Friction Stir Welding

Friction Stir Welding (FSW) is a solid state joining process, particularly suitable for metals with low melting point like aluminium. The process uses a non-consumable rotating tool which is pushed into the material under high pressure. The combination of plastic deformation and friction generates the required heat to soften the material. The tool mechanically stirs the softened material, creating a high-quality welding joint. The heat input into the material and the resulting welding temperature can be controlled by adapting process parameters like the downforce, rotational speed or welding speed. The material never melts and obtains a fine-grain microstructure. This makes the mechanical properties of FSW joint superior to most fusion welding processes. Furthermore, due to the lower temperature gradient, the deformation of the welded product is limited.


Initially the process was only suitable for light-weight alloys like aluminium, magnesium and copper. Recent developments in tool materials make FSW of steel, titanium and nickel alloys feasible.

Temperature measurement in Friction Stir Welding

A new method has been developed for temperature measurement in Friction Stir Welding. The method avoids the need for sensors inside the tool or inside the workpiece and is easy to implement on industrial applications.


Jeroen De Backer, doctor in production technology, talks about the method and its advantages.