| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for a submerged arc welding suitable for preventing a defective penetration, a defective fusion, and a solidification crack without modifying a welding machine when a thick steel plate is welded by a submerged arc welding method. SOLUTION: The first path of a welding is executed by a tree-electrode submerged arc welding, and the welding condition for the first path is so decided that the diameter D of a wire of a preceding electrode Le is given by the relation 4.8 [mm]<D<=5.6 [mm], the electric current density d of the preceding electrode Le is given by the relation 80 [A/mm2]<=d<=100 [A/mm2], the passing time t from the preceding electrode Le to a following electrode Te is given by the relation 40 [s]<=t<=60 [s], the electric current differenceΔI (LM), the electrode distance L (LM), the electric current differenceΔI (MT), and the electrode distance L (MT) satisfy the following relations: 650 [A]<=ΔI (LM)+7.0×L (LM)<=1,120 [A], and 900 [A]<=ΔI (MT)+12×L (MT)<=1,800 [A].
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