Non-oriented electrical steel sheet and method for preparing same
A non-oriented electrical steel sheet according to an exemplary embodiment of the present invention includes, by weight, Si: 2.0 to 3.5%, Al: 0.3 to 2.5%, Mn: 0.3 to 3.5%, Sn: 0.0030 to 0.2%, Sb: 0.0030 to 0.15%, P: 0.0040 to 0.18%, individually or in a total amount of 0.0005 to 0.03% of at least one of Ga and Ge, and a remainder including Fe and unavoidable impurities, and satisfies Equation 1 below. 0.05≤([Sn]+[Sb])/[P]≤25 [Equation 1] ([Sn], [Sb], and [P] respectively represent the content (% by weight) of Sn, Sb, and P.)
1. A non-oriented electrical steel sheet comprising, by weight,
Si: 2.0 to 3.5%,
Al: 0.3 to 2.5%,
Mn: 0.3 to 3.5%,
Sn: 0.0030 to 0.2%,
Sb: 0.0030 to 0.15%,
P: 0.0040 to 0.18%,
Ga: 0.0005 to 0.02%,
Ge: 0.0005 to 0.02% such that a total amount of Ga and Ge is 0.001 to 0.03%, and
a remainder including Fe and unavoidable impurities, and
satisfying Equations 1 to 3 below:
0.05≤([Sn]+[Sb])/[P]≤25 [Equation 1]
0.2≤([Si]+[A1]+0.5×[Mn])/(([Ga]+[Ge])×1000)≤5.27 [Equation 2]
3.3≤([Si]+[A1]+0.5×[Mn])≤5.5 [Equation 3]
where [Si], [Al], [Mn], [Ga], [Ge], [Sn], [Sb], and [P] respectively represent the content, % by weight, of Si, Al, Mn, Ga, Ge, Sn, Sb, and P,
wherein the steel sheet has a texture satisfying a strength ratio of P200/(P211+P310) ≥0.5 as tested by XRD-testing an area of ½t to ¼t of a thickness of the steel sheet,
where ½t refers to ½ of the thickness of the entire steel sheet,
¼t refers to ¼ of the thickness of the entire steel sheet,
P200 refers to a strength of a diffraction peak obtained within 15 degrees of a 200 plane appearing in the XRD test,
P211 refers to a strength of a diffraction peak obtained within 15 degrees of a 211 plane, and
P310 refers to a peak of a diffraction strength obtained within 15 degrees of a 310 plane.
2. The non-oriented electrical steel sheet of claim 1 , further comprising
one or more of 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 of claim 1 , wherein an average diameter of grains is 50 to 95 μm.
4. The non-oriented electrical steel sheet of claim 1 , comprising, by weight, Mn: 1 to 3.5%.
5. The non-oriented electrical steel sheet of claim 1 , wherein Ga: 0.001 to 0.02 wt % and Ge: 0.005 to 0.02 wt % are included.
6. The non-oriented electrical steel sheet of claim 1 , consisting of, by weight,
Si: 2.0 to 3.5%,
Al: 0.3 to 2.5%,
Mn: 0.3 to 3.5%,
Sn: 0.0030 to 0.2%,
Sb: 0.0030 to 0.15%,
P: 0.0040 to 0.18%,
Ga: 0.0005 to 0.02%,
Ge: 0.0005 to 0.02% such that a total amount of Ga and Ge is 0.001 to 0.03%, and a remainder including Fe and unavoidable impurities.
7. A method for manufacturing the non-oriented electrical steel sheet of claim 1 , comprising:
producing a slab including, by weight, Si: 2.0 to 3.5%, Al: 0.3 to 2.5%, Mn: 0.3 to 3.5% %, Sn: 0.0030 to 0.2%, Sb: 0.0030 to 0.15%, P: 0.0040 to 0.18,
Ga: 0.0005 to 0.02% Ge: 0.0005 to 0.02% such that a total amount of Ga and Ge is 0.001 to 0.03%, and a remainder including Fe and unavoidable impurities, and satisfying Equation 1;
heating the slab;
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 sheet:
0.05≤([Sn]+[Sb])/[P]≤25 [Equation 1]
(({Sn], [Sb], and [P] respectively represent the content (% by weight) of Sn, Sb, and P); thereby producing the non-oriented electrical steel sheet of claim 1 .
8. The method for manufacturing the non-oriented electrical steel sheet of claim 7 , wherein
the slab further includes one or more of 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%).
9. The method for manufacturing the non-oriented electrical steel sheet of claim 7 , wherein
the slab satisfies Equation 2 below:
0.2≤([Si]+[A1]+0.5×[Mn])/(([Ga]+[Ge])×1000)≤5.27 [Equation 2]
([Si], [Al], [Mn], [Ga], and [Ge] respectively represent the content (% by weight) of Si, Al, Mn, Ga, and Ge.).
10. The method for manufacturing the non-oriented electrical steel sheet of claim 7 , wherein
the slab satisfies Equation 3 below:
3.3≤([Si]+[A1]+0.5×[Mn])≤5.5 [Equation 3]
([Si], [Al], and [Mn] respectively represent the content (% by weight) of Si, Al, and Mn.).
11. The method for manufacturing the non-oriented electrical steel sheet of claim 7 , further comprising
after producing the hot-rolled sheet,
annealing the hot-rolled sheet.
12. The method for manufacturing the non-oriented electrical steel sheet of claim 11 , wherein
in the annealing of the hot-rolled sheet, the hot-rolled sheet is annealed at a temperature of 1050 to 1150° C.