Ferritic stainless steel sheet for egr coolers

Abstract

A ferritic stainless steel sheet for EGR coolers includes at least, by mass % C: 0.03% or less, N: 0.05% or less, Si: 0.1% to 1%, Mn: 0.02% to 2%, Cu: 0.2% to 1.5%, Cr: 15% to 25%, Nb: 8 (C+N) % to 1%, Al: 0.5% or less, and Fe and inevitable impurities as the balance, wherein the steel sheet further includes, by mass %, Ti at an amount fulfilling the following formulae (1) and (2), and Cr and Cu are included at amounts fulfilling the following formula (3), Ti-3N≦0.03  (1), 10(Ti-3N)+Al≦0.5  (2), and Cr+2.3Cu≧18  (3).

1 . A ferritic stainless steel sheet for EGR coolers, comprising: at least, by mass %,
 C: 0.03% or less;   N: 0.05% or less;   Si: 0.1% to 1%;   Mn: 0.02% to 2%;   Cu: 0.2% to 1.5%;   Cr: 15% to 25%;   Nb: 8(C+N) % to 1%;   Al: 0.5% or less; and   Fe and inevitable impurities as the balance,   wherein the steel sheet further comprises, by mass %, Ti at an amount fulfilling the following formulae (1) and (2), and   Cr and Cu are included at amounts fulfilling the following formula (3),
   Ti-3N≦0.03  (1)
 
   10(Ti-3N)+Al≦0.5  (2)
 
   Cr+2.3Cu≧18  (3).
 
   
     
     
         2 . The ferritic stainless steel sheet for EGR coolers according to  claim 1 ,
 wherein the steel sheet further comprises, by mass %, either one or both of Mo: 3% or less, and Ni: 3% or less at amounts fulfilling the following formula (4),
   Cr+1.9Mo+1.6Ni+2.3Cu≧18  (4).
 
   
     
     
         3 . The ferritic stainless steel sheet for EGR coolers according to  claim 1 ,
 wherein the steel sheet further comprises, by mass %, either one or both of V: 3% or less, and W: 5% or less.   
     
     
         4 . The ferritic stainless steel sheet for EGR coolers according to  claim 1 ,
 wherein the steel sheet further comprises, by mass %, one or more selected from the group consisting of Ca: 0.002% or less, Mg: 0.002% or less, and B: 0.005% or less.   
     
     
         5 . The ferritic stainless steel sheet for EGR coolers according to  claim 1 ,
 wherein the steel sheet fulfills C+N: 0.015% or more.