| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an austenitic stainless steel which keeps low surface contact resistance and superior corrosion resistance for a long period of time, and is suitable for a separator of a fuel cell such as a solid polymer type. <P>SOLUTION: This austenitic stainless steel used for a substrate of the separator of the fuel cell has a composition comprising 16.0-40.0% Cr, 5.0-26.0% Ni, 0.2-6.0% Cu, and the balance substantially Fe, one or more elements of 0.01-0.5% N, 0.2-6.0% Mo, 0.01-1.0% Co, 0.05-1.0% Nb, 0.05-1.0% Ti, 0.01-3.0% Al, 0.01-1.0% V, 0.001-0.5% rare earth metal, and 0.001-1.0% B, as needed. The austenitic stainless steel has a Cu rich phase precipitated and dispersed in an amount of 0.2 vol.% or more, and Cu concentrated in the surface layer so as to make Cu/(Si+Mn) to be 0.5 or more, to improve the electrical conductivity of the stainless steel sheet of the substrate. The manufacturing method comprises bright annealing the steel sheet in an atmosphere at a dew point of -30°C or lower or pickling it in a mixed acid after annealing it in the air, to precipitate and disperse the Cu rich phase or concentrate Cu in the surface layer. <P>COPYRIGHT: (C)2004,JPO |
