Abstract: Proposed is a method for producing a grain-oriented electrical steel sheet that comprises heating a steel material containing a certain composition and inhibitor-forming ingredients to a temperature in a range of 1300 to 1400° C.; performing hot rolling, hot-band annealing, and cold rolling on the material to obtain a cold-rolled sheet; performing decarburization annealing also serving as primary recrystallization annealing on the cold-rolled sheet; subsequently applying an annealing separator to a surface of the steel sheet; and performing finishing annealing followed by applying an insulation coating. In the method, rapid heating is conducted from 500 and 700° C. in a heating process of the decarburization annealing at a rate of 100 to 1000° C./s while gradual heating is conducted from 860 to 970° C. in a heating process of the finishing annealing at a heating rate of 0.5 to 4.0° C./hr for at least 10 hours.

Abstract: 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 ?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.

Abstract: 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 ?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 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.

Abstract: A grain-oriented electrical steel sheet with extremely excellent magnetic properties by removing an etching resist coating well to form narrow grooves on a metal strip surface even with low-output laser, while reducing thermal effects on the metal strip caused by laser irradiation, and a method for forming grooves on a metal strip surface, having forming an etching resist coating with 0 to 70 lightness L* on at least one side of the metal strip, irradiating laser with less than 1.5 kW output on the etching resist coating while scanning the laser in a direction that intersects a rolling direction of the metal strip to remove a portion of the etching resist coating irradiated by the laser, and etching a portion of the metal strip below the removed portion of the etching resist coating to form grooves, the lightness L* being a L* value in a CIELAB color space (CIE1976L*a*b* color space).

Abstract: A method for forming grooves on a surface of a metal strip, having applying a coating agent for etching resist coating formation to a roller; then, irradiating a laser on the roller while scanning the laser in an axial direction of the roller or in a direction inclined to the axial direction to remove a portion of the coating agent for etching resist coating formation irradiated by the laser; then, bringing the roller into contact with at least one side of the metal strip to transfer the coating agent for etching resist coating formation to the at least one side of the metal strip, with an unapplied area corresponding to the removed portion of the coating agent for etching resist coating formation.

Abstract: 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 ?m of the coating film layer B is 4.0 MPa/?m or more.

Abstract: To reduce variations in iron loss among materials subjected to magnetic domain refining by electron beam irradiation and to stably obtain good iron loss properties, disclosed is a method of producing a grain-oriented electrical steel sheet including performing magnetic domain refining treatment by irradiating with an electron beam, in a pressure reduced area, a surface of a grain-oriented electrical steel sheet after subjection to final annealing, the method further including: before the irradiating with the electron beam, delivering the grain-oriented electrical steel sheet wound in a coil shape and heating the delivered grain-oriented electrical steel sheet to 50° C. or higher; and then cooling the grain-oriented electrical steel sheet such that the grain-oriented electrical steel sheet has a temperature of lower than 50° C. at the time of entering the pressure reduced area.

Abstract: To form linear grooves of desired groove width on a metal strip surface and provide a grain-oriented electrical steel sheet having excellent magnetic properties, a linear groove formation method comprises: forming a resist coating on at least one surface of a metal strip; thereafter irradiating the resist coating with a laser while scanning the laser in a direction crossing a rolling direction of the metal strip, to remove the resist coating in a part irradiated with the laser; and thereafter performing etching treatment to form a linear groove in a part of the metal strip in which the resist coating is removed, wherein the resist coating contains a predetermined amount of an inorganic compound, and on the surface of the metal strip, the laser has a predetermined elliptic beam shape.

Abstract: Provided is a grain-oriented electrical steel sheet which has been subjected to heat-resistant magnetic domain refining treatment and can effectively suppress carburizing and nitriding during stress relief annealing. The grain-oriented electrical steel sheet has a plurality of grooves on one side that extend linearly across the rolling direction and are lined up at intervals in the rolling direction, and has at least a forsterite film on a surface of the steel sheet, where an average thickness of the forsterite film formed on the floor of the grooves is 0.45 ?m or more, and a standard deviation a of the thickness is 0.34 ?m or less.

Abstract: The linear groove formation method includes a resist forming process of forming a coated resist on a surface of a steel sheet, a laser irradiating process of irradiating laser beams onto the steel sheet while repeating a laser scanning in a direction intersecting a rolling direction of the steel sheet cyclically in the rolling direction of the steel sheet to remove the coated resist in portions irradiated with the laser beams, and an etching process of forming linear grooves by etching portions of the steel sheet from which the coated resist is removed. In the laser irradiating process, the coated resist is removed by using two or more laser irradiating devices, with a certain irradiation energy, a certain beam diameter in a direction perpendicular to a laser scanning direction, and a certain incidence angle with respect to the surface of the steel sheet.

Abstract: A grain-oriented electrical steel sheet having linear grooves formed cyclically in a rolling direction of the grain-oriented electrical steel sheet such that a longitudinal direction of the linear grooves intersects the rolling direction, in which each of the linear grooves has a discontinuous portion of center lines where center lines of the groove are shifted in a groove width direction, and when a width of the linear groove is defined as a and a distance in the groove width direction between the center lines in the discontinuous portion of center lines is defined as b, a and b satisfy relational expression (1) below. 0.05?b/a?0.

Abstract: A linear groove formation method including forming a coated resist on a surface of a steel sheet, irradiating two or more laser beams onto the surface of the steel sheet while scanning the laser beams in a direction intersecting the rolling direction of the steel sheet cyclically in a rolling direction of the steel sheet, and forming linear grooves by etching portions of the steel sheet. In the laser irradiating process, the coated resist is removed continuously in a sheet transverse direction of the steel sheet by using the laser beams irradiated from respective ones of two or more laser irradiation devices arranged in the sheet transverse direction, and the laser beams are irradiated by shifting centers of two of the laser beams irradiated from two of the laser two of the laser irradiation devices adjacent to each other in the sheet transverse direction.

Abstract: Disclosed is a grain-oriented electrical steel sheet including: closure domains, each containing a discontinuous region at a part thereof and extending at an angle within 30° with respect to a transverse direction of the steel sheet, wherein a closure domain overlapping portion in the discontinuous region on one surface of the steel sheet has a length ? in the transverse direction that is longer than a length ? in the transverse direction of the closure domain overlapping portion on the other surface of the steel sheet, and the length ? satisfies 0.5???5.0 and the length ? satisfies 0.2????0.8?. Consequently, the iron loss and the deterioration of magnetostrictive properties are suppressed in discontinuous regions, which would be inevitably formed when magnetic domain refining treatment is performed using a plurality of irradiation devices.

Abstract: This device scans a high-energy beam in a direction traversing a feed path of a grain-oriented electrical steel sheet having subjected to final annealing so as to irradiate a surface of the steel sheet being passed through with the high-energy beam to thereby perform magnetic domain refinement, the device including an irradiation mechanism for scanning the high-energy beam in a direction orthogonal to the feed direction of the steel sheet, in which the irradiation mechanism has a function of having the scanning direction of the high-energy beam oriented diagonally, relative to the orthogonal direction, toward the feed direction at an angle determined based on a sheet passing speed of the steel sheet on the feed path.

Abstract: 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.

Abstract: Disclosed is a grain-oriented electrical steel sheet that exhibits excellent iron loss properties and a good building factor, in which damage to a tension coating is suppressed. In a grain-oriented electrical steel sheet having a tension coating, an interlaminar current is 0.15 A or less, a plurality of linear strain regions extending in a direction transverse to the rolling direction are formed, the strain regions are formed at line intervals in the rolling direction of 15 mm or less, each of the strain regions has closure domains formed therein, and each of the closure domains has a length d along the sheet thickness direction of 65 ?m or more and a length w along the rolling direction of 250 ?m or less.

Abstract: 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. (|RFe?RA|/RFe)×100.

Abstract: Provided are: an oriented electromagnetic steel sheet with outstanding coating adhesion and magnetic properties after stress relief annealing; and a method for manufacturing the oriented electromagnetic steel sheet. The oriented electromagnetic steel sheet comprises: a steel sheet; a non-oxide ceramic coating disposed on the steel sheet and containing a non-oxide; and an insulating tensile coating disposed on the non-oxide ceramic coating and containing an oxide. The thickness of the non-oxide ceramic coating is 0.020-0.400 ?m. The thickness of the insulating tensile coating is at least 1.0 ?m. The chromium content on the steel plate side of the non-oxide ceramic coating is less than 25 atomic %, and the chromium content on the insulating tensile coating side of the non-oxide ceramic coating is at least 25 atomic %.

Abstract: A linear groove formation method of forming linear grooves in a steel sheet surface using etching can form linear grooves of a uniform shape while suppressing a decrease in magnetic property of a grain-oriented electrical steel sheet caused by laser irradiation for resist removal. A linear groove formation method includes: coating a surface of a grain-oriented electrical steel sheet with a resist; performing a laser scan cyclically in a rolling direction of the grain-oriented electrical steel sheet, the laser scan being applying a laser while scanning the laser in a direction crossing the rolling direction to remove the resist in a portion irradiated with the laser; and etching the grain-oriented electrical steel sheet in each portion in which the resist is removed, to form a linear groove. A coating thickness of the resist is 0.5 ?m to 10 ?m, and a power of the laser is 1500 W or more.

Abstract: An excellent low noise property and excellent low iron loss property are obtained. A grain-oriented electrical steel sheet includes refined magnetic domains formed by electron beam irradiation. When the maximum magnetic flux density is 1.7 T, the grain-oriented electrical steel sheet has a residual magnetic flux density of 0.1 to 0.7 times the residual magnetic flux density before the electron beam irradiation and a maximum magnetizing force of 1.1 to 2.0 times the maximum magnetizing force before the electron beam irradiation.