Method for producing grain-oriented electrical steel sheet

Abstract

A method for producing a grain-oriented electrical steel sheet according to an embodiment of the present invention comprises the steps of: heating a slab satisfying the following formula 1 and including, by wt %, 3.2 to 4.0% of Si, 0.03 to 0.09% of C, 0.015 to 0.040% of A1, 0.04 to 0.15% of Mn, 0.001 to 0.005% of N, 0.01% or less of S (exclusive of 0%), and the balance of Fe and other inevitable impurities; hot rolling the slab to produce a hot rolled sheet; hot band annealing the hot rolled sheet to at a cracking temperature of 900 to 980□ for 30 to 300 seconds; cold rolling the hot rolled sheet, which has completely been hot band annealed, to produce a cold rolled sheet; subjecting the cold rolled sheet to primary recrystallization annealing; and conducting secondary recrystallization annealing for the cold rolled sheet which has completely been primary recrystallization annealed. [Mn]×[S]≤0.0004  [Formula 1] (wherein [Mn] and [S] are contents (wt %) of Mn and S in the slab, respectively.)

1 . A method for producing a grain-oriented electrical steel sheet comprising:
 heating a slab satisfying the following formula 1 and including, by wt %, 3.2 to 4.0% of Si, 0.03 to 0.09% of C, 0.015 to 0.040% of A1, 0.04 to 0.15% of Mn, 0.001 to 0.005% of N, 0.01% or less of S (exclusive of 0%), and the balance of Fe and other inevitable impurities;   hot rolling the slab to produce a hot rolled sheet;   hot band annealing the hot rolled sheet at a cracking temperature of 900 to 980□ for 30 to 300 seconds;   cold rolling the hot rolled sheet, which has completely been hot band annealed, to produce a cold rolled sheet;   subjecting the cold rolled sheet to primary recrystallization annealing; and   conducting secondary recrystallization annealing for the cold rolled sheet which has completely been primary recrystallization annealed.
   [Mn]×[S]≤0.0004  [Formula 1]
 
   (wherein [Mn] and [S] are contents (wt %) of Mn and S in the slab, respectively.)   
     
     
         2 . The method of  claim 1 , wherein:
 the slab further includes 0.03 to 0.15 wt % of at least one of Sb and Sn, 0.01 to 0.05 wt % of P, and 0.02 to 0.15 wt % of Cr.   
     
     
         3 . The method of  claim 1 , wherein:
 the slab further includes 0.01 to 0.2 wt % of Cu and 0.01 to 0.05 wt % of Mo.   
     
     
         4 . The method of  claim 1 , further comprising,
 after the hot band annealing, cooling the hot rolled sheet at a cooling rate of from 10□/sec to 300□/sec from a starting temperature of 700 to 850□ to 300□.   
     
     
         5 . The method of  claim 1 , wherein:
 the hot rolled sheet has an elongation of 20% or more after the hot band annealing.   
     
     
         6 . The method of  claim 1 , wherein:
 in the heating of the slab, the slab is heated at a temperature of 1050 to 1200□.