ARC WELDING METHOD AND ARC WELDING MACHINE

PROBLEM TO BE SOLVED: To provide an arc welding method and an arc welding machine, that can form the weld zone of a part to be welded by controlling welding arc in a shape corresponding to the shape of a rectangular part to be welded. SOLUTION: The arc welding method applies a fluctuating magnetic flux between an electrode and the part to be welded to oscillate the welding arc to form a flat weld zone where the L/W of the length (L) of the weld zone and the width (W) thereof is between 1.5 and 9 and the D/W of the melting depth (D) of the weld zone and the width (W) thereof is between 0.9 and 2.1. Furthermore, the arc welding machine is provided with an electromagnet for applying the fluctuating magnetic flux to the welding by arranging both of poles of an electromagnet at positions for attacking the welding arc from both sides which occurs in a gap between the electrode and the part to be welded, and applies an AC current by the electromagnet.