Effect of Heat Treatment T6 on the Friction Stir Welded SSM 6061 Aluminum Alloys

The butt joints of semi solid metal 6061 were produced in as cast conditions by friction stir welding process (FSW). This experiment studied in pre/post heat treatment (T6) using the welding speed 160 mm / min with tilt angle tool at 3 degree and straight cylindrical tool pin. The factors of welding were rotating speed rates at 710, 1000, 1400 rpm and heat treatment conditions. They were divided into (1) As welded (AW) joints, (2) T6 Weld (TW) joints, (3) Weld T6 (WT) joints, (4) T6 Weld T6 (TWT) joints, (5) Solution treated Weld Artificially aged (SWA) joints and (6) Weld Artificially aged (WA) joints. Rotating speed and heat treatment (T6) condition were an important factor to micro, macro structure of metal and mechanical properties of the weld. Increasing rotating speed and different heat treatment condition impacted onto tensile strength due to the defects on joints. Therefore the optimum welding parameter on joint was a rotating speed 1400 rpm, the welding speed 160 mm/min, heat treatment condition of Solution treated Weld Artificially aged (SWA) which obtained the highest tensile strength 179.80 MPa, as well as, the maximum average hardness of 92.7 HV at tool rotation speed 1400 rpm, welding speed 160 mm/min, heat treatment condition of Weld T6 (WT).