Spinning a tool to mix metal workpieces together at the joint, without melting them
Friction stir welding (FSW) is a solid-state joining process that uses a non-consumable tool to join two facing workpieces without melting the workpiece material.[1][2] Heat is generated by friction between the rotating tool and the workpiece material, which leads to a softened region near the FSW tool. While the tool is traversed along the joint line, it mechanically intermixes the two pieces of metal, and forges the hot and softened metal by the mechanical pressure, which is applied by the tool, much like joining clay, or dough.[2] It is primarily used on wrought or extruded aluminium and particularly for structures which need very high weld strength. FSW is capable of joining aluminium alloys, copper alloys, titanium alloys, mild steel, stainless steel and magnesium alloys. More recently, it was successfully used in welding of polymers.[3] In addition, joining of dissimilar metals, such as aluminium to magnesium alloys, has been recently achieved by FSW.[4] Application of FSW can be found in modern shipbuilding, trains, and aerospace applications.[5][6][7][8][9][10]
The concept was patented in the Soviet Union by Yu. Klimenko in 1967,[11] but it wasn't developed into a commercial technology at that time. It was experimentally proven and commercialized at The Welding Institute (TWI) in the UK in 1991. TWI held patents on the process, the first being the most descriptive.[12]
^Sheikh-Ahmad, J.Y.; Ali, Dima S.; Deveci, Suleyman; Almaskari, Fahad; Jarrar, Firas (February 2019). "Friction stir welding of high density polyethylene—Carbon black composite". Journal of Materials Processing Technology. 264: 402–413. doi:10.1016/j.jmatprotec.2018.09.033. S2CID139970404.
^Hou, Z.; Sheikh-Ahmad, J.; Jarrar, F.; Ozturk, F. (2018-05-01). "Residual Stresses in Dissimilar Friction Stir Welding of AA2024 and AZ31: Experimental and Numerical Study". Journal of Manufacturing Science and Engineering. 140 (5). doi:10.1115/1.4039074. ISSN1087-1357.