March 2014
44
Automotive
How low can they go? ‘Lightweighting’
pervades the rivalry between steel and
aluminium for rst place in Detroit
“As we methodically eliminate the lightweighting advantage of
alternative materials, we increase both the cost advantage of our
material and the life cycles emissions advantage of our material.”
Speaking at a press conference during the North American
International Auto Show (18
th
-26
th
January in Detroit), Lawrence
W Kavanagh, president of the Washington-based Steel
Market Development Institute (SMDI), seemed con dent of the
continued pre-eminence of steel in automobile manufacturing
despite the steady incursion of aluminium alloys and carbon
bre.
As reported by Nathan Laliberte in
American Metal Market
,
Mr Kavanagh pointed to the 2014 Cadillac ATS. Advanced
high-strength steels (AHSS) account for some 40 per cent of
the vehicle, he said. At an average strength of a little over 400
megapascals – down from the 800 megapascals stipulated in
the WorldAutoSteel “Future Steel Vehicle” project of 2007 – the
steels in the ATS provided an example of the lightweighting
that has become the watchword of the contest between steel
and aluminium for preferment with major auto makers. (“Steel
Unfazed by Auto Aluminum Gains,” 16
th
January)
In an interview with
AMM
, Cadillac’s chief engineer for the ATS,
Dave Masch, described the multiple grades of AHSS utilised in its
design. These include steels, in front in the motor compartment
rails, meant to withstand high crash deformation; ultra-high
strength steels in the side frame; and others in the B-pillar, the
rocker, and in the roof-pillar areas of the vehicle. He also noted
that the ATS utilises lower-grade steel for some of the body
panels – “speci cally to get crisper lines and for formability
reasons.”
But while steel will continue to be heavily featured across the
Cadillac array, Mr Masch acknowledged to Mr Laliberte that
aluminium is not without its attractions. In fact, almost the
entire front suspension of the ATS is aluminium, and its use
by the company will likely increase over the next few years.
According to Mr Masch, “purposeful material application” –
informed by considerations of lightweighting, fuel e ciency and
performance – will guide the selection, every time.
AMM
reported that Mr Kavanagh of SMDI closed the
press conference at the auto show with a warning about
end-of-life issues with aluminium-bodied vehicles.
Aluminium manufacturers will, he said, struggle to properly
recycle their material: “They can’t achieve the recycling they
want to without a great increase in demand, and they can’t
achieve the emissions drop they want to without a great
increase in recycling.”
He proposed a way to avoid a ‘Catch-22’ situation: “With steel,
you melt it, you build it, you use it, you melt it, it becomes
something else. There’s no issue there.” In Mr Kavanagh’s
view the argument for the use of aluminium in automotive
applications is only persuasive if its proponents make “a big
gain in market share.”
Signs are strong that that is exactly what the aluminium
people have in mind.
In brief…
Possibly the greatest attention-getter at the Detroit auto
show was not a sleek newcomer but the new Ford F-150,
the workhorse pickup truck which for years has commanded
the top of the sales charts in its category. While not notably
di erent in appearance from the previous model, the 2015
F-150 has a body built almost entirely of aluminium – for a
weight savings of up to 700 pounds.
Ford claims that its star is tougher, smarter and more
capable than ever. And the new version can be expected to
deliver dividends in performance, handling characteristics,
e ciency and, of course, corrosion resistance.
But whether the reduction in weight will tip the balance
in the competition between steel and aluminium for
automotive applications is an open question. The full-size
truck body of the F-150 still sits on a steel chassis.
“What is most surprising in these data is that the automotive
industry – which less than ve years ago was struggling
with declining sales, bankruptcy, government bailouts
and quality issues – is today seen by nearly six in ten
Americans as being a driver of innovation,” said Billy Mann,
the president of global market research rm Penn Schoen
Berland (PSB). “Clearly, the American people believe the
industry has rebounded and are optimistic about its future.”
(
BWWGeeksWorld.com
, 19
th
January)
The reference was to a nationwide online survey of 1,000
American consumers conducted 2
nd
-6
th
January by PSB,
which disclosed a widely held conviction that the domestic
automotive industry is as strong a driver of innovation as
technology, telecommunications and energy. According
to the study, commissioned by Ford Motor Co, more than
Transatlantic Cable
Image: www.bigstockphoto.com Photographer Zsolt Ercsel
