WELDING CURRENT CONTROL METHOD DURING SHORT-CIRCUIT PERIOD

PROBLEM TO BE SOLVED: To maintain a stable droplet transfer state, even if a droplet size becomes excessive or too small when a short circuit is caused by disturbance during arc welding.SOLUTION: There is provided a welding current control method during a short-circuit period, in which a welding current Iw is raised at a predetermined inclination K when short circuit is caused, and when the welding current reaches a predetermined peak value Ip, welding is performed while maintaining the value Ip. In the method, a value (the time length of an arc period Ta) correlated with droplet size when the short circuit is caused is detected, and when a correlation value Ta1 is less than a first reference value or a second reference value or more, the inclination K and/or the peak value Ip in the short-circuit period Ts is increased more than a predetermined value. Thus, when the droplet size is too small or excessive when the short circuit is caused, since the welding current Iw during the short-circuit period Ts becomes large, the droplet transfer state can be stably kept.