Canadian Manufacturing

GM testing lightweight magnesium sheet metal for future auto production

Magnesium weighs 33 per cent less than aluminum, 75 per cent less than steel, automaker says

DETROIT—GM is looking to make good on R&D promises from its bailout deal, as the Detroit automaker says it is testing the use of magnesium sheet metal for use on its vehicles.

In what GM is calling an industry-first “thermal-forming process and proprietary corrosion resistance treatment” for lightweight magnesium sheet metal, the automaker hopes to increase use of the high-strength alternative to steel and aluminum.

Magnesium weighs 33 per cent less than aluminum, 60 per cent less than titanium and 75 per cent less than steel, according to GM.

Until now, automakers have struggled to make reliably strong and non-corroding magnesium sheet metal panels using traditional panel forming methods.

Automakers also have struggled to make magnesium corrosion resistant.

GM says its proprietary treatment for thermal-formed magnesium resisted 10 consecutive weeks of 24-hour environmental tests involving salt spray, 100 per cent humidity and extreme temperatures.

While die-cast magnesium has been used in a number of parts already used in the automotive world—from steering wheels to engine cradles—GM says it is the first 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.

“This innovative use of magnesium is just one example of how GM is leveraging breakthrough technologies that will benefit our customers around the globe,” GM chief technology officer and vice-president of global R&D Jon Lauckner said in a statement.

“Using high-strength lightweight materials such as magnesium and aluminum is one of the most effective ways to improve vehicle fuel economy and driving performance.”

The United States Automotive Materials Partnership (USAMP) estimates that by 2020, 350 pounds of magnesium will replace 500 pounds of steel and 130 pounds of aluminum per vehicle, an overall weight reduction of 15 per cent.

GM says the trimmed weight would lead to fuel savings of nine to 12 per cent.

“Every gram of weight reduction matters when it comes to improving fuel economy,” GM executive director for global vehicle body engineering Greg Warden said. “Being able to replace heavier metals with one of the lightest will help us deliver better fuel economy to customers around the world while also still providing the safety and durability they expect.”

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