A method of manufacturing a grain oriented electrical steel sheet includes hot rolling a steel slab having a chemical composition including C: 0.002-0.10 mass %, Si: 2.5-5.0 mass %, Mn: 0.01-0.8 mass %, Al: 0.010-0.050 mass % and N: 0.003-0.020 mass % and the remainder being Fe and inevitable impurities to form a hot rolled sheet; subjecting the hot rolled sheet to one cold rolling or two or more cold rollings and interposing an intermediate annealing therebetween after hot band annealing or without hot band annealing to form a cold rolled sheet having a final thickness; subjecting the cold rolled sheet to a primary recrystallization annealing; applying an annealing separator to the surface of the steel sheet; and subjecting the sheet to a finish annealing and forming a tension coating.

To provide a grain-oriented electrical steel sheet that has better magnetic property than conventional ones without requiring high-temperature slab heating, in the case of not performing intermediate annealing, the hot rolled steel sheet obtained by a predetermined step is subjected to hot band annealing, and, in a heating process in the hot band annealing, heating is performed at a heating rate of 10° C./s or less for 10 sec or more and 120 sec or less in a temperature range of 700° C. or more and 950° C. or less, and in the case of performing the intermediate annealing, in a heating process in final intermediate annealing, heating is performed at a heating rate of 10° C./s or less for 10 sec or more and 120 sec or less in a temperature range of 700° C. or more and 950° C. or less.

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 μm to 0.30 μm (inclusive); and the tension of the oxide insulating tension coating film is 10 MPa or more.

A method for refining magnetic domains of a grain-oriented electrical steel sheet according to an exemplary embodiment of the present invention includes: a step of preparing a grain-oriented electrical steel sheet; and a step of forming a groove by irradiating a quasi-continuous laser beam of which a duty is from 98.0 to 99.9% on a surface of the grain-oriented electrical 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.

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

A grain-oriented electrical steel sheet that includes a base coating with a high TiN ratio advantageous for the application of tension to the steel sheet and has excellent magnetic property is provided. The grain-oriented electrical steel sheet includes: a base coating having a peak value PTiN of TiN in the form of osbornite, observed in a range of 42°<2θ<43° and a peak value PSiO.sub.2 of SiO.sub.2 in the form of cristobalite, observed in a range of 23°<2θ<25° of both more than 0 and satisfying a relationship PTiN≥PSiO.sub.2, in thin-film X-ray diffraction analysis; and an iron loss W.sub.17/50 of 1.0 W/kg or less.

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.

A grain-oriented electromagnetic steel sheet exhibits excellent magnetic characteristics and excellent coating film adhesion after strain relieving annealing. The grain-oriented electromagnetic steel sheet includes: a steel sheet; a coating film layer A that is a ceramic coating film which is formed on the steel sheet and has an oxide content of less than 30% by mass; and a coating film layer B that is an insulating tension coating film which is arranged on the coating film layer A and contains an oxide. The binding energy of the 1s orbital of oxygen in the coating film layer B is higher than 530 eV; and tension applied to the steel sheet by the coating film layer B per a thickness of 1.0 μm of the coating film layer B is 4.0 MPa/μm or more.

A grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes a grain-oriented magnetic steel sheet and an insulating tension coating containing a phosphate salt and silica on a surface of the grain-oriented magnetic steel sheet, the coating further including a crystalline compound represented by the general formula (1): M.sup.II.sub.3M.sup.III.sub.4(X.sup.VO.sub.4).sub.6 . . . (1). A method for producing a grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes applying an insulating tension coating liquid to a surface of a finish annealed grain-oriented magnetic steel sheet, the coating liquid including colloidal silica, a phosphate salt and a metal element M-containing compound in a specific ratio, and heat treating the steel sheet at least one time at a temperature of not less than 900° C. in an atmosphere including a non-oxidizing gas and having a dew point of not more than 0° C.