str<strong>on</strong>g>the</str<strong>on</strong>g> air<br />
temperature.<br />
Gas radiati<strong>on</strong><br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> flame radiati<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g>re are two<br />
types radiati<strong>on</strong>: visible and invisible/infrared<br />
radiati<strong>on</strong>. The last <strong>on</strong>e is <str<strong>on</strong>g>the</str<strong>on</strong>g> invisible infrared<br />
radiati<strong>on</strong> emitted by carb<strong>on</strong> di<str<strong>on</strong>g>oxide</str<strong>on</strong>g> and<br />
steam 4 .<br />
The quantity <str<strong>on</strong>g>of</str<strong>on</strong>g> heat transferred through<br />
radiati<strong>on</strong> from a <str<strong>on</strong>g>layer</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> CO 2 respectively H 2O<br />
to a grey surface are:<br />
3.2 3.2<br />
Tg Tw<br />
qCO2 = ε . 10.35(p .<br />
CO2 s) 0.4 [(⎯⎯) - (⎯⎯)<br />
100 100<br />
Tg<br />
0.65<br />
. (⎯) ] Tw 4 After J. H. Brunklaus<br />
Fig. 1: Bilateral (green) and unilateral (red) exposure to radiati<strong>on</strong> (not coated, h = 10 cm)<br />
(5)[[7]→[6]]<br />
60 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011<br />
Abbildungen: Belte
q H2O = ε(46.52 - 94.9p H2Os)(p2 . s) 0.6<br />
3 ⎯⎯<br />
3 ⎯⎯<br />
2.32 + 1.37 √p 2 s 2.32 + 1.37 √p 2 s<br />
Tg Tw [(⎯⎯) -(⎯⎯)<br />
100 100 ]<br />
(6)[[7]→[6]]<br />
Where: q = quantity <str<strong>on</strong>g>of</str<strong>on</strong>g> heat [W/m²]; p = partial<br />
pressure [daN/cm²]; s = <str<strong>on</strong>g>layer</str<strong>on</strong>g> thickness [m];<br />
T g = gas temperature [K]; T w = temperature<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> grey surface [K]; ε = emissivity rapport:<br />
A λ = absorbed radiati<strong>on</strong> and A λs = total radiated<br />
energy<br />
Aλ<br />
ε = ⎯<br />
A λs<br />
Infrared heating <str<strong>on</strong>g>of</str<strong>on</strong>g> massive<br />
<str<strong>on</strong>g>aluminium</str<strong>on</strong>g> castings<br />
Electric radiant burners<br />
(7)[[7]→[6]<br />
Experiment purpose – determinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g>:<br />
• heating rate<br />
• maximal reached temperature<br />
• influence <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
surface quality<br />
������������������������������������������������������<br />
MELTING, RECYCLING & HEAT TREATMENT<br />
coated or not<br />
as cast<br />
100% graphite coated<br />
• distance between <str<strong>on</strong>g>the</str<strong>on</strong>g> infrared source and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> irradiated surface (h);<br />
Experimental c<strong>on</strong>diti<strong>on</strong>s:<br />
• experimental infrared facility<br />
industrial IR installati<strong>on</strong><br />
power : 108 KW/m²<br />
nominal power: 37.8 kW<br />
(active surface <str<strong>on</strong>g>of</str<strong>on</strong>g> 0.35 m²)<br />
air cooling system<br />
• test specimen<br />
die casting: cylinder head<br />
Al-Si-Mg-Cu alloy<br />
weight: 26 kg<br />
wall thickness: 120 mm<br />
• exposure to radiati<strong>on</strong><br />
bilateral and unilateral<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> a unilateral exposure to radiati<strong>on</strong><br />
(<strong>on</strong>e part <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> infrared module is switched<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g>f) we obtain a heating rate <str<strong>on</strong>g>of</str<strong>on</strong>g> 0.11 °C/s (between<br />
50 and 425°C 5 ). In <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> a bilateral<br />
exposure to radiati<strong>on</strong> we obtain a heating<br />
rate <str<strong>on</strong>g>of</str<strong>on</strong>g> 0.43 °C/s. Enhancing <str<strong>on</strong>g>the</str<strong>on</strong>g> installati<strong>on</strong><br />
���������������<br />
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�����������������������������������������������������������������������������������������������������<br />
����������������������������������������������������������������������������������������������������<br />
�����������������������������������������������������������������������������������������������������<br />
�����������������������������������������������<br />
�������������������������������������������������������������������������������������<br />
�������������������������������������<br />
��������������������������������������������<br />
����������@�������������������������������������������<br />
power by 100% (in <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> a bilateral exposure<br />
to radiati<strong>on</strong>) quadruped <str<strong>on</strong>g>the</str<strong>on</strong>g> heating<br />
rate by a coeval reducti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> energy c<strong>on</strong>sumpti<strong>on</strong>.<br />
The unequal temperature maximum<br />
is c<strong>on</strong>spicuous (fig.1).<br />
Energy c<strong>on</strong>sumpti<strong>on</strong>:<br />
• unilateral exposure to radiati<strong>on</strong>: ~ 55 min<br />
55<br />
• E = ⎯ . 18.31 = 16.78kWh<br />
60<br />
• bilateral exposure to radiati<strong>on</strong>: ~ 15 min<br />
15<br />
• E = ⎯ . 18.31 = 4.58kWh<br />
60<br />
Where: 0.35 m²………………………37.8 kW<br />
0.169 m² 6 ………….……………x kW<br />
X = 18.31 kW/side → X = 36.63 kW for a<br />
bilateral exposure<br />
The coating leads to a c<strong>on</strong>siderable enhancement<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> surface heating rate and simultaneously<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> increase <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> temperature<br />
difference between <str<strong>on</strong>g>the</str<strong>on</strong>g> surface and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
5 One has to pay maximum attenti<strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> solidus temperature<br />
(especially for Al alloys c<strong>on</strong>taining Cu).<br />
6 casting surface exposed to radiati<strong>on</strong>
MELTING, RECYCLING & HEAT TREATMENT<br />
center <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> casting.<br />
Energy c<strong>on</strong>sumpti<strong>on</strong> and process efficiency<br />
between 55°C and 535°C<br />
• not coated: heating time = 0.27 h<br />
• E = 36.63 x 0.27 = 9.89 kWh<br />
• η = 3.579 7 /9.89 = 0.361<br />
• coated: heating time = 0.2 h<br />
• E = 36.63 x 0.2 = 7.3 kWh<br />
• η = 3.579 8 /7.3 = 0.49<br />
surface heating rate [°C/s]<br />
coated 0.59<br />
not coated 0.68<br />
Tab. 1: <str<strong>on</strong>g>Influence</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> surface<br />
Gas fired burners<br />
The following experiment was str<strong>on</strong>gly supported<br />
by LOI Italimpianti and performed by<br />
Elster Kromschröder.<br />
Experiment purpose – determinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g>:<br />
• heating rate (furnace preheated<br />
at ~ 500°C)<br />
Experimental c<strong>on</strong>diti<strong>on</strong>s:<br />
• experimental heat treatment furnace<br />
using a ceramic flat flame burner as<br />
infrared radiati<strong>on</strong> source<br />
power : 450 kW<br />
• test specimen<br />
die casting: cylinder head<br />
Al-Si-Mg-Cu alloy<br />
weight: 26 kg<br />
wall thickness: 120 mm<br />
• exposure to radiati<strong>on</strong><br />
unilateral<br />
Fig. 2: Flat flame burner: 450 kW<br />
C<strong>on</strong>clusi<strong>on</strong> and prospects<br />
The industrial use <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> infrared radiati<strong>on</strong> for<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment <str<strong>on</strong>g>of</str<strong>on</strong>g> aluminum castings in Europe<br />
is <strong>on</strong>ly a questi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> time.<br />
808<br />
7 Q = ⎯⎯<br />
26<br />
x ∫(4.8 + 3.2 . 10-3T)dT = 3075.44kcal = 3.579kWh<br />
26.9 328<br />
808<br />
8 Q = ⎯⎯<br />
26<br />
x ∫(4.8 + 3.2 . 10-3T)dT = 3075.44kcal = 3.579kWh<br />
26.9 328<br />
Fig. 3: Heating rate: 450 kW<br />
Belte’s industrial c<strong>on</strong>cept is illustrated in Fig.<br />
4.<br />
Our c<strong>on</strong>cept proves that <str<strong>on</strong>g>the</str<strong>on</strong>g> next generati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> heat treatment plants will<br />
be:<br />
• extreme mobile<br />
commissi<strong>on</strong>ing/decommissi<strong>on</strong>ing<br />
durati<strong>on</strong>: ~ three weeks<br />
• extreme flexible<br />
without base and ancillary frames<br />
• extreme short processing time<br />
• extreme envir<strong>on</strong>mentally friendly<br />
without gas emissi<strong>on</strong> (in <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> use <str<strong>on</strong>g>of</str<strong>on</strong>g> electric radiant burners)<br />
References<br />
[1] http://www.britannica.com/<br />
[2] M. Wagner, P. Buchet, W. Kesteleyn, A. Molin –<br />
Radiant heating in industrial processes, 22nd World<br />
Gas C<strong>on</strong>ference June 1-5, 2003 Tokyo, Japan<br />
Fig. 4: Industrial infrared heating facility for <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> alloys<br />
[3] C. Samoila, L. Druga, L.Stan – Cuptoare si Instalatii<br />
de Incalzire, EDP, Bukarest, 1983<br />
[4] D. Dragulin, M. Belte, M. Dragulin – Thermodynamische<br />
Aspekte der Wärmebehandlung v<strong>on</strong><br />
Metallen, pro Business Verlag, Berlin, 2010<br />
[5] M. Orfeuil – Electric Process Heating, Battelle<br />
Press, 1987<br />
[6] J. H. Brunklaus – Cuptoare Industriale, Editura<br />
Technica, Bukarest, 1977<br />
[7] A. Schack – der industrielle Wärmeübergang, 5.<br />
Auflage, Stahl-Eisen Verlag, 1957<br />
Authors<br />
Markus Belte is CEO <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Belte AG, located in<br />
Delbrück, Germany.<br />
Dr. Dan Dragulin is head <str<strong>on</strong>g>of</str<strong>on</strong>g> research and development<br />
at Belte AG.<br />
62 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Abbildungen: promeos<br />
Resource efficiency at increased process quality<br />
becomes <str<strong>on</strong>g>the</str<strong>on</strong>g> dominating driver for investments<br />
in industry, and so in <str<strong>on</strong>g>the</str<strong>on</strong>g> world <str<strong>on</strong>g>of</str<strong>on</strong>g> casting.<br />
An optimized melting and material logis-<br />
tics process requires optimum temperature<br />
c<strong>on</strong>trol <str<strong>on</strong>g>of</str<strong>on</strong>g> material and casting equipment, including<br />
melting furnace, transportati<strong>on</strong> ladles<br />
or launders and casting moulds.<br />
MELTING, RECYCLING & HEAT TREATMENT<br />
New standards in gas-fired heating <str<strong>on</strong>g>of</str<strong>on</strong>g> moulds, ladles, launders<br />
and melting furnaces through flameless burner technology<br />
Jochen Volkert, promeos GmbH<br />
Fig.1: Porous burner<br />
Fig. 2: Different designs <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> porous burner<br />
Based <strong>on</strong> its flameless high performance industry<br />
burner portfolio, promeos <str<strong>on</strong>g>of</str<strong>on</strong>g>fers new<br />
preheating and tempering soluti<strong>on</strong>s all al<strong>on</strong>g<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> process line. Energy savings <str<strong>on</strong>g>of</str<strong>on</strong>g> up to 75%<br />
and increased process stability due to enhanced<br />
c<strong>on</strong>trol measures have been approved<br />
at numerous foundries all across <str<strong>on</strong>g>the</str<strong>on</strong>g> metal<br />
processing market.<br />
The clou is as easy as impressing: <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
absence <str<strong>on</strong>g>of</str<strong>on</strong>g> a free flame as spot-type heating<br />
source and <str<strong>on</strong>g>the</str<strong>on</strong>g> infinitely adjustable heat flux<br />
(similar to a dimming lamp) are core features<br />
to avoid inhomogeneity and inefficiency in<br />
heating ladles, launders or moulds.<br />
Porous burner technology<br />
In a porous burner (Fig. 1) <str<strong>on</strong>g>the</str<strong>on</strong>g> combusti<strong>on</strong> takes<br />
place in a porous high temperature ceramic,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> combusti<strong>on</strong> reactor, instead <str<strong>on</strong>g>of</str<strong>on</strong>g> in an open<br />
flame. This results in a flameless, volumetric<br />
combusti<strong>on</strong> in <str<strong>on</strong>g>the</str<strong>on</strong>g> form <str<strong>on</strong>g>of</str<strong>on</strong>g> glowing ceramic<br />
foam which can be used as a radiating surface<br />
as well as a homogenous source <str<strong>on</strong>g>of</str<strong>on</strong>g> heat. Any<br />
shapes are possible such as round or square<br />
burners, lines, cylinders, rings, rhombuses and<br />
o<str<strong>on</strong>g>the</str<strong>on</strong>g>r specially tailored shapes (Fig. 2).<br />
Special applicati<strong>on</strong>s require special soluti<strong>on</strong>s,<br />
for example line shaped burner heads<br />
Table 1: Heating systems for casting moulds: benefits / value propositi<strong>on</strong><br />
which c<strong>on</strong>centrate <str<strong>on</strong>g>the</str<strong>on</strong>g> heat from c<strong>on</strong>vecti<strong>on</strong><br />
and radiati<strong>on</strong> exactly where it is needed.<br />
The length <str<strong>on</strong>g>of</str<strong>on</strong>g> a reactor can thus be extended<br />
if desired. Dimensi<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> several meters in<br />
length with a reactor width from 15 to 200 mm<br />
allow specific burning performances from 2<br />
to 600 kW/m in length.<br />
Based <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> unique features <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> flameless<br />
porous burner combusti<strong>on</strong> technology,<br />
promeos develops and manufactures tailored<br />
heating systems for process applicati<strong>on</strong>s.<br />
Furnace engineering is required for both<br />
process technology and manufacturing to ensure<br />
optimum product quality. The outstanding<br />
design features <str<strong>on</strong>g>of</str<strong>on</strong>g> promeos burners and its<br />
ease <str<strong>on</strong>g>of</str<strong>on</strong>g> integrati<strong>on</strong> into any kind <str<strong>on</strong>g>of</str<strong>on</strong>g> apparatus<br />
allow <str<strong>on</strong>g>the</str<strong>on</strong>g> heat to be distributed over / into <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
required area / volume and applied where <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
process needs it, as opposed to being directed<br />
to <strong>on</strong>ly <strong>on</strong>e spot. promeos supplies ‘tailor<br />
made suits’ for your individual needs, powerful<br />
and efficient.<br />
The unique combinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> features like <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
power density, a rapid and precise power adjustment<br />
(similar to electric heating devices),<br />
a homogeneous heat flux and its compact and<br />
modular design result in <str<strong>on</strong>g>the</str<strong>on</strong>g> following benefits:<br />
• enhanced quality <str<strong>on</strong>g>of</str<strong>on</strong>g> your products<br />
+ reduced preheating times The high energy density and heat transfer via<br />
infrared radiati<strong>on</strong> and c<strong>on</strong>trolled c<strong>on</strong>venti<strong>on</strong> allow<br />
an unmatched quick heating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> moulds.<br />
Generally <str<strong>on</strong>g>the</str<strong>on</strong>g> preheating times are cut down<br />
50% and more.<br />
+ homogeneous temperature distributi<strong>on</strong> So called ‘hot spots’ that are due to local fire or<br />
flames are completely eliminated because <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
homogeneity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> heat input. In combinati<strong>on</strong><br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tinuously variable power c<strong>on</strong>trol <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> burners <str<strong>on</strong>g>the</str<strong>on</strong>g> preheating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> mould can be<br />
c<strong>on</strong>trolled optimally.<br />
+ producti<strong>on</strong> time Producti<strong>on</strong> time is gained due to <str<strong>on</strong>g>the</str<strong>on</strong>g> shortened<br />
heating-up time and corresp<strong>on</strong>ding process c<strong>on</strong>trol.<br />
+ less scrap producti<strong>on</strong> The ideal preheating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> mould reduces <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
number <str<strong>on</strong>g>of</str<strong>on</strong>g> required ‘warm castings’ – waste reducti<strong>on</strong><br />
is <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>sequence.<br />
+ durability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> tools The homogeneous temperature distributi<strong>on</strong> reduces<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>rmal stress and <str<strong>on</strong>g>the</str<strong>on</strong>g>reby automatically<br />
increases <str<strong>on</strong>g>the</str<strong>on</strong>g> lifetime <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> tools.<br />
Σ ROI < 24 m<strong>on</strong>ths, guaranteed<br />
< 12 m<strong>on</strong>ths, mostly<br />
Usually your investment is recovered within a<br />
period <str<strong>on</strong>g>of</str<strong>on</strong>g> max. 12 m<strong>on</strong>ths. We will compile you<br />
with a detailed amortizati<strong>on</strong> calculati<strong>on</strong> with<br />
every <str<strong>on</strong>g>of</str<strong>on</strong>g>fer you receive from us.<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 63
MELTING, RECYCLING & HEAT TREATMENT<br />
• increased performance<br />
• reduced warm-up time or start-up time <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
your equipment<br />
• energy saving potential <str<strong>on</strong>g>of</str<strong>on</strong>g> up to 70% for<br />
your processes<br />
• operati<strong>on</strong>al cost saving <str<strong>on</strong>g>of</str<strong>on</strong>g> 50% by<br />
substituting electrical heating systems.<br />
Heating systems for casting moulds:<br />
higher producti<strong>on</strong> rates, quicker<br />
and more precise preheating<br />
The final step in <str<strong>on</strong>g>the</str<strong>on</strong>g> casting process is <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
most sensible – <str<strong>on</strong>g>the</str<strong>on</strong>g> temperature pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
casting tools is essential for <str<strong>on</strong>g>the</str<strong>on</strong>g> quality <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
products. Since every individual mould requires<br />
its optimum heating device, promeos<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g>fers customized heating tools, individually<br />
adapted to shape and process (Fig. 3).<br />
The modular ‘Lego-like’ design <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> flamefree<br />
porous burner units enables promeos in<br />
a unique way to design ‘custom-made suits’<br />
for different tools at reas<strong>on</strong>able cost. Opti-<br />
mum mould preheating, leading to significantly<br />
reduced scrap producti<strong>on</strong> (‘initial cast-<br />
Fig. 3: Drying curve refractory c<strong>on</strong>crete<br />
+ reduced preheating time The homogeneously distributed heat input at a<br />
high energy density allows an unmatched quick<br />
heating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> ladle. Generally <str<strong>on</strong>g>the</str<strong>on</strong>g> heating-up<br />
times are cut down 50% and more.<br />
+ increased durability(exact heat-up curves,<br />
homogeneous temperature distributi<strong>on</strong> with<br />
functi<strong>on</strong>s for drying, sintering and warming)<br />
So called ‘hot spots’ that are due to local fire or<br />
flames as well as cold areas (‘temperature holes’)<br />
are completely eliminated. A minimal loss <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
material and an increased durability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> ladle<br />
lining are <str<strong>on</strong>g>the</str<strong>on</strong>g> positive c<strong>on</strong>sequences. The temperature<br />
c<strong>on</strong>trol device allows c<strong>on</strong>tinuously variable<br />
temperature regulati<strong>on</strong> and even a precise<br />
realizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> given temperature curves.<br />
+ 65% reducti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> operating costs* Energy savings <str<strong>on</strong>g>of</str<strong>on</strong>g> 65% are not unusual. This is<br />
due to <str<strong>on</strong>g>the</str<strong>on</strong>g> extremely improved heat transfer and<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tinuously variable power c<strong>on</strong>trol, required<br />
for temperature holding during stand-by time.<br />
+ 80% CO 2 emissi<strong>on</strong> savings* 70% less CO 2 emissi<strong>on</strong>s and significantly lower<br />
levels <str<strong>on</strong>g>of</str<strong>on</strong>g> pollutants (CxHy and NOx) mean > 80%<br />
reducti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> CO 2 equivalents.<br />
Σ ROI < 24 m<strong>on</strong>ths, guaranteed<br />
< 12 m<strong>on</strong>ths, mostly<br />
* Maximum value proven by customer data<br />
Table 2: Ladle heating systems: benefits / value propositi<strong>on</strong><br />
Fig. 4: Heating system for casting moulds<br />
ing’) is not l<strong>on</strong>ger a miracle. The required investments<br />
pay back in less than 24 m<strong>on</strong>ths –<br />
a must in times <str<strong>on</strong>g>of</str<strong>on</strong>g> increasing resource efficiency<br />
c<strong>on</strong>straints (see Table 1).<br />
Ladle heating systems: preheating<br />
allows energy savings <str<strong>on</strong>g>of</str<strong>on</strong>g> up to 65%<br />
The transport ladles lined with refractory material<br />
are heated to a target temperature in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> empty state. A well-adapted insulated cap,<br />
which includes <str<strong>on</strong>g>the</str<strong>on</strong>g> burner, is placed <strong>on</strong> top <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
Usually your investment is recovered within a<br />
period <str<strong>on</strong>g>of</str<strong>on</strong>g> max. 12 m<strong>on</strong>ths. We will compile you<br />
with a detailed amortizati<strong>on</strong> calculati<strong>on</strong> with<br />
every <str<strong>on</strong>g>of</str<strong>on</strong>g>fer you receive from us.<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> ladle. The burner transmits <str<strong>on</strong>g>the</str<strong>on</strong>g> heat <strong>on</strong>to<br />
a radiating body which transfers <str<strong>on</strong>g>the</str<strong>on</strong>g> combusti<strong>on</strong><br />
energy as infrared radiati<strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> lining<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> ladle.<br />
The heat is homogeneously and effectively<br />
transmitted all over <str<strong>on</strong>g>the</str<strong>on</strong>g> ladle wall. The hot<br />
gas flow is directed to <str<strong>on</strong>g>the</str<strong>on</strong>g> bottom <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> ladle<br />
and afterwards through a slit between <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
radiating body and <str<strong>on</strong>g>the</str<strong>on</strong>g> lining <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> ladle to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> hot gas outlet, whereby <str<strong>on</strong>g>the</str<strong>on</strong>g> heat transfer<br />
is additi<strong>on</strong>ally improved. The promeos ladle<br />
heating substitutes existing ‘fires’ to closed<br />
systems with energy savings <str<strong>on</strong>g>of</str<strong>on</strong>g> up to 65%. It<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>refore combines maximum energy efficiency<br />
with ideal industrial safety and maximum<br />
process reliability.<br />
Reliable Drying and Sintering: The variable<br />
power c<strong>on</strong>trol enables <str<strong>on</strong>g>the</str<strong>on</strong>g> realizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> ex-<br />
Fig. 5:<br />
Ladle heating<br />
system<br />
act given drying and sintering pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles and in<br />
additi<strong>on</strong> an optimum stand-by functi<strong>on</strong>ality<br />
with minimum energy c<strong>on</strong>sumpti<strong>on</strong>. promeos’<br />
ladle heating systems is a reliable soluti<strong>on</strong> for<br />
an optimum casting process (see Fig. 3 and<br />
Table 2).<br />
Heating <str<strong>on</strong>g>of</str<strong>on</strong>g> launders and filter<br />
boxes: for a better process c<strong>on</strong>trol<br />
The above explained advantages <str<strong>on</strong>g>of</str<strong>on</strong>g> homogeneously<br />
and efficiently heated ladles are also<br />
valid for launders and filter boxes – <str<strong>on</strong>g>the</str<strong>on</strong>g> better<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> material transportati<strong>on</strong> systems, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
better <str<strong>on</strong>g>the</str<strong>on</strong>g> casting quality.<br />
promeos burner systems, integrated into<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> lid <str<strong>on</strong>g>of</str<strong>on</strong>g> filter or into <str<strong>on</strong>g>the</str<strong>on</strong>g> covers <str<strong>on</strong>g>of</str<strong>on</strong>g> launders<br />
provide a homogeneous heating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> filter<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> refractory lining. While hot spots are<br />
avoided and <str<strong>on</strong>g>the</str<strong>on</strong>g> lifetime <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> refractory is<br />
enhanced, <str<strong>on</strong>g>the</str<strong>on</strong>g> temperature loss <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> liquid<br />
metal can be reduced tremendously. Increased<br />
energy efficiency by reduced melting temperatures<br />
and improved material quality are evident<br />
(see Fig. 6 and 7 and Table 3 next page).<br />
64 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
New: Hot air heating system<br />
for industrial applicati<strong>on</strong>s<br />
promeos <str<strong>on</strong>g>of</str<strong>on</strong>g>fers a compact and mobile, robust<br />
and modular hot air heating system for industrial<br />
applicati<strong>on</strong>s – to be used for drying, preheating,<br />
tempering or whatsoever.<br />
Fig. 6: Heating system for filterboxes<br />
Operating mode: The exhaust gases <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
central burner are mixed with sec<strong>on</strong>dary air in<br />
a compact mixing chamber inside <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> heating<br />
system. While <str<strong>on</strong>g>the</str<strong>on</strong>g> burner c<strong>on</strong>trol defines<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> heat capacity, <str<strong>on</strong>g>the</str<strong>on</strong>g> air (heating) temperaure<br />
can be c<strong>on</strong>trolled by <str<strong>on</strong>g>the</str<strong>on</strong>g> ratio <str<strong>on</strong>g>of</str<strong>on</strong>g> exhaust<br />
gas and sec<strong>on</strong>dary air mass flow (see Fig. 8).<br />
The hot air is <str<strong>on</strong>g>of</str<strong>on</strong>g>fered as point source, line<br />
source, area source or 3D source using different<br />
nozzles, almost unlimited applicati<strong>on</strong>s<br />
flexibility, which was <strong>on</strong>ly known from electrically<br />
heated blowers up to now.<br />
Fig. 7: Heating system for launders<br />
MELTING, RECYCLING & HEAT TREATMENT<br />
promeos <str<strong>on</strong>g>of</str<strong>on</strong>g>fers ‘gas heat in electric quality’<br />
without <str<strong>on</strong>g>the</str<strong>on</strong>g> existing shortcomings <str<strong>on</strong>g>of</str<strong>on</strong>g> electrical<br />
hot air guns such as limited temperature,<br />
limited power density or limited lifetime due<br />
to unsatisfying robustness.<br />
The hot air heating system from promeos<br />
is designed even for rough boundary c<strong>on</strong>diti<strong>on</strong>s,<br />
such as steel plants and foundries etc..<br />
It is both robust and compact and can be used<br />
stati<strong>on</strong>ary and as mobile heat source. A crane<br />
Fig. 8: Operating range <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> hot air heating system for industrial applicati<strong>on</strong>s<br />
hook and transportati<strong>on</strong> wheels enables <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
user to move it quickly where it is needed.<br />
Benefits: While <str<strong>on</strong>g>the</str<strong>on</strong>g> cost saving potential<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 50% through substituting electrical energy<br />
by gas is self-arguing, a CO 2-reducti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> more<br />
+ no loss <str<strong>on</strong>g>of</str<strong>on</strong>g> temperature / no freezing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
melt<br />
The extremely uniform heating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> refractory<br />
surface and <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> filters prevents an unc<strong>on</strong>trol-<br />
led cooling <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> melt.<br />
+ no overheating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> furnaces The heat loss from <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace to <str<strong>on</strong>g>the</str<strong>on</strong>g> casting stati<strong>on</strong><br />
can be reduced / prevented so far, that an<br />
unwanted overheating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> furnaces can be<br />
avoided.<br />
+ increased durability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> refractory materials So called ‘hot spots’ that are due to local fire<br />
or flames as well as <str<strong>on</strong>g>the</str<strong>on</strong>g> n<strong>on</strong>-uniform heating <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> launders and filters are completely avoided.<br />
Thereby <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmo-mechanical loading is significantly<br />
reduced and <str<strong>on</strong>g>the</str<strong>on</strong>g> lifetime <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
is increased.<br />
+ reduced energy c<strong>on</strong>sumpti<strong>on</strong> An overheating <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> furnaces is not necessary.<br />
+ increased product quality The material is melted, prepared, transported and<br />
casted at an optimum metallurgical temperature.<br />
+ lower costs The saving <str<strong>on</strong>g>of</str<strong>on</strong>g> energy costs and <str<strong>on</strong>g>the</str<strong>on</strong>g> avoidance <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
‘warm casting / tapping’ lead to lower operating<br />
costs without plant down-times and thus to higher<br />
productivity.<br />
Σ ROI < 24 m<strong>on</strong>ths, guaranteed<br />
< 12 m<strong>on</strong>ths, mostly<br />
Table 3: Heating <str<strong>on</strong>g>of</str<strong>on</strong>g> launders and filterboxes: benefits / value propositi<strong>on</strong><br />
than 60% in Germany and most world markets<br />
is worth to be menti<strong>on</strong>ed.<br />
promeos has set new standards in pre-<br />
heating soluti<strong>on</strong>s for <str<strong>on</strong>g>the</str<strong>on</strong>g> casting industry.<br />
Based <strong>on</strong> its unique combusti<strong>on</strong> technology,<br />
promeos developed from a technology supplier<br />
to a reliable system manufacturer and<br />
service supplier. Energy efficiency, product<br />
quality and process reliability were and are<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> driving force. Future subjects in product<br />
development focus <strong>on</strong> a new type <str<strong>on</strong>g>of</str<strong>on</strong>g> melting<br />
and tempering furnace and fur<str<strong>on</strong>g>the</str<strong>on</strong>g>r energy<br />
efficiency improvements including internal<br />
energy recovery by combusti<strong>on</strong> air preheating.<br />
�<br />
Usually your investment is recovered within a<br />
period <str<strong>on</strong>g>of</str<strong>on</strong>g> max. 12 m<strong>on</strong>ths. We will compile you<br />
with a detailed amortizati<strong>on</strong> calculati<strong>on</strong> with<br />
every <str<strong>on</strong>g>of</str<strong>on</strong>g>fer you receive from us.<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 65
MELTING, RECYCLING & HEAT TREATMENT<br />
Effects <str<strong>on</strong>g>of</str<strong>on</strong>g> gaseous pyrolysis<br />
products <strong>on</strong> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> recycling yield<br />
1 Jar<strong>on</strong>i, B.; 1 Gisbertz, K.; 2 Rombach, G.; 1 Friedrich, B.<br />
1 RWTH Aachen University, IME Process Metallurgy and Metals Recycling, Germany<br />
2 Hydro Aluminium Rolled Products GmbH, Germany<br />
After a coated aluminum product has<br />
reached <str<strong>on</strong>g>the</str<strong>on</strong>g> end <str<strong>on</strong>g>of</str<strong>on</strong>g> life cycle it needs to<br />
be recycled in an ec<strong>on</strong>omical, effective<br />
and ecological way. State-<str<strong>on</strong>g>of</str<strong>on</strong>g>-<str<strong>on</strong>g>the</str<strong>on</strong>g>-art is <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>rmal removal <str<strong>on</strong>g>of</str<strong>on</strong>g> coatings and o<str<strong>on</strong>g>the</str<strong>on</strong>g>r organic<br />
fracti<strong>on</strong>s via treatment by pyrolysis<br />
prior to melting. In modern twin chamber<br />
furnaces this step takes place inside <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
scrap melting chamber. Through different<br />
c<strong>on</strong>structi<strong>on</strong> methods, it is possible<br />
to use <str<strong>on</strong>g>the</str<strong>on</strong>g> gaseous pyrolysis products for<br />
an internal combusti<strong>on</strong> in order to safe<br />
<str<strong>on</strong>g>natural</str<strong>on</strong>g> gas. Lab-scale experiments have<br />
shown that <str<strong>on</strong>g>the</str<strong>on</strong>g> average residence time is<br />
too short to complete <str<strong>on</strong>g>the</str<strong>on</strong>g> pyrolysis. It has<br />
to be c<strong>on</strong>sidered that <str<strong>on</strong>g>the</str<strong>on</strong>g> pyrolysis c<strong>on</strong>tinuous<br />
while <str<strong>on</strong>g>the</str<strong>on</strong>g> scrap block is pushed<br />
under <str<strong>on</strong>g>the</str<strong>on</strong>g> aluminum melt. By reas<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
this producti<strong>on</strong> procedure, gaseous reacti<strong>on</strong><br />
products, e. g. CO, CO 2 and C xH y,<br />
have a l<strong>on</strong>g c<strong>on</strong>tact time inside <str<strong>on</strong>g>the</str<strong>on</strong>g> melt.<br />
It is assumed that <str<strong>on</strong>g>the</str<strong>on</strong>g> dross formati<strong>on</strong><br />
increases rapidly as a result <str<strong>on</strong>g>of</str<strong>on</strong>g> various<br />
gas-melt reacti<strong>on</strong>s. Based <strong>on</strong> this assumpti<strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> aim <str<strong>on</strong>g>of</str<strong>on</strong>g> this work is <str<strong>on</strong>g>the</str<strong>on</strong>g> evaluati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> gaseous pyrolysis<br />
reacti<strong>on</strong> products <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> dross formati<strong>on</strong><br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> simulati<strong>on</strong> in lab-scale experiments.<br />
Therefore, typical pyrolysis gases<br />
are injected into <str<strong>on</strong>g>the</str<strong>on</strong>g> melt via a gas purging<br />
device. Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>rmore, <str<strong>on</strong>g>the</str<strong>on</strong>g> magnesium<br />
c<strong>on</strong>tent <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> aluminum melt is varied to<br />
show its impact in additi<strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> gases.<br />
1 Introducti<strong>on</strong><br />
The pyrolytic process in chamber furnaces is<br />
located <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> bridge inside <str<strong>on</strong>g>the</str<strong>on</strong>g> scrap melting<br />
chamber. In modern twin chamber furnaces<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> average charging time is 25 minutes. The<br />
time interval depends <strong>on</strong> bath temperature,<br />
bath level, atmosphere compositi<strong>on</strong> and security<br />
door lock time. This time interval simultaneously<br />
limits <str<strong>on</strong>g>the</str<strong>on</strong>g> durati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> scrap heating,<br />
organic scissi<strong>on</strong> and combusti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> carb<strong>on</strong> released<br />
from <str<strong>on</strong>g>the</str<strong>on</strong>g> scrap surface. With <str<strong>on</strong>g>the</str<strong>on</strong>g> next<br />
scrap charge <str<strong>on</strong>g>the</str<strong>on</strong>g> de-coated scrap is pushed into<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> aluminum melt which means that charging<br />
time is equal to <str<strong>on</strong>g>the</str<strong>on</strong>g> durati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal<br />
pretreatment. The industrial de-coating time<br />
Fig. 1: Balance <str<strong>on</strong>g>of</str<strong>on</strong>g> forces<br />
seems to be too short for a complete pyrolysis<br />
step especially inside compacted scrap, e.g.<br />
coil-leftovers and packages. The de-coating<br />
grade is a functi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> time, temperature, heat<br />
transfer and package density. In comparis<strong>on</strong><br />
with aluminum blocks <str<strong>on</strong>g>the</str<strong>on</strong>g> heat transfer <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
scrap packages is reduced. As a result <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
package structure <str<strong>on</strong>g>the</str<strong>on</strong>g> pyrolysis products cannot<br />
leave <str<strong>on</strong>g>the</str<strong>on</strong>g> compacted material with a typical<br />
density is well below 2 g/cm 3 .<br />
2 Gas-liquid reacti<strong>on</strong>s<br />
The reacti<strong>on</strong> between gaseous reacti<strong>on</strong> products<br />
and liquid aluminum follows a certain<br />
pattern. The bubble formati<strong>on</strong> depends <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> porosity <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> medium. In <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> a<br />
scrap package <str<strong>on</strong>g>the</str<strong>on</strong>g>re is a high variati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
hole diameter. Generally speaking, <str<strong>on</strong>g>the</str<strong>on</strong>g> bubble<br />
diameter is a functi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> surface tensi<strong>on</strong>, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
pore diameter and <str<strong>on</strong>g>the</str<strong>on</strong>g> amount <str<strong>on</strong>g>of</str<strong>on</strong>g> formed gas.<br />
With a porous medium as gas distributor <strong>on</strong>ly<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> larges pores are outgassing at low gas flow<br />
rates. An increasing gas flow rate also enables<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> gas evoluti<strong>on</strong> <strong>on</strong> / at / <str<strong>on</strong>g>of</str<strong>on</strong>g> smaller openings,<br />
so that <str<strong>on</strong>g>the</str<strong>on</strong>g> gas flow is distributed more <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
entire surface <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> porous medium. The most<br />
comm<strong>on</strong> example <str<strong>on</strong>g>of</str<strong>on</strong>g> viewing bubble formati<strong>on</strong><br />
as a result <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> bubble size goes back to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
balancing forces <str<strong>on</strong>g>of</str<strong>on</strong>g> a single bubble (Fig. 1).<br />
Depending <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> predominant /prevailing<br />
bubble formati<strong>on</strong> mechanism, some forces are<br />
negligible. The directi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> resistance force<br />
is a result <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> liquid stream. In quiescent<br />
fluids <str<strong>on</strong>g>the</str<strong>on</strong>g> breakaway point <str<strong>on</strong>g>of</str<strong>on</strong>g> bubbles is later<br />
than in turbulent fluids. The bubble size can be<br />
calculated with equati<strong>on</strong> 1. [1] (1)<br />
d[(p] gV Bv)<br />
⎯⎯⎯⎯⎯ = F inertia = F Resistance = F Flotati<strong>on</strong><br />
dt<br />
= F Pressure = F σ = F virtual Mass<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> scrap melting chamber <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>diti<strong>on</strong>s<br />
are turbulent because <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> electromagnetic<br />
pumps (EMP) which are used to homogenize<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> melt temperature as well as <str<strong>on</strong>g>the</str<strong>on</strong>g> alloying<br />
element pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile in <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace and c<strong>on</strong>sequently<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> increase <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> melting rate. In this<br />
paper we will focus <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmochemical<br />
modelling and <str<strong>on</strong>g>the</str<strong>on</strong>g> experimental pro<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>of</str<strong>on</strong>g> our<br />
results.<br />
3 Thermochemical modelling<br />
‘FactSage’ is used for <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmochemical<br />
modelling <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> melting experiments to provide<br />
an overview <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> possible reacti<strong>on</strong>s<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g>ir reacti<strong>on</strong> products. It is taken into<br />
account in all <str<strong>on</strong>g>the</str<strong>on</strong>g> representati<strong>on</strong>s shown in<br />
this chapter that <str<strong>on</strong>g>the</str<strong>on</strong>g> calculati<strong>on</strong>s are always<br />
based <strong>on</strong> reacti<strong>on</strong> equilibrium. The modelling<br />
s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware FactSage can access various materials<br />
databases (here Fact53, SGPS and SGTE).<br />
The equilibrium phases, which represent <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
system with <str<strong>on</strong>g>the</str<strong>on</strong>g> lowest total free enthalpy as<br />
a functi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> predetermined variables is based<br />
<strong>on</strong> Steady state c<strong>on</strong>diti<strong>on</strong>s. The temperature<br />
is set to 750°C while <str<strong>on</strong>g>the</str<strong>on</strong>g> pressure <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> melt<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> added gas are set to 1 bar. The high<br />
metal volume used in <str<strong>on</strong>g>the</str<strong>on</strong>g> calculati<strong>on</strong>s has<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>sequence that <str<strong>on</strong>g>the</str<strong>on</strong>g> gases CO 2, CH 4 and<br />
CO are completely c<strong>on</strong>verted into solid reac-<br />
66 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Fig. 2: Equilibrium phases for <str<strong>on</strong>g>the</str<strong>on</strong>g> reacti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> 2350 g AlMg3 + CO 2 with <br />
up to 15 mol and under c<strong>on</strong>siderati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> oxycarbide phases<br />
Fig. 3: Al and Mg losses in relati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> Mg c<strong>on</strong>tent and injected gas<br />
Fig. 4: Experimental setup with used gas analyzing system<br />
MELTING, RECYCLING & HEAT TREATMENT<br />
ti<strong>on</strong> products except for H 2.<br />
In industrial scale <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace atmosphere including <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
injected gas is c<strong>on</strong>stantly replaced and <str<strong>on</strong>g>the</str<strong>on</strong>g> remaining gaseous<br />
products are c<strong>on</strong>tinuously removed from <str<strong>on</strong>g>the</str<strong>on</strong>g> reacti<strong>on</strong> chamber.<br />
Accordingly <str<strong>on</strong>g>the</str<strong>on</strong>g> real system is an open <strong>on</strong>e.<br />
An example for a typical calculati<strong>on</strong> d<strong>on</strong>e in this project<br />
can be seen in Fig. 2. In this calculati<strong>on</strong> <strong>on</strong>e liter <str<strong>on</strong>g>of</str<strong>on</strong>g> AlMg3 alloy<br />
melt reacts with a variable amount <str<strong>on</strong>g>of</str<strong>on</strong>g> CO 2. The main products<br />
are MgO, Al 2O 3, Al 4C 3, MgAl 2O 4 and Al 2CO.<br />
It is easy to recognize that in <str<strong>on</strong>g>the</str<strong>on</strong>g> range up to 1.5 mol CO 2<br />
magnesium is preferably oxidized from <str<strong>on</strong>g>the</str<strong>on</strong>g> alloy melt, while<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> carb<strong>on</strong> c<strong>on</strong>tent <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> gas is fully c<strong>on</strong>verted into Al 4C 3.<br />
Magnesium is no l<strong>on</strong>ger present in <str<strong>on</strong>g>the</str<strong>on</strong>g> melt at at an additi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
1.5 mol CO 2. At that point aluminum c<strong>on</strong>sumpti<strong>on</strong> increases.<br />
When <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>centrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> CO 2 reaches three mol, <str<strong>on</strong>g>the</str<strong>on</strong>g> balance<br />
shifts increasingly to <str<strong>on</strong>g>the</str<strong>on</strong>g> oxycarbide phase Al 2CO, while <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
amount <str<strong>on</strong>g>of</str<strong>on</strong>g> MgO phase remains c<strong>on</strong>stant. Above three moles<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> CO 2 <str<strong>on</strong>g>the</str<strong>on</strong>g>re is no more aluminum carbide in <str<strong>on</strong>g>the</str<strong>on</strong>g> system. At<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> same point magnesium <str<strong>on</strong>g>oxide</str<strong>on</strong>g> is transformed into <str<strong>on</strong>g>the</str<strong>on</strong>g> spinel<br />
MgAl 2O 4, so that <str<strong>on</strong>g>the</str<strong>on</strong>g> amount <str<strong>on</strong>g>of</str<strong>on</strong>g> this equilibrium phase starts<br />
to increase. The magnesium <str<strong>on</strong>g>oxide</str<strong>on</strong>g> is completely transformed<br />
into <str<strong>on</strong>g>the</str<strong>on</strong>g> spinel at a CO 2 c<strong>on</strong>centrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> 11.5 mol. Alumina<br />
appears as an additi<strong>on</strong>al oxidati<strong>on</strong> product <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> reacti<strong>on</strong> between<br />
aluminum and carb<strong>on</strong> di<str<strong>on</strong>g>oxide</str<strong>on</strong>g> as a result <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> complete<br />
c<strong>on</strong>sumpti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> MgO.<br />
In Fig. 3 <str<strong>on</strong>g>the</str<strong>on</strong>g> specific metal losses are presented in a bar<br />
chart diagram. The diagram shows <str<strong>on</strong>g>the</str<strong>on</strong>g> simulated aluminum and<br />
magnesium losses <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> three investigated alloys. The results<br />
are grouped by <str<strong>on</strong>g>the</str<strong>on</strong>g> intended alloy and <str<strong>on</strong>g>the</str<strong>on</strong>g> gas species in different<br />
colours. The aluminum losses are shown in <str<strong>on</strong>g>the</str<strong>on</strong>g> lower<br />
bar part, while <str<strong>on</strong>g>the</str<strong>on</strong>g> magnesium losses <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> AlMg alloys are<br />
added above in a weaker colour. The calculati<strong>on</strong>s revealed<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> metal losses for circa 87 mol aluminum or aluminum alloy<br />
(2,350 g) by additi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> 1 mol <str<strong>on</strong>g>of</str<strong>on</strong>g> gas. The parameters have<br />
been pre-estimated to provide <str<strong>on</strong>g>the</str<strong>on</strong>g> opportunity to compare <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
calculated with <str<strong>on</strong>g>the</str<strong>on</strong>g> experimental results. As a c<strong>on</strong>sequence <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
this <strong>on</strong>e mol <str<strong>on</strong>g>of</str<strong>on</strong>g> injected gas is used in <str<strong>on</strong>g>the</str<strong>on</strong>g> calculati<strong>on</strong>s, leading<br />
to a lack <str<strong>on</strong>g>of</str<strong>on</strong>g> oxygen in <str<strong>on</strong>g>the</str<strong>on</strong>g> system for full magnesium oxida-<br />
ti<strong>on</strong>. As a result <str<strong>on</strong>g>the</str<strong>on</strong>g>re is no observable difference between <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
AlMg3 and <str<strong>on</strong>g>the</str<strong>on</strong>g> AlMg5 alloy in <str<strong>on</strong>g>the</str<strong>on</strong>g> calculati<strong>on</strong>.<br />
4 Experiment<br />
4.1 Experimental setup: For <str<strong>on</strong>g>the</str<strong>on</strong>g> experimental campaign <str<strong>on</strong>g>of</str<strong>on</strong>g> this<br />
work three different aluminum alloys AlMg3, AlMg5 and pure<br />
Al were used. The feeding material <str<strong>on</strong>g>of</str<strong>on</strong>g> all experiments has always<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> same size and surface in order to minimize a failure<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> different aluminum <str<strong>on</strong>g>oxide</str<strong>on</strong>g> amounts inherent to <str<strong>on</strong>g>the</str<strong>on</strong>g> charge<br />
materials. CO, CO 2 and CH 4 as typical de-coating products<br />
are injected into <str<strong>on</strong>g>the</str<strong>on</strong>g> melt. The following sketch (Fig. 4) shows<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> experimental setup.<br />
All experiments are realized in an inducti<strong>on</strong> furnace. The<br />
used Al 2O 3 crucible has a volume <str<strong>on</strong>g>of</str<strong>on</strong>g> 1.3 litres. The inducti<strong>on</strong><br />
coil is installed into a vacuum chamber which allows c<strong>on</strong>trolling<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> atmosphere inside <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace. In all experiments <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
furnace atmosphere is 100% N 2. To realize a c<strong>on</strong>stant N 2 flow<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> gas is injected at <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace bottom while <str<strong>on</strong>g>the</str<strong>on</strong>g> pressure is<br />
kept at 1 bar by an over pressure valve at <str<strong>on</strong>g>the</str<strong>on</strong>g> upper furnace. For<br />
injecti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> different gasses into <str<strong>on</strong>g>the</str<strong>on</strong>g> melt a glass lance is used.<br />
<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 67
MELTING, RECYCLING & HEAT TREATMENT<br />
Fig. 5: a) Gas injecti<strong>on</strong> system; b) Inducti<strong>on</strong> coil with hood<br />
An exhaust hood above <str<strong>on</strong>g>the</str<strong>on</strong>g> crucible is used to<br />
collect <str<strong>on</strong>g>the</str<strong>on</strong>g> gaseous reacti<strong>on</strong> products and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
unc<strong>on</strong>sumed gasses. An exhaust fan supplies<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>line quality gas measurement with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
collected gasses. To make sure that no furnace<br />
atmosphere is sucked into <str<strong>on</strong>g>the</str<strong>on</strong>g> hood during <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
experiment more gas is injected than removed<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> fan. Due to that <str<strong>on</strong>g>the</str<strong>on</strong>g> system has a slight<br />
over pressure under <str<strong>on</strong>g>the</str<strong>on</strong>g> hood, too.<br />
Fig. 5a) shows a drawing <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> gas injecti<strong>on</strong><br />
system. The inducti<strong>on</strong> coil and <str<strong>on</strong>g>the</str<strong>on</strong>g> used hood<br />
to collect <str<strong>on</strong>g>the</str<strong>on</strong>g> gaseous products are shown in<br />
Fig. 5b).<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> first experimental campaign 12 tests<br />
are performed (Table 1). The gas injecti<strong>on</strong> time<br />
is limited by <str<strong>on</strong>g>the</str<strong>on</strong>g> crucible volume. The injecti<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> gas was stopped when <str<strong>on</strong>g>the</str<strong>on</strong>g> crucible is<br />
fully filled by dross. The gas compositi<strong>on</strong> is<br />
limited by <str<strong>on</strong>g>the</str<strong>on</strong>g> range <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> installed gas analyzing<br />
system and also for security reas<strong>on</strong>s.<br />
4.2 Results<br />
a) b)<br />
In Fig. 6 <str<strong>on</strong>g>the</str<strong>on</strong>g> metal losses <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> tests are presented.<br />
They are grouped according to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
used feedstock materials. The chart shows <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
gross-remelting losses, which are calculated<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> ratio <str<strong>on</strong>g>of</str<strong>on</strong>g> final weight <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> cast to initial<br />
weight <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> feedstock, see equati<strong>on</strong> 2.<br />
For <str<strong>on</strong>g>the</str<strong>on</strong>g> gross-remelting losses <str<strong>on</strong>g>the</str<strong>on</strong>g> metal c<strong>on</strong>tent<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> dross is not c<strong>on</strong>sidered. The column<br />
chart compares <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> different gases<br />
as well as <str<strong>on</strong>g>the</str<strong>on</strong>g> influence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> main alloying<br />
element (magnesium) <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> gross-remelting<br />
losses.<br />
The metal losses decrease for all three materials<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> order <str<strong>on</strong>g>of</str<strong>on</strong>g> CO2 , CO and CH4 . The<br />
c<strong>on</strong>trol experiments already indicated significant<br />
losses <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> melt phase. In presence <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
magnesium <str<strong>on</strong>g>the</str<strong>on</strong>g> effect <str<strong>on</strong>g>of</str<strong>on</strong>g> carb<strong>on</strong> di<str<strong>on</strong>g>oxide</str<strong>on</strong>g> <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
metal losses are doubled. The maximum loss<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> more than 45% is represent by <str<strong>on</strong>g>the</str<strong>on</strong>g> combinati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> alloy AlMg3 and CO2 as injected<br />
gas. A linear dependence <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> magnesium<br />
c<strong>on</strong>tent <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> alloy to <str<strong>on</strong>g>the</str<strong>on</strong>g> gross metal loss is<br />
not evident.<br />
To divide <str<strong>on</strong>g>the</str<strong>on</strong>g> metallic part from <str<strong>on</strong>g>the</str<strong>on</strong>g> n<strong>on</strong>metallic<br />
dross comp<strong>on</strong>ents a subsequent salt<br />
melt step is c<strong>on</strong>ducted. A typical salt flux (55%<br />
Experiment No. Injected gas compositi<strong>on</strong> Mg-C<strong>on</strong>tentin Mass.-% Treatment in min<br />
NV1 N2 (Chamber atmosphere) 0 120<br />
NV2 N2 (Chamber atmosphere) 2.82 20<br />
NV3 N2 (Chamber atmosphere) 4.86 20<br />
HV1KD Ar + 15 Vol.-% CO 2 0 32<br />
HV2KD Ar + 15 Vol.-% CO 2 2.82 21<br />
HV3KD Ar + 15 Vol.-% CO 2 4.86 14<br />
HV4KM Ar + 7 Vol.-% CO 0 32<br />
HV5KM Ar + 7 Vol.-% CO 2.82 20<br />
HV6KM Ar + 7 Vol.-% CO 4.86 20<br />
HV7KW Ar + 5 Vol.-% CH 4 0 19<br />
HV8KW Ar + 5 Vol.-% CH 4 2.82 19<br />
HV9KW Ar + 5 Vol.-% CH 4 4.86 19<br />
Table 1: Experimental plan<br />
Fig. 6: Gross-remelting losses<br />
mcast<br />
remelting loss gross in % = ⎯⎯⎯⎯ (2)<br />
m feedstock<br />
NaCl, 45% KCl and ≤ 1% CaF 2 ) is used. To<br />
guarantee a complete separati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> metal and<br />
dross a high salt factor is adjusted.<br />
The net-remelting losses <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> melting experiments<br />
can be determined from <str<strong>on</strong>g>the</str<strong>on</strong>g> measured<br />
metal yields <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> salt experiments, see<br />
equati<strong>on</strong> 3: (3)<br />
mcast + m recovered from dross<br />
remelting loss net in % = ⎯⎯⎯⎯⎯⎯⎯⎯⎯<br />
m feedstock<br />
The results are shown in Fig. 7. The metal<br />
c<strong>on</strong>tents <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> dross vary between 30 and<br />
97% (average 70%). The net metal losses decrease<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> same way like <str<strong>on</strong>g>the</str<strong>on</strong>g> gross metal<br />
losses according to <str<strong>on</strong>g>the</str<strong>on</strong>g> oxidati<strong>on</strong> effect <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
treatment gas, in <str<strong>on</strong>g>the</str<strong>on</strong>g> order <str<strong>on</strong>g>of</str<strong>on</strong>g> CO 2 , CO and<br />
CH 4 . The net-remelting losses <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>trol<br />
experiments increase from 0.1% via 0.4%<br />
through to 1.3% with rising magnesium c<strong>on</strong>tent<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> melt. In c<strong>on</strong>trast to <str<strong>on</strong>g>the</str<strong>on</strong>g> gross metal<br />
losses <str<strong>on</strong>g>the</str<strong>on</strong>g> losses after metal separati<strong>on</strong> by<br />
salt treatment rise for all three injected gases<br />
with increasing magnesium c<strong>on</strong>tent. Thus, <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
metal loss values for CO and CH 4 treatment<br />
based <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> three points show a linear dependence<br />
<strong>on</strong> magnesium c<strong>on</strong>centrati<strong>on</strong>.<br />
Comparing <str<strong>on</strong>g>the</str<strong>on</strong>g> gross and net metal losses it<br />
is good to see that <str<strong>on</strong>g>the</str<strong>on</strong>g> dross has a high metal<br />
c<strong>on</strong>tent. This can be a result <str<strong>on</strong>g>of</str<strong>on</strong>g> dross handling<br />
and manual stripping but it can also be a result<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> dross structure. It could be observed<br />
that especially in experiments with CO 2 injecti<strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> dross structure had a lot <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>layer</str<strong>on</strong>g>s each<br />
with metal film.<br />
Before <str<strong>on</strong>g>the</str<strong>on</strong>g> dross is remelted under salt<br />
some samples are taken to analyze parts <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> dross. The sampling is accomplished by<br />
optical criteria. XRD analyses have proven<br />
nei<str<strong>on</strong>g>the</str<strong>on</strong>g>r carbide nor oxycarbide phase while<br />
EDX analyses have shown <str<strong>on</strong>g>the</str<strong>on</strong>g> appropriate<br />
c<strong>on</strong>centrati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> Al, O and C, so that <str<strong>on</strong>g>the</str<strong>on</strong>g>re is<br />
68 <strong>ALU</strong>MINIUM · EAC CONGRESS 2011
Fig. 7: Net-remelting losses<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> possibility <str<strong>on</strong>g>of</str<strong>on</strong>g> an existing Aluminum-oxycarbide<br />
phase. Fig. 8 illustrates a typical SEM<br />
picture <str<strong>on</strong>g>of</str<strong>on</strong>g> <strong>on</strong>e sample which is taken from <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
red marked area (see macroscopic photography<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> upper right).<br />
The average element level <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> two red<br />
marked areas c<strong>on</strong>sists <str<strong>on</strong>g>of</str<strong>on</strong>g> 17,10 At.-% C, 18,70<br />
At.-% O, 8,63 At.-% Mg and 55,58 At.-% Al<br />
(Fig. 8). The atomic comp<strong>on</strong>ents <str<strong>on</strong>g>of</str<strong>on</strong>g> aluminum<br />
and carb<strong>on</strong> are str<strong>on</strong>gly represented. In c<strong>on</strong>trast<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> XRD analysis includes <str<strong>on</strong>g>the</str<strong>on</strong>g> EDX<br />
analysis <str<strong>on</strong>g>the</str<strong>on</strong>g> possibility <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> presence <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
carbide phase (Al 4 C 3 ) and <str<strong>on</strong>g>the</str<strong>on</strong>g> oxycarbid phase<br />
(Al 2 OC).<br />
Fig. 8: SEM picture <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> analyzed area (Experiment HV6KM)<br />
5 C<strong>on</strong>clusi<strong>on</strong>s<br />
MELTING, RECYCLING & HEAT TREATMENT<br />
It should be underlined that all identified dependencies<br />
are related to <str<strong>on</strong>g>the</str<strong>on</strong>g> experimental<br />
scale <str<strong>on</strong>g>of</str<strong>on</strong>g> <strong>on</strong>e litre <str<strong>on</strong>g>of</str<strong>on</strong>g> melt. The behaviour <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> reacti<strong>on</strong> dynamics in a multiple chamber<br />
furnace can <strong>on</strong>ly carried out partially based<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> performed experiments. The interacti<strong>on</strong>s<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> pyrolysis product gases and <str<strong>on</strong>g>the</str<strong>on</strong>g> aluminum<br />
melt and <str<strong>on</strong>g>the</str<strong>on</strong>g>refore <str<strong>on</strong>g>the</str<strong>on</strong>g> produced dross<br />
amount can diversify significantly through<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> increased scale and should <str<strong>on</strong>g>the</str<strong>on</strong>g>refore be<br />
tested in scale up trials.<br />
The definiti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> direct reacti<strong>on</strong> prod-<br />
ucts (mechanism) in accordance with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
structural analysis is difficult, because <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<strong>on</strong>e hand, a subsequent oxidati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> possibly<br />
formed carbides and oxycarbides seems to<br />
be likely, and <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> o<str<strong>on</strong>g>the</str<strong>on</strong>g>r hand, due to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
high aluminum c<strong>on</strong>tent in <str<strong>on</strong>g>the</str<strong>on</strong>g> taken samples<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> detecti<strong>on</strong> limit for minor comp<strong>on</strong>ents is<br />
quickly reached. Since carbide or oxycarbides<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>sidered regi<strong>on</strong> were not detected, it<br />
is unclear whe<str<strong>on</strong>g>the</str<strong>on</strong>g>r <str<strong>on</strong>g>the</str<strong>on</strong>g> result from FactSage<br />
issued for equilibrium phases are correct at<br />
all or if <str<strong>on</strong>g>the</str<strong>on</strong>g> phases are not present because<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>ir post-oxidati<strong>on</strong> under normal atmosphere.<br />
Since <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>rmochemical modelling<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> melting experiments refers to <str<strong>on</strong>g>the</str<strong>on</strong>g> reacti<strong>on</strong><br />
equilibrium also a kinetic inhibiti<strong>on</strong> cannot<br />
be excluded.<br />
The remelting losses decrease with decreasing<br />
oxygen c<strong>on</strong>tent <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> treatment gases, in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> order from CO 2 , CO, CH 4 . By varying <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
feed material it has to be noted that <str<strong>on</strong>g>the</str<strong>on</strong>g> influence<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> each gas increases with increasing<br />
magnesium c<strong>on</strong>tent <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> melt. This trend is<br />
c<strong>on</strong>firmed by <str<strong>on</strong>g>the</str<strong>on</strong>g> net metal losses, additi<strong>on</strong>ally<br />
approved by <str<strong>on</strong>g>the</str<strong>on</strong>g> <strong>on</strong>line gas measurement.<br />
Acknowledgement<br />
The authors would like to thank <str<strong>on</strong>g>the</str<strong>on</strong>g> Hydro<br />
Aluminium Rolled Products GmbH for funding<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> studies, providing scrap materials for<br />
trails and also for <str<strong>on</strong>g>the</str<strong>on</strong>g>ir analytical support.<br />
References<br />
[1] Jar<strong>on</strong>i, B., Lucht, A., et al.: C<strong>on</strong>diti<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> Pyrolythic<br />
Processes in Multi Chamber Furnaces for<br />
Aluminium Recycling, Proceedings <str<strong>on</strong>g>of</str<strong>on</strong>g> European<br />
Metallurgical C<strong>on</strong>ference EMC 2011<br />
[2] Gnotke, O.: Experimentelle und <str<strong>on</strong>g>the</str<strong>on</strong>g>oretische<br />
Untersuchungen zur Bestimmung v<strong>on</strong> veränderlichen<br />
Blasengrößen und Blasengrößenverteilungen<br />
in turbulenten Gas-Flüssgkeitsströmungen,<br />
Dissertati<strong>on</strong>, Fachbereich Maschinenbau, TU Darmstadt,<br />
2004<br />
[3] v<strong>on</strong> Röpenack, I.: Minimierung v<strong>on</strong> Chlorgasemissi<strong>on</strong>en<br />
bei der Spülgasraffinati<strong>on</strong> v<strong>on</strong> Aluminiumschmelze,<br />
Dissertati<strong>on</strong>, IME Aachen – Institut für<br />
Metallhüttenkunde und Elektrometallurgie, 1997<br />
[4]Antrekowitsch, H. et al.: Spülgastechnik in der<br />
Kupferindustrie, in Berg- und Hüttenmännische<br />
M<strong>on</strong>atshefte, 149. Jahrgang, Heft Nr. 3, S.186-192,<br />
2004<br />
�<br />
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<strong>ALU</strong>MINIUM · EAC CONGRESS 2011 69
SESSION SOFTWARE & SIMULATION<br />
Optimizing <str<strong>on</strong>g>the</str<strong>on</strong>g> energy c<strong>on</strong>sumpti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> coil annealing<br />
furnaces by ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical modelling <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> annealing process<br />
Günter Valder and Bernd Deimann, Otto Junker GmbH<br />
Multi-coil annealing furnaces <str<strong>on</strong>g>of</str<strong>on</strong>g> Otto Junker design<br />
The coils <str<strong>on</strong>g>of</str<strong>on</strong>g> strip made in <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> mills by<br />
hot and cold rolling are subjected to a variety<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> intermediate and finish annealing treat-<br />
ments for metallurgical reas<strong>on</strong>s. It is comm<strong>on</strong><br />
practice that coils <str<strong>on</strong>g>of</str<strong>on</strong>g> different alloy compositi<strong>on</strong>,<br />
geometry and residual heat c<strong>on</strong>tent<br />
are placed in shop floor buffer storage and<br />
allowed to cool down before undergoing <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
actual heat treatment in so-called chamber<br />
furnaces.<br />
Chamber furnaces may be <str<strong>on</strong>g>of</str<strong>on</strong>g> single or<br />
multi-coil design. A major benefit <str<strong>on</strong>g>of</str<strong>on</strong>g> single-coil<br />
units, as <str<strong>on</strong>g>the</str<strong>on</strong>g> name implies, is that <str<strong>on</strong>g>the</str<strong>on</strong>g>y allow<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> operator to anneal each coil individually.<br />
As a result, a change <str<strong>on</strong>g>of</str<strong>on</strong>g> alloy, product geometry<br />
or start temperature is easily possible between<br />
batches.<br />
Drawbacks <str<strong>on</strong>g>of</str<strong>on</strong>g> this equipment type include<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> large space requirement, relatively high<br />
investment cost and somewhat higher specific<br />
energy needs, all <str<strong>on</strong>g>of</str<strong>on</strong>g> which must be taken into<br />
account. In view <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se factors, multi-coil<br />
furnaces still have <str<strong>on</strong>g>the</str<strong>on</strong>g>ir justificati<strong>on</strong>. Let’s<br />
briefly review <str<strong>on</strong>g>the</str<strong>on</strong>g> status <str<strong>on</strong>g>of</str<strong>on</strong>g> some recent Otto<br />
Junker developments here, which are expected<br />
to implement <str<strong>on</strong>g>the</str<strong>on</strong>g> aforementi<strong>on</strong>ed advantages<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> single-coil furnace in <str<strong>on</strong>g>the</str<strong>on</strong>g> multi-coil unit<br />
to a very broad extent.<br />
One requirement in multi-coil furnace operati<strong>on</strong><br />
is that <str<strong>on</strong>g>the</str<strong>on</strong>g> coils placed in <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace<br />
should have <str<strong>on</strong>g>the</str<strong>on</strong>g> same geometry and start<br />
temperature so that <str<strong>on</strong>g>the</str<strong>on</strong>g> desired metallurgical<br />
properties can be obtained in a reproducible<br />
manner by <str<strong>on</strong>g>the</str<strong>on</strong>g> recipe-based heat treatment.<br />
Major deviati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g>se two parameters<br />
can be allowed if <str<strong>on</strong>g>the</str<strong>on</strong>g> coil temperatures are<br />
measured throughout <str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment cycle<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g>se temperature readings are fed to <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
furnace c<strong>on</strong>trol system. For c<strong>on</strong>trol purposes<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> multi-coil furnace is divided into several<br />
individually c<strong>on</strong>trolled<br />
heating<br />
z<strong>on</strong>es with a view<br />
to heating each coil<br />
separately by <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
jet heating principle<br />
using specially<br />
designed nozzle<br />
fields.<br />
Coil temperature<br />
measurements<br />
can be taken via<br />
c<strong>on</strong>tact <str<strong>on</strong>g>the</str<strong>on</strong>g>rmocouples<br />
or by<br />
means <str<strong>on</strong>g>of</str<strong>on</strong>g> shea<str<strong>on</strong>g>the</str<strong>on</strong>g>d<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>rmocouples em-<br />
bedded in <str<strong>on</strong>g>the</str<strong>on</strong>g> coil.<br />
A disadvantage <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g>se methods is<br />
that <str<strong>on</strong>g>the</str<strong>on</strong>g> strip sur-<br />
face quality may become locally impaired,<br />
e. g., by imprint marks. Moreover, it is necessary<br />
to allow set-up time for embedding <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
shea<str<strong>on</strong>g>the</str<strong>on</strong>g>d <str<strong>on</strong>g>the</str<strong>on</strong>g>rmocouples into <str<strong>on</strong>g>the</str<strong>on</strong>g> coil, and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
maintenance cost for <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tact <str<strong>on</strong>g>the</str<strong>on</strong>g>rmocouples<br />
needs to be c<strong>on</strong>sidered as well.<br />
In <str<strong>on</strong>g>the</str<strong>on</strong>g> past few years, Otto Junker has been<br />
able to accumulate initial experience with<br />
ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical modelling <str<strong>on</strong>g>of</str<strong>on</strong>g> heat treatment<br />
processes <strong>on</strong> copper strip treatment lines and<br />
copper billet heaters. It was c<strong>on</strong>firmed that<br />
integrated ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical models can enhance<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> reliability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> process while also helping<br />
to save energy [1].<br />
The objective defined for <str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> strip coils in multi-coil furnaces was<br />
that <str<strong>on</strong>g>the</str<strong>on</strong>g> temperature distributi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> each coil<br />
should be calculated in real time, and that <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
result <str<strong>on</strong>g>of</str<strong>on</strong>g> that calculati<strong>on</strong> should be used as furnace<br />
c<strong>on</strong>trol input. For metallurgical reas<strong>on</strong>s,<br />
a calculati<strong>on</strong> accuracy <str<strong>on</strong>g>of</str<strong>on</strong>g> better than ± 5 K must<br />
be repeatably achieved in this applicati<strong>on</strong>.<br />
As a general rule, ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical models are<br />
intended to describe a system’s resp<strong>on</strong>se to a<br />
change in exterior relati<strong>on</strong>s.<br />
One critically important task in <str<strong>on</strong>g>the</str<strong>on</strong>g> present<br />
c<strong>on</strong>text lies in computing <str<strong>on</strong>g>the</str<strong>on</strong>g> energy transfer<br />
from <str<strong>on</strong>g>the</str<strong>on</strong>g> fluid to <str<strong>on</strong>g>the</str<strong>on</strong>g> coil – a step which calls<br />
for an accurate understanding <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> underlying<br />
energy transfer mechanisms. In <str<strong>on</strong>g>the</str<strong>on</strong>g> case<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> heating process is clearly<br />
dominated by <str<strong>on</strong>g>the</str<strong>on</strong>g> forced c<strong>on</strong>vective porti<strong>on</strong>,<br />
although for <str<strong>on</strong>g>the</str<strong>on</strong>g> accuracy required, <str<strong>on</strong>g>the</str<strong>on</strong>g> radi-<br />
Diagram 1: Temperature curves obtained for a multi-coil heat treatment furnace.<br />
The diagram shows <str<strong>on</strong>g>the</str<strong>on</strong>g> supply air and return air temperatures (GasInlet, GasOutlet),<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> measured coil temperatures (MeasCoil), and <str<strong>on</strong>g>the</str<strong>on</strong>g> difference between<br />
calculated and measured temperature values (DevCalc Coil3) plotted by way <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
example for Coil 3.<br />
70 <strong>ALU</strong>MINIUM · EAC C<strong>on</strong>gress 2011<br />
Images: Otto Junker
ant heat transfer between <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
coil must not be neglected, ei<str<strong>on</strong>g>the</str<strong>on</strong>g>r. To this end,<br />
basic research was undertaken in cooperati<strong>on</strong><br />
with <str<strong>on</strong>g>the</str<strong>on</strong>g> Technical University <str<strong>on</strong>g>of</str<strong>on</strong>g> Aachen<br />
(RWTH) to gain a physically correct grasp<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> key correlati<strong>on</strong>s and to ensure that <str<strong>on</strong>g>the</str<strong>on</strong>g>se<br />
would be duly represented in <str<strong>on</strong>g>the</str<strong>on</strong>g> ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical<br />
model.<br />
The aim in <str<strong>on</strong>g>the</str<strong>on</strong>g>se investigati<strong>on</strong>s was to<br />
minimize <str<strong>on</strong>g>the</str<strong>on</strong>g> number <str<strong>on</strong>g>of</str<strong>on</strong>g> parameters requiring<br />
adaptati<strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> actual situati<strong>on</strong> during startup<br />
and in subsequent producti<strong>on</strong> operati<strong>on</strong>s,<br />
and to ensure that <str<strong>on</strong>g>the</str<strong>on</strong>g> programmed modules<br />
would be transferable to similar applicati<strong>on</strong>s<br />
elsewhere.<br />
The temperature distributi<strong>on</strong> over space<br />
and time within <str<strong>on</strong>g>the</str<strong>on</strong>g> coil can be described with<br />
sufficient accuracy by a partial differential<br />
equati<strong>on</strong>, assuming c<strong>on</strong>sistent metal characteristics.<br />
Although in <str<strong>on</strong>g>the</str<strong>on</strong>g> case <str<strong>on</strong>g>of</str<strong>on</strong>g> coils it is necessary<br />
to note significant differences between<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> radial and axial <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal c<strong>on</strong>ductance.<br />
The differential equati<strong>on</strong> is solved by <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
finite differences (FD) method, dividing <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
coil into <str<strong>on</strong>g>layer</str<strong>on</strong>g>s and <str<strong>on</strong>g>the</str<strong>on</strong>g> time into intervals. For<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> FD process to become stable, <str<strong>on</strong>g>the</str<strong>on</strong>g> time<br />
resoluti<strong>on</strong> and spatial resoluti<strong>on</strong> must at all<br />
times be mutually matched <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> basis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
coil‘s <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal c<strong>on</strong>ductivity.<br />
Once <str<strong>on</strong>g>the</str<strong>on</strong>g> ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical model is calibrated<br />
and stabilized, <str<strong>on</strong>g>the</str<strong>on</strong>g> following benefits are to<br />
be anticipated:<br />
1. Given <str<strong>on</strong>g>the</str<strong>on</strong>g> ability to support greater geometrical<br />
and temperature differences between<br />
coils, <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace can be filled to 100% capacity<br />
more frequently, i. e. furnace capacity<br />
utilizati<strong>on</strong> will be improved while <str<strong>on</strong>g>the</str<strong>on</strong>g> energy<br />
c<strong>on</strong>sumpti<strong>on</strong> is reduced.<br />
2. Since greater temperature differences between<br />
coils are allowed, it will be possible,<br />
ideally, to charge coils in <str<strong>on</strong>g>the</str<strong>on</strong>g>ir ‘as rolled’ temperature<br />
state. As a result, <str<strong>on</strong>g>the</str<strong>on</strong>g> mean temperature<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g> start <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment cycle<br />
will be clearly increased. The energy requirement<br />
will diminish accordingly.<br />
3. Unlike <str<strong>on</strong>g>the</str<strong>on</strong>g> physical temperature measuring<br />
methods menti<strong>on</strong>ed earlier, a ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical<br />
model will need no set-up time or maintenance<br />
in this respect.<br />
The first results obtained with a ma<str<strong>on</strong>g>the</str<strong>on</strong>g>-<br />
Spouts and Stoppers Ceramic Foam Filters<br />
www.drache-gmbh.de · mail@drache-gmbh.de<br />
SESSION SOFTWARE & SIMULATION<br />
matical model developed al<strong>on</strong>g <str<strong>on</strong>g>the</str<strong>on</strong>g> principles<br />
described above are shown in diagram 1. The<br />
illustrati<strong>on</strong> shows <str<strong>on</strong>g>the</str<strong>on</strong>g> temperature pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
three coils as measured during <str<strong>on</strong>g>the</str<strong>on</strong>g> heat-up<br />
phase. The coils were placed in <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace<br />
with starting temperatures <str<strong>on</strong>g>of</str<strong>on</strong>g> 25 to 75°C, and<br />
were heated to <str<strong>on</strong>g>the</str<strong>on</strong>g> same target temperature<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> 320°C ± 3 K from <str<strong>on</strong>g>the</str<strong>on</strong>g>ir respective state.<br />
For testing purposes, <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace was c<strong>on</strong>trolled<br />
using data from a ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical model<br />
which has been in use since mid-2010. In <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
case <str<strong>on</strong>g>of</str<strong>on</strong>g> Coil 3, <str<strong>on</strong>g>the</str<strong>on</strong>g> difference between <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
measured temperatures (MeasCoil 3) and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
calculated <strong>on</strong>es are not greater than -1 K and<br />
+ 8 K, respectively, at any time (DevCalcCoil<br />
3). During <str<strong>on</strong>g>the</str<strong>on</strong>g> last third <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> heat-up cycle,<br />
this difference was even better than -1 K and<br />
+ 2 K throughout.<br />
The rise in mean coil temperature prevailing<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g> start <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment will save<br />
energy while also reducing CO 2 emissi<strong>on</strong>s.<br />
Diagram 2 illustrates <str<strong>on</strong>g>the</str<strong>on</strong>g> CO 2 savings achievable<br />
at different annual annealing capacities<br />
by increasing <str<strong>on</strong>g>the</str<strong>on</strong>g> mean coil temperature at <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
start <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment cycle. The compar-<br />
For Aluminium DC Casting<br />
<strong>ALU</strong>MINIUM · EAC C<strong>on</strong>gress 2011 71
SESSION SOFTWARE & SIMULATION<br />
Diagram 2: CO 2 savings as a functi<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> mean coil temperature at <str<strong>on</strong>g>the</str<strong>on</strong>g> start <str<strong>on</strong>g>of</str<strong>on</strong>g> heat treatment<br />
is<strong>on</strong> was made between two state-<str<strong>on</strong>g>of</str<strong>on</strong>g>-<str<strong>on</strong>g>the</str<strong>on</strong>g>-art<br />
annealing furnaces <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> multi-coil type. The<br />
reducti<strong>on</strong> in CO 2 output has been calculated<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> basis <str<strong>on</strong>g>of</str<strong>on</strong>g> specific CO 2 emissi<strong>on</strong> figures<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> current mix <str<strong>on</strong>g>of</str<strong>on</strong>g> electricity sources in<br />
Germany. Around two-thirds <str<strong>on</strong>g>of</str<strong>on</strong>g> this reducti<strong>on</strong><br />
are attributable to fuel savings (assuming<br />
that <str<strong>on</strong>g>the</str<strong>on</strong>g> furnace is running <strong>on</strong> <str<strong>on</strong>g>natural</str<strong>on</strong>g> gas), <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
remaining <strong>on</strong>e-third reflects electrical power<br />
savings (assuming that <str<strong>on</strong>g>the</str<strong>on</strong>g> increased coil temperature<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g> start <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> heat treatment will<br />
shorten <str<strong>on</strong>g>the</str<strong>on</strong>g> heat-up cycle and hence, reduce<br />
fan operating times).<br />
In mid-2011, Otto Junker supplied five<br />
multi-coil furnaces – al<strong>on</strong>g with <str<strong>on</strong>g>the</str<strong>on</strong>g> charging<br />
machine and a complete automati<strong>on</strong><br />
system – to Aluminium Norf GmbH. At <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
automati<strong>on</strong> level, a computer cluster linking<br />
Numerical analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> seam welds <str<strong>on</strong>g>of</str<strong>on</strong>g> industrial extrusi<strong>on</strong> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles<br />
T. Kloppenborg 1 , M. Schwane 1 , M. Fiderer 2 , A. Reeb 3 ,<br />
N. Ben Khalifa 1 , K. A. Weidenmann 3 , A. Brosius 1 , A. Erman Tekkaya 1<br />
1 Institute <str<strong>on</strong>g>of</str<strong>on</strong>g> Forming Technology and Lightweight C<strong>on</strong>structi<strong>on</strong>, Technische Universität Dortmund,<br />
Germany; 2 Kistler-IGeL GmbH, Schönaich, Germany; 3 Institute for Applied Materials – Materials<br />
Science and Engineering (IAM–WK), Karlsruher Institute <str<strong>on</strong>g>of</str<strong>on</strong>g> Technology (KIT), Karlsruhe, Germany<br />
The increasing number <str<strong>on</strong>g>of</str<strong>on</strong>g> regulatory requirements<br />
as well as <str<strong>on</strong>g>the</str<strong>on</strong>g> rising expectati<strong>on</strong>s in comfort<br />
result in a c<strong>on</strong>tinuous weight increase <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
automobiles. The weight <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> vehicles influences<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> fuel c<strong>on</strong>sumpti<strong>on</strong> and increases air<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> PLC, HMI and modelling computers is<br />
created and tied in with <str<strong>on</strong>g>the</str<strong>on</strong>g> manufacturing<br />
requirements planning (MRP) system. An <str<strong>on</strong>g>of</str<strong>on</strong>g>fline<br />
versi<strong>on</strong> can be used to load data <str<strong>on</strong>g>of</str<strong>on</strong>g> coils<br />
currently in shop floor buffer storage; <str<strong>on</strong>g>the</str<strong>on</strong>g>se<br />
coils can <str<strong>on</strong>g>the</str<strong>on</strong>g>n be arranged into energy-optimized<br />
or time-optimized furnace batches<br />
comprising four coils in each case. The batches<br />
determined by means <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> optimizing calculati<strong>on</strong>s<br />
are <str<strong>on</strong>g>the</str<strong>on</strong>g>n returned to <str<strong>on</strong>g>the</str<strong>on</strong>g> MRP system<br />
and cleared for heat treatment. The heat<br />
treatment process is <str<strong>on</strong>g>the</str<strong>on</strong>g>n c<strong>on</strong>trolled with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<strong>on</strong>line versi<strong>on</strong>, which relies <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> same computing<br />
core.<br />
This innovati<strong>on</strong> project is subsidized by <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
Federal Ministry <str<strong>on</strong>g>of</str<strong>on</strong>g> Envir<strong>on</strong>ment because <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
integrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> a ma<str<strong>on</strong>g>the</str<strong>on</strong>g>matical model is expected<br />
to yield a significant reducti<strong>on</strong> in energy<br />
polluti<strong>on</strong>. The automobile industry has pursued<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> strategy to reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> weight <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
vehicles by an intelligent car body for a l<strong>on</strong>g<br />
time. Therefore, an increasing number <str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong><br />
pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles made <str<strong>on</strong>g>of</str<strong>on</strong>g> aluminum have been<br />
c<strong>on</strong>sumpti<strong>on</strong> and hence, CO 2 emissi<strong>on</strong>s. Since<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> comparis<strong>on</strong> was carried out against ‘earlier<br />
generati<strong>on</strong>’ multi-coil furnaces, <str<strong>on</strong>g>the</str<strong>on</strong>g> anticipated<br />
savings <str<strong>on</strong>g>of</str<strong>on</strong>g> approx. 8,300 t<strong>on</strong>nes <str<strong>on</strong>g>of</str<strong>on</strong>g> CO 2 at<br />
an annual producti<strong>on</strong> output <str<strong>on</strong>g>of</str<strong>on</strong>g> 180,000<br />
t<strong>on</strong>nes <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> still exceed <str<strong>on</strong>g>the</str<strong>on</strong>g> results illustrated<br />
in diagram 2 [3]. The project is slated<br />
to be completed by <str<strong>on</strong>g>the</str<strong>on</strong>g> end <str<strong>on</strong>g>of</str<strong>on</strong>g> 2011, so that<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> first reports <strong>on</strong> operating experience are to<br />
be anticipated for 2012.<br />
References<br />
[1] Cüppers, J.: Betriebserfahrungen mit verschiedenen<br />
prozeßrechnerunterstützten Erwärmungsstrategien<br />
an Hubbalkenöfen in der Buntmetallindustrie<br />
[Operating experience gained with diverse process<br />
computer-assisted heating strategies <strong>on</strong> walking<br />
beam furnaces in <str<strong>on</strong>g>the</str<strong>on</strong>g> n<strong>on</strong>-ferrous metals industry],<br />
Blech Rohre Pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile 28, 1991, pp. 882-890<br />
[2] Bölling, R.: Allgemeine Systemtechnik – Einführung<br />
in die Finite-Volumen-Methode, Lösung strömungs-<br />
und wärmetechnischer Probleme des Industrie<str<strong>on</strong>g>of</str<strong>on</strong>g>enbaus<br />
mittels numerischer Methoden [General<br />
systems engineering – Introducti<strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> finite<br />
volume method, soluti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> fluid and <str<strong>on</strong>g>the</str<strong>on</strong>g>rmal engineering<br />
problems in industrial furnace c<strong>on</strong>structi<strong>on</strong><br />
using numerical methods], Lecture Notes, Technical<br />
University <str<strong>on</strong>g>of</str<strong>on</strong>g> Aachen (RWTH), Winter Term 2010<br />
[3] Federal Ministry <str<strong>on</strong>g>of</str<strong>on</strong>g> Envir<strong>on</strong>ment, www.bmu.de.<br />
Press release dated February 8, 2011: Innovative<br />
Glühöfen für die Aluminium-Industrie [Innovative<br />
annealing furnaces for <str<strong>on</strong>g>the</str<strong>on</strong>g> <str<strong>on</strong>g>aluminium</str<strong>on</strong>g> industry]<br />
Authors<br />
Dr.Ing. Günter Valder, Technology Business Unit<br />
Manager, Thermoprocess Equipment Divisi<strong>on</strong>, Otto<br />
Junker GmbH, Simmerath, Germany<br />
Dipl.Ing. Bernd Deimann, Senior Sales Manager,<br />
Thermoprocess Equipment Divisi<strong>on</strong>, Otto Junker<br />
GmbH, Simmerath, Germany<br />
used as semi-finished products. The complexity<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile cross secti<strong>on</strong>s varies depending<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> automobile manufacturer and <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> number <str<strong>on</strong>g>of</str<strong>on</strong>g> produced vehicles.<br />
Currently, <str<strong>on</strong>g>the</str<strong>on</strong>g> estimati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> produc-<br />
72 <strong>ALU</strong>MINIUM · EAC C<strong>on</strong>gress 2011
Fig. 1: Tool c<strong>on</strong>cept for <str<strong>on</strong>g>the</str<strong>on</strong>g> visioplastic analyses in a porthole die<br />
ibility <str<strong>on</strong>g>of</str<strong>on</strong>g> complex cross secti<strong>on</strong>s is based <strong>on</strong><br />
expert’s knowledge and cost-intensive prototyping.<br />
A more efficient method to predict <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
producibility and to reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> risk <str<strong>on</strong>g>of</str<strong>on</strong>g> producti<strong>on</strong><br />
failure in advance is presently not available.<br />
Hence, during <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>ceptual designing<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> new automobiles not all possibilities can be<br />
c<strong>on</strong>sidered. One factor is <str<strong>on</strong>g>the</str<strong>on</strong>g> positi<strong>on</strong> and <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
quality <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> l<strong>on</strong>gitudinal seam welds. Insufficient<br />
seam welds can influence <str<strong>on</strong>g>the</str<strong>on</strong>g> mechanical<br />
properties <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles.<br />
In this paper, <str<strong>on</strong>g>the</str<strong>on</strong>g> recent results <str<strong>on</strong>g>of</str<strong>on</strong>g> a transfer<br />
project within <str<strong>on</strong>g>the</str<strong>on</strong>g> scope <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> Transregi<strong>on</strong>al<br />
Collaborative Research Center / TR10, which<br />
is kindly supported by <str<strong>on</strong>g>the</str<strong>on</strong>g> German Research<br />
Foundati<strong>on</strong> (DFG), are presented. In this<br />
project, extrusi<strong>on</strong> companies, die makers,<br />
automobile companies, extrusi<strong>on</strong> s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware<br />
companies, and <str<strong>on</strong>g>the</str<strong>on</strong>g> Gesamtverband der Aluminiumindustrie<br />
e.V. work toge<str<strong>on</strong>g>the</str<strong>on</strong>g>r to evaluate<br />
how present simulati<strong>on</strong> s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware based<br />
<strong>on</strong> finite element methods is able to simulate<br />
complex industrial extrusi<strong>on</strong> processes.<br />
For <str<strong>on</strong>g>the</str<strong>on</strong>g> validati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> numerical results<br />
in porthole die extrusi<strong>on</strong> by visioplastic plastic<br />
analysis a new modular die c<strong>on</strong>cept <str<strong>on</strong>g>of</str<strong>on</strong>g> a porthole<br />
die was developed. This tooling c<strong>on</strong>cept<br />
allows preparing <str<strong>on</strong>g>the</str<strong>on</strong>g> material out <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> die<br />
without post plastificati<strong>on</strong>s <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
surface. Especially <str<strong>on</strong>g>the</str<strong>on</strong>g> analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> tribological<br />
effects near <str<strong>on</strong>g>the</str<strong>on</strong>g> die walls can be d<strong>on</strong>e<br />
[1,2]. The die is used for <str<strong>on</strong>g>the</str<strong>on</strong>g> producti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
Fig. 2: Modeling <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> process in Deform and HyperXrude<br />
a rectangular pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile with a cross secti<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
40 mm x 10 mm. It c<strong>on</strong>sists <str<strong>on</strong>g>of</str<strong>on</strong>g> twelve single<br />
parts. The fundamental part is a divided c<strong>on</strong>ical<br />
part, which is necessary to extract <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
out <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> die. Additi<strong>on</strong>ally, <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
which is prepared for <str<strong>on</strong>g>the</str<strong>on</strong>g> visioplastic analysis<br />
can be inserted into <str<strong>on</strong>g>the</str<strong>on</strong>g> die again (Fig. 1).<br />
Only a billet preparati<strong>on</strong> would result in<br />
high deformati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>trast material inside<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> feeders. In this case a determinati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material flow and <str<strong>on</strong>g>the</str<strong>on</strong>g> tribological effects<br />
<strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g> die wall would be inaccurate. Due to<br />
this, to analyze <str<strong>on</strong>g>the</str<strong>on</strong>g> material flow inside <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
billet, <str<strong>on</strong>g>the</str<strong>on</strong>g> feeders and <str<strong>on</strong>g>the</str<strong>on</strong>g> welding chamber <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> die were filled by extruding an EN AW-<br />
6063 alloy. The material was <str<strong>on</strong>g>the</str<strong>on</strong>g>n extracted<br />
and prepared with <str<strong>on</strong>g>the</str<strong>on</strong>g> grid pattern technique<br />
[1, 3]. In <str<strong>on</strong>g>the</str<strong>on</strong>g> vertical symmetry plane cylindrical<br />
pins with a diameter <str<strong>on</strong>g>of</str<strong>on</strong>g> 5 mm were used as<br />
c<strong>on</strong>trast material. To visualize <str<strong>on</strong>g>the</str<strong>on</strong>g> horiz<strong>on</strong>tal<br />
and <str<strong>on</strong>g>the</str<strong>on</strong>g> vertical material flow in <strong>on</strong>e experiment,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> pins were inserted vertically and<br />
horiz<strong>on</strong>tally in <str<strong>on</strong>g>the</str<strong>on</strong>g> symmetrical upper and<br />
lower part <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> die. An EN AW-4043A alloy<br />
was used as c<strong>on</strong>trast material. The distance<br />
between <str<strong>on</strong>g>the</str<strong>on</strong>g> pins was 15 mm. But in <str<strong>on</strong>g>the</str<strong>on</strong>g> area <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
transiti<strong>on</strong> from <str<strong>on</strong>g>the</str<strong>on</strong>g> billet to <str<strong>on</strong>g>the</str<strong>on</strong>g> feeder as well<br />
as in <str<strong>on</strong>g>the</str<strong>on</strong>g> area <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> welding chamber, different<br />
distances were necessary. After preparati<strong>on</strong>,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> material was reinserted in <str<strong>on</strong>g>the</str<strong>on</strong>g> modular die<br />
for <str<strong>on</strong>g>the</str<strong>on</strong>g> experiment. After <str<strong>on</strong>g>the</str<strong>on</strong>g> preparati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> billet <str<strong>on</strong>g>the</str<strong>on</strong>g> extrusi<strong>on</strong> process was performed<br />
SESSION SOFTWARE & SIMULATION<br />
<strong>on</strong> a 10 MN extrusi<strong>on</strong> press at <str<strong>on</strong>g>the</str<strong>on</strong>g> IUL to visualize<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> material flow inside <str<strong>on</strong>g>the</str<strong>on</strong>g> die.<br />
For <str<strong>on</strong>g>the</str<strong>on</strong>g> numerical analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
flow, <str<strong>on</strong>g>the</str<strong>on</strong>g> finite element method was used. The<br />
simulati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> process was d<strong>on</strong>e with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
commercial s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware HyperXtrude and Deform3D.<br />
As initial data for <str<strong>on</strong>g>the</str<strong>on</strong>g> threedimensi<strong>on</strong>al<br />
finite element models <str<strong>on</strong>g>the</str<strong>on</strong>g> geometrical<br />
data <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> experimental investigati<strong>on</strong>s was<br />
used. Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> fact that each s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware uses<br />
varying formulati<strong>on</strong>s a different modeling <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> process becomes necessary.<br />
The implicit finite element code from Altair<br />
Engineering uses <str<strong>on</strong>g>the</str<strong>on</strong>g> Euler formulati<strong>on</strong><br />
where <str<strong>on</strong>g>the</str<strong>on</strong>g> material is meshed with a fixed<br />
mesh. Hence, <str<strong>on</strong>g>the</str<strong>on</strong>g> overall material flow in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
process has to be modeled. It includes <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
70 mm l<strong>on</strong>g billet (diameter <str<strong>on</strong>g>of</str<strong>on</strong>g> 105 mm), <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
material inside <str<strong>on</strong>g>the</str<strong>on</strong>g> die, and <str<strong>on</strong>g>the</str<strong>on</strong>g> exiting pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile.<br />
Additi<strong>on</strong>ally, <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tainer and <str<strong>on</strong>g>the</str<strong>on</strong>g> die were<br />
c<strong>on</strong>sidered as rigid bodies to calculate <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
heat transfer. Only a symmetrical part was<br />
modeled to reduce <str<strong>on</strong>g>the</str<strong>on</strong>g> calculati<strong>on</strong> time for <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
quasi stati<strong>on</strong>ary simulati<strong>on</strong>. The inflow velocity<br />
was set to 10 mm/s.<br />
In Deform3D, <str<strong>on</strong>g>the</str<strong>on</strong>g> Lagrange formulati<strong>on</strong> is<br />
used. Here, <str<strong>on</strong>g>the</str<strong>on</strong>g> finite element mesh is linked<br />
to <str<strong>on</strong>g>the</str<strong>on</strong>g> material flow. Particularly in <str<strong>on</strong>g>the</str<strong>on</strong>g> simulati<strong>on</strong><br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong> processes, where high deformati<strong>on</strong><br />
occurs, frequent remeshing is required<br />
in order to maintain a good mesh quality. In<br />
this model comp<strong>on</strong>ents were discretized with<br />
linear tetrahedral elements. The block with a<br />
length <str<strong>on</strong>g>of</str<strong>on</strong>g> 80 mm and <str<strong>on</strong>g>the</str<strong>on</strong>g> material in <str<strong>on</strong>g>the</str<strong>on</strong>g> filled<br />
die were modeled as <strong>on</strong>e part, which has been<br />
assigned a homogeneous initial temperature <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
430°C. Both <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tainer and <str<strong>on</strong>g>the</str<strong>on</strong>g> die were<br />
assumed to be rigid. They were also discretized<br />
in order to incorporate <str<strong>on</strong>g>the</str<strong>on</strong>g> heat exchange between<br />
material and tools during <str<strong>on</strong>g>the</str<strong>on</strong>g> process.<br />
The diameter <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> block was chosen to be<br />
equal to <str<strong>on</strong>g>the</str<strong>on</strong>g> inner diameter <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tainer<br />
to increase <str<strong>on</strong>g>the</str<strong>on</strong>g> comparability to <str<strong>on</strong>g>the</str<strong>on</strong>g> HyperXtrude<br />
model. Due to this, <str<strong>on</strong>g>the</str<strong>on</strong>g> upsetting <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<strong>ALU</strong>MINIUM · EAC C<strong>on</strong>gress 2011 73
SESSION SOFTWARE & SIMULATION<br />
Fig. 3: Visualizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> flow lines from <str<strong>on</strong>g>the</str<strong>on</strong>g> experiment and <str<strong>on</strong>g>the</str<strong>on</strong>g> simulati<strong>on</strong><br />
block was also not c<strong>on</strong>sidered in <str<strong>on</strong>g>the</str<strong>on</strong>g> Deform<br />
model. Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>rmore, <strong>on</strong>ly a quarter model was<br />
setup and a c<strong>on</strong>stant punch speed <str<strong>on</strong>g>of</str<strong>on</strong>g> 10 mm/s<br />
was chosen.<br />
Flow lines were calculated based <strong>on</strong> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
velocity field out <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> HyperXtrude simulati<strong>on</strong>.<br />
The integrati<strong>on</strong> time was set to <str<strong>on</strong>g>the</str<strong>on</strong>g> press<br />
time to make a qualitative validati<strong>on</strong> with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
experimental directly visible. Due to <str<strong>on</strong>g>the</str<strong>on</strong>g> results,<br />
a high strain distributi<strong>on</strong> occurs in <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
area <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> welding chamber which is shown<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> plastificati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>trast material<br />
(Fig. 3). The calculated vertical flow is in accurate<br />
agreement with <str<strong>on</strong>g>the</str<strong>on</strong>g> visioplastic result.<br />
Additi<strong>on</strong>ally, it can be seen that <str<strong>on</strong>g>the</str<strong>on</strong>g> material<br />
sticks <strong>on</strong> to <str<strong>on</strong>g>the</str<strong>on</strong>g> die wall. This effect is also<br />
shown by <str<strong>on</strong>g>the</str<strong>on</strong>g> finite element model. It can be<br />
seen that <str<strong>on</strong>g>the</str<strong>on</strong>g> material shears near <str<strong>on</strong>g>the</str<strong>on</strong>g> die wall.<br />
Outside this area, <str<strong>on</strong>g>the</str<strong>on</strong>g> velocity is mainly c<strong>on</strong>stant<br />
in <str<strong>on</strong>g>the</str<strong>on</strong>g> feeders. Errors occur due to <str<strong>on</strong>g>the</str<strong>on</strong>g> fact<br />
that HyperXtrude is not able to calculate <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
billet upsetting <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> block at <str<strong>on</strong>g>the</str<strong>on</strong>g> beginning <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> process. The error can be established by <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
decreasing error in press directi<strong>on</strong> in <str<strong>on</strong>g>the</str<strong>on</strong>g> billet<br />
as well as in <str<strong>on</strong>g>the</str<strong>on</strong>g> increasing error radial from<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> billet center to <str<strong>on</strong>g>the</str<strong>on</strong>g> c<strong>on</strong>tainer.<br />
Additi<strong>on</strong>ally <str<strong>on</strong>g>the</str<strong>on</strong>g> fricti<strong>on</strong> modeling in Deform<br />
was analyzed. The shear fricti<strong>on</strong> model<br />
according to Tresca with m = 1 was used in<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> calculati<strong>on</strong>s. Physically, this corresp<strong>on</strong>ds<br />
Fig. 4: Qualitative comparis<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> HyperXtrude and Deform3D results<br />
to sticking between material and tool surface,<br />
since <str<strong>on</strong>g>the</str<strong>on</strong>g> fricti<strong>on</strong> stress equals <str<strong>on</strong>g>the</str<strong>on</strong>g> shear yield<br />
stress <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> material. In order to evaluate <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
impact <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> fricti<strong>on</strong> boundary c<strong>on</strong>diti<strong>on</strong>s <strong>on</strong><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> material flow and <str<strong>on</strong>g>the</str<strong>on</strong>g> flow grid pattern,<br />
respectively, fricti<strong>on</strong> was also modeled using<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> sticking c<strong>on</strong>diti<strong>on</strong> solely as well as with <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
sticking c<strong>on</strong>diti<strong>on</strong> in c<strong>on</strong>juncti<strong>on</strong> with m = 1.<br />
The movement <str<strong>on</strong>g>of</str<strong>on</strong>g> nodes <strong>on</strong> a c<strong>on</strong>tact surface<br />
is prevented when <str<strong>on</strong>g>the</str<strong>on</strong>g> sticking c<strong>on</strong>diti<strong>on</strong> is applied.<br />
The results revealed that <str<strong>on</strong>g>the</str<strong>on</strong>g> flow lines<br />
partially deb<strong>on</strong>d in case <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> shear fricti<strong>on</strong><br />
model. Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>rmore, <str<strong>on</strong>g>the</str<strong>on</strong>g> material slides al<strong>on</strong>g<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> die wall in <str<strong>on</strong>g>the</str<strong>on</strong>g> feeder, which is also clearly<br />
shown by <str<strong>on</strong>g>the</str<strong>on</strong>g> depicted velocity pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile. These<br />
effects do not match <str<strong>on</strong>g>the</str<strong>on</strong>g> experimental results.<br />
Here, full sticking between material and die<br />
can be observed, so that shearing in <str<strong>on</strong>g>the</str<strong>on</strong>g> subsurface<br />
<str<strong>on</strong>g>layer</str<strong>on</strong>g>s occurs. This flow characteristic<br />
is qualitatively achieved by an activati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> sticking opti<strong>on</strong>. The difference between<br />
sticking and sticking in c<strong>on</strong>juncti<strong>on</strong> with shear<br />
fricti<strong>on</strong> turned out to be insignificant. Due to<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> presented results, <str<strong>on</strong>g>the</str<strong>on</strong>g> model incorporating<br />
volume compensati<strong>on</strong> as well as sticking c<strong>on</strong>diti<strong>on</strong><br />
was determined to give best results.<br />
The Deform results were validated using<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> HyperXtrude results, which already had<br />
turned out to be reliable. Hence, a flow net<br />
with equally spaced lines was computed with<br />
both Deform3D and<br />
HyperXtrude. It can be<br />
shown that <str<strong>on</strong>g>the</str<strong>on</strong>g> results<br />
computed by HyperXtrude<br />
and Deform3D<br />
are in good accordance<br />
in terms <str<strong>on</strong>g>of</str<strong>on</strong>g> flow<br />
line pattern as well as<br />
flow velocity predicti<strong>on</strong><br />
(Fig. 4).<br />
The hints regarding an<br />
appropriate modeling <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> material flow in port-<br />
hole dies, which where gained by <str<strong>on</strong>g>the</str<strong>on</strong>g> visioplastic<br />
analysis will also be incorporated into <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
<strong>DE</strong>FORM models <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> industrial extrusi<strong>on</strong><br />
tests, which were c<strong>on</strong>ducted by <str<strong>on</strong>g>the</str<strong>on</strong>g> collaborating<br />
companies <str<strong>on</strong>g>of</str<strong>on</strong>g> this project. First results <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> numerical process simulati<strong>on</strong> are already<br />
in good correlati<strong>on</strong> with <str<strong>on</strong>g>the</str<strong>on</strong>g> experimental results.<br />
In particular <str<strong>on</strong>g>the</str<strong>on</strong>g> simulati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile<br />
exhibiting different wall thicknesses shows<br />
some significant characteristics. The different<br />
wall thicknesses <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile generate an inhomogeneous<br />
velocity distributi<strong>on</strong> at <str<strong>on</strong>g>the</str<strong>on</strong>g> die<br />
orifice which, in turn, causes a curved shape<br />
<str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g> exiting pr<str<strong>on</strong>g>of</str<strong>on</strong>g>ile. A higher flow velocity<br />
is predicted at <str<strong>on</strong>g>the</str<strong>on</strong>g> thicker walls. Fur<str<strong>on</strong>g>the</str<strong>on</strong>g>rmore,<br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> extruded pr<str<strong>on</strong>g>of</str<strong>on</strong>g>iles showed slight underfillings<br />
at <str<strong>on</strong>g>the</str<strong>on</strong>g> outer face. The process simulati<strong>on</strong><br />
is also capable <str<strong>on</strong>g>of</str<strong>on</strong>g> representing <str<strong>on</strong>g>the</str<strong>on</strong>g>se failures.<br />
It should be menti<strong>on</strong>ed here that <str<strong>on</strong>g>the</str<strong>on</strong>g> numerical<br />
analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> this process still requires some<br />
effort since <str<strong>on</strong>g>the</str<strong>on</strong>g> material flow is not symmetric.<br />
Therefore, <str<strong>on</strong>g>the</str<strong>on</strong>g> material and <str<strong>on</strong>g>the</str<strong>on</strong>g> mesh, respectively,<br />
has to be merged manually at <str<strong>on</strong>g>the</str<strong>on</strong>g> welding<br />
lines when Deform s<str<strong>on</strong>g>of</str<strong>on</strong>g>tware is used.<br />
Acknowledgement<br />
This paper is based <strong>on</strong> investigati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
subprojects B1 – ‘Integral design, simulati<strong>on</strong><br />
and optimizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> extrusi<strong>on</strong> dies’ and T6 –<br />
‘Efficient industrial extrusi<strong>on</strong> simulati<strong>on</strong>’ <str<strong>on</strong>g>of</str<strong>on</strong>g><br />
<str<strong>on</strong>g>the</str<strong>on</strong>g> Transregi<strong>on</strong>al Collaborative Research<br />
Center / Transregio 10, which is kindly supported<br />
by <str<strong>on</strong>g>the</str<strong>on</strong>g> German Research Foundati<strong>on</strong><br />
(DFG).<br />
Additi<strong>on</strong>ally, <str<strong>on</strong>g>the</str<strong>on</strong>g> support <str<strong>on</strong>g>of</str<strong>on</strong>g> our industrial<br />
partners Audi AG, Altair Engineering GmbH,<br />
F.W. Brökelmann Aluminiumwerk GmbH &<br />
Co. KG, Daimler AG, Gesamtverband der<br />
Aluminiumindustrie e.V., H<strong>on</strong>sel AG, Kistler-<br />
IGel GmbH, and S+C ETS GmbH is greatly<br />
acknowledged. Particularly, we want to thank<br />
Wilke Werkzeugbau GmbH for <str<strong>on</strong>g>the</str<strong>on</strong>g> die manufacture.<br />
We also want to thank <str<strong>on</strong>g>the</str<strong>on</strong>g> Institute for Innovative<br />
Mechanics and Management <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>the</str<strong>on</strong>g><br />
University <str<strong>on</strong>g>of</str<strong>on</strong>g> Padova in Italy for <str<strong>on</strong>g>the</str<strong>on</strong>g> experimental<br />
tests for <str<strong>on</strong>g>the</str<strong>on</strong>g> flow curve evaluati<strong>on</strong>.<br />
Literature<br />
[1] L. D<strong>on</strong>ati, L. Tomesani, M. Schikkora, N. Ben<br />
Khalifa and A.E. Tekkaya: Fricti<strong>on</strong> model selecti<strong>on</strong><br />
in FEM simulati<strong>on</strong>s <str<strong>on</strong>g>of</str<strong>on</strong>g> aluminum extrusi<strong>on</strong>, Int. j.<br />
Surface Science and Engineering, Vol. 4, No. 1 (2010)<br />
[2] H. S. Valberg: Applied metal forming: including<br />
FEM analysis, Cambridge University Press (2010)<br />
[3] H. S. Valberg: Experimental techniques to characterize<br />
large plastic deformati<strong>on</strong>s in unlubricated<br />
hot aluminum extrusi<strong>on</strong>, Key Engineering Materials<br />
Vol. 367, pp. 17-24 (2008)<br />
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