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TeChNoLogY
Advanced casting research to boost auto industry production
Metal casting process innovations will enable
new generations of high quality car
parts to be produced from recycled scrap
metal and derive more savings in natural
resources.
Further advances in solidification metallurgy related
to micro structures will boost casting integrity
and extend lightweighting options
Together with the careful control of metallurgical
process parameters and as-cast micro
structures, optimised conditioning and purification
of the molten metal are vital considerations
in casting aluminium, particularly from
recycled metal. The key objective is to ensure
the quality and integrity of foundry products
in a variety of applications, not least in the
automotive sector. Now, car makers in Britain
are likely to be the first to benefit from what
is hailed as revolutionary new metal casting
techniques developed at Brunel University
in London, through a UK Government-supported
programme to develop laboratory
discoveries for exploitation in industrial-scale
applications.
The £14 million Advanced Metal Casting
Centre (AMCC) at Brunel will bridge the gap
between fundamental research and full-scale
industrial trials. Along with the University, the
development is jointly funded by the Engineering
and Physical Sciences Research Council,
the aluminium automotive sheet and extrusions
solutions provider Constellium, and the
luxury car manufacturer Jaguar Land Rover.
The new facility will draw on the work carried
out by Professor Zhongyun Fan and his
university team at the Brunel Centre for Advanced
Solidification Technology to improve
the recyclability of metals. “Our long term
aim,” he says, “is to reduce the amount of new
metal mined from the ground to a minimum,
by finding ways to make high quality parts and
materials from metal that has already been
used at least once.”
“For example, in the UK alone we send
New AMCC at Brunel University – research work
programmes at the leading edge ...
around 300,000 tonnes of aluminium to landfill
every year. That is a direct economic loss
of nearly £800 million and represents a further
loss of around 11 million barrels of oil, representing
the energy used to make that amount
of aluminium. Clearly, there are many environmental
and economic benefits to be gained
from reusing that material.”
One project that will be pursued in the
AMCC is the replacement of the hundreds of
registered aluminium alloys currently in commercial
use with just over ten highly versatile
alloys that can be used over and over again.
Another research programme is aimed at
developing a set of very efficient techniques
for purifying and conditioning liquid metal to
support reliable industrial processes, that can
be used to make high quality castings for cars
and other applications. “Every failed casting
represents a huge waste of energy, time and
money,” says Professor Fan. “We know that
our new techniques can reliably create first
class components from recycled metal. Our
challenge now is to scale these methods up
for commercial use and to show that they can
reduce cost, improve quality, and conserve
natural resources.”
The basis for these new techniques generated
by the research work is essentially a
change in emphasis for the study of metal solidification.
The rate of cooling during metal
solidification has a key influence on gas porosity
and as-cast micro structure, including the
morphology of inclusions, which help to define
the subsequent mechanical and surface properties,
performance and integrity of the alloy
casting. The traditional approach has been to
look at the process of crystal growth as metal
cools, but this has been replaced with a focus
on nucleation, the effect that microscopic
impurities in the metal have on the solidification
process. By controlling the interface at
a microscopic level between the liquid metal
and the impurity particles, the characteristics
of the solidified metal casting can be manipulated
to produce the required properties. The
aim is to produce materials and components
with fine and uniform micro structure, uniform
chemical composition and reduced or
eliminated cast defects.
The AMCC will be housed in a 1,000 m 3
laboratory on Brunel’s campus in west London,
with industrial partners, including Constellium,
providing funding as well sponsoring
Research Fellows and providing technical support.
The centre will initially serve the automotive
industry, but the longer term aim is
to extend its knowledge to other engineering
sectors.
UK Minister for Universities and Science
David Willetts says: “For Britain to get ahead
in the global race we have to back emerging
technologies and ensure our universities have
... of aluminium casting technology
the latest equipment. This capital investment
will help scientists make new discoveries and
take their research through to commercial
success. It will drive growth and support the
Government’s industrial strategy.”
Ken Stanford, contributing editor
ALUMINIUM · 11/2013 59