Friction stir spot welding process: an innovative approach for transforming from engineering design to production

In the present work, an innovative approach for transforming from engineering design to production has been carried out to achieve enhanced joint strength during a new type of friction stir spot welding (FSSW) process. A process for double spot friction stir welding (DSFSW) and double spot zigzag friction stir welding (DSZFSW) has been developed to achieve higher strength in welded joints. Various mechanical properties of these joints were compared with single spot friction stir welding, considering the effect of tool geometry and spindle speed. The welding material chosen for the process was an AA6063 series of 1 mm thickness. The experiments were carried out by using three different probe shape tools at three different spindle speeds. It was found that at low welding speed, the tensile-shear strength of the welding specimen is higher. The DSFSW joints, welded by a triangular probe tool have higher tensile strength as compared to a single spot and DSZFSW joint. It was also observed that at high spindle speed, the hardness value of the welding specimen decreases while the grain size increases.