Ferritic stainless steel for polymer electrolyte fuel cell separator, polymer electrolyte fuel cell separator and polymer electrolyte fuel cell

摘要

This stainless steel is suitable for a polymer electrolyte fuel cell separator that has little elution of metal ions even when exposed to a high humidity acidic atmosphere in the cell and maintains a low surface contact resistance over a long period of time. C: 0.020 mass% or less, Si: 0.50 mass% or less, Mn: 0.50 mass% or less, P: 0.020 to 0.080 mass%, S: 0.005 mass% or less, Ni: 0.50 mass% or less, Cr: 28-32 mass%, Mo: 1.5-2.5 mass%, Cu: 0.80 mass% or less, Nb: 0.03-0.25 mass%, Ti: 0.03 to 0.25% by mass, Al: 0.04 to 0.20% by mass, N: 0.020% by mass or less, V: If necessary, 0.2 to 1.0% by mass, C + N ≦ 0.025% by mass and Ni + Cu ≦ 0.80% by mass are satisfied.