A non-oriented electrical steel sheet includes, as a chemical composition, by mass %: C: 0.0015% to 0.0040%; Si: 3.5% to 4.5%; Al: 0.65% or less; Mn: 0.2% to 2.0%; Sn: 0% to 0.20%; Sb: 0% to 0.20%; P: 0.005% to 0.150%; S: 0.0001% to 0.0030%; Ti: 0.0030% or less; Nb: 0.0050% or less; Zr: 0.0030% or less; Mo: 0.030% or less; V: 0.0030% or less; N: 0.0010% to 0.0030%; O: 0.0010% to 0.0500%; Cu: less than 0.10%; Ni: less than 0.50%; and a remainder including Fe and impurities, in which a product sheet thickness is 0.10 mm to 0.30 mm, an average grain size is 10 μm to 40 μm, an iron loss W10/800 is 50 W/Kg or less, a tensile strength is 580 MPa to 700 MPa, and a yield ratio is 0.82 or more.

A method for producing a grain oriented electrical steel sheet includes a decarburization annealing process where an oxidation degree PH.sub.2O/PH.sub.2 is controlled, an annealing separator applying process where a mass ratio of MgO and Al.sub.2O.sub.3 in an annealing separator is controlled, a final annealing process where hydrogen in mixed gas atmosphere is controlled to 50 volume % or more, an annealing separator removing process where water-washing is conducted using solution with inhibitor and then pickling is conducted, a smoothing process where mixed gas and temperature are controlled for annealing, and an insulation coating forming process where a baking temperature and a heat treatment temperature are controlled.

A method for manufacturing a grain-oriented electrical steel sheet includes: a silicon steel material production process of producing a silicon steel material; a hot rolling process of obtaining a hot rolled sheet by subjecting the silicon steel material to hot rolling; a cold rolling process of obtaining a steel sheet of a final sheet thickness by subjecting the hot rolled sheet to a single cold rolling process or multiple cold rolling processes having intermediate annealing performed between the cold rolling processes; a decarburization annealing process of subjecting the steel sheet to decarburization annealing; and a final annealing process of applying an annealing separator containing alumina as a main component to the steel sheet and subjecting the steel sheet to final annealing. The silicon steel material contains: in terms of mass %, Si: 0.8 to 7.0%; C: 0.085% or less; acid-soluble Al: 0.010 to 0.065%; N: 0.004 to 0.012%; Mn: 1.00% or less; S: 0.050% or less; a total of 0.01 to 0.20% of one or both of Sn and Sb; and the remainder: Fe and impurities.

This manufacturing method of a grain-oriented electrical steel sheet is a manufacturing method of a grain-oriented electrical steel sheet having no forsterite film, in which in a decarburization annealing process, a cold-rolled steel sheet is (i-1) heated at an average heating rate (HR1) of 40 to 500° C./sec in a temperature range of 550° C. or higher and lower than 720° C., (i-2) heated at an average heating rate (HR2), which is 5 to 50° C./sec, in a temperature range of 720° C. to T1° C. (770° C.≤T1 (° C.)≤900° C.), and (ii) retained at the temperature of T1° C. for 50 to 1000 seconds to make an amount of C 25 ppm or less in an atmosphere of an oxygen partial pressure (P1) which is 0.0010 to 0.20.

A grain oriented electrical steel sheet includes a base steel sheet, an oxide layer, and a tension-insulation coating. When the iron oxide layer is analyzed by a fourier transform infrared spectroscopy, an absorbance A.sub.650 at 650 cm.sup.−1 and an absorbance A.sub.1250 at 1250 cm.sup.−1 satisfy 0.2≤A.sub.650/A.sub.1250≤5.0. Moreover, a magnetic flux density B8 in a rolling direction of the grain oriented electrical steel sheet is 1.90 T or more.

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.

A method for producing a grain oriented electrical steel sheet includes a decarburization annealing process where an oxidation degree PH.sub.2O/PH.sub.2 is controlled, a final annealing process where hydrogen in mixed gas atmosphere is controlled to 50 volume % or more, an annealing separator removing process where water-washing is conducted using solution with inhibitor, a smoothing process where mixed gas and temperature are controlled for annealing, and an insulation coating forming process where a baking temperature and a heat treatment temperature are controlled.

A method for producing a grain-oriented electrical steel sheet which has an intermediate layer containing silicon oxide as a main component on a surface of a base steel sheet in which a forsterite film is substantially absent and has an insulation coating on a surface of the intermediate layer includes: a decarburization annealing process of obtaining a decarburization-annealed steel sheet which has the oxygen content or 320 ppm or less and the carbon content of 25 ppm or less by subjecting a cold rolled steel sheet containing Si to decarburization annealing; a final annealing process of heating the decarburization-annealed steel sheet in a state in which a surface of the decarburization-annealed steel sheet is coated with an annealing separator to subject a steel sheet to secondary recrystallization; a removal process of obtaining a finally-annealed steel sheet by removing the annealing separator on the steel sheet which has been subjected to the final annealing process; an intermediate layer forming process of forming the intermediate layer by subjecting the finally-annealed steel sheet to thermal oxidation annealing; and an insulation coating forming process of forming the insulation coating on the finally-annealed steel sheet having the intermediate layer formed thereon.

A grain oriented electrical steel sheet includes a base steel sheet, an oxide layer, and a tension-insulation coating. When a glow discharge spectroscopy is conducted in a region from a surface of the tension-insulation coating to an inside of the base steel sheet, a sputtering time Fe.sub.0.5 at which a Fe emission intensity becomes 0.5 times as compared with a saturation value thereof and a sputtering time Fe.sub.0.05 at which a Fe emission intensity becomes 0.05 times as compared with the saturation value satisfy (Fe.sub.0.5−Fe.sub.0.05)/Fe.sub.0.5≥0.35. A maximal point of a Cr emission intensity is included between the Fe.sub.0.05 and the Fe.sub.sat. Moreover, a magnetic flux density B8 in a rolling direction of the grain oriented electrical steel sheet is 1.90 T or more.

Grain-oriented electrical steel sheet excellent in magnetic properties and excellent in adhesion of a primary coating to a base steel sheet, an annealing separator utilized for manufacture of grain-oriented electrical steel sheet, and a method for manufacturing grain-oriented electrical steel sheet are proposed. The grain-oriented electrical steel sheet is provided with a base metal steel sheet containing comprising a predetermined chemical composition and a primary coating formed on a surface of the base steel sheet and comprising Mg2SiO.sub.4 as a main constituent. The primary coating satisfies the conditions of (1) the number density D3 of the A1 concentrated region: 0.020 to 0.180/μm.sup.2 , (2) (total area S5 of regions which is anchoring oxide layer regions and is also A1 concentrated regions)/(total area S3 of Al concentrated regions)≥33%, (3) distance H5 of mean value of length in thickness direction of regions which is anchoring oxide layer regions and is also A1 concentrated regions minus H0: 0.4 to 4.0 μm, (4) (total area S1 of anchoring oxide layer regions)/(observed area S0)≥15%.