Effect of shoulder diameter on friction stir welding of Al 6061 to SS 304

Abstract

Friction stir welding, a solid-state welding process, is an emerging technology for welding various dissimilar metals. It is characterized by rotation and translation of a non-consumable tool along the centerline of the weld. Welding of aluminium and steel alloys is gaining worldwide momentum as this combination is utilized prominently in fabrication of vehicles and shipbuilding industries. The present study investigated the effect of shoulder diameter on the tensile strength, microhardness and microstructure for the butt joint of Al 6061 to SS 304. It was observed that the shoulder diameter of 22 mm yielded maximum tensile strength than 18 and 20 mm shoulder diameters, respectively. The same effect was observed for percentage elongation for the joints. The maximum microhardness in the nugget region was found to be about 100 VHN.