Method of welding projection bolt and welding apparatus

摘要

An apparatus for welding a projection bolt includes a control unit which outputs an actuating signal for an advancing pressurizing means in response to at least a signal indicating completion of insertion of the projection bolt into a receiving hole and a signal indicating completion of movement of a steel plate part. Electrodes are provided for welding the projection bolt, and advancement of the electrodes from a retracted state is started in response to the actuating signal.