1. Principle

Rotation is the means almost exclusively used to create friction (figure 1 ). The rotating workpiece is clamped in a rotating chuck driven by a motor or flywheel, so it must be rotationally symmetrical at least in the welding zone.

In this process, the surfaces in contact heat up and become the source of heat which, through diffusion, raises the temperature of the part ends. These become plastic and creep towards the periphery, forming a characteristic bead, while the heat continues to diffuse. When the welding temperature is reached, rotation is stopped and a forging force is applied to form the weld.

In practice, friction welding is naturally applied to joints between two cylindrical parts, solid or hollow, with a common axis and the same cross-section...