Automakers interested in reducing the weight of their cars know that swapping out steel parts for aluminum ones saves weight. But General Motors is currently working with an even lighter material – magnesium-- to form into sheet metal panels, and saving even more weight in the process.
Magnesium has never been a very easy material to work with, but it's still used in parts like engine cradles and steering wheels. Until now, it's been extremely difficult to process magnesium into sheet metal, but General Motors' new method heats the metal to over 800 degrees Fahrenheit, which allows workers to bend the newly flexible, hot metal into a defined form. The process is not necessarily efficient in the short term--it takes twice as many BTUs to heat up magnesium as, say, carbon steel--but swapping out steel or aluminum parts for magnesium ones would increase long-term efficiencies.
That's because magnesium parts or sheets weigh one third less than aluminum, 60 percent less than titanium, and 2/3 less than steel. The US Automotive Materials Partnership estimates that 350 pounds of magnesium parts and sheets can replace 630 pounds of aluminum and steel. All heavy automotive parts (including things like engines, running gear, and safety features) considered, magnesium could be the driving metal behind a 15 percent weight reduction in cars over the next decade.
That all leads to one question: if General Motors is marching out new magnesium panels now, where are we going to see this metal in GM’s lineup? For research and development purposes, GM created a trunklid inner panel (which sits under the trunk's exterior sheet metal), and the final product weighed one pound less than a steel one while also delivering the same strength. The use of a trunklid would lead us to believe that the first application could be a passenger car, but it's likely that we'll see extensive use of the new magnesium panels on the new 2014 Chevrolet Silverado and 2014 GMC Sierra pickup trucks. Like the Ford F-150, the Chevrolet Silverado must go on a diet to increase fuel economy, and we've heard that GM is working on improving the Chevrolet Silverado's small-block V-8 and reducing its curb weight to gain meaningful savings at the pump.
What do you think--is magnesium "in?" And if it is, where are we likely to see it on the General Motors lineup?