Austenitic stainless steel excellent in corrosion resistance and brazeability

Abstract

The present invention provides austenitic stainless steel which is not only excellent in brazeability, but is also excellent in corrosion resistance in an environment where condensation of combustion exhaust gas causes formation of condensed water which contains nitric acid ions or sulfuric acid ions and which is low in pH or in an environment of an aqueous solution which contains chloride ions, which contains, by mass %, C: 0.080% or less, Si: 1.2 to 3.0%, Mn: 0.4 to 2.0%, P: 0.03% or less, S: 0.003% or less, Ni: 6.0 to 12.0%, Cr: 16.0 to 20.0%, Cu: 0.2 to 3.0%, Al: 0.002 to 0.10%, N: 0.030 to 0.150%, and Mo: 0.1 to 1.0%, has a balance of Fe and unavoidable impurities, and satisfies Formula (A): 1.6≦[Cu]×[Si≦]4.4 and Formula (B): 0.16≦2[N]+[Mo≦]1.0.

1 - 3 . (canceled) 
     
     
         4 . Austenitic stainless steel which is excellent in corrosion resistance and brazeability characterized by containing, by mass %, C: 0.080% or less, Si: 1.2 to 3.0%, Mn: 0.4 to 2.0%, P: 0.03% or less, S: 0.003% or less, Ni: 6.0 to 12.0%, Cr: 16.0 to 20.0%, Cu: 0.2% to 3.0%, Al: 0.002 to 0.10%, N: 0.030 to 0.150%, and Mo: 0.1 to 1.0%, having a balance of Fe and unavoidable impurities, and satisfying the following Formula (A) and Formula (B):
   1.6≦[Cu]×[Si<]4.4  Formula (A)
     0.16≦2[N]+[Mo≦]1.0  Formula (B)
   where, [Cu], [Si], [N], and [Mo] are contents of elements expressed by mass %.   
     
     
         5 . Austenitic stainless steel which is excellent in corrosion resistance and brazeability characterized by containing, by mass %, C: 0.080% or less, Si: 1.2 to 3.0%, Mn: 0.4 to 2.0%, P: 0.03% or less, S: 0.003% or less, Ni: 6.0 to 12.0%, Cr: 16.0 to 20.0%, Cu: 0.2% to 3.0%, Al: 0.002 to 0.10%, N: 0.030 to 0.150%, and Mo: 0.1 to 1.0%, having a balance of Fe and unavoidable impurities, and satisfying the following Formula (A) and Formula (B):
   1.6≦[Cu]×[Si≦]4.4  Formula (A)
     0.16≦2[N]+[Mo≦]1.0  Formula (B)
   where, [Cu], [Si], [N], and [Mo] are contents of elements expressed by mass %.   
     
     
         6 . Austenitic stainless steel which is excellent in corrosion resistance and brazeability as set forth in  claim 4  characterized by further containing, by mass %, one or more of Nb: 0.1 to 0.7%, Ti: 0.1 to 0.5%, V: 0.1 to 3.0%, and B: 0.0002% to 0.003%. 
     
     
         7 . Austenitic stainless steel which is excellent in corrosion resistance and brazeability as set forth in  claim 5  characterized by further containing, by mass %, one or more of Nb: 0.1 to 0.7%, Ti: 0.1 to 0.5%, V: 0.1 to 3.0%, and B: 0.0002% to 0.003%.