FERRITIC STAINLESS STEEL FOR BIOFUEL SUPPLY SYSTEM PART, BIOFUEL SUPPLY SYSTEM PART, FERRITIC STAINLESS STEEL FOR EXHAUST HEAT RECOVERY UNIT, AND EXHAUST HEAT RECOVERY UNIT

摘要

An aspect of a ferritic stainless steel contains, by mass %: C: 0.03% or less; N: 0.03% or less; Si: more than 0.1% to 1% or less; Mn: 0.02% to 1.2%; Cr: 15% to 23%; Al: 0.002% to 0.5%; and either one or both of Nb and Ti, with the remainder being Fe and unavoidable impurities, wherein Expression (1) and Expression (2) illustrated below are satisfied, an oxide film is formed on a surface thereof, and the oxide film contains Cr, Si, Nb, Ti and Al in a total cationic fraction of 30% or more, 8(C+N)+0.03@Nb+Ti@0.6(1) Si+Cr+Al+{Nb+Ti-8(C+N)}>=15.5(2).