Austenitic stainless steel sheet

Abstract

An austenitic stainless steel sheet consists, (mass %), of: C: 0.03 to 0.15%; Si: 0.20 to 2.5%; Mn: 0.2 to 4.5%; P: 0.010 to 0.030%; S: 0.0001 to 0.0010%; Cr: 20.0 to 26.0%; Ni: 10.0 to 15.0%; Cu: 0.01 to 2.0%; Mo: 0.01 to 2.0%; Co: 0.05 to 2.50%; Al: 0.01 to 0.20%; N: 0.1 to 0.6%; V: 0.02 to 0.15%; B: 0.0002 to 0.0050%; Nb: 0 to 0.10%; Ti: 0 to 0.10%; Y: 0 to 0.10%; Ca: 0 to 0.010%; Mg: 0 to 0.010%; and REM: 0 to 0.10%, balance Fe and impurities. Contents of [Mn] and [S] satisfy [Mn]×[S]≤0.0020. Sheet thickness is 0.5 mm or smaller, an aspect ratio value L1/L2 satisfies L1/L2≥1.5 where L1 and L2 denote major and minor axis lengths of a crystal grain. A surface hardness (HV) is 300 or higher after retention at 600° C. for 400 hours.

1 . An austenitic stainless steel sheet consisting, by mass %, of:
 C: 0.03 to 0.15%;   Si: 0.20 to 2.5%;   Mn: 0.2 to 4.5%;   P: 0.010 to 0.030%;   S: 0.0001 to 0.0010%;   Cr: 20.0 to 26.0%;   Ni: 10.0 to 15.0%;   Cu: 0.01 to 2.0%;   Mo: 0.01 to 2.0%;   Co: 0.05 to 2.50%;   Al: 0.01 to 0.20%;   N: 0.1 to 0.6%;   V: 0.02 to 0.15%;   B: 0.0002 to 0.0050%;   Nb: 0 to 0.10%;   Ti: 0 to 0.10%;   Y: 0 to 0.10%;   Ca: 0 to 0.010%;   Mg: 0 to 0.010%; and   REM: 0 to 0.10%,   the balance being Fe and impurities, wherein   a content of Mn [Mn] (by mass %) and a content of S [S] (by mass %) satisfy [Mn]×[S]≤0.0020,   a sheet thickness of the austenitic stainless steel sheet is 0.5 mm or smaller,   an aspect ratio value L1/L2 satisfies L1/L2≥1.5   where L1 denotes a length of a major axis of a crystal grain and L2 denotes a length of a minor axis of the crystal grain, and   a surface hardness (HV) is 300 or higher after retention at 600° C. for 400 hours.   
     
     
         2 . The austenitic stainless steel sheet according to  claim 1 , containing, by mass %,
 Nb: 0.01 to 0.10%, and/or   Ti: 0.01 to 0.10%.   
     
     
         3 . The austenitic stainless steel sheet according to  claim 1 , containing one or more elements selected from, by mass %:
 Y: 0.01 to 0.10%;   Ca: 0.001 to 0.010%;   Mg: 0.0002 to 0.010%; and   REM: 0.01 to 0.10%.   
     
     
         4 . The austenitic stainless steel sheet according to  claim 1 , wherein the austenitic stainless steel sheet is subjected to a temper rolling with a rolling reduction of 20% or higher, in cold rolling. 
     
     
         5 . The austenitic stainless steel sheet according to  claim 2 , containing one or more elements selected from, by mass %:
 Y: 0.01 to 0.10%;   Ca: 0.001 to 0.010%;   Mg: 0.0002 to 0.010%; and   REM: 0.01 to 0.10%.   
     
     
         6 . The austenitic stainless steel sheet according to  claim 2 , wherein the austenitic stainless steel sheet is subjected to a temper rolling with a rolling reduction of 20% or higher, in cold rolling. 
     
     
         7 . The austenitic stainless steel sheet according to  claim 3 , wherein the austenitic stainless steel sheet is subjected to a temper rolling with a rolling reduction of 20% or higher, in cold rolling. 
     
     
         8 . The austenitic stainless steel sheet according to  claim 5 , wherein the austenitic stainless steel sheet is subjected to a temper rolling with a rolling reduction of 20% or higher, in cold rolling.