Provided is a non-oriented electrical steel sheet having an average crystal grain size of crystal grains being not more than 80 μm, an area ratio of crystal grains having a grain size of not less than 1.5 times the average crystal grain size being not less than 10%; and an area ratio of crystal grains having aspect ratios of not more than 0.3 being not more than 20%, by subjecting a steel raw material containing, in mass %, C: not more than 0.005%, Si: 2.0 to 5.0%, Mn: 0.05 to 5.0%, Al: not more than 3.0%, and Zn: 0.0003 to 0.0050% to hot rolling, cold rolling, and cold-rolled sheet annealing and by heating the cold-rolled sheet to an annealing temperature between 700 to 850° C. at the average heating rate between 500 and 700° C. in a heating process of the cold-rolled sheet annealing to be not less than 10° C./s.

An annealing separator for an oriented electrical steel sheet including: a first component includes a Mg oxide or a Mg hydroxide; and a second component including one kind among oxides and hydroxides of a metal selected from Al, Ti, Cu, Cr, Ni, Ca, Zn, Na, K, Mo, In, Sb, Ba, Bi, and Mn, or two or more kinds thereof.

Provided is a method for manufacturing a grain-oriented electrical steel sheet. A steel slab having a specific chemical composition is heated and hot rolled. A hot-rolled steel sheet thus obtained is subjected to hot band annealing to obtain a cold-rolled steel sheet, which is then subjected to primary recrystallization annealing to obtain a primary recrystallized steel sheet. An annealing separator is applied to the primary recrystallized steel sheet, which is then coiled. The coil is subjected to secondary recrystallization annealing to obtain a grain-oriented electrical steel sheet having an average value of a deviation angle (α.sup.2+β.sup.2).sup.1/2 calculated from a deviation angle α from ideal Goss orientation around an ND rotation axis and a deviation angle β from ideal Goss orientation around a TD rotation axis of 4.5° or less, and an area ratio R.sub.β of crystal grains with β≤0.50° of 15% or less.

Provided is a method for manufacturing a grain-oriented electrical steel sheet. The method comprises: hot rolling a slab to obtain a hot rolled sheet; subjecting the hot rolled sheet to hot band annealing as necessary; subjecting the hot rolled sheet to cold rolling; subjecting the cold rolled sheet to decarburization annealing; applying an annealing separator having MgO as a main component onto a surface of the decarburization annealed sheet and subjecting the decarburization annealed sheet to final annealing to form the forsterite film; and applying an insulating coating treatment liquid onto the final annealed sheet and subjecting the final annealed sheet to flattening annealing to form a tension-applying insulating coating. A difference in total tensions between one and opposite surfaces of the sheet is less than 0.5 MPa. A difference in tensions between the forsterite films in one and opposite surfaces of the sheet is 0.5 MPa or more.

A non-oriented electrical steel sheet according to one embodiment of the present invention includes a base metal steel sheet, and a composite coating film composed of a Zn-containing phosphate and an organic resin, the composite coating film being formed on a surface of the base metal steel sheet, wherein: a content of Zn in the composite coating film is 10 mg/m.sup.2 or more per side; and the product of an amount of oxygen in the base metal steel sheet and a sheet thickness of the base metal steel sheet is 50 ppm.Math.mm or less.

The present disclosure provides a manufacturing method and a grain-oriented electrical steel sheet manufactured thereby, the manufacturing method comprising the steps of: heating a slab; hot rolling the heated slab so as to manufacture a hot-rolled sheet; cold rolling the hot-rolled sheet so as to manufacture a cold-rolled sheet; decarburizing and annealing the cold-rolled steel sheet; forming a ceramic coating layer on a portion or the whole of one surface or two sides of the decarburized and annealed cold-rolled sheet by using a chemical vapor deposition (CVD) process; and finally annealing the cold-rolled sheet on which the ceramic coating layer is formed.

A grain-oriented electrical steel sheet according to an embodiment of the present invention may comprise: by weight %, 2.0-4.0% of Si, 0.04-0.2% of Mn, 0.010% or less (exclusive of 0%) of N, 0.01-0.05% of Sb, 0.005% or less (exclusive of 0%) of C, 0.03-0.08% of Sn, 0.01-0.2% of Cr, and the balance of Fe and inevitable impurities; and precipitates which have an average particle size of 5-50 nm and contain at least one of AIN, (Al, Si)N, (Al, Si, Mn)N, Mns, and CuS.

A non-oriented electrical steel sheet according to an embodiment of the present invention includes, in wt %, Si: 2.1 to 3.8%, Mn: 0.001 to 0.6%, Al: 0.001 to 0.6%, Bi: 0.0005 to 0.003%, and Ge: 0.0003 to 0.001%, and the balance of Fe and inevitable impurities.

In a double-oriented electrical steel sheet according to an embodiment of the present invention, the fraction of crystal grains having an orientation within 15° from {100}<001> is 50 to 75%, and the fraction of crystal grains having an orientation within 15° from {100}<380> is 50 to 75%.

A grain oriented electrical steel sheet includes a base steel sheet, a glass film, and a tension-insulation coating. When a glow discharge emission spectroscopy is conducted from a surface of the glass film toward a depth direction, an analysis starting time Ts, a time T.sup.Al.sub.p at which Al shows a maximum emission intensity, an Al emission intensity F(T.sup.Al.sub.p) at the T.sup.Al.sub.p, a time T.sup.Si.sub.p at which Si shows a maximum emission intensity, and an Al emission intensity F(T.sup.Si.sub.p) at the T.sup.Si.sub.p satisfy 0.05≤F(T.sup.Si.sub.p)/F(T.sup.Al.sub.p)≤0.50 and 2.0≤(T.sup.Al.sub.p−Ts)/(T.sup.Si.sub.p−Ts)≤5.0.