CHICAGO General Motors
Co. is testing a thermal-forming process and proprietary
corrosion-resistance treatment for magnesium sheet that would
allow the automaker to increasingly use it as a substitute
for steel and aluminum.
GM said that it wants to expand
its use of low-mass parts on its vehicles and that it will
pursue licensing opportunities related to this technology. The
goal is for suppliers to use the process to produce a
significant volume of magnesium parts in order to trim pounds
from vehicle mass.
Magnesium weighs 33 percent less
than aluminum, 60 percent less than titanium and 75 percent
less than steel, according to GM.
Until now, carmakers have
struggled to make reliably strong and non-corroding magnesium
sheet panels. GMs patented process heats magnesium to 842
degrees Fahrenheit, which allows the material to be molded into
precise, rigid shapes.
The Detroit-based company has
built a production-ready magnesium rear deck lid inner panel
that withstood 77,000 robotic slams and 250-kilogram impact
drops without any issues.
Die-cast magnesium has
historically been used in multiple critical parts, but GM
claims that this is the first time thermal-formed magnesium
sheet has been used in structural applications. The company
expects magnesium sheet applications to grow with additional
materials and process improvements.
On the production-ready rear
deck lid inner panel, GM said that it can remove 2.2 pounds of
weight compared with an aluminum deck lid inner panel.
"Every gram of weight reduction
matters," Greg Warden, GMs executive director for global
vehicle body engineering, said in a statement. "Being able to
replace heavier metals with one of the lightest will help us
deliver better fuel economy while still providing the safety
and durability (customers) expect."
Separately, the companys research and development team
recently developed a welding technology for aluminum which is
expected to facilitate the use of that material in future