Patent ID: 7800016

Claim:
A method of performing polarity switching short circuiting arc welding, in which a welding wire is fed at a constant feeding rate, in which a state of short circuiting and a state of arcing appear repeatedly between the welding wire and a base metal, and in which output polarity of a welding power source is switched in accordance with a polarity switching signal for performing electrode positive welding and electrode negative welding, the method comprising the steps of: beginning to supply the welding wire based on a welding start signal; starting an arc during a predetermined start initial period starting at a time when the supplied welding wire makes contact with the base metal; reducing a welding current during a predetermined short circuit initial period starting at a time when first short circuiting occurs after the polarity switching signal changes upon lapsing of the start initial period; changing the output polarity of the welding power source upon lapsing of the short circuit initial period; and increasing the welding current for terminating the first short circuiting; wherein the polarity switching signal is prevented from changing during the start initial period, and an output of the welding power source has a maximum peak value during a period between a time when the supply of the welding wire is begun and the time when the supplied welding wire makes contact with the base metal.