Abstract: This disclosure discloses a method for manufacturing a grain-oriented electrical steel sheet and a grain-oriented electrical steel sheet manufactured by the method. The method comprises heating a slab having a predetermined composition by induction heating in a frequency range of 20 to 1000 Hz under predetermined conditions, where the average current flowing in the coil is monotonically decreased as time passes during slab heating; subjecting the slab to finish rolling performed with the rolling finish temperature set to 950° C. or lower at one or both of the leading or trailing end; soaking the hot-rolled sheet at 750° C. or higher for 5 to 90 seconds to obtain a hot band annealed sheet; then cold rolling the annealed sheet once, or twice or more with intermediate annealing performed therebetween to obtain a cold-rolled sheet having a final sheet thickness; and subjecting the cold-rolled sheet to primary and secondary recrystallization annealings.

Abstract: Provided is a grain-oriented electrical steel sheet with good film adhesion. Among the elements present at grain boundaries between ceramic particles contained in a base film of the grain-oriented electrical steel sheet, either or both of S and Se elements are contained in a range of 0.02 at % to 2.00 at %.

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 steel sheet has a chemical composition containing a predetermined amount of C, Si, Mn, Cu, P, S, Al, and N, and optionally a predetermined amount of one or more selected from the group consisting of Ti, B, Nb, Cr, V, Mo, Ni, As, Sb, Sn, Ta, Ca, Mg, Zn, Co, Zr, and REM, with the balance being Fe and inevitable impurities; a microstructure comprising, in volume fraction, tempered martensite: 90% or more, retained austenite: 1% to 7%, one or both of bainitic ferrite and fresh martensite: 3% to 9% in total, and ferrite: 0% to 5%, where the retained austenite has a carbon concentration of 0.35% or more; a tensile strength TS of 1470 MPa to 1650 MPa, and a yield strength YS of 1100 MPa or more.

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 method for producing a grain-oriented electrical steel sheet comprises heating a steel material containing a certain composition to a temperature in a range of 1150 to 1250° C.; performing hot rolling, hot-band annealing, and cold rolling on the material to obtain a cold-rolled sheet with a final thickness; 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 800 to 900° 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: 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: 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: 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: 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.