| General Motors has announced that it is testing a new process for forming magnesium sheetmetal panels that will allow it to make thinner, stronger, and lighter pieces than the competition. Before you declare this story too snooze-worthy, keep in mind that magnesium is much lighter than aluminum or steel, and its expanded use in automotive applications not only would benefit fuel economy but performance, too. Currently, most magnesium parts are die-cast (like the fixed-roof structure for the Corvette Z06), meaning only parts with a significant section thickness can be rendered from the stuff. GM's new thermal-forming process for magnesium enables the company to shape thin structural panels from the lightweight material. Automakers have been using magnesium for a long time—recently, BMW's engine blocks incorporated the material, portions of the Porsche Panamera's unibody and door frames are made up of the stuff, and even the epic Chevrolet Corvette SS 1960s race car used magnesium body panels—but GM's breakthrough here is in the process by which it is manufactured into thinner parts. Basically, instead of casting molten magnesium into shapes—the process of die-casting—GM's thermal-forming process involves heating up magnesium sheet stock to 842 degrees fahrenheit before molding it. Besides developing a new way to make magnesium bits narrower, GM claims it has solved magnesium's corrosion sensitivity—the metal doesn't play nice with salt—by drumming up a new corrosion-resistant treatment. Given that cars that exist in the snow belt annually encounter a Red Sea's worth of road salt, making sure future magnesium parts can handle such adversity clears a major production hurdle. To prove its new magnesium thermo-forming chops, GM is showing off a new, production-ready inner trunklid panel. Exciting stuff, this isn't, but, again, we implore you to focus on the incremental value of switching mundane car parts like the inner decklid skin from steel or aluminum to lighter goods like magnesium. GM says this piece alone saves 2.2 pounds—extrapolate that to many, many more sheet metal pieces like inner door skins or hood liners, and that's quite a few more pounds of weight saved.
Speaking of GM's fancy "production-ready" decklid liner, it isn't immediately clear which production model it belongs to. According to GM, the part is going into limited production by the end of this month. On what, you may ask? The company only told us that the inner trunk-lid skin would grace an existing model on a different continent. Read full story »  from Car and Driver Blog http://blog.caranddriver.com | |||
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