Paper Title
Defect Analysis Of Friction Stir Welded Steel Plates On Different Tool Profiles

Tool design in Friction stir welding (FSW) of steel is a critical problem and hence experiments were carried on with three combinations of tool profiles having tapered pin, concave and flat shoulders. The study of tool wear resulted in a new finding of Sub shoulder tool and gave reduced tool wear. The tool wear is indirectly being reduced by using a shorter pin length of 2.6mm. Rupture of material surfaces which were in contact created reduction in the tool geometry and defect on welds were obtained. Based on the tool shape corresponding to its weld length, defects were occurred in the weld zone. This study is concentrated on finding the possible defects during welding by using different tool profiles using ultrasonic, radiography and thermography techniques. It was observed from the weld that the flat shoulder gave improper joining defects while the concave shoulder gave reduced defects when compared to flat shoulder, and the Sub shoulder is defect free.