Friction Stir Welded of SSM Cast 356 Aluminium Alloys with T6 Heat Treatment

Abstract

The butt joints of semi solid 356 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
1320, 1750 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. Non Destructive Inspection (NDT) using Phased Arrays
Ultrasonic inspection was applied after welding. 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 1320 rpm, the welding speed 160
mm/min, heat treatment condition of Weld T6 (WT) which obtained the highest tensile strength 228.92 MPa In
addition, the rotation speed 1,750 rpm, welding speed 160 mm / min and the condition of heat treatment
before and after welding (TWT) indicated the depth of weld defect 0.93 mm from surface.