A grain-oriented electrical steel sheet having excellent iron loss property is produced from a steel slab containing, by mass %, C: 0.002-0.15%, Si: 2.5-6.0%, Mn: 0.01-0.80%, Al: 0.010-0.050% and N: 0.003-0.020%, when: a heating rate between 500-700 C. In decarburization annealing is not less than 80 C./s, a surface roughness Ra of a work roll in final cold rolling is 0.01-3.0 m, a total content of alkaline earth metals to MgO in annealing separator is 0-5 mass %, an average length L in rolling direction of passed crystal grains is not more than 25 mm, a ratio of crystal grains having a length in rolling direction of not less than 0.5 m is 40-90%, and an existence ratio of alkaline earth metal sulfides having a size corresponding to circle of not less than 0.5 m in a cross section of forsterite film is not more than 0.2/m per unit length in sheet width direction.

Provided are: a grain-oriented electromagnetic steel sheet exhibiting excellent coating film adhesion and excellent magnetic characteristics; and a method for producing this grain-oriented electromagnetic steel sheet. This grain-oriented electromagnetic steel sheet is provided with a ceramic coating film arranged on a steel sheet, and an oxide insulating tension coating film arranged on the ceramic coating film. The ceramic coating film contains a nitride and an oxide; the nitride contains at least one element selected from the group consisting of Cr, Ti, Zr, Mo, Nb, Si, Al, Ta, Hf, W and Y; and the oxide has a corundum crystal structure. The Young's modulus of the ceramic coating film as determined by a nanoindentation method is 230 GPa or more; the average film thickness of the ceramic coating film is from 0.01 m to 0.30 m (inclusive); and the tension of the oxide insulating tension coating film is 10 MPa or more.

A grain-oriented electrical steel sheet subjected to magnetic domain refining by linearly introducing strains in a direction intersecting a rolling direction of the steel sheet repeatedly with intervals in the rolling direction, wherein if a repeating interval of the strains in the rolling direction is d (mm) and, when the steel sheet is placed on a flat surface, a mean value of difference between a height from the flat surface in linear strain-introduced areas of a steel sheet surface and a height from the flat surface in intermediate points between adjacent linear strain-introduced areas is h (mm), then the ratio h/d of the h to the d is 0.0025 or more and 0.015 or less.

In a base sheet for a grain-oriented electrical steel sheet of the present invention, an amount of surface oxygen x per one surface of the base sheet and a value y of a peak (R/R.sub.0 @1250 cm.sup.1) of SiO.sub.2 on the surface of the base sheet obtained by infrared reflection spectroscopy satisfy y1500x.sup.2.5 and y0.24. A method of manufacturing the base sheet for a grain-oriented electrical steel sheet of the present invention includes: adjusting the amount of surface oxygen per one surface of a final-annealed grain-oriented silicon steel sheet to more than 0.01 g/m.sup.2 and 0.05 g/m.sup.2 or less, or more than 0.05 g/m.sup.2 and 0.10 g/m.sup.2 or less; and performing thermal oxidation annealing in an atmosphere in which an oxidation potential represented by a ratio P.sub.H2O/P.sub.H2 of water vapor pressure to hydrogen pressure is 0.0081 or less in a case where the amount of surface oxygen is more than 0.01 g/m.sup.2 and 0.05 g/m.sup.2 or less, or in an atmosphere in which the oxidation potential is 0.005 or less in a case where the amount of surface oxygen is more than 0.05 g/m.sup.2 and 0.10 g/m.sup.2 or less, at a soaking temperature of 1000 C. or lower to form an externally oxidized layer on a surface of the grain-oriented silicon steel sheet.

Provided are: a grain-oriented electrical steel sheet that has an excellent magnetic property and coating adhesiveness after stress relief annealing; and a production method therefor. This grain-oriented electrical steel sheet has: a steel sheet; a metal coating which contains a metal element and which is disposed on the steel sheet; a coating layer A which is a ceramic coating having an oxide content of less than 30 mass % and which is disposed on the metal coating; and a coating layer B which is an insulating tensile coating containing an oxide and which is disposed on the coating layer A, wherein the metal coating has a thickness of 1.0-10.0 nm, and in the metal element, the atomic radius ratio represented by formula (1) is at least 10%, when the atomic radius of iron is defined as RFe and the atomic radius of the metal element as RA.

(|R.sub.FeR.sub.A|/R.sub.Fe)100.Formula (1):

The present invention has been made in an effort to provide an annealing separator component for an oriented electrical steel sheet, an oriented electrical steel sheet, and a manufacturing method thereof. According to an exemplary embodiment of the present invention, an annealing separator composition for an oriented electrical steel sheet, includes: 100 weight parts of at least one of magnesium oxide and magnesium hydroxide; and 5 to 200 weight parts of aluminum hydroxide.

An electrical steel sheet with an insulating film, the steel sheet having an insulating film containing a crystalline fibrous material on a surface of the steel sheet, in which a ratio (L.sub.RD/L.sub.TD) of a length in a rolling direction (L.sub.RD) of the crystalline fibrous material in a cross section in the rolling direction of the insulating film to a length in a direction perpendicular to the rolling direction (L.sub.TD) of the crystalline fibrous material in a cross section in the direction perpendicular to the rolling direction of the insulating film is 1.5 or more and 50.0 or less.

Increasing the chromium content of an electrical steel substrate to a level greater than or equal to about 0.45 weight percent (wt %) produced a much improved forsterite coating having superior and more uniform coloration, thickness and adhesion. Moreover, the so-formed forsterite coating provides greater tension potentially reducing the relative importance of any secondary coating.

The method includes slab-heating a steel slab to a temperature of higher than a ?-phase precipitation temperature and 1380? C. or lower, subjecting the steel slab to rough rolling including at least two passes of rolling at a predetermined temperature with an introduced sheet thickness true strain ?.sub.t of 0.50 or more and to finish rolling with a rolling finish temperature of 900? C. or higher to obtain a hot-rolled sheet, cooling the hot-rolled sheet for 1 second or longer at a cooling rate of 70? C./s or higher within 2 seconds after finish rolling, coiling the sheet at a coiling temperature of 600? C. or lower, performing hot-rolled sheet annealing for soaking at a predetermined soaking temperature, and then performing cold rolling, primary recrystallization annealing, and secondary recrystallization annealing.

Provided is a grain-oriented electrical steel sheet including a base steel sheet, an intermediate layer which is disposed in contact with the base steel sheet and mainly includes silicon oxide, and an insulation coating which is disposed in contact with the intermediate layer and mainly includes phosphate and colloidal silica, in which the base steel sheet contains predetermined chemical composition, BN having an average particle size of 50 to 300 nm is present, when an emission intensity of B is measured using glow discharge emission analysis, predetermined conditions are satisfied, and a ratio of a major axis to a minor axis of BN is 1.5 or less.