What does FSW mean in UNCLASSIFIED

Friction Stir Welding (FSW) is an innovative welding process that combines the plastic deformation of materials with friction heat to join them together. It was invented in 1991 by The Welding Institute (TWI), a leading research and technology organisation based in the United Kingdom. FSW is used in various industries, such as shipbuilding, aerospace, automotive and defence.

In FSW, a rotating pin tool is inserted between two pieces of material that need to be joined together. The pin creates friction heat due to its rotation against the surface of the materials while simultaneously applying pressure that causes plastic deformation of the materials, which allows them to bond together.

FSW offers many advantages compared to other welding methods such as increased joint strength, improved weld geometry, reduced distortion and increased weld speeds. FSW also minimises costly pre-weld cleaning operations and welding fumes since it uses no additional filler metal. Overall this makes it more cost efficient than other methods.

A potential disadvantage of FSW is that there is limited access for full visual inspection due to the design of the tool itself. It can also be difficult to control parameters such as rotational speed and traverse speed which can adversely affect weld quality if not monitored closely.

FSW has been applied successfully on a wide range of different metals including aluminium alloys, steels and titanium alloys. With advances in technologies, it has been possible to join dissimilar materials such as steel-aluminium or copper-titanium alloys providing greater flexibility for product designers.

Due to its relatively low temperatures during operation, certain metals that would otherwise require higher temperatures for successful joining cannot be effectively welded using FSW. These include nickel-based superalloys and copper-based alloys.

No - unlike traditional welding processes that use a filler metal which produces smoke when melted off at high temperatures causing air pollution, FSW does not generate any smoke or fumes since no additional filler metal is used.

Yes - one advantage of FSW is that it can join sheets as thin as 0.25mm thick without any difficulty.

Yes - since no additional filler metal is used, there are no harmful emissions generated during the process making it one of safest welding techniques available today.

No - due to its nature, there are very minimal post-weld operations required such as reworking or grinding which greatly reduces production costs over traditional methods.