In what seems like a never-ending quest to decrease the weight of automobiles, General Motors has announced that its Research & Development center has invented a welding technology that is expected to facilitate increased use of aluminum in future vehicles.
The new resistance spot welding process is an industry-first method to weld aluminum; the technique uses a patented multi-ring domed electrode that is able to do what smooth electrodes are unreliable in doing — welding aluminum to aluminum. The use of the welding technique can result in the elimination of two pounds of rivets from aluminum body parts (like hoods, liftgates, and doors) — eliminating the cost of adding rivets that are limited to the restricted range of joint configurations found on riveting guns. In addition, the rivets in aluminum parts make end-of-life-recycling more complex.
Using two opposing electrode pincers to compress and fuse pieces of metal together, spot welding utilizes an electrical current to create intense heat and form a weld. The process, according to GM, is inexpensive, fast, and reliable — and, until now, there was no way to robustly use it in a manufacturing environment. As such, the technology will give The General a unique manufacturing advantage that will grow in importance in the future. More importantly, the increased use of aluminum in vehicles promises to result in improved fuel economy and driving performance characteristics, such as acceleration, handling, and breaking.
Currently, the resistance spot welding process is already in place on the Cadillac CTS-V as well as the liftgates of the Hybrid variants of the Chevy Tahoe and GMC Yukon, but GM has plans to establish a more large-scale use of the technology in 2013.
Industry analysts expect the use of aluminum in vehicles to increase significantly over then next decade thanks to the specific promise of decreasing vehicle mass. A kilogram of aluminum, for instance, can replace 2 kilos of steel — effectively having the ability to cut a car’s weight in half. Aluminum also has other desirable properties: it’s corrosion resistant and offers substantial tensile strength at a low mass.
General Motors said it is open to licensing the welding technology for non-GM use in auto, heavy truck, rail and aerospace applications.