Effect of tool plunging downforce on friction stir welding of ADC12 die cast alloy

Friction Stir Welding (FSW) has been attracting attention as a useful joining process for casts with superior characteristics to conventional fusion welding. It is well known that arc welding of aluminum die cast alloy is very difficult because of the formation of blowholes and cracks. In this research, the effect of the tool plunge downforce on FSW joints of ADC12 was evaluated for establishing the range of the optimum welding conditions in FSW. The range of the optimum FSW conditions for sound joints expanded with increasing tool plunge downforce, because the area of contact of the tool shoulder with the workpiece increased and plastic metal flow was activated.