Raw material for cold-rolled stainless steel sheet and method for manufacturing the same

Abstract

A raw material for a cold-rolled stainless steel sheet has a chemical composition containing, in terms of mass %, C: 0.005 to 0.030%, Si: 0.05 to 1.00%, Mn: 0.05 to 1.00%, P: 0.040% or less, S: 0.030% or less, Al: 0.001 to 0.150%, Cr: 10.8 to 14.4%, Ni: 0.01 to 2.50%, and N: 0.005 to 0.060%, with the balance being Fe and incidental impurities, in which the raw material has a structure containing 10 to 90% of a martensite phase in terms of area ratio with the balance being a ferrite phase.

1 . A raw material for a cold-rolled stainless steel sheet, the raw material having a chemical composition containing, in terms of mass %,
 C: 0.005 to 0.030%,   Si: 0.05 to 1.00%,   Mn: 0.05 to 1.00%,   P: 0.040% or less,   S: 0.030% or less,   Al: 0.001 to 0.150%,   Cr: 10.8 to 14.4%,   Ni: 0.01 to 2.50%, and   N: 0.005 to 0.060%,   with the balance being Fe and incidental impurities,   wherein the raw material has a structure containing 10 to 90% of a martensite phase in terms of area ratio with the balance being a ferrite phase.   
     
     
         2 . The raw material for a cold-rolled stainless steel sheet according to  claim 1 , wherein the chemical composition further contains, in terms of mass %, one or two or more selected from
 Co: 0.01 to 0.50%,   Cu: 0.01 to 0.80%,   Mo: 0.01 to 0.30%, and   W: 0.01 to 0.50%.   
     
     
         3 . The raw material for a cold-rolled stainless steel sheet according to  claim 1 , wherein the chemical composition further contains, in terms of mass %, one or two or more selected from
 Ti: 0.01 to 0.30%,   V: 0.01 to 0.10%,   Zr: 0.01 to 0.10%, and   Nb: 0.01 to 0.30%; and   a value of formula (1) below is 0.0 or less:
   54×(Ti+V+Zr+Nb)−5×Mn−19×Ni+1.0  formula (1)
 
   where, in formula (1) above, respective element symbols represent contents (mass %) of respective elements, or represent 0 when corresponding elements are not contained.   
     
     
         4 . The raw material for a cold-rolled stainless steel sheet according to  claim 2 , wherein the chemical composition further contains, in terms of mass %, one or two or more selected from
 Ti: 0.01 to 0.30%,   V: 0.01 to 0.10%,   Zr: 0.01 to 0.10%, and   Nb: 0.01 to 0.30%; and   a value of formula (1) below is 0.0 or less:
   54×(Ti+V+Zr+Nb)−5×Mn−19×Ni+1.0  formula (1)
 
   where, in formula (1) above, respective element symbols represent contents (mass %) of respective elements, or represent 0 when corresponding elements are not contained.   
     
     
         5 . The raw material for a cold-rolled stainless steel sheet according to  claim 1 , wherein the chemical composition further contains, in terms of mass %, one or two or more selected from
 B: 0.0003 to 0.0030%,   Mg: 0.0005 to 0.0100%,   Ca: 0.0003 to 0.0030%,   Y: 0.01 to 0.20%, and   REM (rare earth metal): 0.001 to 0.100%.   
     
     
         6 . The raw material for a cold-rolled stainless steel sheet according to  claim 2 , wherein the chemical composition further contains, in terms of mass %, one or two or more selected from
 B: 0.0003 to 0.0030%,   Mg: 0.0005 to 0.0100%,   Ca: 0.0003 to 0.0030%,   Y: 0.01 to 0.20%, and   REM (rare earth metal): 0.001 to 0.100%.   
     
     
         7 . The raw material for a cold-rolled stainless steel sheet according to  claim 3 , wherein the chemical composition further contains, in terms of mass %, one or two or more selected from
 B: 0.0003 to 0.0030%,   Mg: 0.0005 to 0.0100%,   Ca: 0.0003 to 0.0030%,   Y: 0.01 to 0.20%, and   REM (rare earth metal): 0.001 to 0.100%.   
     
     
         8 . The raw material for a cold-rolled stainless steel sheet according to  claim 4 , wherein the chemical composition further contains, in terms of mass %, one or two or more selected from
 B: 0.0003 to 0.0030%,   Mg: 0.0005 to 0.0100%,   Ca: 0.0003 to 0.0030%,   Y: 0.01 to 0.20%, and   REM (rare earth metal): 0.001 to 0.100%.   
     
     
         9 . The raw material for a cold-rolled stainless steel sheet according to  claim 1 , wherein the chemical composition further contains, in terms of mass %, one or two selected from
 Sn: 0.001 to 0.500% and   Sb: 0.001 to 0.500%.   
     
     
         10 . The raw material for a cold-rolled stainless steel sheet according to  claim 2 , wherein the chemical composition further contains, in terms of mass %, one or two selected from
 Sn: 0.001 to 0.500% and   Sb: 0.001 to 0.500%.   
     
     
         11 . The raw material for a cold-rolled stainless steel sheet according to  claim 3 , wherein the chemical composition further contains, in terms of mass %, one or two selected from
 Sn: 0.001 to 0.500% and   Sb: 0.001 to 0.500%.   
     
     
         12 . The raw material for a cold-rolled stainless steel sheet according to  claim 4 , wherein the chemical composition further contains, in terms of mass %, one or two selected from
 Sn: 0.001 to 0.500% and   Sb: 0.001 to 0.500%.   
     
     
         13 . The raw material for a cold-rolled stainless steel sheet according to  claim 5 , wherein the chemical composition further contains, in terms of mass %, one or two selected from
 Sn: 0.001 to 0.500% and   Sb: 0.001 to 0.500%.   
     
     
         14 . The raw material for a cold-rolled stainless steel sheet according to  claim 6 , wherein the chemical composition further contains, in terms of mass %, one or two selected from
 Sn: 0.001 to 0.500% and   Sb: 0.001 to 0.500%.   
     
     
         15 . The raw material for a cold-rolled stainless steel sheet according to  claim 7 , wherein the chemical composition further contains, in terms of mass %, one or two selected from
 Sn: 0.001 to 0.500% and   Sb: 0.001 to 0.500%.   
     
     
         16 . The raw material for a cold-rolled stainless steel sheet according to  claim 8 , wherein the chemical composition further contains, in terms of mass %, one or two selected from
 Sn: 0.001 to 0.500% and   Sb: 0.001 to 0.500%.   
     
     
         17 . A method for manufacturing the raw material for a cold-rolled stainless steel sheet according to  claim 1 , the method comprising:
 hot-rolling a steel slab having the chemical composition to prepare a hot-rolled sheet, and performing hot-rolled sheet annealing that involves holding the hot-rolled sheet in a temperature range of 900° C. or more and 1100° C. or less for 5 seconds to 15 minutes.   
     
     
         18 . A method for manufacturing the raw material for a cold-rolled stainless steel sheet according to  claim 16 , the method comprising:
 hot-rolling a steel slab having the chemical composition to prepare a hot-rolled sheet, and performing hot-rolled sheet annealing that involves holding the hot-rolled sheet in a temperature range of 900° C. or more and 1100° C. or less for 5 seconds to 15 minutes.