| 摘要 |
PROBLEM TO BE SOLVED: To provide a two electrode type heavy heat input submerged arc welding method which can provide a weld metal with superior and stable toughness and a sound penetration shape and bead appearance free from welding defects, even when the heavy heat input submerged arc welding is performed on a high strength steel of 490-570 MPa grade with a welding heat input of 500 kJ/cm or more. SOLUTION: The two electrode type heavy heat input submerged arc welding method is characterized in that the welding is performed by using a combination of first and second electrodes together with a flux; wherein the first electrode contains, by mass%, 0.02-0.18% C, 0.02-0.5% Si, 1.35-2.2% Mn, 0.1-0.9% Mo, 0.1-1.5% Ni, 0.005-0.05% Ti and the balance being Fe and inevitable impurities, and the second electrode contains 0.01-0.12% C, 0.02-0.4% Si, 1.2-2.2% Mn, 0.1-0.8% Mo,≤0.05% Ni, 0.005-0.025% Ti and the balance being Fe and inevitable impurities; the flux contains 13-24% SiO<SB>2</SB>, 8-20% MgO, 5-13% CaO, 1-6% CaF<SB>2</SB>, 9-23% Al<SB>2</SB>O<SB>3</SB>, 3-11% TiO<SB>2</SB>, 11-23% Fe, 0.1-0.6% B<SB>2</SB>O<SB>3</SB>, 1-4.2% Mo and 1-4.5% Ni. COPYRIGHT: (C)2006,JPO&NCIPI |
