News Column

GM Light, Aluminum Spot-on Works

Sept. 24, 2012

Nathan Bomey

Cadillac CTS-V sedan. Photo courtesy of Cadillac.
Cadillac CTS-V sedan. Photo courtesy of Cadillac.

General Motors plans to accelerate the replacement of steel with aluminum after researchers achieved what the company described as a "breakthrough" in welding technology.

GM hopes the technological advancement will boost fuel economy by making its vehicles lighter. Aluminum is lighter than steel, making it an enticing alternative when it is not too expensive. But several hurdles remain for aluminum, including production challenges.

GM believes it has solved one of those challenges: the frustrating process of welding aluminum body panels.

Blair Carlson, GM's lab group manager for lightweight material processing, said researchers at the company's technical center in Warren developed a spot-welding technology that uses a special electrode to help two pieces of aluminum clamp together.

He said the technology also involves a proprietary process for controlling electrical current and cleaning the electrodes, which use protruding rings to pierce the hard oxide surface of aluminum, enabling the metals to fuse together.

GM has already used the technology to use aluminum in the hood of the Cadillac CTS-V sedan and the lift gate of Chevrolet Tahoe and GMC Yukon hybrids.

"There's going to be a significant increase in the application of aluminum in our vehicles in the next five years," Carlson said. He declined to say how much weight GM believes it can save in the average vehicle using the technology.

Carlson said researchers happened upon the spot-welding technology by accident when they experimented with software during a test.

"As it turned out, it was like, 'Wow, that really worked, what did we do?' " Carlson said. "We had to go back and figured out what we did, and that actually led to a breakthrough in one of our patents in the area of controls."

GM has dabbled in aluminum welding before, dating back to the EV1 in 1996 and some SUVs in 1999. But the process needed to be refined.


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Source: (c)2012 the Detroit Free Press. Distributed by MCT Information Services