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: 2.5 to 6.0%, Al: 0.2 to 3.5%, Mn: 0.2 to 4.5%, Cr: 0.01 to 0.2%, P: 0.005 to 0.08%, Mg: 0.0005 to 0.05%, and a remainder including Fe and inevitable impurities, while satisfying Equation 1 below, and formed with an inner oxidation layer of a 0.2 to 5 μm thickness inside a base steel sheet. −2.5≤[P]/[Cr]−[Mg]×100≤6.5 [Equation 1] (In Equation 1, [P], [Cr], and [Mg] respectively represent a content (by wt %) of P, Cr, and Mg).
1. A non-oriented electrical steel sheet comprising, by a weight %, Si: 2.5 to 6.0%, Al: 0.2 to 3.5%, Mn: 0.2 to 4.5%, Cr: 0.01 to 0.2%, P: 0.005 to 0.08%, Mg: 0.0005 to 0.05%, and a remainder including Fe and inevitable impurities, satisfying Equation 1 below and formed with an inner oxidation layer of a 1 to 3 μm thickness inside a base steel sheet:
−2.5≤[P]/[Cr]−[Mg]×100≤6.5 [Equation 1]
in Equation 1, [P], [Cr, and [Mg] respectively represent a content (by wt %) of P, Cr, and Mg.
2. The non-oriented electrical steel sheet of claim 1 , wherein
the inner oxidation layer is formed in a range of 1.2-2.5 μm.
3. The non-oriented electrical steel sheet of claim 1 , wherein
the inner oxidation layer includes one oxide or more of Cr 2 O 3 and MgO.
4. The non-oriented electrical steel sheet of claim 1 , wherein
an average roughness of an interface of the inner oxidation layer and the base steel sheet is 1 to 5 μm.
5. The non-oriented electrical steel sheet of claim 1 , further comprising
a surface oxidation layer in contact with the surface of the base steel sheet and formed in the inner direction of the base steel sheet.
6. The non-oriented electrical steel sheet of claim 5 , wherein
the inner oxidation layer and surface oxidation layer include 0.05 wt % or more of oxygen.
7. The non-oriented electrical steel sheet of claim 5 , wherein
the thickness of the inner oxidation layer is thicker than the thickness of the surface oxidation layer.
8. The non-oriented electrical steel sheet of claim 1 , wherein
the resistivity of the non-oriented electrical steel sheet is 45 μΩ·cm or more.
9. The non-oriented electrical steel sheet of claim 1 , wherein
the non-oriented electrical steel sheet further comprises at least one of C, S, N, Ti, Nb, and V at 0.004 wt % or less.