General Motors announced today that it is testing a thermal-forming process and proprietary corrosion resistance treatment for lightweight magnesium sheet metal — an industry-first. This is awesome, as it allows for increased possibilities for high-strength, light-weight alternative uses to both heavier aluminum and steel sheetmetal. And with weight reduction comes enhanced fuel economy.
Specifically, magnesium weighs 75 percent less than steel, 60 percent less than titanium, and 33 percent lighter than even aluminum. And most of us know how light aluminum can be.
Magnesium sheetmetal is produced differently than conventional die-cast magnesium shapes, which range from engine cradles to paddle shifters. Historically it’s been a struggle for the entire auto industry to make reliable, strong and non-corroding magnesium sheetmetal panels using traditional panel-forming methods. But GM’s new patented process turns up the heat on magnesium to 450 degrees Celsius (842 degrees Fahrenheit), allowing the material to be formed into sturdy and precise shapes.
The photo above showcases a magnesium the inner panel of a rear deck lid that went through 77,000 robotic slams, and 250-kilogram impact drops without failing. And it’s a production ready example. GM says that replacing a conventional steel rear deck lid panel will yield 1 kilogram (2.2 pounds) of weight loss. Apply that throughout an entire vehicle, such as, say, the 2014 Chevrolet Silverado, and we could see amazing weight savings. As with aluminum or titanium, our only concern is keeping magnesium cost-effective.