Investigation of Shear Strength of the Bonding Region for Dissimilar Aluminum Alloy Sheets in Friction Stir Spot Welding Process

Compared to the resistance spot welding (RSW) process, Friction stir spot welding (FSSW) is an ideal process for aluminum alloys. In this study, the effect of welding parameter such as tool penetration depth, tool rotational speed, tool penetration speed and the arrangement of aluminum alloy sheets of 7075-T6 and 2024-T3 on the shear strength of the joining zone in the friction stir spot welding process have been investigated. By properly choosing these parameters, the optimum shear strength of the joint can be attainable. The result of the shear test showed that the increase of tool rotational speed from 800 up to 1250 rpm caused the increase of shear force, However further increase up to at 1600 and 2000 rpm resulted in the decrease of the shear force. By increasing in tool penetration depth, shear force increases. If the alloy Al2024 -T3 is selected to be the upper plate, the connection will have better shear strength.