Friction stir welding (FSW)

is a solid-state joining process that uses a non-consumable welding tool to join workpieces without melting the material. Some heat is generated by friction between the rotating tool and the workpiece, which softens region below the FSW tool. Then the tool is traversed along the joint line. Due to the high forces, high pressure and stirring, which is applied by the tool a solid welding seam is produced. FSW can for example be found in the automotive industries for the e-mobility, trains, and aerospace applications.