Effect of processing parameters on the strength of keyhole free friction stir spot aluminum welds

Abstract

Intermediate layer friction stir spot welding (IL-FSSW) is a new solid-state welding method appropriate for making spot joints, particularly in light-weight materials, especially notable on account of the weight saving opportunity. Using a welding tool consisting of a non-consumable flat rotating pin, joint between overlapped sheets are fabricated, including an intermediate layer in the middle that eliminates keyhole formation. This study investigates the effect of IL-FSSW parameters on the lap shear strength of 1 mm thick 6061 aluminum alloy joints. Parameter optimization was performed via experimental design based on the Taguchi method and the analysis of variance method was used to identify the importance of each process parameter on the resulting joint strength. The outcome of this work demonstrated that the tool rotational speed has the major effect followed by the tool descending depth and the welding feed rate.