Effect of stirring time on the quality of aluminum-steel lap joints of friction stir spot welding

Abstract

Abstract AA6061 aluminum alloy sheet and TRIP steel plate were welded by friction stir spot welding using a tungsten-based hard alloy stirring head, and the effect of stirring time on the formation and connection strength of spot welded lap joints was studied. The results showed that as the stirring time increased from 0 s to 7 s, all spot welded joints formed well, and the size of the hooks appearing in the stirring needle’s action area gradually increased. The connection strength of the joint gradually increases with the increase of stirring time. When the stirring time is 5 seconds, it reaches a maximum value. At this time, when the stirring time is increased, the joint strength decreases significantly. The strength of the joint is influenced by the size of the bending hook and the formation of intermetallic compounds.