Ni-Fe-Cr Alloy

Abstract

An objective of the present invention is to provide a Ni—Fe—Cr alloy having an excellent intergranular corrosion resistance. A Ni—Fe—Cr alloy of the present embodiment has a chemical composition consisting of, in mass percent, C: 0.005 to 0.015%, Si: 0.05 to 0.50%, Mn: 0.05 to 1.5%, P: 0.030% or less, S: 0.020% or less, Cu: 1.0 to 5.0%, Ni: 30.0 to 45.0%, Cr: 18.0 to 30.0%, Mo: 2.0 to 4.5%, Ti: 0.5 to 2.0%, N: 0.001 to 0.015%, and Al: 0 to 0.50%, with the balance being Fe and impurities. An average grain size d (μm) satisfies Formula (1): d <4.386/(C rel +0.15)  (1) where, C rel in Formula (1) is defined by Formula (2): C rel =C−0.125Ti+0.8571N  (2) where, symbols of elements in Formula (1) and Formula (2) are to be substituted by contents of corresponding elements (mass %).

1 . A Ni—Fe—Cr alloy comprising a chemical composition consisting of, in mass percent:
 C: 0.005 to 0.015%; 
 Si: 0.05 to 0.50%; 
 Mn: 0.05 to 1.5%; 
 P: 0.030% or less; 
 S: 0.020% or less; 
 Cu: 1.0 to 5.0%; 
 Ni: 30.0 to 45.0%; 
 Cr: 18.0 to 30.0%; 
 Mo: 2.0 to 4.5%; 
 Ti: 0.5 to 2.0%; 
 N: 0.001 to 0.015%; and 
 Al: 0 to 0.50%, with the balance being Fe and impurities, wherein an average grain size d (μm) satisfies Formula (1):
     d< 4.386/(C rel +0.15)  (1)
 
 
 where, C rel  in Formula (1) is defined by Formula (2):
   C rel =C−0.125Ti+0.8571N  (2)
 
 
 where, symbols of elements in Formula (1) and Formula (2) are to be substituted by contents of corresponding elements (mass %). 
 
     
     
         2 . The Ni—Fe—Cr alloy according to  claim 1 , wherein the chemical composition contains Al: 0.05 to 0.50%.