GM tests magnesium

Magnesium sheet metal may soon appear in GM vehicles

The technology could help reduce fuel costs

General Motors is testing a thermal-forming process and proprietary corrosion resistance treatment for lightweight magnesium sheet metal. This process—the first of its kind in the automotive industry—will allow GM to increase the use of magnesium as a high-strength alternative to steel and aluminum.

According to a press release from the company, GM wants to expand its use of low-mass parts on vehicles, and the company plans to pursue licensing opportunities related to the new technology. The goal is for suppliers to be able to use the process to provide significant amounts of magnesium sheet, which will decrease the weight of each vehicle.

Magnesium weighs 33 percent less than aluminum, 60 percent less than titanium and 75 percent less than steel. When used with more efficient conventional engines and electric powertrains, the magnesium could help reduce fuel costs for customers.

In order to prevent erosion, GM’s patented process heats magnesium to 842 degrees Fahrenheit. This also allows the material to be molded into precise, rigid shapes. Additionally, GM’s proprietary treatment for thermal-formed magnesium resisted 10 consecutive weeks of 24-hour environmental tests involving salt spray, 100 percent humidity and extreme temperatures.

Using this process, GM developed a production-ready magnesium rear deck lid inner panel, which withstood 77,000 robotic slams and 250-kilogram impact drops.

On the production ready rear deck lid inner panel, GM can remove 1 kilogram (2.2 pounds) of weight compared to a steel deck lid inner panel.

The United States Automotive Materials Partnership estimates 350 pounds of magnesium will replace 500 pounds of steel and 130 pounds of aluminum per vehicle—an overall weight reduction of 15 percent—by the year 2020. This decrease in weight would lead to 9 to 12 percent in fuel savings.   

Although die-cast magnesium has already been used in a variety of parts such as steering wheels and engine cradles, GM is the first to use thermal-formed magnesium sheet metal in structural applications.

To read the full press release, click here.

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