Self-Reacting Friction Stir Welding of Al–Zn–Mg Aluminum Alloy

Three millimeter thick plates of 7039 aluminum alloy were welded with the Self-Reacting Friction Stir Welding process to assess the feasibility of such welding. Heat-treated hot working steel was used to develop and manufacture the welding tool. To achieve a defect-free joint, the influence of different process factors such as the shoulder pinching gap, tool transverse speed, and tool rotation speed is examined. Following the welding procedure, non-destructive techniques such as visual inspection and X-ray radiography were used to validate the welds' integrity. According to the transverse tensile test findings, the as-weld joint efficiency was 76%, increasing to 80.4% after natural aging. The tensile test pieces failed from the HAZ, because the joining region was flawless. Furthermore, the weld grain size was significantly smaller than the base metal grain size. The weld's hardness was likewise somewhat lower than the base metal's hardness, and the zones with the lowest hardness were associated with heat-affected zones.