2. Principle

The principle of Friction Stir Welding (FSW), which for simplicity will be referred to here as FSW, is shown in figure 1 .

It uses a rotating mandrel to receive the actual welding tool, which takes the form of a cylinder of revolution made of high-strength steel, with a shoulder (shoulder ) extended by a coaxial active rod or tip (pin ), itself cylindrical or frustoconical, and featuring various types of surface relief.

The welding head thus formed is fixed to a support which presents the tool in rotation on the joint of the two metal sheets to be welded, themselves fixed to a support assembly, and then brings it into contact with them. The heat generated by the friction brings the surrounding material into a pasty state (figure