| 摘要 |
PURPOSE:To improve stress corrosion cracking resistance and hydrogen cracking resistance by adding a limited amount of Cu and by specifying the relationship among the additive quantities of Cr, Mo, and W as well as the relationship between the additive quantities of Mo and W in an Ni-base alloy having a specific composition. CONSTITUTION:The alloy has a composition consisting of, by weight ratio, <=0.10% C, >0.05-0.30% Si, <=2.0% Mn, <=0.030% P, <=0.0050% S, 50-60% Ni, 15-25% Cr, Mo and/or W so that Mo and W are <=20% and <=5.0%, respectively, and inequality I is satisfied, 0.30-3.0% Cu, <=0.050% Ti, 0.30-3.0% Nb, <=1.0% Al, >0.050-0.25% N, and the balance Fe with inevitable impurities. Moreover, in the above composition, conditions represented by inequality II are satisfied. Further, Co, one or more elements among V, Ta, Zr, and Hf, and one or more elements among rare earth elements, mg, Ca, and Y are incorporated, if necessary. The above high-strength Ni-base alloy excellent in corrosion resistance is applicable to material for oil well tubes, etc.
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