Friction stir welding for the masses

Invented by TWI (formerly known as the welding institute) in 1991, friction stir welding (FSW) is an attractive technique for a number of reasons: it requires no melting (the weld is made in solid state) and produces high-quality welds on a wide variety of metals from aluminium through to magnesium, copper, steels and titanium alloys

The process involves a spinning tool, in contact with the material to be welded, applied with sufficient force to create frictional heat in the material (about 80 per cent of the material’s melting point). This causes the material to become soft, allowing the spinning tool to create the weld.

FSW has significant advantages over other joining techniques including good mechanical properties, low distortion and an ability to weld some materials that cannot be welded by other methods.

However, its industrial take up has been limited to those sectors with sufficient capital to invest in the high technology costs. The need for purpose-built ‘FSW’ machines can make it difficult for product manufacturers to justify implementation of the technology.