Ferritic stainless steel for member of exhaust gas flow passage

Abstract

A ferritic stainless steel useful as conduit members for emission of automotive exhaust gas consists of C up to 0.03 mass %, Si up to 1.0 mass %, Mn up to 1.5 mass %, Ni up to 0.6 mass %, 10-20 mass % of Cr, Nb up to 0.50 mass %, 0.8-2.0 mass % of Cu, Al up to 0.03 mass %, 0.03-0.20 mass % of V, N up to 0.03 mass % and the balance being Fe except inevitable impurities with a provision of Nb≧8(C+N). The steel may further contain 0.05-0.30 mass % of Ti and/or 0.0005-0.02 mass % of B. Mo as an inevitable impurity is controlled less than 0.10 mass %. The steel has excellent formability, low-temperature toughness and weldability as well as the same heat-resistance as Nb, Mo-alloyed steel.

1 . A ferritic stainless steel for use as a conduit member for emission of automotive exhaust gas, which consists of C up to 0.03 mass %, Si up to 1.0 mass %, Mn up to 1.5 mass %, Ni up to 0.6 mass %, 10-20 mass % of Cr, Nb up to 0.50 mass %, 0.8-2.0 mass % of Cu, Al up to 0.03 mass %, 0.03-0.20 mass % of V, N up to 0.03 mass % and the balance being Fe except inevitable impurities with a provision of Nb≧8(C+N).  
     
     
         2 . The ferritic stainless steel defined by  claim 1 , wherein Mo as an inevitable impurity is controlled less than 0.10 mass %.  
     
     
         3 . The ferritic stainless steel defined by  claim 1  or  2 , which further contains0.05-3.0 mass % of Ti.  
     
     
         4 . The ferritic stainless steel defined by either one of  claims 1  to  3 , which further contains 0.0005-0.02 mass % of B.