Audi 2012 Annual Report Download - page 70

The body’s steel-aluminum
composite construction helps
to reverse the weight spiral.
It weighs around 15 percent
less than comparable all-steel
constructions. More than
one-fifth of the body is made
of aluminum, including the
doors, engine hood, rear hatch
and multiple cross-members
and cross-bars. Hot-shaped,
high-end steels also make up a
large portion of the body. They
are heated to nearly 1,000
degrees Celsius in a continuous
furnace and then shaped in a
water-cooled pressing tool at
around 200 degrees Celsius.
The change in temperature
imparts the material with
tremendous tensile strength
despite its relatively low
weight. The hot-shaped steels
are used at the transition
from the front end to the
cabin, in the A- and B-pillars
and as floor bracings. Joining
technologies such as bonding,
punch riveting or clinching
– a technique which enables
two pieces of sheet metal to
be joined without additional
components – are used in
order to attach the materials
together precisely and without
corrosion.
Steel, aluminum, CFRP: The body of the Audi TT ultra concept represents
the ideal combination of the materials according to the ultra principle.
Pioneers of
lightweight
construction
at Audi: Peter
Fromm, Head of
Body Development
(top left), Heinz
Hollerweger, Head
of Total Vehicle
Development
(top right) and
Dr.-Ing. Lutz-Eike
Elend, Head of the
Audi Lightweight
Design Center.
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