Non-oriented electrical steel sheet and manufacturing method therefor
A non-oriented electrical steel sheet according to an embodiment of the present invention may include, by weight, by weight, 2.0 to 3.5% of Si, 0.3 to 2.5% of Al, 0.3 to 2.5% of Mn, individually or in a total amount of 0.0005 to 0.03% of at least one of Ga and Ge, and the remainder including Fe and impurities, and may satisfy the following Formula 1. 0.2≤([Si]+[Al]+0.5×[Mn])/(([Ga]+[Ge])×1000)≤5.27 [Formula 1] ([Si], [Al], [Mn], [Ga] and [Ge] represent the content (% by weight) of Si, Al, Mn, Ga and Ge, respectively).
1. A non-oriented electrical steel sheet, comprising: by weight, 2.0 to 3.5% of Si, 0.3 to 2.5% of Al, 0.3 to 2.5% of Mn, individually or in a total amount of 0.0005 to 0.03% of at least one of Ga and Ge, and the remainder comprising Fe and unavoidable impurities, wherein the non-oriented electrical steel sheet satisfies the following Formula 1 and Formula 2:
0.2≤([Si]+[Al]+0.5×[Mn])/(([Ga]+[Ge])×1000)≤5.27 [Formula 1]
3.3≤([Si]+[Al]+0.5×[Mn])≤5.5 [Formula 2]
wherein ([Si], [Al], [Mn], [Ga], and [Ge] represent the content, by weight %, of Si, Al, Mn, Ga, and Ge, respectively.
2. The non-oriented electrical steel sheet according to claim 1 ,
further comprising N: 0.0040% or less, excluding 0%, C: 0.0040% or less excluding 0%, S: 0.0040% or less, excluding 0%, Ti: 0.0030% or less, excluding 0%, Nb: 0.0030% or less, excluding 0%, and V: 0.0040% or less, excluding 0%.
3. The non-oriented electrical steel sheet according to claim 1 , comprising 0.0005 to 0.02% by weight of Ga and 0.0005 to 0.02% by weight of Ge.
4. The non-oriented electrical steel sheet according to claim 1 ,
wherein the strength ratio of the set tissue satisfies P200/(P211+P310)≥0.5 when XRD test is performed on the area of ½t to ¼t of the thickness of the steel sheet
wherein ½t means ½ of the thickness of the entire steel sheet, ¼t means ¼ of the thickness of the entire steel sheet, P200 means the surface strength of the set tissue in which the <200> plane lies parallel to the vertical direction of the steel sheet within 15 degrees, P211 means the surface strength of the set tissue in which the <211> plane lies parallel to the vertical direction of the steel sheet within 15 degrees, and P310 means the surface strength of the set tissue in which the <300> plane lies parallel to the vertical direction of the steel sheet within 15 degrees, in XRD test.
5. The non-oriented electrical steel sheet according to claim 1 ,
wherein the average diameter of grain is 50 to 95 μm.
6. The non-oriented electrical steel sheet according to claim 1 ,
having a magnetic permeability at 100 A/m of 8000 or more and a coercive force at B=2.0T of 40 A/m or less.
7. The non-oriented electrical steel sheet according to claim 1 , having a resistivity of 55 to 75 μΩcm.
8. A method for manufacturing a non-oriented electrical steel sheet, comprising:
heating the slab comprising, by weight, 2.0 to 3.5% of Si, 0.3 to 2.5% of Al, 0.3 to 2.5% of Mn, individually or in a total amount of 0.0005 to 0.03% of at least one of Ga and Ge, and the remainder comprising Fe and unavoidable impurities, and satisfying the following Formula 1;
hot rolling the slab to produce a hot-rolled sheet;
cold rolling the hot-rolled sheet to produce a cold-rolled sheet; and
finally annealing the cold-rolled steel sheet;
0.2≤([Si]+[Al]+0.5×[Mn])/(([Ga]+[Ge])×1000)≤5.27 [Formula 1]
([Si], [Al], [Mn], [Ga], and [Ge] represent the content (% by weight) of Si, Al, Mn, Ga, and Ge, respectively).
9. The method for manufacturing a non-oriented electrical steel sheet according to claim 8 ,
wherein the slab further comprises N: 0.0040% or less (excluding 0%), C: 0.0040% or less (excluding 0%), S: 0.0040% or less (excluding 0%), Ti: 0.0030% or less (excluding 0%), Nb: 0.0030% or less (excluding 0%), and V: 0.0040% or less (excluding 0%).
10. The method for manufacturing a non-orietned electrical steel sheet according to claim 8 ,
wherein the slab comprises 0.0005 to 0.02% by weight of Ga and 0.0005 to 0.02% by weight of Ge.
11. The method for manufacturing a non-orietned electrical steel sheet according to claim 8 , wherein the slab satisfies the following Formula:
3.3≤([Si]+[Al]+0.5×[Mn])≤5.5 [Formula 2]
([Si], [Al], and [Mn] represent the content, (% by weight of Si, Al, and Mn, respectively).
12. The method for manufacturing a non-oriented electrical steel sheet according to claim 8 ,
prior to the step of heating the slab, further comprising: producing molten steel;
adding Si alloy iron, Al alloy iron, and Mn alloy iron to the molten steel; and
adding at least one of Ga and Ge to the molten steel and continuously casting the molten steel to produce a slab.
13. The method for manufacturing a non-oriented electrical steel sheet according to claim 8 ,
after the step of producing the hot-rolled sheet, further comprising the step of annealing the hot-rolled sheet.