| 摘要 |
Provided is a steel strip for electric-resistance-welded steel pipes or tubes which has a strength on the level of the X70 grade or higher and has highly excellent resistance to HIC and SSC. The steel strip for electric-resistance-welded steel pipes or tubes has a composition which contains, in terms of mass%, 0.02-0.06% C, 0.1-0.3% Si, 0.8-1.3% Mn, up to 0.01% P, up to 0.001% S, 0.04-0.07% V, 0.04-0.07% Nb, 0.01-0.04% Ti, 0.1-0.3% Cu, 0.1-0.3% Ni, 0.001-0.005% Ca, 0.01-0.07% Al, and up to 0.007% N, with the remainder comprising Fe and unavoidable impurities, the contents of C, Nb, V, and Ti satisfying the following relationship (1), the steel strip having an areal ferrite proportion of 90% or higher. [C]-12([Nb]/92.9+[V]/50.9+[Ti]/47.9)≤0.03% (1) |
