Bypass-current plasma arc welding of aluminum alloy: thermal behavior, residual stress, and distortion

In this study, bypass-current plasma arc welding (BC-PAW) was innovatively proposed to join aluminum AA 5083 alloy. A comparative analysis between simulation and experimental results was performed to further explore the effects of bypass-current on the thermal behaviors, residual stress, and distortion of as-received weld. The results show that adding bypass-current in plasma arc welding is beneficial to the welds, and it helps to reduce the heat input into the workpiece and subsequently improve the weld thermal concentration. In addition, due to the bypass-current induced less heat flow density, the residual stress of the as-received welds can be reduced maximumly to 22 MPa, contributing to a significant improvement in the weld distortion. The research work develops a new route to the welding field, and has a significant contribution to further welding aluminum process improvement and optimization.