High-productivity and high-strength Fe/Al dissimilar metal joining by spot forge welding

Abstract To develop a high-productivity dissimilar joining technique, which is highly sought after in the automobile assembly process, I developed a new method based on spot forge-welding. In the lap joint of 1-mm-thick SPCC steel and A5083 aluminum plates, within the 10-mm forge diameter, a base metal fracture occurred at a reduction ratio R of 1.8. The maximum tensile-shear load reached 3.8 kN during the approximately 80-ms forge welding process. The newly formed surface at the bonded interface exhibited a mesoscopic reaction layer, in which the brittleness was minimal given the short diffusion time. Thus, this approach shows great potential to replace conventional resistance spot welding for next-generation solid-state spot welding of dissimilar joints, for high-throughput welding applications and high-strength joints.