TK Stainless

94 MaGaZine high-performance materials
in eXhausT sysTeMs for motor vehicles,
titanium helps reduce weight.
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MaTeriaLs FroM ThyssenKrupp TiTaniuM
MaKe Cars eCo-FrienDLier
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The future limits to be placed on CO 2 emissions are forcing auto manufacturers
to rethink their designs. They have recognized that particular improvements
can be achieved by reducing body weight. “There’s an increasing acceptance
that more has to be invested in lightweight construction,” says Dr. Jürgen
Kiese, head of research and development at ThyssenKrupp Titanium in Essen.
“The advantages offered by titanium are so great that it is worth using the
material in cars despite its higher costs.” Exhaust systems made of titanium
can frequently cut weight by tens of kilograms. Specially for this application,
ThyssenKrupp Titanium has developed the alloy Ti-X which includes the
relatively low-cost elements iron and silicon.
“Unlike commercially pure titanium, which cannot be used at very
high temperatures, the new material is a high-temperature alloy that is also
resistant to oxidation and can be used at temperatures up to 750 degrees
Celsius,” explains Kiese. To enhance the alloy for use at higher temperatures
up to 1000 degrees Celsius, ThyssenKrupp Titanium developed a thin aluminum
cladding which is applied to the alloy as a special protective layer. “This
layer protects the material against oxidation under high thermal loads and
makes it suitable for use in the hot parts of exhaust systems close to the
engine,” says Kiese.
Titanium has the same strength as steel, so the advantage of
production use in auto construction would be its significantly lower weight,
which in turn helps reduce emissions. For manufacturers of exhaust systems,
who are currently testing the new material, this opens up unprecedented
opportunities. That’s why Kiese is positive about the future: “As the material is
also particularly low in price, we see great opportunities to increase its use in
automotive applications.“ --