Friction stir welding is another process
that aids the performance of extruded profiles. The innovative friction stir
welding results in a total freedom of design in case of friction stir
welding. After the friction stir welding is carried out the surface of the
resulting profiles are smooth, and the high point is that there is no
requirement of further grinding or brushing for improving the finish. The
following image is of a heat sink panel, that is formed by the friction stir
welding of aluminum profiles into the form of tray.

Extrusions are joined using the process of friction stir welding. The side
panels of Extruded aluminium used in train cars are produced this way. The
working of the friction stir welding process is described here.
The process of Friction stir welding process gets carried out by moving of
one component relative to the other via an interface that is common. A
compressive force is applied across the joint. The amount of friction
heating that gets generated at the interface is able to soften up both the
components. As they become plasticised, the interface material is gradually
extruded out of the edges of the joint. The clean material from each of the
component is subsequently left along the original interface.
Finally there is stopping of the relative motion. The joint is then cooled,
before that an optional higher final compressive force can be applied.
Advantages of Friction Stir Welding
- Excellent weld quality
- No question of porosity
- Weld is being formed in the solid state
- Low distortion and residual stress
- Environment friendly process
- Capable of welding aluminium alloys that are not easily welded by
fusion welding process.
- Minimal influence on the material properties
- Added density