Forget German car maker Audi, it is now American car maker General Motors that is shaping the world of lightweight car design. At a recent press conference in Detroit, General Motors let us know that they were testing an industry-first thermal-forming process and proprietary corrosion resistance treatment for lightweight magnesium sheet metal that will allow increased use of the high-strength alternative to steel and aluminum.
The goal is for suppliers to be able to use the process to provide significant amounts of magnesium sheet that will trim pounds from vehicle mass. The use of magnesium, which weighs 33% less than aluminum, 60% less than titanium, and 75% less than steel, will help customers save money at the gas pump, as will more efficient conventional engines and electric powertrains.
GM’s patented process turns up the heat on magnesium to 450 degrees Celsius (842 degrees Fahrenheit), allowing the material to be molded into precise rigid shapes, which was very hard to do in the past. Using this process, GM has developed 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 been used in the past in a variety of parts ranging from steering wheels to engine cradles, but GM is the first car maker to use thermal-formed magnesium sheet metal in structural applications, and it expects magnesium sheet applications to grow with additional materials and process improvements targeted at reducing cost.
