Evaluation of Friction Spot Welds in Aluminum Alloys

The Friction Spot Welding (FSSW) process as invented by GKSS in Germany has shown potential for application in several industrial fields as a solid state joining technology. This study evaluates this “refill” method of friction spot welding in aluminum sheet. Efforts to date have concentrated on simple flat lap joints. Process and tool development studies have been performed and have focused on understanding and managing material flow in order to minimize flash, ensure full consolidation and produce a nearly flush surface. The metallurgical and mechanical properties as a function of tool geometry and processing parameters are discussed and the lap shear strength is shown in this preliminary work to compare favorably to riveting and resistance spot welding.