Material Flow Behavior during Friction Stir Welding of Copper and Steel

Abstract

The joining of dissimilar metals, T2 copper and Q235 mild steel was carried out by friction stir welding. The material flow of different shapes of the probe and different forms of welding joints were studied, the material flow behavior on different locations from the probe was also analyzed. The experimental results showed that the screw thread in probe is the main factor in driving material flow along the thickness direction of the weld during FSW of copper and steel, the flow morphology of the weld is significantly different with vary forms of welding joints, and the material flow on different locations from the probe are quite different from each other. Instantaneous cavity will form at the upper of the weld with the use of left screw thread probe during FSW, and if not promptly and adequate padding, it is prone to appear hole-type defects.