| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-strength UOE steel pipe having excellent earthquake resistance. SOLUTION: The high-strength UOE steel pipe for line pipes has a metal structure having a steel composition containing ≥0.03 to ≤1.20% C, ≥0.5 to ≤0.50% Si, ≥1.50 to ≤2.2% Mn, ≤0.025% P, ≤0.02% S, ≤1.0% Cu, ≤1.0% Cr, ≤2.0% Ni, ≤1.0% Mo, ≤0.1% Nb, ≤0.1% V, ≤0.025% Ti, ≤0.06% Al, ≤0.005% N, and ≤0.0050% Ca, having Ti/N ≥40, having a steel composition consisting of the balance Fe and inevitable impurities, and has a metal structure composed of ferrite and bainite, and has a metal structure composed of ferrite, bainite and martensite. COPYRIGHT: (C)2010,JPO&INPIT
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