| 摘要 |
PURPOSE:To enable application under high-temp. environment, by specifying respective contents of C, N, and Al in a stainless steel so as to improve ductility as well as strength at high temp. CONSTITUTION:An austenitic stainless steel for high temp. service has a composition consisting of, by weight, <=0.025% C, <=1% Si, <=2% Mn, <=0.045% P, <=0.03% S, 10-15% Ni, 16-28% Cr, 2-3% Mo, 0.03-0.12% N, <=0.04% Al, and the balance Fe with inevitable impurities. In this composition, the precipitation of carbide is inhibited by reducing C content, creep rupture strength is improved by increasing N content to a higher value than heretofore, and the deterioration in creep rupture strength and ductility is inhibited by limiting Al content. This steel combines strength at high temp. with ductility higher than those of conventional material, so that it is applicable to nuclear pressure vessels, tubes, heat exchangers, etc., and also to structural material for boilers, chemical plants, etc.
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