Hot rolled ferritic stainless steel sheet, hot rolled and annealed ferritic stainless steel sheet and method for manufacturing the same

Abstract

Provided are a hot rolled ferritic stainless steel sheet and a hot rolled and annealed ferritic stainless steel sheet and methods for manufacturing these steel sheets. A hot rolled ferritic stainless steel sheet having a chemical composition containing, by mass %, C: 0.005% to 0.060%, Si: 0.02% to 0.50%, Mn: 0.01% to 1.00%, P: 0.04% or less, S: 0.01% or less, Cr: 15.5% to 18.0%, Al: 0.001% to 0.10%, N: 0.005% to 0.100%, Ni: 0.1% to 1.0%, and the balance being Fe and inevitable impurities and an absolute value of planar anisotropy in terms of modulus of longitudinal elasticity below of 35 GPa or less.

1 . A hot rolled ferritic stainless steel sheet having a chemical composition containing, by mass %, C: 0.005% to 0.060%, Si: 0.02% to 0.50%, Mn: 0.01% to 1.00%, P: 0.04% or less, S: 0.01% or less, Cr: 15.5% to 18.0%, Al: 0.001% to 0.10%, N: 0.005% to 0.100%, Ni: 0.1% to 1.0%, and the balance being Fe and inevitable impurities and
 an absolute value |ΔE| of planar anisotropy in terms of modulus of longitudinal elasticity calculated by using equation (1) below of 35 GPa or less:
   |Δ E |=|( E   L −2× E   D   +E   C )/2|  (1),
 
   where, E L  denotes modulus of longitudinal elasticity (GPa) in a direction parallel to the rolling direction, E D  denotes modulus of longitudinal elasticity (GPa) in a direction at an angle of 45° to the rolling direction, and E C  denotes modulus of longitudinal elasticity (GPa) in a direction at a right angle to the rolling direction.   
     
     
         2 . The hot rolled ferritic stainless steel sheet according to  claim 1 , the steel sheet having the chemical composition further containing, by mass %, one, two, or more selected from Cu: 0.1% to 1.0%, Mo: 0.1% to 0.5%, and Co: 0.01% to 0.5%. 
     
     
         3 . The hot rolled ferritic stainless steel sheet according to  claim 1 , the steel sheet having the chemical composition further containing, by mass %, one, two, or more selected from V: 0.01% to 0.25%, Ti: 0.001% to 0.015%, Nb: 0.001% to 0.025%, Mg: 0.0002% to 0.0050%, B: 0.0002% to 0.0050%, Ca: 0.0002% to 0.0020%, and REM: 0.01% to 0.10%. 
     
     
         4 . The hot rolled ferritic stainless steel sheet according to  claim 2 , the steel sheet having the chemical composition further containing, by mass %, one, two or more selected from V: 0.01% to 0.25%, Ti: 0.001% to 0.015% Nb: 0.001% to 0.025%, Mg: 0.0002% to 0.0050%, B: 0.0002% to 0.0050% Ca: 0.0002% to 0.0020%, and REM: 0.01% to 0.10%. 
     
     
         5 . A hot rolled and annealed ferritic stainless steel sheet obtained by performing hot rolled sheet annealing on the hot rolled ferritic stainless steel sheet according to  claim 1 . 
     
     
         6 . A hot rolled and annealed ferritic stainless steel sheet obtained by performing hot rolled sheet annealing on the hot rolled ferritic stainless steel sheet according to  claim 2 . 
     
     
         7 . A hot rolled and annealed ferritic stainless steel sheet obtained by performing hot rolled sheet annealing on the hot rolled ferritic stainless steel sheet according to  claim 3 . 
     
     
         8 . A hot rolled and annealed ferritic stainless steel sheet obtained by performing hot rolled sheet annealing on the hot rolled ferritic stainless steel sheet according to  claim 4 . 
     
     
         9 . A method for manufacturing the hot rolled ferritic stainless steel sheet according to  claim 1 , the method comprising performing a hot rolling process involving finish rolling composed of 3 passes or more, wherein rolling in the final 3 passes of the finish rolling is performed in a temperature range of 900° C. to 1100° C. with an accumulated rolling reduction ratio of 25% or more. 
     
     
         10 . A method for manufacturing the hot rolled ferritic stainless steel sheet according to  claim 2 , the method comprising performing a hot rolling process involving finish rolling composed of 3 passes or more, wherein rolling in the final 3 passes of the finish rolling is performed in a temperature range of 900° C. to 1100° C. with an accumulated rolling reduction ratio of 25% or more. 
     
     
         11 . A method for manufacturing the hot rolled ferritic stainless steel sheet according to  claim 3 , the method comprising performing a hot rolling process involving finish rolling composed of 3 passes or more, wherein rolling in the final 3 passes of the finish rolling is performed in a temperature range of 900° C. to 1100° C. with an accumulated rolling reduction ratio of 25% or more. 
     
     
         12 . A method for manufacturing the hot rolled ferritic stainless steel sheet according to  claim 4 , the method comprising performing a hot rolling process involving finish rolling composed of 3 passes or more, wherein rolling in the final 3 passes of the finish rolling is performed in a temperature range of 900° C. to 1100° C. with an accumulated rolling reduction ratio of 25% or more. 
     
     
         13 . A method for manufacturing a hot rolled and annealed ferritic stainless steel sheet, the method comprising using the method for manufacturing a hot rolled ferritic stainless steel sheet according to  claim 9 , and
 further performing hot rolled sheet annealing at a temperature of 800° C. to 900° C. after the hot rolling process.   
     
     
         14 . A method for manufacturing a hot rolled and annealed ferritic stainless steel sheet, the method comprising using the method for manufacturing a hot rolled ferritic stainless steel sheet according to  claim 10 , and
 further performing hot rolled sheet annealing at a temperature of 800° C. to 900° C. after the hot rolling process.   
     
     
         15 . A method for manufacturing a hot rolled and annealed ferritic stainless steel sheet, the method comprising using the method for manufacturing a hot rolled ferritic stainless steel sheet according to  claim 11 , and
 further performing hot rolled sheet annealing at a temperature of 800° C. to 900° C. after the hot rolling process.   
     
     
         16 . A method for manufacturing a hot rolled and annealed ferritic stainless steel sheet, the method comprising using the method for manufacturing a hot rolled ferritic stainless steel sheet according to  claim 12 , and
 further performing hot rolled sheet annealing at a temperature of 800° C. to 900° C. after the hot rolling process.