Ferritic stainless steel excellent in heat resistance and toughness

Abstract

A ferritic stainless steel excellent in thermal fatigue resistance and oxidation resistance and also having toughness equivalent to or higher than that of Type 429 does not need to add an expensive element such as Mo or W. Specifically, the ferritic stainless steel includes C: 0.015 mass % or less, Si: 0.5 mass % or less, Mn: 0.5 mass % or less, P: 0.04 mass % or less, S: 0.006 mass % or less, Cr: 16 to 20 mass %, N: 0.015 mass % or less, Nb: 0.3 to 0.55 mass %, Ti: 0.01 mass % or less, Mo: 0.1 mass % or less, W: 0.1 mass % or less, Cu: 1.0 to 2.5 mass %, Al: 0.2 to 1.2 mass %, and the balance of Fe and inevitable impurities.

1 . A terrific stainless steel comprising C: 0.015 mass % or less, Si: 0.5 mass % or less, Mn: 0.5 mass % or less, P: 0.04 mass % or less, S: 0.006 mass % or less, Cr: 16 to 20 mass %, N: 0.015 mass % or less, Nb: 0.3 to 0.55 mass %, Ti: 0.01 mass % or less, Mo: 0.1 mass % or less, W: 0.1 mass % or less, Cu: 1.0 to 2.5 mass %, Al: 0.2 to 1.2 mass %, and the balance of Fe and inevitable impurities. 
     
     
         2 . The ferritic stainless steel according to  claim 1 , further comprising one or more selected from the group consisting of B: 0.003 mass % or less, REM: 
     
     
         0 . 08 mass % or less, Zr: 0.5 mass % or less, V: 0.5 mass % or less, Co: 0.5 mass % or less, and Ni: 0.5 mass % or less.