Page 52 - Best of 2019 English

Steel/others
SResearch dedicated to safety
alzgitter AG develops and optimizes high- the manufacturers’ designers new steel grades for strength steel grades for automotive engi- new vehicles to be produced in the future. There’s neering, enabling the production of compo- no way car makers can avoid looking into the
nents with reduced sheet thickness that are equally availability of new steels before a new vehicle is de-
softer deep- drawing steel
high-strength steel
strong – or indeed stronger. As a result, body areas can be designed to be more rigid and therefore safer. Multiphase steels with maximum strength in particular absorb a great deal of energy due to their plastic deformation capacity. They are used
for safety-related structural components in numerous series-produc-
tion vehicles.
veloped. As a rule, a Salzgitter Flachstahl (SZFG) and SZMF team meets with the manufacturers’ vehicle designers once or twice a year.
This collaboration is vital in terms of the safe- ty-related design of load paths (see page 50). The body parts are produced from various steel types: a total of up to 100 different types are likely to
be found in any given car – the exact number is difficult to determine.
High-strength steel grades are also essential in the chassis since it is subject to high loads. But the sheets used for the vehicle outer shell are of sec- ondary importance in terms of safety. The only ex- ception is the engine hood, as is well known: it has
to give way so as to offer pedestrians maximum protection in the event of an accident, but it mustn’t impact on the engine below.
This is why the hood is combined with an internal stiffening plate.
Designers are given a specifica- tion sheet containing full details to familiarize themselves with all the properties of the steel types.
Digital documentation of the material is particularly important.
“Every steel grade has to be available in digital form and have a virtual twin,” says Ansgar Geffert, Head of the Engineer-
ing and Simulation Department at Salzgitter Mannesmann Forschung GmbH. His department maps out the physical parameters of each steel grade as data and collects this in the form of so-called material cards, enabling vehicle devel- opers to calculate and test their designs by way of simulations.
The question remains as to how future steel grades will develop in future to make cars even safer. “Strength will certainly continue to increase,”
as Michael Braun is convinced. “But new steels will have to remain formable too, of course.”
E-mobility will not make any dif- ference here – on the contrary: Far more, Michael Braun and Ansgar Geffert perceive opportunities for Salzgitter Flachstahl in connection with electro-mobility. “Just the bat- tery box and its protection require some 70 to 80 kg more sheet steel per vehicle than vehicles powered by combustion engines,” says Michael Braun. This makes electric cars heavier, meaning that their chassis has to be more resilient.
As a result, demand for innovative types of steel and manufacturing processes is likely to increase.
A Mercedes M-Class exemplifying the use of different high-strength steels: More than 62 % of all bodyshell panels are made of high-strength steel alloys
Salzgitter Mannesmann Forschung GmbH (SZMF) is largely responsible for the development of new steels.
Asked how often new steel grades become avail- able for automotive engineering, Michael Braun, Head of the Applications Technology Department at SZMF, replies: “Let me put it this way: we offer
Experts of Salzgitter Mannesmann Forschung: Michael Braun (left) and Ansgar Geffert
52 STEEL AS A LIFE-SAVER
Photo: Carsten Brand
Photo: © Daimler AG