| 摘要 |
PROBLEM TO BE SOLVED: To provide a welding method providing a welded part having high-strength, high toughness and excellent elongation by suppressing cracking due to deterioration of ductility in welding an ultra-high tensile steel of 950 MPa or higher.SOLUTION: A steel material is welded by gas shield arc welding by using a wire containing one or more of CaF, BaF, SrFand MgFin total content α higher than 2.0% and equal to or lower than 8.0%, one or more of Ti, Si, Mg and Al oxides in a total content &bgr; of 0.01-1.20% and CaCO, BaCO, SrCOand MgCOin a total content lower than 0.60% in the wire and having a content of iron powder in the flux of lower than 5.0%, a ratio of the content of CaFto α of 0.50 or higher, a ratio of α to &bgr; of 2.0 or higher and 800.0 or lower, a chemical composition comprising C, Si, Mn, Al, Ni, V, P, S, Cu, Cr, Mo, Ti, Nb, B, Mg, Ca, REM and remaining iron and impurities and a Ceq of 0.60-1.20%. |
