Effect of pin profiles on the mechanical properties of friction-stir-welded AA5383 and AA7075

Abstract

Friction-stir welding (FSW) is an unyielding-state welding process developed by The Welding Institute, United Kingdom. FSW is mainly based on the tool geometry, process parameters and welding material. The tool geometry plays the principle role in obtaining desirable microstructures of the welds, improving the strength and fatigue resistance of the joints. Currently, friction-stir-welding tools are designed using the trial-and-error method. In this study, three different types of FSW tools are considered for the fabrication of butt joints from AA5383 and AA7075. Various tool profiles such as the cylindrical taper projection, cylindrical thread-pin projection and triangle-pin projection are considered in the present study. The pin profiles are assessed based on the weld quality during tensile tests and hardness tests conducted on welded samples. With the analysis, it is found that the triangular pin produces sound welds at an 800-min-1 speed, 20-mm/min feed and 4-kN load.