Abstract: In a method for producing a grain-oriented electrical steel sheet by comprising a series of steps of hot rolling a raw steel material comprising C: 0.002-0.10 mass %, Si: 2.0-8.0 mass %, and Mn: 0.005-1.0 mass %, subjecting the steel sheet to a hot band annealing as required, cold rolling to obtain a cold rolled sheet having a final sheet thickness, subjecting the steel sheet to primary recrystallization annealing combined with decarburization annealing, applying an annealing separator to the steel sheet surface and then subjecting to final annealing, rapid heating is performed at a rate of not less than 50° C./s in a region of 200-700° C. in the heating process of the primary recrystallization annealing, and the steel sheet is held at any temperature of 250-600° C. in the above region for 1-10 seconds, while a soaking process of the primary recrystallization annealing is controlled to a temperature range of 750-900° C., a time of 90-180 seconds and PH2O/PH2 in an atmosphere of 0.25-0.

Abstract: In a method for producing a grain-oriented electrical steel sheet by hot rolling a raw steel material containing C: 0.002˜0.10 mass %, Si: 2.0˜8.0 mass % and Mn: 0.005˜1.0 mass % to obtain a hot rolled sheet, subjecting the hot rolled sheet to a hot band annealing as required and further to one cold rolling or two or more cold rollings including an intermediate annealing therebetween to obtain a cold rolled sheet having a final sheet thickness, subjecting the cold rolled sheet to a primary recrystallization annealing combined with decarburization annealing, applying an annealing separator to the steel sheet surface and then subjecting to a final annealing, when rapid heating is performed at a rate of not less than 50° C./s in a range of 100˜700° C. in the heating process of the primary recrystallization annealing, the steel sheet is subjected to a holding treatment at any temperature of 250˜600° C. for 0.

Abstract: When a steel sheet containing Si: 2-5 mass % after cold rolling is subjected to a primary recrystallization annealing and a finishing annealing for secondary recrystallization to form a grain-oriented electrical steel sheet, the primary recrystallization annealing is performed by rapid heating in the heating process and temperature keeping treatment at a certain temperature in the course of the heating to thereby obtain a grain-oriented electrical steel sheet having plural peaks in a distribution of misorientation angle between crystal orientation of secondary recrystallized grains and Goss orientation, wherein misorientation angle of the second smallest peak among the plural peaks is preferably not less than 5° and a grain size of secondary recrystallized grains is not more than 15 mm.

Abstract: In a method for producing a grain-oriented electrical steel sheet by hot rolling a steel slab having a chemical composition including C: 0.001˜0.10 mass %, Si: 1.0˜5.0 mass %, Mn: 0.01˜0.5 mass %, Al: less than 0.0100 mass %, each of S, Se, O and N: not more than 0.0050 mass % and the remainder being Fe and inevitable impurities, subjecting the resulting hot rolled sheet to a single cold rolling or two or more cold rollings sandwiching an intermediate annealing therebetween to a final thickness, subjecting to a primary recrystallization annealing, applying an annealing separator thereto and then subjecting to a finish annealing, a zone of 550˜700° C. in a heating process of the primary recrystallization annealing is rapidly heated at an average heating rate of 40˜200° C./s, while any temperature zone of 250˜550° C. is kept at a heating rate of not more than 10° C.

Abstract: A method for producing a grain-oriented electrical steel sheet includes hot rolling a raw steel material containing C: 0.002˜0.10 mass %, Si: 2.0˜8.0 mass % and Mn: 0.005˜1.0 mass % to obtain a hot rolled sheet, subjecting the sheet after or without hot band annealing to one or two or more stage cold rollings including an intermediate annealing to obtain a cold rolled sheet having a final sheet thickness, subjecting the rolled sheet to decarburization annealing and primary recrystallization annealing, applying an annealing separator to the sheet surface and subjecting to a final annealing, when rapid heating is performed at a rate of at least 50° C./s in a range of 200˜700° C. of the decarburization annealing, the rolled sheet is subjected to holding at any temperature of 250˜600° C. for 1˜10 seconds to produce a grain-oriented electrical steel sheet being low in the iron loss and small in the deviation of the iron loss value.

Abstract: In a method of producing a grain-oriented electrical steel sheet by hot rolling a steel slab having a chemical composition including C: 0.001˜0.10 mass %, Si: 1.0˜5.0 mass %, Mn: 0.01˜0.5 mass %, S and/or Se: 0.01˜0.05 mass %, sol. Al: 0.003˜0.050 mass % and N: 0.0010˜0.020 mass %, subjecting to single cold rolling or two or more cold rollings including an intermediate annealing therebetween to a final thickness, performing primary recrystallization annealing, and thereafter applying an annealing separator to perform final annealing, a temperature range of 550° C. to 700° C. in a heating process of the primary recrystallization annealing is rapidly heated at an average heating rate of 40˜200° C./s, while any temperature zone of from 250° C. to 550° C. is kept at a heating rate of not more than 10° C./s for 1˜10 seconds, whereby the refining of secondary recrystallized grains is attained and grain-oriented electrical steel sheets are stably obtained with a low iron loss.

Abstract: Provided is a grain-oriented electrical steel sheet, with reduced iron loss by magnetic domain refining treatment, exhibiting an excellent noise property and effectively reducing noise generated when stacked in an iron core of a transformer. In a grain-oriented electrical steel sheet including a forsterite film and a tension coating on both surfaces, magnetic domain refining treatment has been performed to apply linear thermal strain to the grain-oriented electrical steel sheet, the magnitude of deflection in the rolling direction of the steel sheet is 600 mm or more and 6000 mm or less as the curvature radius of the deflected surface with the surface having the strain applied thereto being the inner side, and the magnitude of deflection in the direction orthogonal to the rolling direction is 2000 mm or more as the curvature radius of the deflected surface with the surface having the strain applied thereto being the inner side.

Abstract: The present invention proposes a method that can reduce the noise generated by a transformer core and the like when formed by laminations of a grain-oriented electrical steel sheet in which core loss has been reduced by a magnetic domain refinement process. In this steel sheet, linear distortion extending with an orientation in which an angle formed with a direction perpendicular to the rolling direction of the steel sheet is an angle of 30° or less is periodic in the direction of rolling of the steel sheet, core loss (W17/50) is 0.720 W/kg or less, and magnetic flux density (B8) is 1.930 T. The volume of the closure domain arising in the distortion part is 1.00-3.00% of the total magnetic domain volume within the steel sheet.

Abstract: A grain-oriented electrical steel sheet allows for manufacture of a transformer that exhibits, when the steel sheet is applied to an iron core thereof, extremely low iron loss and extremely low noise properties, makes highly efficient use of energy, and can be used in various environments. The grain-oriented electrical steel sheet has a strain distribution in regions where closure domains are formed, when observed in a cross section in the rolling direction, with a maximum tensile strain in a sheet thickness direction being 0.45% or less, and with a maximum tensile strain t (%) and a maximum compressive strain c (%) in the rolling direction satisfying Expression (1): t+0.06?t+c?0.35??(1).