Combined Effect of Welding Speed and Tool Pin Profiles on Tensile properties of FSWAA6061-T6 Joint

Abstract

Friction stir welding is a solid state welding process for joining two similar and dissimilar materials, in which non-consumable tool with rotary motion along with transverse motion with intimate contact to weld coupon generates sound joint. In this study, tool rotation speed, tool travel speed and tool pin profile are taken to know their effect on mechanical properties of AA6061-T6. The main objective for this research is to evaluate the combined effect of rotation speed (1200 and 1500 rpm), different tool travel speed (50, 65 and 80 mm/min) and tool pin profiles (straight cylindrical, taper threaded and hexagonal pin). Maximum UTL obtained by straight cylindrical pin profile tool is 16.34 MPa at 1200 rpm and 80 mm/min (tool rotation and travel speed), taper threaded pin tool is 18.02 MPa at 1200 rpm and 65 mm/min and hexagonal pin profile is 19.94 MPa at 1500 rpm and 65 mm/min; whereas, base material UTL is 21.3 MPa. Among all FSWed coupons of AA6061-T6 max, UTL observed by straight cylindrical pin profile tool, taper threaded pin profile tool and hexagonal pin profile tool is 76.71, 84.60 and 93.62% respectively compare to base material; which directly concludes that welded coupons welded by hexagonal pin profile tools can have highest UTL compared to welded coupons welded by other pin profile tools. So, it is clear that FSWed coupons welded by hexagonal pin profile at 1500 rpm tool rotation speed and 65 mm/min tool travel speed are having highest UTL compare to welded coupons welded by other pin profile tools. We observed that the FSW joints prepared of AA6061-T6 plate having 6 mm thickness by hexagonal pin profile generates the ultimate tensile strength of 173.496 MPa compared to base material values of 241.735 MPa which can produce welded joint. Straight hexagonal pin profile tool produces joints which has UTL of 93.61% compared to base material.