A method for manufacturing a grain-oriented electrical steel sheet according to an aspect of the present invention includes a step of obtaining a hot-rolled steel sheet by carrying out hot rolling on a slab containing a predetermined component composition with a remainder including Fe and impurities, a step of obtaining a hot-rolled annealed sheet by carrying out hot-rolled sheet annealing as necessary, a step of carrying out pickling to obtain a pickled sheet, a step of carrying out cold rolling to obtain a cold-rolled steel sheet, a step of carrying out primary recrystallization annealing, a step of applying an annealing separating agent including MgO to a surface and then carrying out final annealing to obtain a final-annealed sheet, and a step of applying an insulating coating and then carrying out flattening annealing.

This electrical steel sheet is an electrical steel sheet in which at least part of either or both surfaces of a base steel sheet is coated with an insulation coating having an adhesive ability, wherein a logarithmic decrement of the insulation coating in a temperature range of 25 to 100° C. is 0.3 or less.

This electrical steel sheet is an electrical steel sheet in which at least part of either or both surfaces of a base steel sheet is coated with an insulation coating having an adhesive ability, wherein a logarithmic decrement of the insulation coating in a temperature range of 25 to 100° C. is 0.3 or less.

A grain oriented electrical steel sheet includes: a base steel sheet; a lower layer which is arranged in contact with the base steel sheet; and an insulation coating which is arranged in contact with the lower layer and which includes a phosphate and a colloidal silica as main components. The base steel sheet includes the predetermined chemical composition and includes a B compound whose major axis length is 1 to 20 μm and whose number density is 1×10 to 1×10.sup.6 pieces/mm.sup.3. The lower layer is a glass film which includes a forsterite as main component or an intermediate layer includes a silicon oxide as main component.

A grain oriented electrical steel sheet includes: a base steel sheet; a glass film which is arranged in contact with the base steel sheet; and an insulation coating which is arranged in contact with the glass film and which includes a phosphate and a colloidal silica as main components. The base steel sheet includes the predetermined chemical composition. A BN whose average particle size is 50 to 300 nm is included at a predetermined number density in a region which is from an interface between the glass film and the insulation coating till 5 μm toward the base steel sheet in a depth direction. A B emission intensity obtained inside the glass film is more than a B emission intensity obtained inside the base steel sheet, when a B emission intensity is measured from a surface of the insulation coating by a glow discharge emission spectroscopy.

A transformer core includes two stacks, each of first thickness with ≥1 flat parts, the cutting directions rectilinear and parallel or perpendicular to one another, the stacks facing across a gap, the flat parts made of an austenitic FeNi alloy 30-80% Ni and 10% alloying elements, with a sharp {100} <001> cubic texture, the cutting directions of the flat parts parallel to the rolling or transverse direction, the flat parts having magnetic losses, for a maximum induction of 1 T, <20 W/kg at 400 Hz, producing apparent magnetostriction for maximum induction values and field directions as follows: 1.2 T<5 ppm, large side of the sample parallel to rolling direction; 1.2 T<5 ppm, large side of the sample parallel to transverse direction in the rolling plane; and 1.2 T<10 ppm, length direction parallel to intermediate direction 45° to rolling and transverse directions.

A transformer core includes two stacks, each of first thickness with ≥1 flat parts, the cutting directions rectilinear and parallel or perpendicular to one another, the stacks facing across a gap, the flat parts made of an austenitic FeNi alloy 30-80% Ni and 10% alloying elements, with a sharp {100} <001> cubic texture, the cutting directions of the flat parts parallel to the rolling or transverse direction, the flat parts having magnetic losses, for a maximum induction of 1 T, <20 W/kg at 400 Hz, producing apparent magnetostriction for maximum induction values and field directions as follows: 1.2 T<5 ppm, large side of the sample parallel to rolling direction; 1.2 T<5 ppm, large side of the sample parallel to transverse direction in the rolling plane; and 1.2 T<10 ppm, length direction parallel to intermediate direction 45° to rolling and transverse directions.

Disclosed is a grain-oriented electrical steel sheet capable of obtaining excellent magnetic properties stably over the entire coil length. A grain-oriented electrical steel sheet includes: a chemical composition containing, in mass %, C: 0.005% or less, Si: 2.0% to 4.5%, and Mn: 0.01% to 0.5%, and, in mass ppm, N: 20 ppm or less, each of Se, Te, and O: less than 50 ppm, S: less than 30 ppm, and acid-soluble Al: less than 40 ppm, and Ti: less than 30 ppm, of which 5 ppm or more and 25 ppm or less is acid-soluble Ti, with the balance being Fe and inevitable impurities; and precipitates containing Ti and N with a grain size of 200 nm or more at a frequency of 0.05 grains/mm.sup.2 or more.

There is provided a non-oriented electrical steel sheet that includes a base metal steel sheet and an insulating coating film that is formed on a surface of the base metal steel sheet, wherein the insulating coating film mainly contains metal phosphate, organic resin, and water-soluble organic compound, the metal phosphate contains at least aluminum as a metallic element, the organic resin has an SP value being within a range of 18.0 (MPa).sup.0.5 or more to less than 24.0 (MPa).sup.0.5, the water-soluble organic compound has an SP value being within a range of 19.0 (MPa).sup.0.5 or more to less than 35.0 (MPa).sup.0.5, and when measurement by X-ray diffractometry is performed on the insulating coating film, a degree of crystallinity of aluminum phosphate calculated from a peak from the metal phosphate is within a range of 0.5 to 5.0%.

There is provided a non-oriented electrical steel sheet that includes a base metal steel sheet and an insulating coating film that is formed on a surface of the base metal steel sheet, wherein the insulating coating film mainly contains metal phosphate, organic resin, and water-soluble organic compound, the metal phosphate contains at least aluminum as a metallic element, the organic resin has an SP value being within a range of 18.0 (MPa).sup.0.5 or more to less than 24.0 (MPa).sup.0.5, the water-soluble organic compound has an SP value being within a range of 19.0 (MPa).sup.0.5 or more to less than 35.0 (MPa).sup.0.5, and when measurement by X-ray diffractometry is performed on the insulating coating film, a degree of crystallinity of aluminum phosphate calculated from a peak from the metal phosphate is within a range of 0.5 to 5.0%.