A variation of friction welding in which the energy required to make the weld is supplied to the welding machine through a direct motor connection for a preset period of the welding cycle. See Figure D-6.
One of the workpieces is held in a locked position while the other is rotated by a direct motor connection. When the rotated part is up to speed, pressure is applied to move the rotating part against the stationary part. The resulting friction melts the forging surfaces. Molten metal is ejected from the joint as the pressure is increased. When the rotational force is stopped, forging pressure is increased to complete the weld.
