| 摘要 |
PURPOSE:To improve yield strength, elongation, stress corrosion cracking resistance, pitting resistance, etc., by subjecting a two-phase cast stainless steel with a specific composition to solution annealing at a specific temp. and to rapid cooling, by raising the temp. of the above steel again to apply soaking treatment, and then by cooling the above steel rapidly again. CONSTITUTION:A cast steel has a composition consisting of, by weight, <=0.1% C, 0.2-2.0% Si, 0.2-2.0% Mn, 20.0-30.0% Cr, 3.0-10.0% Ni, 1.0-5.0% Mo, <=3.0% Cu, 0.05-0.3% N, 0.5-2.0% W, and the balance essentially Fe, in which the area ratio of ferritic phase is regulated to 40-70%. This two-phase cast stainless steel is subjected to solution annealing at 1100-1200 deg.C and then to rapid cooling. Subsequently, the temp. of this steel is raised again up to 1000-1080 deg.C to undergo soaking and holding for several hours and then cooled rapidly. If necessary, 0.3-2.0% Co is incorporated to the above steel. Since this cast steel has superior 0.2% yield strength and corrosion resistance, it is suitable for centrifugal separator, sea-water corrosion-resisting material, etc. |
