| 摘要 |
PURPOSE:To improve the corrosion resistance and the stress corrosion cracking resistance of an alloy for an oil well by limiting the component of a two-phase stainless steel, controlling especially the quantity of C, P and S, and adding the very small quantity of Ca thereon. CONSTITUTION:The high corrosion resistant alloy for the oil well contains <=0.05wt% C, <=1.0% Si, 0.3-2.0% Mn, 18.0-28.0% Cr, 3.0-8.0% Ni, 2.0-5.0% Mo, 0.01-0.10% Al, 0.0005-0.0050% Ca, <=0.020% P, <=0.003% S, 0.03-0.3% N, and <=0.0040% O, and consists of one kind or more among 0.01-0.20% Ti, 0.01-0.25% Zr, and 0.001-0.02% La, and the balance Fe with inevitable impurities. Also, in accordance with necessity, one kind or more among 0.01-0.25% Nb, 0.01-0.25% V, and 0.01-0.25% W are incorporated. According to this composition, the corrosion resistance and stress corrosion cracking resistance of a two-phase stainless steel can be improved.
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