ThyssenKrupp Magazin

duce a car’s weight by about 100 kilograms, resulting in better fuel
economy and less pollution. Magnesium is not, however, a simple material,
and has a relatively low melting and boiling point. When heated
under exposure to air, it burns into magnesium oxide from about 500 degrees
centigrade with the characteristic blinding white flame. Still, magnesium
only appears hazardous to those who know too little about it, explains
Engl, who holds a doctorate in material and forming engineering.
Obviously, the melting and processing center in Freiberg knows
about magnesium’s reaction to extreme heat, and the team has put in
place comprehensive precautionary measures. Liquid magnesium is
processed only in a gas-shielded atmosphere, with three-level security.
Yet magnesium is a problematic material only in its liquid form, whereas
a magnesium body is actually less flammable than other vehicle
parts. And when individual components in a car are made of magnesium
the material also does not represent a risk, according to Engl; at
a fire, firefighters will initially struggle with materials much more prone
to be ignited.
The precautions that have to be taken in magnesium processing
are therefore not the reason why so few parts in a vehicle are currently
made of magnesium: the reason is that magnesium sheets are still too
expensive.
In fact, only about 1 percent of magnesium produced worldwide is
used in sheets, although there is more than enough magnesium around.
While “Mg” does not exist in its elementary form, but only in compounds,
it is found everywhere, for example in the earth’s crust or in the mineral
dolomite, of which the Dolomite Mountains of northern Italy are made.
And also in the sea: when sea water is desalinated to obtain drinking
water, a large amount of magnesium chloride is a by-product, and
by using this refuse to produce magnesium, two birds are killed with
one stone; not only is there no cost for storing or disposing of the
“refuse,” but processed magnesium is every recycler’s dream, since it
can be easily remelted.
A raw material with
no volume problems
TK Magazine | 1 | 2004 |
MAGNESIUM 99
Engl confirms that there is no shortage of magnesium as a raw
material, but because pricing uncertainty renders estimates regarding
the use of magnesium sheets in cars highly unpredictable, one of the
key tasks of the Freiberg research group is to find out at what price
ThyssenKrupp can offer magnesium sheets. Since the company cannot
influence the world market price of this material, its research team
has to develop ideas and optimize plant level processes intelligently.
Together with the University of Freiberg, ThyssenKrupp has thus
developed – and filed an application to patent – a casting-rolling technology
that allows for the industrial production of top-quality magnesium
sheets that can sell for less than the sheets now on the market.
ThyssenKrupp already knows that this is possible, and that its sheets,
with their measurements and consistency, could be put to immediate
use. For at a maximum 1.3 millimeters, the sheets are relatively thin,
but nonetheless stable. The first deep-drawn test components that Engl
can present prove that magnesium components do not have to be cast;
from the technical side, then, nothing stands in the way of using magnesium
sheets.
The problem lies on the sales side, because it is the customers
who decide whether magnesium sheets will be accepted in substantial
volume for lightweight assembly and can therefore be offered at prices
that are competitive with other materials. It is precisely this issue,
though, that has so far proven difficult: one would have to know, for example,
how many sheets a carmaker would be prepared to buy, and at
what price.
As soon as auto makers fully understand the advantages of this
material, the first manufacturers could be using ThyssenKrupp magnesium
sheets in serial production. And when used in the automotive and
aviation industries, the new sheets offer an immense diversity of applications,
from hoods, roofs and dash panels to seat pans.
In other words, magnesium is one lightweight that can look forward
to a great future. 7