Abstract: In a pulse welding method, an optimum pulse current waveform defined by the amplitudes of the current pulse and base current and the width of the current pulse is maintained throughout the welding operation while the average welding current is varied by changing the frequency of the current pulse.

Abstract: An arc welding robot control system includes a control console where a plurality of points on a workpiece taught by a teaching box and a welding voltage, a welding current and a welding speed set by a key board to be specified to each of the taught points are stored in a central control unit and displayed on a cathode ray tube, and a welding electric source for selectively delivering two sets of a welding voltage and a welding current which are specified for a pulsed and a short arc welding process respectively. With the pulsed arc welding process displayed, a set of normally open contacts disposed within the central control unit is closed to cause an electromagnetic contactor disposed within the welding source to operate the source with the that process. Otherwise the contact set is maintained open to operate the source with the short arc welding process.

Abstract: An arc welding process for welding a circumferential surface of a fixed pipe etc. by shielding a work part with a shield gas is provided. It is welded by a flat arc formed in a flat sectional view by simultaneously ejecting a gas from nozzles (19) to the arc formed between a welding torch (10) and a product for welding by placing a pair of the gas nozzle (19) for ejecting the gas at the end of the welding torch (10).