| 摘要 |
<p>A highly tough, ERW steel pipe (1) having a distinguished sour resistance is disclosed. The steel pipe (1) is prepared from steel for production of ERW steel pipe containing 0.01 to 0.35% by weight of C; 0.02 to 0.5% by weight of Si; 0.1 to 1.8% by weight of Mn; more than 0.005% to 0.05% by weight of Al; 0.0005 to 0.008% by weight of Ca; 0.001 to 0.015% by weight of Zr; not more than 0.015% by weight of P; and not more than 0.003% by weight of S; a ratio of Zr/Al or (Ti + Zr)/Al being less than 2 by weight; or further containing (A) at least one of 0.2 to 0.6% by weight of Cu, 0.1 to 1.0% by weight of Ni and 0.2 to 3.0% by weight of Cr, and/or (B) at least one of 0.10 to 1.0% by weight of Mo, 0.01 to 0.15% by weight of Nb, 0.005 to 0.10% by weight of Ti and 0.01 to 0.15% by weight of V; the balance being Fe and impurities as a steel material; and the steel pipe has a welding part (2) in which the content of Al2O3 contained in inclusions at the welding heat affected zone (3) is not more than 50% by weight.</p> |
