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 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: Provided is a grain-oriented electrical steel sheet including: a forsterite base film formed on a surface of the steel sheet; and an insulating tension coating formed on the base film, in which when Ti intensity FX(Ti), Al intensity FX(Al), and Fe intensity FX(Fe) obtained through quantitative analysis by performing fluorescent X-ray analysis on the surface of the steel sheet satisfy FX(Ti)/FX(Al)?0.15 and FX(Ti)/FX(Fe)?0.004, the frequency of crystal boundaries of secondary recrystallized grains in the direction orthogonal to the rolling direction is 20 grain boundaries/100 mm or less, the mean thickness of the forsterite base film t(Fo) and the thickness of the insulating tension coating t(C) satisfies t(Fo)/t(C)?0.3, and magnetic domain refining treatment is performed by irradiation with a laser beam, plasma flame, or electron beam, a sufficient iron loss reducing effect is achieved in a range where coating detachment does not occur.

Abstract: Provided is a grain-oriented electrical steel sheet including: a forsterite base film formed on a surface of the steel sheet; and an insulating tension coating formed on the base film, in which when Ti intensity FX(Ti), Al intensity FX(Al), and Fe intensity FX(Fe) obtained through quantitative analysis by performing fluorescent X-ray analysis on the surface of the steel sheet satisfy FX(Ti)/FX(Al)?0.15 and FX(Ti)/FX(Fe)?0.004, the frequency of crystal boundaries of secondary recrystallized grains in the direction orthogonal to the rolling direction is 20 grain boundaries/100 mm or less, the mean thickness of the forsterite base film t(Fo) and the thickness of the insulating tension coating t(C) satisfies t(Fo)/t(C)?0.3, and magnetic domain refining treatment is performed by irradiation with a laser beam, plasma flame, or electron beam, a sufficient iron loss reducing effect is achieved in a range where coating detachment does not occur.

Abstract: In a method of producing a grain-oriented electrical steel sheet by hot-rolling a steel slab of a chemical composition containing C: 0.001˜0.10%, Si: 1.0˜5.0%, Mn: 0.01˜1.0%, at least one of S and Se: 0.01˜0.05% in total, sol. Al: 0.003˜0.050%, N: 0.001˜0.020% by mass, subjecting to cold rolling, a primary recrystallization annealing, application of an annealing separator mainly composed of MgO and a finish annealing, a temperature rising rate S1 between 500˜600° C. in the primary recrystallization annealing is made to not less than 100° C./s and a temperature rising rate S2 between 600˜700° C. is made to 30° C./s˜0.6×S1° C./s, while a total content W (mol %) of an element having an ionic radius of 0.6˜1.3 ? and an attracting force between the ion and oxygen of not more than 0.7 ??2 included in the annealing separator to MgO is adjusted to satisfy 0.01S2?5.5?Ln (W)?0.01S2?4.3 to produce a grain-oriented electrical steel sheet having excellent iron loss properties and coating properties.

Abstract: In a method for producing a grain-oriented electrical steel sheet by hot rolling a steel slab containing, in terms of mass %, C: 0.001˜0.20%, Si: 1.0˜5.0%, Mn: 0.03˜1.0%, one or two of S and Se: 0.005˜0.040% in total, sol. Al: 0.003˜0.050% and N: 0.0010˜0.020%, subjecting to a cold rolling to a final thickness and to a primary recrystallization annealing, applying an annealing separator composed mainly of MgO and then subjecting to final annealing, a heating rate S1 at a zone of 500˜600° C. in a heating process of the primary recrystallization annealing is not less than 100° C./s and a heating rate S2 at a zone of 600˜700° C. is a range of 30˜(0.5×S1)° C./s and an oxidation potential PH2O/PH2 of an atmosphere at a zone of 500˜700° C. is preferably not more than 0.05, whereby secondary recrystallized grains are refined over a full length of a product coil to decrease an iron loss.

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 (3 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: In a method of producing a grain-oriented electrical steel sheet by hot-rolling a steel slab of a chemical composition containing C: 0.001˜0.10%, Si: 1.0˜5.0%, Mn: 0.01˜1.0%, at least one of S and Se: 0.01˜0.05% in total, sol. Al: 0.003˜0.050%, N: 0.001˜0.020% by mass, subjecting to cold rolling, a primary recrystallization annealing, application of an annealing separator mainly composed of MgO and a finish annealing, a temperature rising rate S1 between 500˜600° C. in the primary recrystallization annealing is made to not less than 100° C./s and a temperature rising rate S2 between 600˜700° C. is made to 30° C./s˜0.6×S1° C./s, while a total content W (mol %) of an element having an ionic radius of 0.6˜1.3 ? and an attracting force between the ion and oxygen of not more than 0.7 ??2 included in the annealing separator to MgO is adjusted to satisfy 0.01S2-5.5?Ln (W)?0.01S2?4.3 to produce a grain-oriented electrical steel sheet having excellent iron loss properties and coating properties.

Abstract: In the production of a grain-oriented electrical steel sheet by hot rolling a steel slab comprising C: 0.001˜0.10 mass %, Si: 1.0˜5.0 mass %, Mn: 0.01˜0.5 mass %, sol. Al: 0.003˜0.050 mass %, N: 0.0010˜0.020 mass %, one or two selected from S and Se: 0.005˜0.040 mass % in total, cold rolling, primary recrystallization annealing, and final annealing, a heating rate S1 between a temperature T1 (° C.): 500+2×(NB?NA) and a temperature T2 (° C.): 600+2×(NB?NA) in a heating process of the primary recrystallization annealing is set to not less than 80° C./sec, and an average heating rate S2 from the temperature T2 to 750° C. is set to 0.1˜0.7 times of S1, whereby a grain-oriented electrical steel sheet having a low iron loss over a full length of a product coil is obtained.

Abstract: A method of manufacturing a grain oriented electrical steel sheet includes subjecting a steel slab to rolling to obtain a steel sheet, subjecting the steel sheet to decarburizing annealing, coating of an annealing separator mainly composed of MgO onto a surface of the steel sheet, and final annealing to obtain a grain oriented electrical steel sheet having at least 4.0 g/m2 of coating weight of forsterite coating formed on the surface of the steel sheet, 0.9 ?m or less of the average grain size of the forsterite coating, and at least 1.91 T of magnetic flux density B8; and linearly irradiating a surface of the grain oriented electrical steel sheet this obtained with a laser having wavelength of 0.2 ?m to 0.9 ?m in a direction intersecting the rolling direction of the steel sheet.

Abstract: A grain-oriented electromagnetic steel sheet having a multiplicity of fine grains having a diameter of about 3 mm or less on the surface of the steel sheet, in a numerical ratio of about 65% or more and of about 98% or less relative to the constituting grains that penetrate the sheet along the direction parallel to its thickness, and a method for producing the same. The fine grains are artificially created and regularly disposed with a random orientation in the steel sheet, and contribute to decreasing the strain susceptibility of the steel. More preferably, a treatment for finely dividing magnetic domains is applied on the surface of the steel sheet. Transformers based upon the steel sheet have excellent magnetic characteristics (iron loss and magnetic flux density) together with strain resistance, and the steel sheet has good practical device characteristics (building factor) after being assembled into a transformer.

Abstract: A grain oriented electrical steel sheet comprises metal part containing Si: about 2.5 to about 5.0 mass % and Cr: about 0.05 to about 1.0 mass %, and an insulation coating formed on a surface of the metal part. A tension imparted to the metal part in the rolling direction by the insulation coating is not smaller than about 3.0 MPa. Magnetic flux density B8 satisfies a specific relation formula. A plurality of linear strains or grooves are formed in a surface of the steel sheet and linearly extended at an angle of not larger than about 45° (in each direction) relative to a direction perpendicular to a rolling direction such that an interval D of the linear strains or grooves satisfies a specific relation formula depending on the Cr content. A grain oriented electrical steel sheet is thereby obtained which has lower iron loss after domain refining treatment than conventional values.

Abstract: A grain-oriented electromagnetic steel sheet having a multiplicity of fine grains having a diameter of about 3 mm or less on the surface of the steel sheet, in a numerical ratio of about 65% or more and of about 98% or less relative to the constituting grains that penetrate the sheet along the direction parallel to its thickness, and a method for producing the same. The fine grains are artificially created and regularly disposed with a random orientation in the steel sheet, and contribute to decreasing the strain susceptibility of the steel. More preferably, a treatment for finely dividing magnetic domains is applied on the surface of the steel sheet.

Abstract: Grain-oriented silicon steel sheet with Bi as an auxiliary inhibitor and a forsterite coating film having a Cr spinel oxide subscale of FeCr2O4 or FexMn1-xCr2O4 (0.6≦x≦1), made from a steel slab containing 0.005-0.20 wt % of Bi and 0.1-1.0 wt % of Cr.

Abstract: A grain oriented electrical steel sheet comprises metal part containing Si: about 2.5 to about 5.0 mass % and Cr: about 0.05 to about 1.0 mass %, and an insulation coating formed on a surface of the metal part. A tension imparted to the metal part in the rolling direction by the insulation coating is not smaller than about 3.0 MPa. Magnetic flux density B8 satisfies a specific relation formula. A plurality of linear strains or grooves are formed in a surface of the steel sheet and linearly extended at an angle of not larger than about 45° (in each direction) relative to a direction perpendicular to a rolling direction such that an interval D of the linear strains or grooves satisfies a specific relation formula depending on the Cr content. A grain oriented electrical steel sheet is thereby obtained which has lower iron loss after domain refining treatment than conventional values.

Abstract: A grain-oriented electromagnetic steel sheet having a multiplicity of fine grains having a diameter of about 3 mm or less on the surface of the steel sheet, in a numerical ratio of about 65% or more and of about 98% or less relative to the constituting grains that penetrate the sheet along the direction parallel to its thickness, and a method for producing the same. The fine grains are artificially created and regularly disposed with a random orientation in the steel sheet, and contribute to decreasing the strain susceptibility of the steel. More preferably, a treatment for finely dividing magnetic domains is applied on the surface of the steel sheet. Transformers based upon the steel sheet have excellent magnetic characteristics (iron loss and magnetic flux density) together with strain resistance, and the steel sheet has good practical device characteristics (building factor) after being assembled into a transformer.

Abstract: In a grain oriented electrical steel sheet used for cores of transformers and generators, a high alignment degree of grain orientations reduces iron loss, by precipitating very fine AlN or/and BN and providing strong inhibiting effect against the growth of the primary recrystallized grains, providing radically improved texture and grain structure in the steel.

Abstract: Method of making a grain oriented electromagnetic steel sheet having excellent magnetic properties, by a series of steps ranging from hot rolling to final finishing annealing for a silicon steel slab containing from about 0.001 to 0.07 wt % bismuth, wherein the average cooling rate for about five seconds measured immediately after the end of hot rolling is controlled within a range of from about 30 to 120° C./second; the value of the ratio PH2O/PH2 of the atmosphere for the soaking step in decarburization annealing is adjusted within a range of from about 0.45 to 0.70; and a treatment is provided for inhibiting decomposition of the surface inhibitor during final finishing annealing.

Abstract: Grain-oriented silicon steel sheet with Bi as an auxiliary inhibitor and a forsterite coating film having a Cr spinel oxide subscale of FeCr2O4 or FexMn1−xCr2O4 (0.6≦x≦1), made from a steel slab containing 0.005-0.20 wt % of Bi and 0.1-1.0 wt % of Cr.

Abstract: A grain-oriented electromagnetic steel sheet is provided which has a low ratio of iron loss in a weaker magnetic field to that in a stronger magnetic field and has special advantage in EI cores and the like. Also provided is a process for producing that steel sheet. The grain-oriented electromagnetic steel sheet is characterized in that its crystal grains of important components are specified in terms of their proportions in number, and the contents of Al, Ti and B, with a forsterite film formed on a surface of the steel sheet. In the process a low-Al silicon slab is heated at below 1,250° C. before hot rolling and the hot-rolled sheet is annealed with a temperature rise in the range of from 5 to 25° C./sec and at a temperature of from about 800 to 1,000 for a period of time of shorter than about 100 seconds.