Grain-oriented electrical steel sheet and method for manufacturing the same

Abstract

The grain-oriented electrical steel sheet according to one embodiment of the present invention includes, by weight, Si: 1.0 to 7.0%, B: 0.001 to 0.1%, and Ba and Y individually or in a total amount of 0.005 to 0.5%, and the remainder includes Fe and other unavoidable impurities.

What claimed is: 
     
         1 . A grain-oriented electrical steel sheet comprising, by weight, Si: 1.0 to 7.0%, B: 0.001 to 0.1%, and Ba and Y individually or in a total amount of 0.005 to 0.5%, and the remainder comprising Fe and other unavoidable impurities. 
     
     
         2 . The grain-oriented electrical steel sheet according to  claim 1 ,
 satisfying the following formula (1).
   0.5≤([Ba]+[Y])/([B]*10)≤3   [Formula 1]
 
   (In the Formula (1), [Ba], [Y], and [B] represent the contents (% by weight) of Ba, Y and B, respectively.)   
     
     
         3 . The grain-oriented electrical steel sheet according to  claim 1 ,
 further comprising C: 0.005% or less (excluding 0%), Al: 0.005% or less (excluding 0%), N: 0.0055% or less (excluding 0%), and S: 0.0055% or less (excluding 0%).   
     
     
         4 . The grain-oriented electrical steel sheet according to  claim 1 ,
 further comprising Mn: 0.01% to 0.5%.   
     
     
         5 . The grain-oriented electrical steel sheet according to  claim 1 ,
 wherein the average particle diameter of the grains having a particle diameter of 2 mm or more is 10 mm or more.   
     
     
         6 . The grain-oriented electrical steel sheet according to  claim 1 ,
 comprising B and, Ba or Y segregated in the grain boundaries.   
     
     
         7 . A method for manufacturing grain-oriented electrical steel sheet comprising:
 a step of heating the slab comprising, by weight, Si: 1.0 to 7.0%, B: 0.001 to 0.1%, and Ba and Y individually or in a total amount of 0.005 to 0.5%, and the remainder comprising Fe and other unavoidable impurities;   a step of hot-rolling the slab to produce a hot-rolled sheet;   a step of cold-rolling the hot-rolled sheet to produce a cold-rolled sheet;   a step of the primary recrystallization annealing the cold-rolled sheet; and   a step of the second recrystallization annealing the cold-rolled sheet after the primary recrystallization annealing is completed.   
     
     
         8 . The method for manufacturing grain-oriented electrical steel sheet according to  claim 7 ,
 wherein the slab satisfies the following Formula (1).
   0.5≤([Ba]+[Y])/([B]*10)≤3   [Formula 1]
 
   (In the formula (1), [Ba], [Y], and [B] represent the contents (% by weight) of Ba, Y, and B, respectively.)   
     
     
         9 . The method for manufacturing grain-oriented electrical steel sheet according to  claim 7 ,
 wherein the slab further comprises C: 0.001 to 0.1%, Al: 0.01% or less (excluding 0%), N: 0.0055% or less (excluding 0%), and S: 0.0055% or less (excluding 0%).   
     
     
         10 . The method for manufacturing grain-oriented electrical steel sheet according to  claim 7 ,
 wherein the slab further comprises Mn: 0.01 to 0.5%.   
     
     
         11 . The method for manufacturing grain-oriented electrical steel sheet according to  claim 7 ,
 wherein the slab is heated to 1000 to 1280° C. in the step of heating the slab.   
     
     
         12 . The method for manufacturing grain-oriented electrical steel sheet according to  claim 7 ,
 wherein the final reduction roll is 80% or more in the step of cold-rolling the hot-rolled sheet to produce a cold-rolled sheet.   
     
     
         13 . The method for manufacturing grain-oriented electrical steel sheet according to  claim 7 ,
 wherein the second recrystallization annealing step comprises a temperature elevating step and a cracking step, and the temperature of the cracking step is 900 to 1250° C.