Patents by Inventor Kohei Tokuda

Kohei Tokuda 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: 20240043980
    Abstract: A plated steel material having a plating layer having an average chemical composition containing, in mass %, Zn: more than 50.00%, Al: more than 15.0% and less than 30.0%, Mg: more than 5.0% and less than 15.0%, and Si: 0.25% or more and less than 3.50%, and impurities, and wherein a total amount (?A) of at least one selected from the group consisting of Sn, Bi and In is less than 1.00%, a total amount (?B) of at least one selected from the group consisting of Ca, Y, La, Ce and Sr is 0.02% or more and less than 0.60%, 2.0?SMg/Si<20.0 (Formula 1), 3.0?Si/?B<24.0 (Formula 2), and 26.0?(Si/?B)×(Mg/Si)<375.0 (Formula 3) are satisfied, and in an X-ray diffraction pattern of the surface of the plating layer, a diffraction intensity ratio R1 defined by R1={I(16.18°)+I(32.69°)}/I(27.0°) (Formula 4) satisfies 2.5<R1 (Formula 5) is used.
    Type: Application
    Filed: November 30, 2021
    Publication date: February 8, 2024
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Kohei TOKUDA, Mamoru SAITO, Takuya MITSUNOBU, Tetsuya TOBA, Yasuto GOTO, Atsushi MORISHITA, Yasuaki KAWAMURA, Fumiaki NAKAMURA, Koji KAWANISHI
  • Patent number: 11851764
    Abstract: The plated steel material is a plated steel material including a steel material and a plating layer provided on the surface of the steel material, wherein the plating layer has a predetermined average chemical composition, when the amount of Mg is % Mg and the amount of Al is % Al, % Mg/% Al is 0.80 or more, and a metal structure in a total field of view of 25,000 ?m2 in a vertical cross section which is a cross section in a thickness direction of the plating layer includes 10 to 40 area % of a MgZn2 phase, 10 to 30 area % of an Al—Zn phase with a Zn content of 10% or more, 0 to 15 area % of an Al phase with a Zn content of less than 10%, and 25 area % or more of an Al/MgZn2/Zn ternary eutectic structure.
    Type: Grant
    Filed: November 18, 2021
    Date of Patent: December 26, 2023
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kotaro Ishii, Kohei Tokuda, Yoshinari Ishida, Yasuto Goto, Mamoru Saito
  • Patent number: 11814732
    Abstract: A hot-dip plated steel includes a base steel and a hot-dip plating layer on a surface of the base steel, a chemical composition of the hot-dip plating layer contains, by mass %, Al: 10.00% to 30.00%, Mg: 3.00% to 12.00%, Sn: 0% to 2.00%, Si: 0% to 2.50%, Ca: 0% to 3.00%, Ni: 0% or more and less than 0.25%, Fe: 0% to 5.00%, and the like, a remainder includes Zn and impurities, a metallographic structure of the hot-dip plating layer contains 5 to 45 area % of an ? phase having a grain diameter of 0.5 to 2 ?m, the metallographic structure of the hot-dip plating layer contains 15 to 70 area % of a MgZn2 phase, and, among the ? phases having the grain diameter of 0.5 to 2 ?m, an area ratio of an ? phase having a (111)?//(0001)MgZn2 orientation relationship to the adjacent MgZn2 phase is 25% to 100%.
    Type: Grant
    Filed: September 7, 2021
    Date of Patent: November 14, 2023
    Assignee: Nippon Steel Corporation
    Inventors: Takuya Mitsunobu, Mamoru Saito, Kohei Tokuda, Hiroshi Takebayashi
  • Patent number: 11781200
    Abstract: A plated steel including a plated layer on a surface of a steel, in which Expression 1 of 0?Cr+Ti+Ni+Co+V+Nb+Cu+Mn?0.25 and Expression 2 of 0?Sr+Sb+Pb+B+Li+Zr+Mo+W+Ag+P?0.50 are satisfied, and Expression 3 of I(MgZn2 (41.31°))/I?(MgZn2)?0.265 and Expression 6 of 0.150?{I(MgZn2 (20.79°))+I(MgZn2 (42.24°))}/I?(MgZn2) are further satisfied in an X-ray diffraction pattern of a surface of the plated layer measured using Cu-K? rays under a condition that an X-ray output is 40 kV and 150 mA.
    Type: Grant
    Filed: July 9, 2021
    Date of Patent: October 10, 2023
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kohei Tokuda, Takuya Mitsunobu, Mamoru Saito, Yuto Fukuda, Yasuto Goto, Hidetoshi Shindo, Fumiaki Nakamura, Koji Kawanishi, Ryohei Mimura
  • Publication number: 20230304136
    Abstract: The plated steel material is a plated steel material including a steel material and a plating layer provided on the surface of the steel material, wherein the plating layer has a predetermined average chemical composition, when the amount of Mg is % Mg and the amount of Al is % Al, % Mg/% Al is 0.80 or more, and a metal structure in a total field of view of 25,000 ?m2 in a vertical cross section which is a cross section in a thickness direction of the plating layer includes 10 to 40 area % of a MgZn2 phase, 10 to 30 area % of an Al—Zn phase with a Zn content of 10% or more, 0 to 15 area % of an Al phase with a Zn content of less than 10%, and 25 area % or more of an Al/MgZn2/Zn ternary eutectic structure.
    Type: Application
    Filed: November 18, 2021
    Publication date: September 28, 2023
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Kotaro ISHII, Kohei TOKUDA, Yoshinari ISHIDA, Yasuto GOTO, Mamoru SAITO
  • Patent number: 11725259
    Abstract: A plated steel sheet having excellent chemical convertibility includes: a steel; and a plating layer that is provided on a surface of the steel, in which the plating layer includes, by mass %, Al: 5.00% to 35.00%, Mg: 2.50% to 13.00%, Fe: 5.00% to 35.00%, Si: 0% to 2.00%, Ca: 0.03% to 2.00%, and a remainder consisting of Zn and impurities, and in a surface of the plating layer, the area fraction of a Fe—Al phase is 0% to 30%, the area fraction of a rod-like lamellar structure of Zn and MgZn2 is 5% to 90%, the area fraction of a massive MgZn2 phase is 10% to 70%, and the area fraction of a remainder is 10% or less.
    Type: Grant
    Filed: April 16, 2020
    Date of Patent: August 15, 2023
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takuya Mitsunobu, Jun Maki, Hiroshi Takebayashi, Takehiro Takahashi, Kohei Tokuda
  • Patent number: 11697266
    Abstract: A plated steel includes: a steel; and a plating layer that is provided on a surface of the steel, in which the plating layer includes, by mass %, Al: 5.00% to 35.00%, Mg: 2.50% to 13.00%, Fe: 5.00% to 40.00%, Si: 0% to 2.00%, Ca: 0% to 2.00%, and a remainder of Zn and impurities, and in a cross section of the plating layer, the area fraction of a Zn solid-solution Fe2Al5 phase in which 5% or more of Zn is solid-soluted is 10% to 60% and the area fraction of a MgZn2 phase is 10% to 90%.
    Type: Grant
    Filed: April 16, 2020
    Date of Patent: July 11, 2023
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takuya Mitsunobu, Jun Maki, Hiroshi Takebayashi, Takehiro Takahashi, Kohei Tokuda
  • Publication number: 20230203635
    Abstract: A hot-dip plated steel according to one aspect includes a base steel and a hot-dip plating layer disposed on a surface of the base steel, a chemical composition of the hot-dip plating layer contains, by mass%, Al: 10.00% to 30.00%, Mg: 3.00% to 12.00%, Sn: 0% to 2.00%, Si: 0% to 2.50%, Ca: 0% to 3.00%, Ni: 0% or more and less than 0.25%, Fe: 0% to 5.00%, and the like, a remainder consists of Zn and impurities, a metallographic structure of the hot-dip plating layer contains 5 to 45 area% of an ? phase having a grain diameter of 0.5 to 2 µm, the metallographic structure of the hot-dip plating layer contains 15 to 70 area% of a MgZn2 phase, and, among the ? phases having the grain diameter of 0.5 to 2 µm, an area ratio of an ? phase having a (111)?//(0001)MgZn2 orientation relationship to the adjacent MgZn2 phase is 25% to 100%.
    Type: Application
    Filed: September 7, 2021
    Publication date: June 29, 2023
    Inventors: Takuya MITSUNOBU, Mamoru SAITO, Kohei TOKUDA, Hiroshi TAKEBAYASHI
  • Publication number: 20230193425
    Abstract: A plated steel including a plated layer on a surface of a steel, in which Expression 1 of 0?Cr+Ti+Ni+Co+V+Nb+Cu+Mn 0.25 and Expression 2 of 0?Sr+Sb+Pb+B+Li+Zr+Mo+W+Ag+P?0.50 are satisfied, and Expression 3 of I(MgZn2 (41.31°))/I?(MgZn2)?0.265 and Expression 6 of 0.150?{I(MgZn2 (20.79°))+I(MgZn2 (42.24°))}/I?(MgZn2) are further satisfied in an X-ray diffraction pattern of a surface of the plated layer measured using Cu-K? rays under a condition that an X-ray output is 40 kV and 150 mA.
    Type: Application
    Filed: July 9, 2021
    Publication date: June 22, 2023
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Kohei TOKUDA, Takuya MITSUNOBU, Mamoru SAITO, Yuto FUKUDA, Yasuto GOTO, Hidetoshi SHINDO, Fumiaki NAKAMURA, Koji KAWANISHI, Ryohei MIMURA
  • Patent number: 11634790
    Abstract: A plated steel sheet includes: a steel sheet; and a plating layer that is formed on at least a part of a surface of the steel sheet, in which a chemical composition of the plating layer includes, by mass %, Al: more than 5.00% and 35.00% or less, Mg: 3.00% to 15.00%, Si: 0% to 2.00%, Ca: 0% to 2.00%, and a remainder of Zn and impurities, in which in a cross section of the plating layer in a thickness direction, the area ratio of a lamellar structure in which an (Al—Zn) phase and a MgZn2 phase are arranged in layers is 10% to 90%, a lamellar spacing of the lamellar structure is 2.5 ?m or less, and the area ratio of an (Al—Zn) dendrite is 35% or less.
    Type: Grant
    Filed: April 16, 2020
    Date of Patent: April 25, 2023
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takuya Mitsunobu, Jun Maki, Hiroshi Takebayashi, Takehiro Takahashi, Kohei Tokuda
  • Patent number: 11634791
    Abstract: A hot-dip coated steel product including: a steel product; and a coating layer including a Zn—Al—Mg alloy layer disposed on a surface of the steel product, in which the Zn—Al—Mg alloy layer includes a Zn phase, an Al phase, and a MgZn2 phase, and contains a Mg—Sn intermetallic compound phase in the Zn phase, and the coating layer has a chemical composition satisfying a predetermined average composition, a total area proportion of the Al phase and the MgZn2 phase is 70% or more, an area proportion of the Zn phase is 30% or less, an average value of cumulative circumferential lengths of the Al phase is less than 88 mm/mm2, and a total frequency in number of the Al phase having a circumferential length of 50 ?m or more is less than 100.
    Type: Grant
    Filed: April 16, 2020
    Date of Patent: April 25, 2023
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kohei Tokuda, Mamoru Saito, Jun Maki, Takuya Mitsunobu, Yasuto Goto
  • Patent number: 11584981
    Abstract: A plated steel sheet having excellent post-coating corrosion resistance includes: a steel; and a plating layer that is provided on a surface of the steel, in which the plating layer includes, by mass %, Al: 5.00% to 35.00%, Mg: 2.50% to 13.00%, Fe: 5.00% to 35.00%, Si: 0% to 2.00%, Ca: 0% to 2.00%, and a remainder consisting of Zn and impurities, and in a cross section of the plating layer, the area fraction of a Fe2Al5 phase is 5.0% to 60.0%, the area fraction of an eutectic structure of Zn and MgZn2 is 10.0% to 80.0%, the area fraction of a massive MgZn2 phase is 5.0% to 40.0%, and the area fraction of a remainder is 10.0% or less.
    Type: Grant
    Filed: April 16, 2020
    Date of Patent: February 21, 2023
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takuya Mitsunobu, Jun Maki, Hiroshi Takebayashi, Takehiro Takahashi, Kohei Tokuda
  • Patent number: 11555235
    Abstract: Provided is a metallic coated steel product which is less likely to experience LME and blowhole formation and is likely to exhibit an improved corrosion resistance at welding heat affected zones. The metallic coated steel product is a hot-dip metallic coated steel product including a steel product and a plating layer that is provided on a surface of the steel product and includes a Zn—Al—Mg alloy layer. In a cross-section of the Zn—Al—Mg alloy layer an area fraction of MgZn2 phase is from 45 to 75%, a total area fraction of MgZn2 and Al phases is not less than 70%, and an area fraction of Zn—Al—MgZn2 ternary eutectic structure is from 0 to 5%; and the plating layer has a predetermined chemical composition.
    Type: Grant
    Filed: January 26, 2018
    Date of Patent: January 17, 2023
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kohei Tokuda, Yoshinari Ishida, Takuya Mitsunobu, Nobuyuki Shimoda
  • Publication number: 20220356547
    Abstract: A hot-dip coated steel product including: a steel product; and a coating layer including a Zn—Al—Mg alloy layer disposed on a surface of the steel product, in which the Zn—Al—Mg alloy layer includes a Zn phase, an Al phase, and a MgZn2 phase, and contains a Mg—Sn intermetallic compound phase in the Zn phase, and the coating layer has a chemical composition satisfying a predetermined average composition, a total area proportion of the Al phase and the MgZn2 phase is 70% or more, an area proportion of the Zn phase is 30% or less, an average value of cumulative circumferential lengths of the Al phase is less than 88 mm/mm2, and a total frequency in number of the Al phase having a circumferential length of 50 ?m or more is less than 100.
    Type: Application
    Filed: April 16, 2020
    Publication date: November 10, 2022
    Inventors: Kohei TOKUDA, Mamoru SAITO, Jun MAKI, Takuya MITSUNOBU, Yasuto GOTO
  • Patent number: 11473174
    Abstract: The present invention provides a coated steel product including: a steel product; a coating layer that is coated on the surface of the steel product and that includes from 8 to 50% by mass of Mg, from 2.5 to 70.0% by mass of Al, and from 0.30 to 5.00% by mass of Ca, with the balance consisting of Zn and impurities; and an intermediate layer interposed between the steel product and the coating layer, in which the intermediate layer has a sea-island structure constituted by a sea portion composed of an Al—Fe alloy phase, and island portions including a Zn—Mg—Al alloy phase having a Mg content of 8% by mass or more, and in which the sea portion composed of the Al—Fe alloy phase has an area fraction of from 55 to 90%.
    Type: Grant
    Filed: January 16, 2017
    Date of Patent: October 18, 2022
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kohei Tokuda, Hisashi Baba, Nobuyuki Shimoda, Kenichiro Matsumura, Yasuto Goto
  • Publication number: 20220298646
    Abstract: A hot stamped steel includes a base material, a plated layer that is formed on a surface of the base material, and an oxide film that is formed on a surface of the plated layer; chemical composition of the plated layer contains 20.00 to 45.00 mass % of Al, 10.00 to 45.00 mass % of Fe, 4.50 to 15.00 mass % of Mg, 0.10 to 3.00 mass % of Si, 0.05 to 3.00 mass % of Ca, 0 to 0.50 mass % of Sb, 0 to 0.50 mass % of Pb, 0 to 1.00 mass % of Cu, 0 to 1.00 mass % of Sn, 0 to 1.00 mass % of Ti, 0 to 0.50 mass % of Sr, 0 to 1.00 mass % of Cr, 0 to 1.00 mass % of Ni, and 0 to 1.00 mass % of Mn with a remainder of Zn and impurities; and chemical composition of the oxide film contains 20.0 to 55.0 at % of Mg, 0.5 to 15.0 at % of Ca, 0 to 15.0 at % of Zn, and 0 at % or more and less than 10.0 at % of Al with a remainder of O and a total of 5.0 at % or less of impurities, and the adhesion amount of the oxide film per one surface is in a range of 0.01 to 10 g/m2.
    Type: Application
    Filed: August 28, 2020
    Publication date: September 22, 2022
    Inventors: Takuya MITSUNOBU, Kohei TOKUDA, Takehiro TAKAHASHI, Hiroshi TAKEBAYASHI
  • Publication number: 20220275481
    Abstract: A hot stamped steel includes a base material that is formed of steel, a plated layer that is formed on a surface of the base material, and a phosphate coating that is formed on a surface of the plated layer; chemical composition of the plated layer contains 20.00 to 45.00 mass % of Al, 10.00 to 45.00 mass % of Fe, 4.50 to 15.00 mass % of Mg, 0.10 to 3.00 mass % of Si, 0.05 to 3.00 mass % of Ca, 0 to 0.50 mass % of Sb, 0 to 0.50 mass % of Pb, 0 to 1.00 mass % of Cu, 0 to 1.00 mass % of Sn, 0 to 1.00 mass % of Ti, 0 to 0.50 mass % of Sr, 0 to 1.00 mass % of Cr, 0 to 1.00 mass % of Ni, and 0 to 1.00 mass % of Mn with a remainder of Zn and impurities; the phosphate coating consists of zinc phosphate crystals containing 5.0 to 50.0 mass % of Mg and 0.5 to 5.0 mass % of Ca; and the adhesion amount of the phosphate coating per one surface is in a range of 0.1 to 10.0 g/m2.
    Type: Application
    Filed: August 28, 2020
    Publication date: September 1, 2022
    Inventors: Takuya MITSUNOBU, Kohei TOKUDA, Takehiro TAKAHASHI, Hiroshi TAKEBAYASHI
  • Patent number: 11338550
    Abstract: There is provided a hot-stamped body including: a steel base metal; and a metallic layer formed on a surface of the steel base metal, wherein the metallic layer includes: an interface layer that contains, in mass %, Al: 30.0 to 36.0%, has a thickness of 100 nm to 5 ?m, and is located in an interface between the metallic layer and the steel base metal; and a principal layer that includes coexisting MgZn2 phases and insular FeAl2 phases, is located on the interface layer, and has a thickness of 3 ?m to 40 ?m.
    Type: Grant
    Filed: March 20, 2018
    Date of Patent: May 24, 2022
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kohei Tokuda, Takuya Mitsunobu, Akihiro Sengoku, Kenichiro Matsumura
  • Publication number: 20220152983
    Abstract: A plated steel includes: a steel; and a plating layer that is provided on a surface of the steel, in which the plating layer includes, by mass %, Al: 5.00% to 35.00%, Mg: 2.50% to 13.00%. Fe: 5.00% to 40.00%, Si: 0% to 2.00%, Ca: 0% to 2.00%, and a remainder of Zn and impurities, and in a cross section of the plating layer, the area fraction of a Zn solid-solution Fe2Al5 phase in which 5% or more of Zn is solid-soluted is 10% to 60% and the area fraction of a MgZn2 phase is 10% to 90%.
    Type: Application
    Filed: April 16, 2020
    Publication date: May 19, 2022
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Takuya MITSUNOBU, Jun MAKI, Hiroshi TAKEBAYASHI, Takehiro TAKAHASHI, Kohei TOKUDA
  • Publication number: 20220145473
    Abstract: A surface-treated metal material includes a metal sheet, a plating layer formed on the metal sheet and containing aluminum, magnesium, and zinc, and a composite coating formed on a surface of the plating layer, the composite coating including an organic silicon compound, one or two of a zirconium compound and a titanium compound, a phosphoric acid compound, a fluorine compound, and a vanadium compound, wherein, when a surface of the composite coating is analyzed at a spot size of ?30 ?m using micro-fluorescent X-rays, a maximum value of V/Zn, which is a mass ratio of a V content to a Zn content, is 0.010 to 0.100.
    Type: Application
    Filed: March 19, 2020
    Publication date: May 12, 2022
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Hiromasa SHOJI, Kiyokazu ISHIZUKA, Kohei TOKUDA, Mamoru SAITO, Yasuto GOTO, Ikumi TOKUDA