Friction welding or friction welding is a pressure welding process. Both parts of the metal, which will boil, must be located rotationally symmetrically to each other. Friction welding uses heat generated by friction to melt the metal. The parts to be welded are rotated and moved towards each other, so that their surfaces begin to come into contact. After the material is heated to the point where it becomes plastic, the parts are pressed against each other with high pressure.