A method for manufacturing a grain-oriented electrical steel sheet, according to an embodiment of the present invention includes: heating a slab, based on 100 wt % of a total composition thereof, including N at 0.0005 wt % to 0.015 wt %, Ti at 0.0001 wt % to 0.020 wt %, V at 0.0001 wt % to 0.020 wt %, Nb at 0.0001 wt % to 0.020 wt %, B at 0.0001 wt % to 0.020 wt %, and the remaining portion including Fe and other impurities, and then hot rolling it to prepare a hot-rolled steel sheet; annealing the hot-rolled steel sheet; after the hot-rolled steel sheet is annealed, cooling the hot-rolled steel sheet, and then cold rolling it to prepare a cold-rolled steel sheet; decarburization-annealing the cold-rolled steel sheet and then nitriding-annealing it, or simultaneously performing the decarburization-annealing and the nitriding-annealing; and final-annealing the decarburization-annealed and nitriding-annealed steel sheet.

Provided is an oriented electrical steel sheet including a groove existing on the surface of the electrical steel sheet and a forsterite layer formed on a part or all of the surface of the electrical steel sheet, in which forsterite which is extended from the forsterite layer and penetrates to a base steel sheet in an anchor form is present on the surface of the side of the groove.

An oriented electrical steel sheet according to an embodiment of the present invention includes, in a unit of wt %, Si at 1.0 wt % to 5.0 wt %, C at 0.005 wt % or less (excluding 0 wt %), Mn at 0.001 wt % to 0.1 wt %, Cu at 0.001 wt % to 0.1 wt %, S at 0.001 wt % to 0.020 wt %, Se at 0.001 wt % to 0.050 wt %, Al at 0.0005 wt % to 0.010 wt %, N at 0.0005 wt % to 0.005 wt %, and the remainder of Fe and inevitable impurities.

The oriented electrical steel sheet according to the embodiment of the present invention satisfies Equation 1.

16≤(10×[Mn]+[Cu])/([S]+[Se])+(0.02−[Al])/[N]≤20  [Equation 1]

(In Equation 1, [Mn], [Cu], [S], [Se], [Al], and [N] represent contents (wt %) of Mn, Cu, S, Se, Al, and N, respectively.)

A method of production non grain-oriented Fe—Si steel sheet is provided. The method includes the steps of melting a steel composition that contains in weight percentage: C≤0.006, 2.0≤Si≤5.0, 0.1≤Al≤3.0, 0.1≤Mn≤3.0, N≤0.006, 0.04≤Sn≤0.2, S≤0.005, P≤0.2, Ti≤0.01, the balance being Fe and other inevitable impurities, casting said melt into a slab, reheating said slab, hot rolling said slab, coiling said hot rolled steel, optionally annealing the hot rolled steel, cold rolling, annealing and cooling the cold rolled steel down to room temperature.

A method for manufacturing a grain-oriented electrical steel sheet according to an embodiment of the present invention comprises the steps of: hot-rolling a slab to prepare a hot-rolled sheet, the slab containing, in wt %, 2.0 to 6.0% of Si, 0.04 to 0.12% of Mn, 0.001 to 0.022% of N, 0.027 to 0.060% of C, 0.01 to 0.08% of Nb, 0.01% or less of Ti, and the balance of Fe and other inevitable impurities; cold-rolling the hot-rolled sheet to prepare a cold-rolled sheet; and subjecting the primarily recrystallization-annealed cold-rolled sheet to secondary recrystallization annealing.

An exemplary embodiment in the present disclosure provides a grain-oriented electrical steel sheet containing, by wt %: 3.0 to 4.5% of Si; 0.05 to 0.2% of Mn; 0.015 to 0.035% of Al; 0.0015% or less (excluding 0%) of C; 0.0015% or less (excluding 0%) of N; 0.0015% or less (excluding 0%) of S; and a balance of Fe and other unavoidable impurities, wherein the grain-oriented electrical steel sheet satisfies the following Relational Expressions 1 and 2:

(W.sub.13/50/W.sub.17/50)≤0.57  [Relational Expression 1]

(W.sub.15/50/W.sub.17/50)≤0.76  [Relational Expression 2] where Wx/y represents a core loss value under conditions in which a magnitude of an applied magnetic field is x/10 T and a frequency is y Hz.

The present invention relates to a grain-oriented electrical steel sheet including 2.0 to 6.0 wt % of Si, 0.01 wt % or less (excluding 0 wt %) of C, 0.01 wt % or less (excluding 0 wt %) of N, and 0.005 to 0.1 wt % of Co, and including a balance of Fe and other inevitable impurities.

Provided are a motor core having excellent fatigue resistance and a method of manufacturing the motor core at a low cost. The motor core that is an electrical-steel-sheet-stacked body has an outer peripheral surface in which an appearance ratio of recrystallized grains with a grain size of 15 μm or less is 70% or more of a sheet thickness of the motor core.

A laminated core (100) has a plurality of legs having an extension direction in a direction perpendicular to a lamination direction of electrical steel sheets and a plurality of yokes having an extension direction in a direction orthogonal to the lamination direction of the electrical steel sheets and the extension direction of the legs, and, in the same position of the electrical steel sheet in the lamination direction, at least a partial region of the legs and at least a partial region of the yokes are configured by the same electrical steel sheet. The electrical steel sheet is disposed such that a first direction of directions of easy magnetization of the electrical steel sheet is along the extension direction of the legs and a second direction of the directions of easy magnetization of the electrical steel sheet is along the extension direction of the yokes.

A grain oriented electrical steel sheet includes the texture aligned with Goss orientation. In the grain oriented electrical steel sheet, when (α.sub.1 β.sub.1 γ.sub.1) and (α.sub.2 β.sub.2 γ.sub.2) represent deviation angles of crystal orientations measured at two measurement points which are adjacent on the sheet surface and which have an interval of 1 mm, the boundary condition BA is defined as |γ.sub.2−γ.sub.1|≥0.5°, and the boundary condition BB is defined as [(α.sub.2−α.sub.1).sup.2+(β.sub.2−β.sub.1).sup.2+(γ.sub.2−γ.sub.1).sup.2].sup.1/2≥2.0°, the boundary which satisfies the boundary condition BA and which does not satisfy the boundary condition BB is included.