Ferrite stainless steel for use in producing urea water tank

Abstract

This ferrite stainless steel for use in producing a urea water tank includes: in terms of mass %, C: 0.05% or less; N: 0.05% or less; Si: 0.02 to 1.5%; Mn: 0.02 to 2%; Cr: 15 to 23%; and either one or both of Nb and Ti at a content within a range of 8(C+N) to 1% (herein, C and N represent the contents of C and N (expressed by mass %), respectively, and the numerical values shown in front of the atomic symbols represent constant numbers), with the remainder being iron and unavoidable impurities, wherein an effective amount of Cr expressed by any one of the following Equations (I), (II), and (III) is 15% or more (herein, the atomic symbols in Equations (I) to (III) represent the contents of the elements (expressed by mass %), and the numerical values shown in front of the atomic symbols represent constant numbers). Here, the effective amount of Cr=Cr+4Si−2Mn in the case where only Nb is contained, the effective amount of Cr=Cr+4Si−2Mn−10Ti in the case where only Ti is contained, and the effective amount of Cr=Cr+4Si−2Mn−(10Ti−3Nb) in the case where both of Nb and Ti are contained.

Description

TECHNICAL FIELD[0001]The present invention relates to a ferrite stainless steel being used for a device that reduces NOx from exhaust gas by using a urea aqueous solution (urea water) in an internal combustion engine, mainly in a diesel engine, and, in particular, for equipments in a urea-Selective Catalytic Reduction (SCR) system for vehicles and the like, specifically, for a urea water tank that is utilized when storing, producing, and transporting urea water.[0002]The present application claims priority on Japanese Patent Application No. 2008-190065, filed on Jul. 23, 2008, the content of which is incorporated herein by reference.BACKGROUND ART[0003]In recent years, as a result of increased concern about environmental issues, exhaust gas emission regulations are becoming stricter, and major efforts are being made to suppress carbon dioxide emission. In the automotive industry, in addition to efforts made to provide fuels such as bio-ethanol and biodiesel fuel, a variety of effort...

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