Effect of pin length on Friction Stir Spot Welding (FSSW) of dissimilar Aluminum-steel joints

Abstract

In the last years Friction Stir Welding has produced a big impact on several industries due to its advantages. Particularly,automotive industry has developed a variant of the original process named Friction Stir Spot Welding (FSSW), having a stronginfluence on welding of thin sheets of aluminum alloys and dissimilar materials. Nevertheless, the knowledge about the influenceof welding procedure on joint characteristics is scarce, mainly for dissimilar materials. The aim of this work was to study theeffect of the tool penetration depth during welding, as well as, the relative position of the materials used in the superimposedjoints, when AA5052-AA6063 sheets samples were welded. Tool penetration depths between 0.05 and 1.25 mm were analyzed,for both materials positions. Macrostructural and dimension characterization, microhardness profiles and Peel tests (PT) weredone for different conditions. The fracture loads in PT increased with the tool penetration depth for both material positions, beinghigher when AA6063 was the upper material. However, the tool penetration depth has a limit in the increasing of fracture load,for which the fracture mechanism changes from interfacial to circumferential.