Probing residual stresses in stationary shoulder friction stir welding process

Abstract

Stationary shoulder friction stir welding (SSFSW) is a new variant of the conventional FSW with rotation of only the tool probe to reduce the rate of heat generation along the tool–workpiece interface and hence, weld joint residual stresses. Studies on the evolution of residual stresses in SSFSW are rare as the process is new. A detailed investigation on the evolution of welding-induced residual stress is reported here for SSFSW and the conventional FSW of four different aluminum alloys. A finite element method–based numerical model, JWRIAN-Hybrid, is used for the three-dimensional heat transfer and thermo-mechanical stress analyses. The computed results are validated extensively with the corresponding experimentally measured results. The results show approximately 10% to 20% reduction in the peak residual stresses in SSFSW under identical welding conditions.