| 摘要 |
PURPOSE:To provide high cracking resistance under an H2S-containing environment and also to combine superior stress corrosion resistance with coercive corrosion resistance, by specifying respective contents of Cr, Ni, Mo, etc., in an alloy and also specifying the relationships among the contents of respective components. CONSTITUTION:An austenitic alloy has a composition consisting of, by weight, <=0.03% C, 0.02-1.0% Si, 0.02-1.0% Mn, 20-28% Cr, 24-60% Ni, 4-<7% Mo, <=0.1% La, <=0.1% Al, <=0.03% Ca, <=0.01% O, <=0.03% P, <=0.01% S, other inevitable impurities, and the balance Fe. Further,the contents of respective components are regulated so that they satisfy the relationships represented by inequalities I, II, III, and IV. If necessary, one or more kinds among <=2% Cu, <=0.15% Sn, and <=0.15% Sb are incorporated to the above composition. This alloy is subjected to cold working. This alloy shows superior property as a steel-tube material for oil and natural gas development drilling under a severe environment.
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