ARC WELDING METHOD, AND ARC WELDING APPARATUS

PROBLEM TO BE SOLVED: To solve such a problem that a molten state of a welded part becomes unstable when weld defects occur in arc-welding, so that it is difficult to return to a good normal welding state again, and particularly, an opened hole becomes greatly unstable in molten state, so that the returning to a good normal welding state again is more difficult and the hole tends to be lengthened.SOLUTION: A voltage during arc-welding is monitored all the time, and a hole opening is detected by detecting a moment when a deviation of a certain level or more from a specified value set based on data in the normal welding occurs. Then, when detecting the hole opening, an instruction for reducing a welding current is sent to a welding power source, or an electrode is separated from a workpiece by a drive unit for moving the electrode in the height direction. Accordingly, an incoming heat and an arc pressure are reduced, and a welding state is stabilized, thereby suppressing the lengthening of the opened hole and enabling the returning to a normal good welding state immediately after the occurrence of the hole opening.