Abstract: Disclosed are a grain-oriented electrical steel sheet having strain regions extending in a direction transverse to a rolling direction at periodic interval s (mm) in the rolling direction. Each strain region has a closure domain region whose width in the rolling direction varies periodically on a steel sheet surface. Each closure domain region satisfies: Wmax/Wmin=1.2 or more and less than 2.5, where Wmax and Wmin respectively denote a maximum width and a minimum width on the steel sheet surface as measured in the rolling direction; Wave being 80 ?m or more, where Wave denotes an average width on the steel sheet surface as measured in the rolling direction; D being 32 ?m or more, where D denotes a maximum depth as measured in the sheet thickness direction; and (Wave*D)/s being 0.0007 mm or more and 0.0016 mm or less.

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: A grain oriented electrical steel sheet has a magnetic domain structure modified by strain introduction without a trace of treatment, in which noise generated when the grain oriented electrical steel sheet is used laminated on an iron core of a transformer is effectively reduced by: setting a magnetic flux density B8 to 1.92 T or higher; then setting a ratio of average magnetic domain width of treated surface after strain-introducing treatment Wa to average magnetic domain width before strain-introducing treatment W0 as Wa/W0<0.4; and setting a ratio of Wa to average magnetic domain width of untreated surface Wb as Wa/Wb>0.7; and further setting a ratio of average width of magnetic domain discontinuous portion Wd in the untreated surface to average width of magnetic domain discontinuous portion in treated surface resulting from strain-introducing treatment Wc as Wd/Wc>0.8; and setting Wc<0.35 mm.

Abstract: A method of manufacturing a grain oriented electrical steel sheet includes subjecting a steel slab to a rolling process including cold rolling to obtain a steel sheet with a final sheet thickness, the steel slab containing by mass % C: 0.01% to 0.20%, Si: 2.0% to 5.0%, Mn: 0.03% to 0.20%, sol. Al: 0.010% to 0.05%, N: 0.0010% to 0.020%, at least one element selected from S and Se in a total of 0.005% to 0.040%, and the balance including Fe and incidental impurities; forming, by a chemical process, a linear groove extending in a direction forming an angle of 45° or less with a direction orthogonal to a rolling direction of the steel sheet; subjecting the steel sheet to decarburization annealing; applying an annealing separator thereon mainly composed of MgO; and subjecting the steel sheet to final annealing to manufacture a grain oriented electrical steel sheet.

Abstract: A grain-oriented electrical steel sheet produces reduced noise when worked into a transformer, by setting length d of each plastic strain region in the widthwise direction of the steel sheet to 0.05 mm or more and 0.4 mm or less, and a ratio (?d/?w) of a total ?d of the length d to a total ?w of application interval w of each of the above plastic strain regions to 0.2 or more and 0.6 or less.

Abstract: A grain-oriented electrical steel sheet has low iron loss properties obtained though magnetic domain refining treatment by a chemical means. The steel sheet has a linear groove extending in a direction forming an angle of 45° or less with a direction orthogonal to a rolling direction of the steel sheet, in which presence frequency of fine grains with a length in the rolling direction of 1 mm or less in a floor portion of the groove is 10% or less, including 0% indicative of the absence of fine grains, the groove is provided with a forsterite film in an amount of 0.6 g/m2 or more in terms of Mg coating amount per one surface of the steel sheet, and an average of angles (? angles) formed by <100> axes of secondary recrystallized grains facing the rolling direction and a rolling plane of the steel sheet is 3° or less.

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: The objective of the present invention is to provide a method of forming a pressed paper piece by deep drawing a sheet of blank that is primarily made of paper in use of a punch and a die, and a production apparatus for implementing the method, whereby no distinguishable wrinkles are formed in upright portions of the pressed paper piece. The method of producing a pressed paper piece according to the present invention, implemented when deep drawing a sheet-like blank that is primarily made of paper in use of a punch and a die, includes maintaining a predetermined gap between a first blank holder and the die in an outer peripheral region of a process portion of the blank and applying a pressure to a radially inner region thereof via a second blank holder, thereby reducing wrinkling by an effect of integrated functions exerted in both regions of the blank.

Abstract: A grain oriented electrical steel sheet that is subjected to magnetic domain refining treatment by electron beam irradiation and exhibits excellent low-noise properties when assembled as an actual transformer in which tension exerted on the steel sheet by the forsterite film is 2.0 MPa or higher both in a rolling direction and a direction transverse (perpendicular) to the rolling direction, and a ratio of an irradiation pitch in a thermal strain introduced region (B) to a spot diameter (A) on an electron beam irradiation surface satisfies 0.5?B/A?5.0.

Abstract: A grain oriented electrical steel sheet is subjected to magnetic domain refinement by laser irradiation and has magnetic flux density B8 of at least 1.91T, wherein the nitrogen content in the forsterite coating is 3.0 mass % or less. The grain oriented electrical steel sheet satisfies recent demand for iron loss reduction.

Abstract: A grain oriented electrical steel sheet is subjected to magnetic domain refinement by laser irradiation or electron irradiation and exhibits excellent low noise properties and low iron-loss properties when assembled into a real transformer device, by setting: the total tension (A) in rolling direction imparted to the steel sheet by the forsterite coating and the tension coating to be equal to or higher than 10.0 MPa; setting the total tension (B) in a direction orthogonal to the rolling direction imparted to the steel sheet by the forsterite coating and the tension coating to be equal to or higher than 5.0 MPa; and setting the total tension (A) and the total tension (B) to satisfy a formula shown below. 1.0?A/B?5.

Abstract: A magnetic domain refining treatment is performed by dividing a surface of a steel sheet into a plurality of regions in a widthwise direction, disposing a laser irradiation apparatus or an electron beam irradiation apparatus in each of the regions, and forming beam-irradiated regions through beam irradiation, wherein beams are irradiated so that a nature of a juncture between beam-irradiated regions satisfies 0???0.3×a and ?1.2×a+0.02×w?0.5×??6.5????0.13×a?200×(1/w)+5.4 when TD spacing ? at the juncture between the beam-irradiated regions is ?3 to 0 mm, whereby a grain oriented electrical steel sheet having an excellent iron loss property is produced in a good productivity.

Abstract: A method of manufacturing a grain oriented electrical steel sheet includes a rolling a slab for a grain oriented electrical steel sheet to obtain a steel sheet having final sheet thickness; subjecting the steel sheet to decarburizing annealing; coating a surface of the steel sheet with annealing separator mainly composed of MgO; subjecting the steel sheet thus coated to final annealing; providing a tension coating to the steel sheet; and subjecting the steel sheet to magnetic domain refinement by laser irradiation after either the final annealing or provision of the tension coating, wherein (1) the coating weight of the anneal separator is at least 10.0 g/m2; (2) coiling tension at which the steel sheet is coiled after being coated with the annealing separator is 30 N/mm2 to 150 N/mm2; and (3) the average cooling rate in cooling process of the final annealing down to 700° C. is 50° C./hour or less.

Abstract: A grain oriented electrical steel sheet has thickness of forsterite film at bottom portions of grooves formed on a surface of the steel sheet is ?0.3 ?m, groove frequency is ?20%, abundance ratio of grooves crystal grains directly beneath themselves, each crystal grain having orientation deviating from Goss orientation by ?10° and grain size ?5 ?m, total tension exerted on the steel sheet in the rolling direction by the forsterite film and tension coating is ?10.0 MPa, total tension exerted on the steel sheet in a direction perpendicular to the rolling direction by the forsterite film and tension coating is ?5.0 MPa and total tension satisfies 1.0?A/B?5.0, where A is total tension exerted in rolling direction by forsterite film and tension coating, and B is total tension exerted in direction perpendicular to rolling direction by forsterite film and tension coating.

Abstract: A grain oriented electrical steel sheet (1) suppresses the content of Cr in the grain oriented electrical steel sheet to 0.1 mass % or less; (2) sets the coating weight of a forsterite coating, in terms of basis weight of oxygen therein, to at least 3.0 g/m2 and thickness of an anchor portion as a lower portion of forsterite coating to 1.5 ?m or less; and (3) controls setting the magnitude of deflection of a test specimen having length: 280 mm to at least 10mm when the forsterite coating is provided on only one surface thereof and at least 20 mm when forsterite coating and the tension coating are provided on the surface.

Abstract: A grain oriented electrical steel sheet may reduce iron loss of material with linear grooves formed thereon for magnetic domain refinement and offer excellent low iron loss properties when assembled as an actual transformer, where the steel sheet has sheet thickness of 0.30 mm or less, linear grooves are formed at intervals of 2-10 mm in the rolling direction, the depth of each of the linear grooves is 10 ?m or more, the thickness of the forsterite film at bottom portions of the linear grooves is 0.3 ?m or more, total tension applied to the steel sheet by the forsterite film and tension coating is 10.0 MPa or higher in rolling direction, and the proportion of eddy current loss in iron loss W17/50 of the steel sheet is 65% or less when alternating magnetic field of 1.7 T and 50 Hz is applied to the steel sheet in the rolling direction.

Abstract: A iron-based amorphous alloy thin strip having a chemical composition represented by a chemical formula of FexBySiz (wherein x is 78-83 at %, y is 8-15 at % and z is 6-13 at %), wherein the number of air pockets at a surface contacting with a cooling roll is not more than 8 pockets/mm2 and an average length in a circumferential direction of the roll is not more than 0.5 mm.

Abstract: A device reduces dust for safely preventing laser-irradiation capacity from decreasing due to contamination and reliably reducing iron loss of a grain oriented electrical steel sheet. The device improves iron loss properties of a grain oriented electrical steel sheet by irradiating its surface with laser to reduce iron loss, wherein, distance between a laser beam emission port and a laser irradiation point is L (mm); laser irradiation angle formed by a line linking the emission port and the irradiation point with respect to a direction vertical to the sheet is ? (°); and L?50, the emission port is positioned such that L and ? satisfy: 60?0.3L???60 when L?100; 40?0.1L???60 when 100<L?400; ??60 when L>400.

Abstract: A grain-oriented electrical steel sheet subjected to magnetic domain refining by linearly introducing strains in a direction intersecting a rolling direction of the steel sheet repeatedly with intervals in the rolling direction, wherein if a repeating interval of the strains in the rolling direction is d (mm) and, when the steel sheet is placed on a flat surface, a mean value of difference between a height from the flat surface in linear strain-introduced areas of a steel sheet surface and a height from the flat surface in intermediate points between adjacent linear strain-introduced areas is h (mm), then the ratio h/d of the h to the d is 0.0025 or more and 0.015 or less.

Abstract: A grain oriented electrical steel sheet is subjected to magnetic domain refining treatment by electron beam irradiation and exhibits excellent low-noise properties when assembled as an actual transformer, in which a ratio (Wa/Wb) of a film thickness (Wa) of the forsierite film on a strain-introduced side of the steel sheet to a film thickness (Wb) of the forsierite film on a non-strain-introduced side of the steel sheet is 0.5 or higher, a magnetic domain discontinuous portion in a surface of the steel sheet on the strain-introduced side has an average width of 150 to 300 ?m, and a magnetic domain discontinuous portion in a surface of the steel sheet on the non-strain-introduced side has an average width of 250 to 500 ?m.