| 摘要 |
PROBLEM TO BE SOLVED: To provide duplex stainless steel which is used in a severe corrosive environment where it is always exposed to seawater or the like, and can be applied to parts requiring high strength on a level with which only precipitation hardening stainless steel can deal heretofore. SOLUTION: Duplex stainless steel having excellent strength, toughness and seawater resistance, having a composition containing, by weight,≤0.020% C, 0.30 to 1.50% Si, 0.50 to 1.50% Mn,≤0.040% P,≤0.015% S, 1.0 to 3.0% Cu, 3.00 to 5.00% Ni, 22.00 to 28.00% Cr, 2.00 to 5.00% Mo, 0.12 to 0.25% N,≤0.50% W,≤0.0100% Ca, and≤0.0100% B, and the balance Fe with impurity elements, and having a duplex structure of ferrite and austenite, and in which the area ratio of the ferritic phase is 40 to 70% is melted, and is hot-rolled, and is subjected to solution heat treatment so as to be heated and held at 950 to 1,100°C, and be rapid-cooled. COPYRIGHT: (C)2003,JPO
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