Patents by Inventor Hiroi Yamaguchi

Hiroi Yamaguchi 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: 20250101561
    Abstract: Provided is a grain-oriented electrical steel sheet with good film adhesion. Among the elements present at grain boundaries between ceramic particles contained in a base film of the grain-oriented electrical steel sheet, either or both of S and Se elements are contained in a range of 0.02 at % to 2.00 at %.
    Type: Application
    Filed: February 17, 2023
    Publication date: March 27, 2025
    Applicant: JFE STEEL CORPORATION
    Inventors: Takeshi IMAMURA, Makoto WATANABE, Masanari TOMOZAWA, Hiroi YAMAGUCHI, Shigehiro TAKAJO, Mari TAKAHASHI
  • Publication number: 20250075300
    Abstract: The present disclosure proposes a grain-oriented electrical steel sheet that reduces iron loss by controlling the magnetic domain structure and can maintain the iron loss reduction effect even after subjection to stress relief annealing. The grain-oriented electrical steel sheet comprising a predetermined chemical composition and a local area having a misorientation angle of 1.5 degrees or more from surrounding crystals and extending linearly in a direction crossing a rolling direction on at least one of front and back surfaces of the steel sheet, wherein the local area has a volume fraction of 0.1% or more and 2.0% or less and a residual stress of 100 MPa or less, and the surface having the local area has an average amount of roughness on a steel substrate being less than 5 ?m.
    Type: Application
    Filed: December 21, 2022
    Publication date: March 6, 2025
    Applicant: JFE STEEL CORPORATION
    Inventors: Hiroi YAMAGUCHI, Takeshi IMAMURA, Yoshihisa ICHIHARA, Takeshi OMURA
  • Publication number: 20240287659
    Abstract: To provide a method of producing a grain-oriented electrical steel sheet that can stably produce a grain-oriented electrical steel sheet with low iron loss and little variation in iron loss using a tandem mill. Disclosed is a method of producing a grain-oriented electrical steel sheet, including: hot rolling; a single cycle of cold rolling, or multiple cycles of cold rolling with intermediate annealing in between; decarburization annealing; and recrystallization annealing, in which final cold rolling is performed using a tandem mill, where the steel sheet is heated to a temperature range from 70° C. to 200° C. and then introduced into the first pass of the tandem mill in which rolling in the first pass is performed with a biting temperature T (° C.) and a strain rate e (s?1) satisfying: 0.0378e2+0.367e+37.2>T (1).
    Type: Application
    Filed: June 30, 2022
    Publication date: August 29, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Yusuke SHIMOYAMA, Yukihiro SHINGAKI, Hiroi YAMAGUCHI
  • Publication number: 20240279763
    Abstract: To provide a method of producing a grain-oriented electrical steel sheet that can stably produce a grain-oriented electrical steel sheet with low iron loss and little variation in iron loss using a tandem mill. Disclosed is a method of producing a grain-oriented electrical steel sheet, including: hot rolling; a single cycle of cold rolling, or multiple cycles of cold rolling with intermediate annealing in between; decarburization annealing; and secondary recrystallization annealing, in which annealing preceding final cold rolling is performed with an average cooling rate of 20° C./s or higher in a temperature range from 800° C. to 350° C., and the final cold rolling is performed using a tandem mill, where the steel sheet is heated to a temperature range from 70° C. to 200° C. and then cooled to 60° C. or lower within 10 seconds before being introduced into the first pass of the tandem mill.
    Type: Application
    Filed: June 30, 2022
    Publication date: August 22, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Yusuke SHIMOYAMA, Yukihiro SHINGAKI, Hiroi YAMAGUCHI
  • Publication number: 20240247347
    Abstract: In the production of a grain-oriented electrical steel sheet by heating a steel slab containing, in mass %, C: 0.02 to 0.10%, Si: 2.5 to 5.5%, Mn: 0.01 to 0.30%, S: 0.0010 to 0.040%, Se: 0 to 0.040%, sol. Al: 0.010 to 0.040%; and N: 0.004 to 0.020% to 1300° C. or higher; subsequently performing hot rolling, hot-band annealing as necessary, cold rolling, and primary recrystallization annealing which also serves as decarburization annealing; applying an annealing separator on the surface of the steel sheet; and performing finishing annealing, edge cracks that may occur in the hot rolling are effectively prevented by keeping a slab lateral face temperature at a time of starting rough rolling during the hot rolling equal to or lower than a temperature Te defined by the following Expression Te=?120000 [% S]2+1400 (1) and carrying out width reduction after at least one pass in the rough rolling.
    Type: Application
    Filed: May 26, 2022
    Publication date: July 25, 2024
    Applicant: JFE Steel Corporation
    Inventors: Masanori Takenaka, Takeshi Imamura, Takaaki Tanaka, Hiroi Yamaguchi
  • Publication number: 20240240293
    Abstract: To provide a method for producing a grain-oriented electrical steel sheet that can solve the problem of cracking in steel sheets during final cold rolling and that can stably produce a grain-oriented electrical steel sheet with low iron loss. A production method includes predetermined steps, wherein the conditions: T??4000×A+440, and T?360 are satisfied, where A denotes an average C content in mass % in a predetermined region of the steel sheet after subjection to annealing preceding final cold rolling and before subjection to the final cold rolling, and T denotes a time in hours from just after the completion of the annealing preceding the final cold rolling to just before the start of the final cold rolling, and after the final cold rolling and before the decarburization annealing, pickling treatment is performed with a predetermined treatment solution.
    Type: Application
    Filed: May 27, 2022
    Publication date: July 18, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Takeshi IMAMURA, Ayaka YOSHIKAWA, Masanori TAKENAKA, Hiroi YAMAGUCHI
  • Publication number: 20240229199
    Abstract: The method includes slab-heating a steel slab to a temperature of higher than a ?-phase precipitation temperature and 1380° C. or lower, subjecting the steel slab to rough rolling including at least two passes of rolling at a predetermined temperature with an introduced sheet thickness true strain ?t of 0.50 or more and to finish rolling with a rolling finish temperature of 900° C. or higher to obtain a hot-rolled sheet, cooling the sheet for 1 second or longer at a cooling rate of 70° C./s or higher within 2 seconds after finish rolling, coiling the sheet at a coiling temperature of 600° C. or lower, performing hot-rolled sheet annealing for soaking at a predetermined soaking temperature, and then performing cold rolling, primary recrystallization annealing, and secondary recrystallization annealing.
    Type: Application
    Filed: March 2, 2022
    Publication date: July 11, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Shigehiro TAKAJO, Hiroi YAMAGUCHI
  • Publication number: 20240233992
    Abstract: The method includes slab-heating a steel slab to a temperature of higher than a ?-phase precipitation temperature and 1380° C. or lower, subjecting the steel slab to rough rolling including at least two passes of rolling at a predetermined temperature with an introduced sheet thickness true strain ?t of 0.50 or more and to finish rolling with a rolling finish temperature of 900° C. or higher to obtain a hot-rolled sheet, cooling the hot-rolled sheet for 1 second or longer at a cooling rate of 70° C./s or higher within 2 seconds after finish rolling, coiling the sheet at a coiling temperature of 600° C. or lower, performing hot-rolled sheet annealing for soaking at a predetermined soaking temperature, and then performing cold rolling, primary recrystallization annealing, and secondary recrystallization annealing.
    Type: Application
    Filed: March 2, 2022
    Publication date: July 11, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Shigehiro TAKAJO, Hiroi YAMAGUCHI
  • Publication number: 20240183011
    Abstract: A method for producing a grain-oriented electrical steel sheet comprises heating a steel material containing a certain composition to a temperature in a range of 1150 to 1250° C.; performing hot rolling, hot-band annealing, and cold rolling on the material to obtain a cold-rolled sheet with a final thickness; performing decarburization annealing also serving as primary recrystallization annealing on the cold-rolled sheet; subsequently applying an annealing separator to a surface of the steel sheet; and performing finishing annealing followed by applying an insulation coating. In the method, rapid heating is conducted from 500 and 700° C. in a heating process of the decarburization annealing at a rate of 100 to 1000° C./s while gradual heating is conducted from 800 to 900° C. in a heating process of the finishing annealing at a heating rate of 0.5 to 4.0° C./hr for at least 10 hours.
    Type: Application
    Filed: March 28, 2022
    Publication date: June 6, 2024
    Applicant: JFE Steel Corporation
    Inventors: Ryosuke Tani, Takeshi Imamura, Shigehiro Takajo, Hiroi Yamaguchi
  • Publication number: 20240150875
    Abstract: Proposed is a method for producing a grain-oriented electrical steel sheet that comprises heating a steel material containing a certain composition and inhibitor-forming ingredients to a temperature in a range of 1300 to 1400° C.; performing hot rolling, hot-band annealing, and cold rolling on the material to obtain a cold-rolled sheet; performing decarburization annealing also serving as primary recrystallization annealing on the cold-rolled sheet; subsequently applying an annealing separator to a surface of the steel sheet; and performing finishing annealing followed by applying an insulation coating. In the method, rapid heating is conducted from 500 and 700° C. in a heating process of the decarburization annealing at a rate of 100 to 1000° C./s while gradual heating is conducted from 860 to 970° C. in a heating process of the finishing annealing at a heating rate of 0.5 to 4.0° C./hr for at least 10 hours.
    Type: Application
    Filed: March 28, 2022
    Publication date: May 9, 2024
    Applicant: JFE Steel Corporation
    Inventors: Ryosuke Tani, Takeshi Imamura, Shigehiro Takajo, Hiroi Yamaguchi
  • Publication number: 20240133003
    Abstract: The method includes slab-heating a steel slab to a temperature of higher than a ?-phase precipitation temperature and 1380° C. or lower, subjecting the steel slab to rough rolling including at least two passes of rolling at a predetermined temperature with an introduced sheet thickness true strain ?t of 0.50 or more and to finish rolling with a rolling finish temperature of 900° C. or higher to obtain a hot-rolled sheet, cooling the sheet for 1 second or longer at a cooling rate of 70° C./s or higher within 2 seconds after finish rolling, coiling the sheet at a coiling temperature of 600° C. or lower, performing hot-rolled sheet annealing for soaking at a predetermined soaking temperature, and then performing cold rolling, primary recrystallization annealing, and secondary recrystallization annealing.
    Type: Application
    Filed: March 2, 2022
    Publication date: April 25, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Shigehiro TAKAJO, Hiroi YAMAGUCHI
  • Publication number: 20240136095
    Abstract: The method includes slab-heating a steel slab to a temperature of higher than a ?-phase precipitation temperature and 1380° C. or lower, subjecting the steel slab to rough rolling including at least two passes of rolling at a predetermined temperature with an introduced sheet thickness true strain ?t of 0.50 or more and to finish rolling with a rolling finish temperature of 900° C. or higher to obtain a hot-rolled sheet, cooling the hot-rolled sheet for 1 second or longer at a cooling rate of 70° C./s or higher within 2 seconds after finish rolling, coiling the sheet at a coiling temperature of 600° C. or lower, performing hot-rolled sheet annealing for soaking at a predetermined soaking temperature, and then performing cold rolling, primary recrystallization annealing, and secondary recrystallization annealing.
    Type: Application
    Filed: March 2, 2022
    Publication date: April 25, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Shigehiro TAKAJO, Hiroi YAMAGUCHI
  • Publication number: 20240052448
    Abstract: Provided is a method of manufacturing a grain-oriented electrical steel sheet, with which a grain-oriented electrical steel sheet with low iron loss and little variation in iron loss can be stably manufactured by a tandem mill. The method includes subjecting a steel material to hot rolling to obtain a hot-rolled sheet, subjecting the hot-rolled sheet to cold rolling once or twice or more with intermediate annealing performed therebetween to obtain a cold-rolled sheet with a final sheet thickness, and then subjecting the cold-rolled sheet to decarburization annealing and then to secondary recrystallization annealing, wherein final cold rolling is performed by a tandem mill, and in the final cold rolling, the hot-rolled sheet is heated to a temperature range of 70° C. or higher and 200° C. or lower, then cooled to 60° C. or lower, and then introduced into a first pass of the tandem mill.
    Type: Application
    Filed: January 26, 2022
    Publication date: February 15, 2024
    Applicant: JFE STEEL CORPORATION
    Inventors: Yusuke SHIMOYAMA, Yukihiro SHINGAKI, Hiroi YAMAGUCHI
  • Publication number: 20230307160
    Abstract: Provided is a method for manufacturing a grain-oriented electrical steel sheet to reduce iron loss by controlling the magnetic domain structure, in which the iron loss reduction effect can be maintained even when stress relief annealing is applied, and the magnetic flux density does not decrease after the magnetic domain control treatment. In the manufacturing method, on a surface of the grain oriented electrical steel sheet, a laser beam with a ring-shaped intensity distribution in which the intensity in a periphery is lower than that in a center is irradiated in a linear manner in a direction intersecting a rolling direction of the steel sheet.
    Type: Application
    Filed: August 26, 2021
    Publication date: September 28, 2023
    Applicant: JFE STEEL CORPORATION
    Inventors: Hiroi YAMAGUCHI, Takeshi IMAMURA, Takeshi OMURA, Yoshihisa ICHIHARA
  • Publication number: 20220195553
    Abstract: Provided is a method of producing a grain-oriented electrical steel sheet having uniform and good coating properties and magnetic properties throughout the length and/or width of the steel sheet. The method comprises: subjecting a steel slab to hot rolling, to cold rolling once or twice or more with intermediate annealing therebetween, and to primary recrystallization annealing; applying a liquid or slurry annealing separator to a resultant steel sheet; and thereafter coiling the steel sheet and subjecting the steel sheet to final annealing, wherein, before, after, or simultaneously with the application of the annealing separator, an additive for changing a composition of the annealing separator is adhered to the steel sheet at a weight ratio of 15% or less to a total of the annealing separator and the additive so as to vary the composition of the annealing separator in a longitudinal direction and/or width direction of the steel sheet.
    Type: Application
    Filed: March 26, 2020
    Publication date: June 23, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Hiroi YAMAGUCHI, Takashi TERASHIMA, Makoto WATANABE
  • Publication number: 20220186338
    Abstract: A method for producing a non-oriented electrical steel sheet used as an iron core material for a motor or transformer and having excellent magnetic properties including subjecting a raw steel material including, by mass %, C: not more than 0.005%, Si: 1.0 to 5.0%, Mn: 0.04 to 3.0%, sol. Al: not more than 0.005%, P: not more than 0.2%, S: not more than 0.005%, N: not more than 0.005% and the remainder being Fe and impurities forming a hot-rolled sheet, subjecting the hot-rolled sheet to hot-band annealing and a single or two or more cold rollings including an intermediate annealing between each rolling forming a cold-rolled sheet having a final sheet thickness and subjecting the cold-rolled sheet to a finish annealing, wherein at least one pass in the final cold rolling at a friction coefficient ? of not less than 0.030 and a rolling reduction of not less than 15%.
    Type: Application
    Filed: January 17, 2020
    Publication date: June 16, 2022
    Applicant: JFE STEEL CORPORATION
    Inventors: Yusuke SHIMOYAMA, Yukihiro SHINGAKI, Yoshiaki ZAIZEN, Hiroi YAMAGUCHI
  • Patent number: 11286538
    Abstract: In a grain-oriented electrical steel sheet which is manufactured from a thin slab without using an inhibitor forming component, excellent magnetic properties are stably achieved. In a method for manufacturing a grain-oriented electrical steel sheet, a slab heating and annealing are performed under specific conditions.
    Type: Grant
    Filed: February 19, 2018
    Date of Patent: March 29, 2022
    Assignee: JFE STEEL CORPORATION
    Inventors: Masanori Takenaka, Takeshi Imamura, Yuiko Ehashi, Hiroi Yamaguchi
  • Patent number: 11198917
    Abstract: Provided is a method for nitriding a grain-oriented electrical steel sheet which is very useful in obtaining excellent magnetic properties with no variation, that enables generating glow discharge between positive electrodes and negative electrodes disposed in a nitriding zone and irradiating the generated plasma to a strip to perform appropriate nitriding.
    Type: Grant
    Filed: December 17, 2018
    Date of Patent: December 14, 2021
    Assignee: JFE STEEL CORPORATION
    Inventors: Hiroshi Matsuda, Hideyuki Takahashi, Hiroi Yamaguchi, Yasuyuki Hayakawa, Yukihiro Shingaki, Takashi Terashima
  • Publication number: 20200040419
    Abstract: In a grain-oriented electrical steel sheet which is manufactured from a thin slab without using an inhibitor forming component, excellent magnetic properties are stably achieved. In a method for manufacturing a grain-oriented electrical steel sheet, a slab heating and annealing are performed under specific conditions.
    Type: Application
    Filed: February 19, 2018
    Publication date: February 6, 2020
    Applicant: JFE STEEL CORPORATION
    Inventors: Masanori TAKENAKA, Takeshi IMAMURA, Yuiko EHASHI, Hiroi YAMAGUCHI
  • Publication number: 20190323100
    Abstract: Excellent magnetic properties can be stably obtained in grain-oriented electrical steel sheets produced from thin slabs without using inhibitor forming components. Provided is a method for producing a grain-oriented electrical steel sheet comprising: subjecting a molten steel to continuous casting to form a slab with 25 to 100 mm in thickness, the molten steel having a chemical composition containing, in mass %, C: 0.002 to 0.100%, Si: 2.00 to 8.00%, Mn: 0.005 to 1.000%, Al: <0.0100%, N: <0.0050%, S: <0.0050% and Se: <0.0050%, and the balance being Fe and inevitable impurities; heating and then hot rolling the slab to form a hot-rolled steel sheet; wherein the step of heating the slab is performed at 1000 to 1300° C. for 10 to 600 seconds.
    Type: Application
    Filed: November 1, 2017
    Publication date: October 24, 2019
    Applicant: JFE STEEL CORPORATION
    Inventors: Takeshi IMAMURA, Yuiko EHASHI, Masanori TAKENAKA, Hiroi YAMAGUCHI