Factors Affecting the Properties of Swept Friction Stir Spot Welds

In this study, the factors involved in producing a swept friction stir spot weld (FSSW) are investigated to determine their effect on mechanical properties and weld joint morphology. The essential variables involved in producing linear friction stir welds (FSW), namely tool rotation speed, travel speed, and plunge depth, are also significant variables in producing swept FSSW. In addition to these variables, placement of the advancing side, spot diameter, lead angle, and start/stop location can also be influential. A design of experiments (DOE) approach was used to investigate the effect of each of these variables based on unguided lap shear tensile strength and examination of the metallographic cross sections in 1 mm (0.040-in.) thick 7075 and 2024 aluminum alloys.