| 摘要 |
PROBLEM TO BE SOLVED: To provide a welding method suppressing effectively and efficiently the backward flow of molten metal at the time of high speed welding by using an electromagnetic action and preventing weld defects such as the defects, etc., of the undercut, etc., of weld beads resulting from the speeding-up of a welding in a multiple electrode submerged arc welding method. SOLUTION: In the multiple electrode submerged arc welding method using an AC as the welding current of at least rearmost electrode, which is excellent in the shape of weld beads, it is characterized in that just under the tip part of the rearmost electrode, an AC magnetic field is applied in the vertical direction on the left and right of a weld line, and according to the welding speed, at least one out of the flux density of the AC magnetic field and a phase difference in frequency between the AC magnetic field and the welding current of the electrode, is adjusted.
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