Friction Stir Spot Welding: A Review on Joint Macro- and Microstructure, Property, and Process Modelling

Friction stir spot welding (FSSW) is a very useful variant of the conventional friction stir welding (FSW), which shows great potential to be a replacement of single-point joining processes like resistance spot welding and riveting. There have been many reports and some industrial applications about FSSW. Based on the open literatures, the process features and variants, macro- and microstructural characteristics, and mechanical properties of the resultant joints and numerical simulations of the FSSW process were summarized. In addition, some applications of FSSW in aerospace, aviation, and automobile industries were also reviewed. Finally, the current problems and issues that existed in FSSW were indicated.