| 摘要 |
PROBLEM TO BE SOLVED: To provide a large heat input submerged arc welding method that has the ability to obtain superior toughness of a weld metal, sound penetration shape and bead appearance free of welding defects for a high tension steel of 490-590 MPa class, even in large heat input submerged arc welding having a welding heat input of 400 kJ/cm or higher. SOLUTION: The large heat input submerged arc welding method uses a flux composed of, in mass %, 12-25% SiO<SB>2</SB>, 6-20% MgO, 5-13% CaO, 1-6% CaF<SB>2</SB>, 17-25% Al<SB>2</SB>O<SB>3</SB>, 3-15% TiO<SB>2</SB>, 11-23% Fe, 0.1-0.6% B<SB>2</SB>O<SB>3</SB>, 1.0-5.0% Mo, and 1.0-5.0% Ni and a welding wire composed of 0.02-0.20% C, 0.02-1.2% Si, 1.16-2.3% Mn, 0.1-1.0% Mo, 0.1% or less Ni, 0.005-0.025% Ti, 0.006% or less N, and the balance Fe and inevitable impurities. COPYRIGHT: (C)2004,JPO&NCIPI
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