page_title: Friction stir welding
hierarchical_section_title: Friction stir welding
caption_attribution_description: English: This close-up view of the friction stir weld tack tool used to manufacture of space shuttle external tanks shows the process of tack welding barrel panels together. Barrels were previously fabricated using traditional fusion welding, but friction stir welding is different in that the materials are not melted. A rotating tool pin uses friction and applied pressure to join the 20-foot longitudinal panels together. Friction stir welding is the most recent upgrade to the space shuttle's external tank, the largest element of the shuttle and the only element that is not reusable. The new welding technique utilizes frictional heating combined with forging pressure to produce high-strength bonds virtually free of defects. Friction stir welding transforms the metals from a solid state into a "plastic-like" state, and then mechanically stirs the materials together under pressure to form a welded joint. Invented and patented by The Welding Institute, a British research and technology organization, the process is applicable to aerospace, shipbuilding, aircraft and automotive industries. One of the key benefits of this new technology is that it allows welds to be made on aluminium alloys that cannot be readily fusion arc welded, the traditional method of welding.
context_page_description: Friction stir welding is a solid-state joining process that uses a non-consumable tool to join two facing workpieces without melting the workpiece material. 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. It was 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. In addition, joining of dissimilar metals such as aluminium to magnesium alloys has been recently achieved by FSW. Application of FSW can be found in modern shipbuilding, trains, and aerospace applications.
  It was invented and experimentally proven at The Welding Institute in the UK in December 1991.
context_section_description: 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. 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. It was 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. In addition, joining of dissimilar metals such as aluminium to magnesium alloys has been recently achieved by FSW. Application of FSW can be  found in modern shipbuilding, trains, and aerospace applications.
  It was invented and experimentally proven at The Welding Institute (TWI) in the UK in December 1991. TWI held patents on the process, the first being the most descriptive.
caption: Close-up view of a friction stir weld tack tool.
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