Fe-Cr-Ni ALLOY MATERIAL

Abstract

A Fe—Cr—Ni alloy material that has high strength and reduced strength anisotropy is provided. A Fe—Cr—Ni alloy material according to the present disclosure consists of, by mass %, C: 0.030% or less, Si: 0.01 to 1.00%, Mn: 0.01 to 2.00%, P: 0.030% or less, S: 0.0050% or less, Ni: 29.0 to 36.5%, Cr: 23.0 to 27.5%, Mo: 2.00 to 6.00%, Al: 0.01 to 0.30%, rare earth metal: 0.016 to 0.100%, N: 0.220 to 0.500%, and O: 0.010% or less, with the balance being Fe and impurities, and satisfies Formula (1). In a microstructure, a standard deviation of the grain size numbers of austenite grains is 0.80 or less. The tensile yield strength is 758 MPa or more:3×Ni-2×Cr-150×N<15.(1)where, a content of a corresponding element in percent by mass is substituted for each symbol of an element in Formula (1).

1 . A Fe—Cr—Ni alloy material consisting of, by mass %,
 C: 0.030% or less, 
 Si: 0.01 to 1.00%, 
 Mn: 0.01 to 2.00%, 
 P: 0.030% or less, 
 S: 0.0050% or less, 
 Ni: 29.0 to 36.5%, 
 Cr: 23.0 to 27.5%, 
 Mo: 2.00 to 6.00%, 
 Al: 0.01 to 0.30%, 
 rare earth metal: 0.016 to 0.100%, 
 N: 0.220 to 0.500%, 
 O: 0.010% or less, 
 W: 0 to 6.0%, 
 Cu: 0 to 2.00%, 
 Ca: 0 to 0.0100%, 
 Mg: 0 to 0.0100%, 
 V: 0 to 0.50%, 
 Ti: 0 to 0.50%, 
 Nb: 0 to 0.50%, and 
 Co: 0 to 2.00%, 
 with the balance being Fe and impurities, 
 and satisfying Formula (1), 
 wherein: 
 in a microstructure, a standard deviation of grain size numbers of austenite grains is 0.80 or less; and 
 a tensile yield strength is 758 MPa or more; 
 
       
         
           
             
               
                 
                   
                     
                       
                         3 
                         × 
                         Ni 
                       
                       - 
                       
                         2 
                         × 
                         Cr 
                       
                       - 
                       
                         150 
                         × 
                         N 
                       
                     
                     < 
                     15. 
                   
                 
                 
                   
                     ( 
                     1 
                     ) 
                   
                 
               
             
           
         
         where, a content of a corresponding element in percent by mass is substituted for each symbol of an element in Formula (1). 
       
     
     
         2 . The Fe—Cr—Ni alloy material according to  claim 1 , containing one or more elements selected from a group consisting of:
 W: 0.1 to 6.0%, 
 Cu: 0.01 to 2.00%, 
 Ca: 0.0001 to 0.0100%, 
 Mg: 0.0001 to 0.0100%, 
 V: 0.01 to 0.50%, 
 Ti: 0.01 to 0.50%, 
 Nb: 0.01 to 0.50%, and 
 Co: 0.01 to 2.00%. 
 
     
     
         3 . The Fe—Cr—Ni alloy material according to  claim 1 or claim 2 , wherein:
 the Fe—Cr—Ni alloy material is a seamless alloy pipe for oil wells.