Ferritic stainless steel plant components for plant applications with excellent corrosion resistance in environments containing sulfate and chloride ions

摘要

PROBLEM TO BE SOLVED: To provide a plant member having sufficient corrosion resistance in a plant environment generating a concentrated water containing chloride or sulfide from a coal burning thermal powder plant or the like.SOLUTION: A ferritic stainless steel made plant member having excellent corrosion resistance in a plant member environment containing sulfuric acid ion and chloride ion is provided which has a composition containing C:0.005 to 0.025 mass%, Cr:18.00 to 23.00 mass%, Mo:0.05 to 2.50 mass % or less, N:0.01 to 0.025 mass%, Nb:0.15 to 0.80 mass%, Cu:0.05 to 0.50 mass% and the balance Fe with inevitable impurities, and satisfying following formula. The ferritic stainless steel made plant member has: a welded junction subjected to a dry grinding to obtain a roughness Ra of 0.1 μm or more; and a passive coating film in which a coating film composition of a ground portion satisfies Cr mass%/(Cr mass%+Fe mass%)≥0.30. Cr+5×Cu+3×Mo-30×N≥20... (1).SELECTED DRAWING: None