Utility ferritic stainless steel with excellent hot workability and manufacturing method thereof

Abstract

A manufacturing method of a utility ferritic stainless steel with excellent hot workability is disclosed. The manufacturing method of a ferritic stainless steel according to an embodiment of the present disclosure includes: manufacturing a slab including, in percent (%) by weight of the entire composition, C: 0.005 to 0.020%, N: 0.005 to 0.020%, Si: 0.5 to 0.8%, Mn: 0.5 to 1.5%, Cr: 11.0 to 12.5%, Ni: 0.2 to 0.6%, P: 0.035% or less (excluding 0), S: 0.01% or less (excluding 0), the remainder of iron (Fe) and other inevitable impurities; and hot rolling the slab after heating the slab, and the heating of the slab is performed in a temperature range of 1200 to 1250° C. so that the fraction of δ-ferrite phase in the internal structure of the slab is 80 to 95%.

1 . A manufacturing method of a utility ferritic stainless steel with excellent hot workability, the manufacturing method comprising:
 manufacturing a slab comprising, in percent (%) by weight of the entire composition, C: 0.005 to 0.020%, N: 0.005 to 0.020%, Si: 0.5 to 0.8%, Mn: 0.5 to 1.5%, Cr: 11.0 to 12.5%, Ni: 0.2 to 0.6%, P: 0.035% or less (excluding 0), S: 0.01% or less (excluding 0), the remainder of iron (Fe) and other inevitable impurities; and   hot rolling the slab after heating the slab,   wherein the heating of the slab is performed in a temperature range of 1200 to 1250° C. so that the fraction of δ-ferrite phase in the internal structure of the slab is 80 to 95%.   
     
     
         2 . The manufacturing method of  claim 1 , wherein the heating time is 3 hours or more. 
     
     
         3 . The manufacturing method of  claim 1 , further comprising: Cu: 0.2% or less and Ti: 0.03% or less 
     
     
         4 . A utility ferritic stainless steel with excellent hot workability, the ferritic stainless steel comprising, in percent (%) by weight of the entire composition, C: 0.005 to 0.020%, N: 0.005 to 0.020%, Si: 0.5 to 0.8%, Mn: 0.5 to 1.5%, Cr: 11.0 to 12.5%, Ni: 0.2 to 0.6%, P: 0.035% or less (excluding 0), S: 0.01% or less (excluding 0), the remainder of iron (Fe) and other inevitable impurities, and
 wherein a ferrite factor represented by the following equation (1) satisfies the range of 10.5 to 12.0.
   Ferrite factor=[Cr+6Si]−[2Mn+4Ni+40(C+N)]  equation (1):
 
   
     
     
         5 . The ferritic stainless steel of  claim 4 , further comprising: Cu: 0.2% or less and Ti: 0.03% or less. 
     
     
         6 . The ferritic stainless steel of  claim 4 , wherein a reduction of area in the temperature range of 900 to 1200° C. is 70% or more.