Effect of external magnetic field on resistance spot welds of aluminum alloy

Abstract External magnetic field (EMF) has been demonstrated to have significant effect on the improvement of welding quality in the resistance spot welding (RSW) of dual-phase steel. However, very little work in open literature studied the influence of the EMF on the resistance spot welds of aluminum alloy. In this paper, the effect of EMF on the RSW process of aluminum alloy under different welding parameters is studied. Impacts of the EMF on weld size, tensile shear force, microstructure, and microhardness have been systematically discussed. The results show that under the action of the EMF, the weld diameter, tensile shear force, and microhardness were all improved to certain degree. The sensitivity of the EMF on the weld performance is different for different welding parameters. The effect of EMF is more sensitive to the change of welding time, and insensitive to the change of electrode force. Besides, the effect of EMF is declined with the welding current increased. This indicates that a lower welding current with a long welding time may make the effect of EMF more efficient.