Heat-resistant austenitic stainless steel having excellent cyclic oxidation resistance

Abstract

A heat-resistant austenitic stainless steel comprising C: 0.05 to 0.2%, Si: 0.1 to 1%, Mn: 0.1 to 2.5%, Cu: 1 to 4%, Ni: 7 to 12%, Cr: 16 to 20%, Nb: 0.1 to 0.6%, Zr: 0.05 to 0.4%, Ce: 0.005 to 0.1%, Ti: 0.1 to 0.6%, B: 0.0005 to 0.005%, N: 0.001 to 0.15%, S: 0.005% or less (not including 0%), and P: 0.05% or less (not including 0%), with the balance of iron and unavoidable impurities.

1 . A heat-resistant austenitic stainless steel, comprising:
 C in a content by mass of from 0.05 to 0.2%,   Si in a content by mass of from 0.1 to 1%,   Mn in a content by mass of from 0.1 to 2.5%,   Cu in a content by mass of from 1 to 4%,   Ni in a content by mass of from 7 to 12%,   Cr in a content by mass of from 16 to 20%,   Nb in a content by mass of from 0.1 to 0.6%,   Zr in a content by mass of from 0.05 to 0.4%,   Ce in a content by mass of from 0.005 to 0.1%,   Ti in a content by mass of from 0.1 to 0.6%,   B in a content by mass of from 0.0005 to 0.005%,   N in a content by mass of from 0.001 to 0.15%,   S in a content by mass of greater than 0% and no more than 0.005%,   P in a content by mass of greater than 0% and no more than 0.05%, and   iron.   
     
     
         2 . The heat-resistant austenitic stainless steel according to  claim 1 , further comprising:
 at least one element selected from the group consisting of;   Mo in a content by mass of greater than 0% and no more than 3%,   W in a content by mass of greater than 0% and no more than 5%,   Ca in a content by mass of greater than 0% and no more than 0.005%, and   Mg in a content by mass of greater than 0% and no more than 0.005%.   
     
     
         3 . The heat-resistant austenitic stainless steel according to  claim 1 ,
 wherein a crystal grain size number of a microstructure is 6 or more and less than 12 in terms of ASTM grain size number.   
     
     
         4 . The heat-resistant austenitic stainless steel according to  claim 2 ,
 wherein a crystal grain size number of a microstructure is 6 or more and less than 12 in terms of ASTM grain size number.