| 摘要 |
PROBLEM TO BE SOLVED: To provide a submerged arc welding method of a 780 MPa grade high tensile steel in which a good bead shape and welding workability without weld defects, and a weld metal of superior machine performance, can be obtained.SOLUTION: A submerged arc welding method of a 780 MPa grade high tensile steel is characterized by combining to weld: a bonded flux including, by mass%, 10-20% of SiO, 8-20% of CaO, 20-30% of MgO, 21-35% of AlO, 10-15% of CaF, 2-7% in terms of CO, of CaCOand MgCO, and 0.3-0.7% of Si; with a solid wire including, by mass%, 0.03-0.10% of C, 0.1-0.3% of Si, 1.5-3.5% of Mn, 2.0-3.0% of Ni, 0.9-1.5% of Cr, 0.3-1.5% of Mo, 0.05-0.15% of Ti, a carbon equivalent (Ceq) of 0.35-0.55, and the balance Fe with inevitable impurities. |
