Effect of Plate Configuration on the Interfacial Microstructure and Mechanical Properties of Double-Pass Friction Stir Lap Welded A6061/Q235 Lap Joints

Abstract

In this study, double-pass dissimilar friction stir lap welding (FSLW) was used for the dissimilar welding between A6061 aluminum alloy and Q235 steel plate. After the first pass friction stir welding process, the welding position and welding direction were varied during the second pass, and then four double-pass welded joints with different plate configurations were obtained. Compared with the single-pass joint, the double-pass joints enlarged the interface bonding area and therefore the mechanical properties of the joint were significantly improved. When the second pass was located at the advancing side of the first pass, the fracture position of the joint was inside the stir zone of the first pass, and when it was at the retreating side of the first pass, the fracture position was in the heat-affected zone of the second pass and had the highest ultimate tensile load.

Keywords: Keywords: Friction stir welding, Aluminum alloy, Steel, Lap joint, intermetallic compound