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

Abstract

A non-directional electrical steel sheet according to an embodiment of the present disclosure includes, in wt %, 2.5 to 3.3 wt % of Si, 0.05 to 1 wt % of Al, 0.05 to 1 wt % of Mn, 0.01 wt % or less of (not including 0 wt %) S, 0.005 wt % or less of (not including 0 wt %) N, 0.005 wt % or less of (not including 0 wt %) C, 0.005 wt % or less of (not including 0 wt %) Ti, 0.005 wt % or less of (not including 0 wt %) 0.001 to 0.1 wt % of P, 0.001 to 0.1 wt % of Sn, and 0.001 to 0.1 wt % of Sb, with the remainder being Fe and unavoidable impurities, and satisfies Formulas 1 to 3 below. 1.7≤[Si]([Al]+[Mn])≤2.9   [Formula 1] 50≤13.25+11.3*([Si]+[Al][Mn]/2)≤60   [Formula 2] 0.025≤[P]+[Sn]+[Sb]≤0.15   [Formula 3] (In Formulas 1 to 3, [Si], [Al], [Mn], [P], [Sn], and [Sb] represent the content (in wt %) of Si, Al, Mn, P, Sn, and Sb, respectively).

1 . A non-directional electrical steel sheet, comprising, in wt %, 2.5 to 3.3 wt % of Si, 0.05 to 1 wt % of Al, 0.05 to 1 wt % of Mn, 0.01 wt % or less of (not including 0 wt %) S, 0.005 wt % or less of (not including 0 wt %) N, 0.005 wt % or less of (not including 0 wt %) C, 0.005 wt % or less of (not including 0 wt %) Ti, 0.005 wt % or less of (not including 0 wt %) Nb, 0.001 to 0.1 wt % of P, 0.001 to 0.1 wt % of Sn, and 0.001 to 0.1 wt % of Sb, with the remainder being Fe and unavoidable impurities, and satisfying Formulas 1 to 3 below.
   1.7≤[Si]/([Al]+[Mn]/2)≤2.9   [Formula 1]
     50≤13.25+11.3*([Si]+[Al]+[Mn]/2)≤60   [Formula 2]
     0.025≤[P]+[Sn]+[Sb]≤0.15   [Formula 3]
   (In Formulas 1 to 3, [Si], [Al], [Mn], [P], [Sn], and [Sb] represent the content (in wt %) of Si, Al, Mn, P, Sn, and Sb, respectively).   
     
     
         2 . The non-directional electrical steel sheet of  claim 1 , further comprising
 0.001 wt % or less of (not including 0 wt %) B, 0.005 wt % or less of (not including 0 wt %) Mg, Zr and V and 0.025 wt % or less of (not including 0 wt %) Cu.   
     
     
         3 . The non-directional electrical steel sheet of  claim 1 , wherein
 a density of 7.57 to 7.67 g/cm 3  is calculated by Formula 4 below.
   7.865+(−0.0611*[Si]−0.102*[Al]+0.00589*[Mn])  [Formula 4]
 
   (In Formula 4, [Si], [Al] and [Mn] represent the contents (in wt %) of Si, Al and Mn, respectively.)   
     
     
         4 . The non-directional electrical steel sheet of  claim 1 , wherein
 a tensile test elongation is 24% or higher.   
     
     
         5 . The non-directional electrical steel sheet of  claim 1 , wherein
 a thickness is 0.10 to 0.35 mm.   
     
     
         6 . A method for manufacturing a non-directional electrical steel sheet, comprising steps of heating a slab comprising, in wt %, 2.5 to 3.3 wt % of Si, 0.05 to 1 wt % of Al, 0.05 to 1 wt % of Mn, 0.01 wt % or less of (not including 0 wt %) S, 0.005 wt % or less of (not including 0 wt %) N, 0.005 wt % or less of (not including 0 wt %) C, 0.005 wt % or less of (not including 0 wt %) Ti, 0.005 wt % or less of (not including 0 Nb, 0.001 to 0.1 wt % of P, 0.001 to 0.1 wt of Sn, and 0.001 to 0.1 wt % of Sb, with the remainder being Fe and unavoidable impurities, and satisfying Formulas 1 to 3 below and then hot rolling the slab to manufacture a hot rolled sheet;
 cold rolling the hot rolled sheet to manufacture a cold rolled sheet; and   recrystallization annealing the cold rolled sheet.
   1.7≤[Si]/([Al]+[Mn]/2)≤2.9   [Formula 1]
 
   50≤13.25+11.3*([Si]+[Al]+[Mn]/2)≤60   [Formula 2 ]
 
   0.025≤[P]+[Sn]+[Sb]≤0.15   [Formula 3 ]
 
   (In Formulas 1 to 3, [Si], [Al], [Mn], [P], [Sn], and [Sb] represent the content (in wt %) of Si, Al, Mn, P, Sn, and Sb, respectively).   
     
     
         7 . The method of  claim 6 , wherein
 the step of manufacturing the hot rolled sheet comprises heating the slab at 1100 to 1200° C.   
     
     
         8 . The method of  claim 6 , wherein
 the step of manufacturing the hot rolled sheet comprises hot rolling at a finish temperature of 800 to 1000° C.   
     
     
         9 . The method of  claim 6 ,
 after the step of manufacturing the hot rolled sheet, further comprising a step of annealing the hot rolled sheet at a temperature of 850 to 1150° C.   
     
     
         10 . The method of  claim 6 ,
 wherein the slab further includes 0.001 wt % or less of (not including 0 wt %) B, 0.005 wt % or less of (not including 0 wt %) Mg, Zr and V and 0.025 wt % or less of (not including 0 wt %) Cu.   
     
     
         11 . The method of  claim 6 ,
 wherein the manufactured steel sheet has a density of 7.57 to 7.67 g/cm 3  as calculated by Formula 4 below.
   7.865+(−0.0611*[Si]−0.102*[Al]+0.00589*[Mn])  [Formula 4]
 
   (In Formula 4, [Si], [Al] and [Mn] represent the contents (in wt %) of Si, Al and Mn, respectively.)   
     
     
         12 . The method of  claim 6 ,
 wherein the manufactured steel sheet has a tensile test elongation of 24% or higher.   
     
     
         13 . The method of  claim 6 ,
 wherein the step of manufacturing the cold rolled sheet comprises cold rolling at a thickness of 0.10 to 0.35 mm.