GM develops new resistance spot welding process for aluminumEnlarge Photo
General Motors has developed what it says is an industry-first aluminum welding technology, which allows it to use more aluminum in the construction of its cars rather than heavier conventional materials. This will lead to lighter and more fuel efficient cars from the automaker going into the future.
The new welding technology uses a patented multi-ring domed electrode that does what smooth electrodes are unreliable at doing--welding aluminum to aluminum. By using this process, GM expects to eliminate nearly two pounds of rivets from aluminum body parts such as hoods, liftgates and doors.
It works on sheet, extruded and cast aluminum because the multi-ring domed electrode head disrupts the oxide on aluminum’s surface to enable a stronger weld. Previously, for joining aluminum components, GM had to use self-piercing rivets.
However, rivets add cost and riveting guns have a limited range of joint configurations. In addition, end-of-life recycling of aluminum parts containing rivets is more complex.
GM already uses the new process on the hood of the Cadillac CTS-V and the liftgate of the hybrid versions of Chevrolet Tahoe and GMC Yukon, though by next year we should be seeing a lot more GM cars using the special welders in their construction.
Aluminum offers many advantages over steel. Aluminum is corrosion-resistant and offers an excellent blend of strength and low mass that can help improve fuel economy and performance. In fact, on average, every pound of aluminum used in a car’s construction can replace two pounds of steel.