Solid State Spot Welding of Lightweight Alloys

The recent concern about climate change has stimulated research into transport energy efficiency in order to reduce the emission of gases. One of the main solutions is to reduce the structural weight through the application of new materials, such as aluminum and magnesium lightweight alloys. However; new applications are often limited by the difficulty of joining these materials. Friction Stir Welding (FSW) is a solid state joining technique that emerges as a viable alternative to replace or complement the established joining technologies. As a continuous weld is not always requested, two spot welding technologies derived from FSW are under development: Friction Stir Spot Welding (FSSW) and Friction Spot Welding (FSpW). Besides providing almost defect-free and high strength joints, these techniques exhibit high energy efficiency short welding cycle, ease of automation and environmental compatibility, competing against the conventional spot joining techniques, such as Resistance Spot Welding (RSW) and riveting.