| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high-strength and high-toughness welded joint which is obtained by welding a high-strength base material without preheating. <P>SOLUTION: The welded joint consists of a base steel material containing the chemical composition of, C:0.03-0.19%, Si:0.03-0.90%, Mn:0.30-1.80%, P ≤0.030%, S≤0.010%, Cr:0.05-1.20%, Mo:0.05-1.00%, sol.Al:0.01-0.10%, N≤0.0050%, and the balance Fe with impurities, consisting of the structure that the constitution ratio of the martensitic phase is ≥95% in terms of area ratio, with the tensile strength of ≥950 MPa, and a welded metal having the chemical composition of C:0.03-0.08%, Si:0.2-1.0%, Mn:0.3-3.0%, Ni:4.0-7.0%, Cr:11.5-15.0%, and the balance Fe with impurities while satisfying the inequalities [Creq+0.5Nieq>16.5], [Creq+5.7Nieq<58.8], and [Creq-0.63Nieq<10.6]. <P>COPYRIGHT: (C)2013,JPO&INPIT |
