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: A non-oriented electrical steel sheet is produced by performing hot-rolling, hot-band annealing, cold rolling, and finishing annealing with regard to a steel slab containing a certain composition, a soaking temperature in the finishing annealing is set to not lower than 500° C. but not higher than a temperature T determined by the contents of Si, Al, and Mn, a cold-rolled sheet is held at the soaking temperature for a time period of no longer than 60 seconds, and a retention time at a temperature of 500° C. or higher is no longer than 100 seconds, whereby a tensile strength of the steel sheet is 700 to 950 Mpa, and a dislocation density thereof in a central portion of the sheet thickness is 1.2×1014 m?2 or more, thus obtaining a non-oriented electrical steel sheet exhibiting a high strength after performing finishing annealing and a low iron loss after performing stress-relief annealing.

Abstract: Provided are methods that can prevent either or both of kinking and collapsing of a steel sheet coiled in coil form regardless of the characteristics of the steel sheet. A method of determining a tension pattern of tension applied to a steel sheet to coil the steel sheet in coil form comprises calculating the tension pattern using an apparent elastic modulus in a radial direction of a coil.

Abstract: Ridging caused when handling steel containing a large amount of alloying elements such as Si and Al in a low-speed hot rolling process is suppressed. A method of producing a hot-rolled steel sheet for a non-oriented electrical steel sheet comprises: producing a steel slab having a certain chemical composition and a thickness of 50 mm to 200 mm by continuous casting; conveying the steel slab to a hot rolling line while maintaining a surface temperature of the steel slab at 800° C. or more; and performing hot rolling in which the steel slab is sequentially subjected to rough rolling, reheating treatment, and finish rolling in the hot rolling line to obtain a hot-rolled steel sheet, wherein the hot rolling is performed under specific conditions.

Abstract: In a process using a thin slab, ridging is suppressed. A method of producing a hot-rolled steel sheet for a non-oriented electrical steel sheet includes: continuous casting producing a steel slab having a defined chemical composition and a thickness of 50 mm to 200 mm; transferring the steel slab to a furnace while maintaining a surface temperature of the steel slab at 800° C. or more; holding the steel slab in the furnace under conditions including a hold temperature of 1100° C. to 1300° C. and a hold time of 60 s or more; and a hot rolling process under conditions of (1) and (2) of rough rolling, reheating treatment, and finish rolling in sequence to obtain a hot-rolled steel sheet: (1) total rolling reduction of the rough rolling: 80% or more, and (2) total rolling reduction of the finish rolling: 80% or more.

Abstract: When producing a non-oriented electrical steel sheet by subjecting a slab containing predetermined amounts of C, Si, Mn, Al, N, and Cr to hot rolling, hot-band annealing, cold rolling, and finishing annealing in a continuous annealing furnace, the following conditions are used: a maximum reached temperature in the finishing annealing is set to be lower than 900° C.; an average cooling rate from a temperature (maximum reached temperature—50° C.) to 500° C. in a cooling process of the finishing annealing is set to 40° C./s or higher; and a parameter ?/t defined from a plastic elongation ratio ? (%) in a rolling direction between before and after the finishing annealing and a soaking time t (s) in the finishing annealing is set to 0.10 or higher. Thus, a non-oriented electrical steel sheet is obtained.

Abstract: When producing a non-oriented electrical steel sheet by subjecting a slab containing a predetermined composition to hot rolling, hot-band annealing, cold rolling, and finishing annealing in a continuous annealing furnace, the following conditions are used: a maximum reached temperature in the finishing annealing is set to be lower than 900° C.; an average cooling rate from a temperature to 500° C. in a cooling process of the finishing annealing is set to 40° C./s or higher; a parameter ?/t defined from a plastic elongation ratio ? (%) in a rolling direction between before and after the finishing annealing and a soaking time t (s) in the finishing annealing is set to 0.10 or higher; an average ferrite grain size is 50 ?m or larger; and compressive residual stresses ?s and ?c in a sheet width direction at a steel sheet surface and a sheet-thickness center part, respectively, are both 2.0 MPa or higher.

Abstract: A grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes a grain-oriented magnetic steel sheet and an insulating tension coating containing a phosphate salt and silica on a surface of the grain-oriented magnetic steel sheet, the coating further including a crystalline compound represented by the general formula (1): MII3MIII4(XVO4)6 . . . (1). A method for producing a grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes applying an insulating tension coating liquid to a surface of a finish annealed grain-oriented magnetic steel sheet, the coating liquid including colloidal silica, a phosphate salt and a metal element M-containing compound in a specific ratio, and heat treating the steel sheet at least one time at a temperature of not less than 900° C. in an atmosphere including a non-oxidizing gas and having a dew point of not more than 0° C.

Abstract: Provided are methods that can prevent either or both of kinking and collapsing of a steel sheet coiled in coil form regardless of the characteristics of the steel sheet. A method of determining a tension pattern of tension applied to a steel sheet to coil the steel sheet in coil form comprises calculating the tension pattern using an apparent elastic modulus in a radial direction of a coil.

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: A grain-oriented electrical steel sheet having excellent iron loss property is produced from a steel slab containing, by mass %, C: 0.002-0.15%, Si: 2.5-6.0%, Mn: 0.01-0.80%, Al: 0.010-0.050% and N: 0.003-0.020%, when: a heating rate between 500-700° C. in decarburization annealing is not less than 80° C./s, a surface roughness Ra of a work roll in final cold rolling is 0.01-3.0 ?m, a total content of alkaline earth metals to MgO in annealing separator is 0-5 mass %, an average length L in rolling direction of passed crystal grains is not more than 25 mm, a ratio of crystal grains having a length in rolling direction of not more than 5 mm is 40-90%, and an existence ratio of alkaline earth metal sulfides having a size corresponding to circle of not less than 0.5 ?m in a cross section of forsterite film is not more than 0.2/?m per unit length in sheet width direction.

Abstract: A steel strip notching method including forming a notch at an end portion of a joint in a strip width direction formed by joining a trailing end of a preceding steel strip to a leading end of a succeeding steel strip, and removing a region of the notch through grinding by cutting the region with a rotary grinding tool by feeding the tool in the strip width direction, feeding the tool in a strip vertical direction at a feed rate within a predetermined range with respect to a feed rate of the tool in the strip width direction, giving a predetermined feed amount in a strip longitudinal direction while feeding the tool by a predetermined feed amount in the strip width direction simultaneously with feeding the tool in the strip vertical direction, and cutting the region while oscillating the tool in the strip longitudinal direction.

Abstract: A method of manufacturing a grain oriented electrical steel sheet includes hot rolling a steel slab having a chemical composition including C: 0.002-0.10 mass %, Si: 2.5-5.0 mass %, Mn: 0.01-0.8 mass %, Al: 0.010-0.050 mass % and N: 0.003-0.020 mass % and the remainder being Fe and inevitable impurities to form a hot rolled sheet; subjecting the hot rolled sheet to one cold rolling or two or more cold rollings and interposing an intermediate annealing therebetween after hot band annealing or without hot band annealing to form a cold rolled sheet having a final thickness; subjecting the cold rolled sheet to a primary recrystallization annealing; applying an annealing separator to the surface of the steel sheet; and subjecting the sheet to a finish annealing and forming a tension coating.

Abstract: A grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes a grain-oriented magnetic steel sheet and an insulating tension coating containing a phosphate salt and silica on a surface of the grain-oriented magnetic steel sheet, the coating further including a crystalline compound represented by the general formula (1): MII3MIII4(XVO4)6 . . . (1). A method for producing a grain-oriented magnetic steel sheet with chromium-free insulating tension coating includes applying an insulating tension coating liquid to a surface of a finish annealed grain-oriented magnetic steel sheet, the coating liquid including colloidal silica, a phosphate salt and a metal element M-containing compound in a specific ratio, and heat treating the steel sheet at least one time at a temperature of not less than 900° C. in an atmosphere including a non-oxidizing gas and having a dew point of not more than 0° C.

Abstract: Provided are an insulation-coated oriented magnetic steel sheet having an insulating coat with excellent heat resistance; and a method for manufacturing the same. This insulation-coated oriented magnetic steel sheet has an oriented magnetic steel sheet, and an insulating coat arranged on the surface of the oriented magnetic steel sheet, the insulating coat containing Si, P, O, and Cr, and at least one element selected from the group consisting of Mg, Ca, Ba, Sr, Zn, Al, and Mn. The XPS spectrum of the outermost surface of the insulating coat has peaks observed at Cr2p1/2 and Cr2p3/2.

Abstract: Provided are an insulating-coated oriented magnetic steel sheet having an insulating coating of excellent heat resistance, and a method for manufacturing the same. This insulating-coated oriented magnetic steel sheet has an oriented magnetic steel sheet, and an insulating coating arranged on the surface of the oriented magnetic steel sheet. The insulating coating contains Si, P, and O, and at least one element selected from the group consisting of Mg, Ca, Ba, Sr, Zn, Al, and Mn, the K-absorption edge of the P in the insulating coating having an XAFS spectrum that exhibits three absorption peaks from 2156 eV to 2180 eV.

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: A grain-oriented electrical steel sheet having excellent iron loss property is produced from a steel slab containing, by mass %, C: 0.002-0.15%, Si: 2.5-6.0%, Mn: 0.01-0.80%, Al: 0.010-0.050% and N: 0.003-0.020%, when: a heating rate between 500-700° C. In decarburization annealing is not less than 80° C./s, a surface roughness Ra of a work roll in final cold rolling is 0.01-3.0 ?m, a total content of alkaline earth metals to MgO in annealing separator is 0-5 mass %, an average length L in rolling direction of passed crystal grains is not more than 25 mm, a ratio of crystal grains having a length in rolling direction of not less than 0.5 ?m is 40-90%, and an existence ratio of alkaline earth metal sulfides having a size corresponding to circle of not less than 0.5 ?m in a cross section of forsterite film is not more than 0.2/?m per unit length in sheet width direction.

Abstract: Provided is a treatment solution for chromium-free tension coating that can simultaneously achieve excellent moisture absorption resistance and a high iron loss reduction effect obtained by imparting sufficient tension, by using an inexpensive Ti source instead of expensive Ti chelate. The treatment solution for chromium-free tension coating contains: one or more of phosphates of Mg, Ca, Ba, Sr, Zn, Al, and Mn; colloidal silica in an amount of 50 parts by mass to 120 parts by mass per 100 parts by mass of the phosphate in terms of solid content of SiO2; Ti source in an amount of 30 parts by mass to 50 parts by mass per 100 parts by mass of the phosphate in terms of solid content of TiO2; and H3PO4, and the number of moles of metallic elements in the phosphate and of phosphorus in the treatment solution satisfy: 0.20?([Mg]+[Ca]+[Ba]+[Sr]+[Zn]+[Mn]+1.5[Al])/[P]?0.45??(1).

Abstract: Provided is a treatment solution for chromium-free tension coating that can simultaneously achieve excellent moisture absorption resistance and a high iron loss reduction effect obtained by imparting sufficient tension, by using an inexpensive Ti source instead of expensive Ti chelate. The treatment solution for chromium-free tension coating contains: one or more of phosphates of Mg, Ca, Ba, Sr, Zn, Al, and Mn; colloidal silica in an amount of 50 parts by mass to 120 parts by mass per 100 parts by mass of the phosphate in terms of solid content of SiO2; Ti source in an amount of 30 parts by mass to 50 parts by mass per 100 parts by mass of the phosphate in terms of solid content of TiO2; and H3PO4, and the number of moles of metallic elements in the phosphate and of phosphorus in the treatment solution satisfy: 0.20?([Mg]+[Ca]+[Ba]+[Sr]+[Zn]+[Mn]+1.5[Al])/[P]?0.45??(1).