| 摘要 |
PURPOSE:To develop sour resisting steel material superior in weld zone stress corrosion cracking resistance under wet hydrogen sulfide environment, by regulating components in steel material and adjusting the structure of weld heat affected zone at welding to bainitic structure. CONSTITUTION:Steel material contg. by weight 0.02-0.05% C, 0.10-0.50% Si, 0.6-1.2% Mn, <=0.05% Al, 0.02-0.10% Nb, 0.001-0.003% B, 0.01-0.04% Ti, 0.001-0.010% Ca, and impurities regulated to <=0.02% P, <=0.005% S, or ingot of steel to which one or 2 kinds among 0.1-0.7% Ni, 0.2-0.8% Cr, 0.1-0.5% Cu, 0.1-0.7% Mo, 0.02-0.1% V, 0.01-0.08% W are added further for improving strength is rolled to steel material having a desired size and shape. The titled steel material used for line pipe, petrochemical plant, etc., is obtd.
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