Patents by Inventor Karin Kokufu

Karin Kokufu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20240105384
    Abstract: A method for forming a film on a surface of a steel sheet includes applying a treatment solution for forming a film containing a fibrous material to the surface of the steel sheet by using a coater under a condition in which a difference between a speed of the steel sheet and a speed of an applicator of the coater is 1.0 m/min or more, inclining the surface of the steel sheet, to which the treatment solution for forming a film has been applied, at an angle of 10° or more with respect to a horizontal plane until drying is started, and thereafter drying the steel sheet.
    Type: Application
    Filed: September 16, 2020
    Publication date: March 28, 2024
    Applicant: JFE Steel Corporation
    Inventors: Takashi Terashima, Karin Kokufu, Makoto Watanabe, Toshito Takamiya
  • Publication number: 20240102172
    Abstract: An electrical steel sheet with an insulating film, the steel sheet having an insulating film containing a crystalline fibrous material on a surface of the steel sheet, in which a ratio (LRD/LTD) of a length in a rolling direction (LRD) of the crystalline fibrous material in a cross section in the rolling direction of the insulating film to a length in a direction perpendicular to the rolling direction (LTD) of the crystalline fibrous material in a cross section in the direction perpendicular to the rolling direction of the insulating film is 1.5 or more and 50.0 or less.
    Type: Application
    Filed: June 25, 2020
    Publication date: March 28, 2024
    Applicant: JFE Steel Corporation
    Inventors: Takashi Terashima, Karin Kokufu, Makoto Watanabe, Toshito Takamiya
  • Patent number: 11926888
    Abstract: Provided is an annealing separator with which a grain-oriented electrical steel sheet having a forsterite film with excellent appearance uniformity and adhesion can be obtained. The annealing separator for grain-oriented electrical steel sheet comprises: magnesia that contains 0.05 mass % or more and 0.20 mass % or less of B, a phosphate in 0.1 parts by mass or more and 1.0 part by mass or less in terms of P per 100 parts by mass of the magnesia, and titanium oxide in 1.0 part by mass or more and 10.0 parts by mass or less per 100 parts by mass of the magnesia where the titanium oxide contains one or more types of alkali metals in a total amount of 0.050 mass % or more and 1.0 mass % or less, where an amount of P adsorbed on per 1 g of the titanium oxide is 1.0×10?4 g or less.
    Type: Grant
    Filed: December 26, 2019
    Date of Patent: March 12, 2024
    Assignee: JFE STEEL CORPORATION
    Inventors: Takashi Terashima, Makoto Watanabe, Toshito Takamiya, Karin Kokufu
  • Patent number: 11923115
    Abstract: An insulating coating-attached electrical steel sheet has, on at least one surface, an insulating coating including an insulating tensile coating layer A. A tension applied to the steel sheet by an insulating tensile coating layer having a coating weight of M/2 from a surface of the insulating tensile coating layer A is 0.80×?A or more, where M is a weight of the insulating tensile coating layer A, and ?A is the tension applied to the steel sheet by the insulating tensile coating layer A. The insulating coating-attached electrical steel sheet has excellent adhesion of the insulating coating. A method for manufacturing the insulating coating-attached electrical steel sheet is also provided.
    Type: Grant
    Filed: January 21, 2019
    Date of Patent: March 5, 2024
    Assignee: JFE STEEL CORPORATION
    Inventors: Takashi Terashima, Masahiro Suemune, Karin Kokufu, Toshito Takamiya
  • Publication number: 20230392223
    Abstract: A grain oriented electrical steel sheet has excellent insulation property and includes: a steel sheet; and a coating disposed on each of both surfaces of the steel sheet, wherein an interlaminar current value after a rubbing test is not more than 0.10 A, the rubbing test being conducted by stacking two sheets of the grain oriented electrical steel sheet and rubbing the two sheets against each other to make 90 reciprocations under conditions of a surface pressure of 200 Pa, a rubbing speed of 0.10 m/s, and a reciprocating stroke of 50 mm.
    Type: Application
    Filed: July 26, 2021
    Publication date: December 7, 2023
    Applicant: JFE STEEL CORPORATION
    Inventors: Makoto WATANABE, Takashi TERASHIMA, Karin KOKUFU
  • Publication number: 20230106127
    Abstract: A grain-oriented electrical steel sheet has a base film composed mainly of forsterite on a surface of the grain-oriented electrical steel sheet and an insulating film containing mainly silicate-phosphate glass which is formed on a surface of the base film, in which, by controlling concentrations of Sr, Ca, and Ba in the base film and the insulating film to have specified gradients, the adhesion property and film tension of the insulating film are improved.
    Type: Application
    Filed: December 23, 2020
    Publication date: April 6, 2023
    Applicant: JFE Steel Corporation
    Inventors: Karin Kokufu, Makoto Watanabe, Takashi Terashima, Toshito Takamiya
  • Patent number: 11473176
    Abstract: Provided are: an oriented electrical steel sheet having a high tension applied to a steel sheet and excellent adhesion to a film; and a method for producing the same. This oriented electrical steel sheet includes: a steel sheet; a film A containing a crystalline material disposed on the steel sheet; and a film B containing a vitreous material disposed on the film A, wherein an element profile, which is obtained by using a high-frequency glow discharge light-emission surface analysis method, in the direction from the film B to the steel sheet satisfies formulae (1) and (2). 0.35?(tA/tFe/2)?0.75 . . . (1), 0.25?(tA/2/tFe/2)?1.00 . . . (2), where tA represents the peak time of an alkali metal element profile, tA/2 represents the half time of an alkali metal.
    Type: Grant
    Filed: October 12, 2018
    Date of Patent: October 18, 2022
    Assignee: JFE Steel Corporation
    Inventors: Takashi Terashima, Karin Kokufu, Toshito Takamiya
  • Publication number: 20220074012
    Abstract: Provided is an annealing separator with which a grain-oriented electrical steel sheet having a forsterite film with excellent appearance uniformity and adhesion can be obtained. The annealing separator for grain-oriented electrical steel sheet comprises: magnesia that contains 0.05 mass % or more and 0.20 mass % or less of B and 0.01 mass % or more and 0.10 mass % or less of P, and titanium oxide in 1.0 part by mass or more and 10.0 parts by mass or less per 100 parts by mass of the magnesia where the titanium oxide contains one or more types of alkali metals in a total amount of 0.0050 mass % or more and 0.50 mass % or less, where an amount of P adsorbed on per 1 g of the titanium oxide is 1.5×10?4 g or more and 1.0×10?3 g or less.
    Type: Application
    Filed: December 26, 2019
    Publication date: March 10, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Takashi TERASHIMA, Makoto WATANABE, Toshito TAKAMIYA, Karin KOKUFU
  • Publication number: 20220074030
    Abstract: Provided is an annealing separator with which a grain-oriented electrical steel sheet having a forsterite film with excellent appearance uniformity and adhesion can be obtained. The annealing separator for grain-oriented electrical steel sheet comprises: magnesia that contains 0.05 mass % or more and 0.20 mass % or less of B, a phosphate in 0.1 parts by mass or more and 1.0 part by mass or less in terms of P per 100 parts by mass of the magnesia, and titanium oxide in 1.0 part by mass or more and 10.0 parts by mass or less per 100 parts by mass of the magnesia where the titanium oxide contains one or more types of alkali metals in a total amount of 0.050 mass % or more and 1.0 mass % or less, where an amount of P adsorbed on per 1 g of the titanium oxide is 1.0×10?4 g or less.
    Type: Application
    Filed: December 26, 2019
    Publication date: March 10, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Takashi TERASHIMA, Makoto WATANABE, Toshito TAKAMIYA, Karin KOKUFU
  • Publication number: 20220049359
    Abstract: A treatment agent for chromium-free insulating coating formation suitable for forming an insulating coating on a surface of a grain-oriented electrical steel sheet. The treatment agent includes components (A), (B), (C), and (D). The component (B) is contained in an amount of 50 to 150 parts by mass on a SiO2 solid basis, and the component (C) is contained in an amount of 5.0 parts by mass or more on an elemental metal basis, the amounts being based on 100 parts by mass, on a solid basis, of the component (A). The component (D) is contained in an amount that a molar ratio of M2+ and M3+, each being a metal element in the treatment agent for chromium-free insulating coating formation, to a phosphorus element P satisfies a specified relationship, and the treatment agent for chromium-free insulating coating formation has a pH of less than 4.5.
    Type: Application
    Filed: September 2, 2019
    Publication date: February 17, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Karin KOKUFU, Takashi TERASHIMA, Toshito TAKAMIYA
  • Publication number: 20210317319
    Abstract: An insulating coating treatment liquid for forming a chromium-free insulating coating on a surface of a grain-oriented electrical steel sheet, the insulating coating treatment liquid including at least one phosphate salt selected from phosphate salts of any of Mg, Ca, Ba, Sr, Zn, Al, and Mn and including colloidal silica and particles of a metal-element-containing compound. A content of the colloidal silica in terms of SiO2, on a solids basis, is 50 to 120 parts by mass, and a content of the particles of a metal-element-containing compound in terms of elemental metal is 5 to 60 parts by mass, per 100 parts by mass of the at least one phosphate salt, and the insulating coating treatment liquid has a thixotropic index (TI) of 1.00 or greater and 10.00 or less.
    Type: Application
    Filed: June 19, 2019
    Publication date: October 14, 2021
    Applicant: JFE STEEL CORPORATION
    Inventors: Takashi TERASHIMA, Karin KOKUFU, Makoto WATANABE, Toshito TAKAMIYA
  • Publication number: 20210269921
    Abstract: A production method for a treatment solution for forming an insulating coating. The method includes mixing a solution A containing, on a PO43? basis, 0.20 mol/L or more and 10 mol/L or less of at least one of (i) phosphoric acid and (ii) a phosphate salt, and containing, on a metal basis, less than 0.50 mol/L of one or more particulate metal compounds, and a solution B containing, on a metal basis, 0.50 mol/L or more and 20.0 mol/L or less of the one or more particulate metal compounds, and containing, on a PO43? basis, less than 0.20 mol/L of at least one of (i) phosphoric acid and (ii) a phosphate salt, and stirring with a turbine stator-type high-speed stirrer such that a peripheral speed of a turbine reaches 10 m/s or more within 60 seconds after starting the mixing of the solution A and the solution B.
    Type: Application
    Filed: June 27, 2019
    Publication date: September 2, 2021
    Applicant: JFE STEEL CORPORATION
    Inventors: Takashi TERASHIMA, Karin KOKUFU, Makoto WATANABE, Toshito TAKAMIYA
  • Publication number: 20210202145
    Abstract: An electrical steel sheet having an insulating coating is provided. The electrical steel sheet is capable of reducing dielectric loss in a transformer in a case where the electrical steel sheet is used in a transformer core. An electrical steel sheet having an insulating coating, the insulating coating being disposed on at least one of surfaces of the electrical steel sheet, the insulating coating having a relative dielectric constant at 1000 Hz of less than or equal to 15.0 and a dielectric loss tangent at 1000 Hz of less than or equal to 20.0.
    Type: Application
    Filed: May 20, 2019
    Publication date: July 1, 2021
    Applicant: JFE Steel Corporation
    Inventors: Takashi Terashima, Karin Kokufu, Makoto Watanabe, Toshito Takamiya
  • Publication number: 20210035718
    Abstract: An insulating coating-attached electrical steel sheet has, on at least one surface, an insulating coating including an insulating tensile coating layer A. A tension applied to the steel sheet by an insulating tensile coating layer having a coating weight of M/2 from a surface of the insulating tensile coating layer A is 0.80×?A or more, where M is a weight of the insulating tensile coating layer A, and ?A is the tension applied to the steel sheet by the insulating tensile coating layer A. The insulating coating-attached electrical steel sheet has excellent adhesion of the insulating coating. A method for manufacturing the insulating coating-attached electrical steel sheet is also provided.
    Type: Application
    Filed: January 21, 2019
    Publication date: February 4, 2021
    Applicant: JFE STEEL CORPORATION
    Inventors: Takashi TERASHIMA, Masahiro SUEMUNE, Karin KOKUFU, Toshito TAKAMIYA
  • Publication number: 20200354821
    Abstract: Provided are: an oriented electrical steel sheet having a high tension applied to a steel sheet and excellent adhesion to a film; and a method for producing the same. This oriented electrical steel sheet includes: a steel sheet; a film A containing a crystalline material disposed on the steel sheet; and a film B containing a vitreous material disposed on the film A, wherein an element profile, which is obtained by using a high-frequency glow discharge light-emission surface analysis method, in the direction from the film B to the steel sheet satisfies formulae (1) and (2). 0.35?(tA/tFe/2)?0.75 . . . (1), 0.25?(tA/2/tFe/2)?1.00 . . . (2), where tA represents the peak time of an alkali metal element profile, tA/2 represents the half time of an alkali metal.
    Type: Application
    Filed: October 12, 2018
    Publication date: November 12, 2020
    Applicant: JFE Steel Corporation
    Inventors: Takashi Terashima, Karin Kokufu, Toshito Takamiya