Research Progress on Friction Stir Welding Tools

Friction stir welding (FSW) is an advanced green and low cost solid-phase connection technology, which can obtain higher quality and basically flawless welding effect than traditional fusion welding technology. Therefore, FSW is widely used in aerospace, ships and new energy vehicles and other fields. As a key basic part to realize friction stir welding, the tool is subjected to the effect of high temperature and high stress in the welding process, resulting in serious wear, fracture and other phenomena. It affects the tool life and welding quality of joints. Because of mentioned problems in welding such as wear and fatigue, this paper mainly focused on two key parts of the tool: pin and shoulder, discussing factors that affecting tool life and welding quality. Tool material selection, pin geometry and shoulder geometry were reviewed. In addition, some measures for improving the tool life and achieving high quality friction stir welding were put forward from the aspects of new material selection, cooling device and surface coating.