| 摘要 |
PROBLEM TO BE SOLVED: Toprovide a stainless steel plate for flapper valve, combining excellent strength, fatigue characteristic, and corrosion resistance, which are required of a flapper valve for a high efficiency compressor, etc. SOLUTION: This steel plate has a composition which consists of, by mass, <=0.15% C, 1.0-4.0% Si, <=5.0% Mn, 4.0-10.0% Ni, 12.0-18.0% Cr, 0-3.5% Cu, 1.0-5.0% Mo, <=0.15% N, and the balance Fe with inevitable impurity elements and satisfies C+N>=0.10% and Si+Mo>=3.5% and in which the value of Md(N), defined by Md(N)=580-520×[%C] -2×[%Si]-16×[%Mn]-16×[% Cr]-23×[%Ni]-300×[%N]=26×[%Cu]-10×[%Mo], is regulated to 20-100. In this case, precipitates are present in the steel plate and the maximum size of these precipitates is <=0.5μm, and tensile strength is regulated to >=1800N/mm<2> .
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