No. 4, 1998 - Tribology in Industry

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Tribological Behaviour
of Surfacing Layers
for Continual Casting Rolls
Prodactionofroobforcottinualcastingandrollingmills andtheirrenovatianrepresents aphenomenonwhich
is economically very srgnificant for metalluryists. It can be simply proved that the roll as a tool significantly
affects the quality of rolled products and also contirudty of prodaction related to its hfe.
The Welding Research Instilute is devoted to these problems for more than 40 years,
Kcywords: Tibolog, regeneratiott, surface layer, harclening
l.INTRODUCTION
Production of rools for continual casting and rolling mills
and their renovation represents a phenomenon which is
economically very significant for metallurgists. It can be
simply proved that the roll as a tool significantly affects
the quality of rolled products and also continuity of
production related to its life.
In the world we ever more often encounter the metallurgical
rolls with two, or even more surface layers, where
the quality of working surface can be separated from that
of base body of the roll. Such is also the principle of rools
where the working surface is obtained by welding tech'
nologies.
Moreover, the new types of teel rolls [1,2], which were
first succesfully used in Japan in 1986 (HSS rolls), have
shown great possibilities of their renovation but also their
production by welding technologies.
The Welding Research Institute is devoted to these problems
for more than 40 years.
We shall indicatewhat is now available forthe mentioned
purposes.
2. CURRENT APPLICATIONS
The main advantage of surfacing technolory application
is a good comtrol over the process micrometallurry and
consequentnly improved quality and purity of the deposited
layer, and most recently also fabrication of composite
weld overlays.
Pavel Blalkovil,
Department of Fha CoveredArc lAelding and Su(acing
Welding Research Institute, Bratislava, Slavakia
The mostly used surfacing technolory is submerged arc
process (SA). It is used for deposition of block rolls, billet
rolls, prefinishing rolls and for the rolls of continual
casting lines.
2.1The parent material
The base metal of surfaced rolls is selected from the
following steel types:
L.0.6VoC;l.VoCr;O.3VoMo - steel in accordance with
STN 42 2366.5 (Slovak Standard)
2,0,8VoCL,VoCr,0.3VoMo - steel in accordance with'
sTN42 2865.9
3.05VoC;7VoCr - forged steel in accordance with
sTN 14161
4.0.6VoC - forged steel in accordance with
srN 12060.9
5.0.5VoC;0.8VoCr - steel in acrordance with
sTN42 n39.5
The choice of base metal depends on overall loading of
roll and its dimensions.
2.2 Filler materials
For submerged are surfacing of the rolling mill rolls and
rolls for continual casting the following types of tubular
wire and flux cored strip electrodes, including the flux
combination from the production of Welding Research
Institute Bratislava, the types given in Table 1 are used.
[4,6]
In addition to submerged arc surfacing of the continual
casting rolls, also open arc self-shielding process is hpplied.
The used tlpe of tubular wires are shown in Table
2.[s)
L54
Tibologt in indwtry, Volume 20, No. 4,1998.