Ferritic stainless steel having excellent corrosion resistance of weld zone

Abstract

Ferritic stainless steel that is excellent in terms of corrosion resistance of a weld zone. The ferritic stainless steel includes, by mass %, C: 0.001% or more and 0.025% or less, Si: 0.05% or more and 0.30% or less, Mn: 0.35% or more and 2.0% or less, P: 0.05% or less, S: 0.01% or less, Al: 0.05% or more and 0.80% or less, N: 0.001% or more and 0.025% or less, Cr: 16.0% or more and 20.0% or less, Ti: 0.12% or more and 0.50% or less, Nb: 0.002% or more and 0.050% or less, Cu: 0.30% or more and 0.80% or less, Ni: 0.05% or more and less than 0.50%, V: 0.01% or more and 0.50% or less, and Fe and inevitable impurities such that Expression (1) is satisfied: 0.50<25×C+18×N+Ni+0.11×Mn+0.46×Cu  (1).

1 . Ferritic stainless steel having a chemical composition comprising:
 C: 0.001% or more and 0.025% or less, by mass %;   Si: 0.05% or more and 0.30% or less, by mass %;   Mn: 0.35% or more and 2.0% or less, by mass %;   P: 0.05% or less, S: 0.01% or less, by mass %;   Al: 0.05% or more and 0.80% or less, by mass %;   N: 0.001% or more and 0.025% or less, by mass %;   Cr: 16.0% or more and 20.0% or less, by mass %;   Ti: 0.12% or more and 0.50% or less, by mass %;   Nb: 0.002% or more and 0.050% or less, by mass %;   Cu: 0.30% or more and 0.80% or less, by mass %;   Ni: 0.05% or more and less than 0.50%, by mass %;   V: 0.01% or more and 0.50% or less, by mass; and   Fe and inevitable impurities   wherein Expression (1) >0.50,
   25×C+18×N+Ni+0.11×Mn+0.46×Cu  (1),
 
 where, atomic symbols in Expression (1) respectively represent the contents (mass %) of the corresponding elements. 
   
     
     
         2 . The ferritic stainless steel according to  claim 1 , wherein the steel further includes one or more selected from the group consisting of:
 Zr: 0.01% or more and 0.50% or less, by mass %;   W: 0.01% or more and 0.20% or less, by mass %;   REM: 0.001% or more and 0.10% or less, by mass %;   Co: 0.01% or more and 0.20% or less, by mass %;   B: 0.0002% or more and 0.010% or less, by mass %; and   Sb: 0.05% or more and 0.30% or less by mass %.   
     
     
         3 . The ferritic stainless steel according to  claim 1 , wherein the steel includes Mn in the range from 0.50% to 1.5%, by mass %. 
     
     
         4 . The ferritic stainless steel according to  claim 1 , wherein the steel includes Mn in the range from 0.75% to 1.25%, by mass %. 
     
     
         5 . The ferritic stainless steel according to  claim 1 , wherein the steel includes N in the range from 0.003% to 0.015%, by mass %. 
     
     
         6 . The ferritic stainless steel according to  claim 1 , wherein the steel includes Cr in the range from 16.5% to 19.0%, by mass %. 
     
     
         7 . The ferritic stainless steel according to  claim 1 , wherein the steel includes Cu in the range from 0.35% to 0.50%, by mass %. 
     
     
         8 . The ferritic stainless steel according to  claim 1 , wherein the steel includes C in the range from 0.003% to 0.018%, by mass %. 
     
     
         9 . The ferritic stainless steel according to  claim 1 , wherein Expression (1) ≧0.60. 
     
     
         10 . The ferritic stainless steel according to  claim 1 , wherein Expression (1) ≧0.70. 
     
     
         11 . The ferritic stainless steel according to  claim 1 , wherein:
 0.50< Expression (1) ≦1.59.