Oriented electrical steel sheet and method for preparing same

Abstract

(In Equation 1, [Mn], [Cu], [S], [Se], [Al], and [N] represent contents (wt %) of Mn, Cu, S, Se, Al, and N, respectively.)

1 . An oriented electrical steel sheet, comprising, in a unit of wt %, Si at 1.0 wt % to 5.0 wt %, C at 0.005 wt % or less (excluding 0 wt %), Mn at 0.001 wt % to 0.1 wt %, Cu at 0.001 wt % to 0.1 wt %, S at 0.001 wt % to 0.020 wt %, Se at 0.001 wt % to 0.050 wt %, Al at 0.0005 wt % to 0.010 wt %, N at 0.0005 wt % to 0.005 wt %, and the remainder of Fe and inevitable impurities,
 wherein the oriented electrical steel sheet satisfies Equation 1:
   16≤(10×[Mn]+[Cu])/([S]+[Se])+(0.02−[Al])/[N]≤20   [Equation 1]
 
   (in Equation 1, [Mn], [Cu], [S], [Se], [Al], and [N] represent contents (wt %) of Mn, Cu, S, Se, Al, and N, respectively.)   
     
     
         2 . The oriented electrical steel sheet of  claim 1 , wherein
 the oriented electrical steel sheet satisfies Equation 2:
   0.016≤[S]+[Se]≤0.05   [Equation 2]
 
   (in Equation 2, [S] and [Se] represent contents (wt %) of S and Se, respectively.)   
     
     
         3 . The oriented electrical steel sheet of  claim 1 , wherein
 the oriented electrical steel sheet satisfies Equation 3:
   0.5≤[Al]/[N]≤3.0   [Equation 3]
 
   (in Equation 3, [Al] and [N] represent contents (wt %) of Al and N, respectively.)   
     
     
         4 . A preparing method of an oriented electrical steel sheet, comprising:
 preparing a slab including, in a unit of wt %, Si at 1.0 wt % to 5.0 wt %, C at 0.001 wt % to 0.10 wt %, Mn at 0.001 wt % to 0.1 wt %, Cu at 0.001 wt % to 0.1 wt %, S at 0.001 wt % to 0.020 wt %, Se at 0.001 wt % to 0.050 wt %, Al at 0.0005 wt % to 0.010 wt %, N at 0.0005 wt % to 0.005 wt %, and the remainder of Fe and inevitable impurities, and satisfying Equation 1;   heating the slab;   hot rolling the slab to prepare a hot rolled sheet;   cold rolling the hot rolled sheet to prepare a cold rolled sheet;   primary recrystallization annealing the cold rolled sheet; and   secondary recrystallization annealing the cold rolled sheet in which the primary recrystallization annealing is completed:
   16(10×[Mn]+[Cu])/([S]+[Se])+(0.02−[Al])/[N]≤20   [Equation1]
 
   (in Equation 1, [Mn], [Cu], [S], [Se], [Al], and [N] represent contents (wt %) of Mn, Cu, S, Se, Al, and N, respectively.)   
     
     
         5 . The preparing method of the oriented electrical steel sheet of  claim 4 , wherein
 the heating of the slab includes heating the slab at 1000 to 1250° C.   
     
     
         6 . The preparing method of the oriented electrical steel sheet of  claim 4 , wherein
 the cold rolled sheet in which the primary recrystallization annealing is completed includes one or more precipitates of (Fe,Mn,Cu)S and (Fe,Mn,Cu)Se.   
     
     
         7 . The preparing method of the oriented electrical steel sheet of  claim 4 , wherein
 the primary recrystallization annealing is performed in a hydrogen and nitrogen mixed atmosphere at a dew point temperature of 50° C. to 70° C.