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).

  • Patent number: 10982303
    Abstract: There is provided a coated steel product having 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 has a Zn phase, the Zn phase contains a Mg—Sn intermetallic compound phase, and the coating layer consists of Zn: more than 65.0%, Al: from more than 5.0% to less than 25.0%, Mg: from more than 3.0% to less than 12.5%, Sn: 0.1% to 20.0% in terms of percent (%) by mass, given amounts of optional elements, and impurities, and has a chemical composition that satisfies the following Formulas 1 to 5: Bi+In<Sn??Formula 1: Y+La+Ce?Ca??Formula 2: Si<Sn??Formula 3: 0?Cr+Ti+Ni+Co+V+Nb+Cu+Mn<0.25??Formula 4: 0?Sr+Sb+Pb+B<0.5.
    Type: Grant
    Filed: January 26, 2018
    Date of Patent: April 20, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kohei Tokuda, Jun Maki, Yasuto Goto, Takuya Mitsunobu
  • Publication number: 20210039354
    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: Application
    Filed: March 20, 2018
    Publication date: February 11, 2021
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Kohei TOKUDA, Takuya MITSUNOBU, Akihiro SENGOKU, Kenichiro MATSUMURA
  • Publication number: 20210039355
    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 15 ?m, and is located in an interface between the metallic layer and the steel base metal; and a principal layer that includes coexisting Zn phases and insular FeAl2 phases, is located on the interface layer, and has a thickness of 1 ?m to 40 ?m. This hot-stamped body is excellent in fatigue properties, corrosion resistance, and chipping resistance.
    Type: Application
    Filed: March 20, 2018
    Publication date: February 11, 2021
    Applicant: Nippon Steel Corporation
    Inventors: Takuya MITSUNOBU, Kohei TOKUDA, Akihiro SENGOKU, Kenichiro MATSUMURA
  • Patent number: 10563296
    Abstract: The invention provides a coated steel including a steel, a coated metal layer coated on a surface of the steel, and an interfacial alloy layer formed at the boundary between the steel and the coated metal layer, in which the coated metal layer has a predetermined composition and structure, and in which the thickness of the coated metal layer is 0.1 ?m or more, and the thickness of the interfacial alloy layer is 500 nm or less.
    Type: Grant
    Filed: September 29, 2016
    Date of Patent: February 18, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Akinobu Kobayashi, Kohei Tokuda, Nobuyuki Shimoda, Yasuto Goto, Kenichiro Matsumura
  • Publication number: 20200002798
    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: Application
    Filed: January 26, 2018
    Publication date: January 2, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Kohei TOKUDA, Yoshinari ISHIDA, Takuya MITSUNOBU, Nobuyuki SHIMODA
  • Publication number: 20190390303
    Abstract: There is provided a coated steel product having 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 has a Zn phase, the Zn phase contains a Mg—Sn intermetallic compound phase, and the coating layer consists of Zn: more than 65.0%, Al: from more than 5.0% to less than 25.0%, Mg: from more than 3.0% to less than 12.5%, Sn: 0.1% to 20.0% in terms of percent (%) by mass, given amounts of optional elements, and impurities, and has a chemical composition that satisfies the following Formulas 1 to 5: Bi+In<Sn??Formula 1: Y+La+Ce?Ca??Formula 2: Si<Sn??Formula 3: 0?Cr+Ti+Ni+Co+V+Nb+Cu+Mn<0.25??Formula 4: 0?Sr+Sb+Pb+B<0.5.
    Type: Application
    Filed: January 26, 2018
    Publication date: December 26, 2019
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Kohei TOKUDA, Jun MAKI, Yasuto GOTO, Takuya MITSUNOBU
  • Patent number: 10508330
    Abstract: A quasicrystal-containing plated steel sheet including: a plating layer positioned on at least one surface of a steel sheet; and an alloy layer positioned at an interface between the plating layer and the steel sheet and composed of an Al—Fe intermetallic compound. A chemical composition of the plating layer contains at least, in atom %, Zn: 28.5% to 50%, Al: 0.3% to 12%, and the balance: Mg and impurities, and the plating layer includes, in order from the steel sheet side, a first plating layer which is composed of a structure containing an MgZn phase, an Mg phase, and a quasicrystal phase, and a second plating layer which is positioned on the first plating layer and is composed of a structure containing an Mg51Zn20 phase, a Zn phase, and a quasicrystal phase.
    Type: Grant
    Filed: September 5, 2014
    Date of Patent: December 17, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventor: Kohei Tokuda
  • Publication number: 20190368007
    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: Application
    Filed: January 16, 2017
    Publication date: December 5, 2019
    Applicant: Nippon Steel Corporation
    Inventors: Kohei TOKUDA, Hisashi BABA, Nobuyuki SHIMODA, Kenichiro MATSUMURA, Yasuto GOTO
  • Patent number: 10392686
    Abstract: A Mg-containing Zn alloy coated steel including a steel and a metallic coating layer placed on a surface of the steel, in which the metallic coating layer is a layered structure of plural flat-form metal particles having a particle diameter of from 5 to 100 ?m, and a thickness of from 0.5 to 30 ?m, the composition of the metal particles include Zn from 11 to 80 mass %, Al from 3 to 80 mass %, Mg from 8 to 45 mass %, and Ca from 1 to 5 mass %, and the Zn, Al, and Mg content satisfy Zn+Al>Mg, and in which the metal particles include a quasicrystalline phase, an MgZn2 phase, and optionally a balance structure.
    Type: Grant
    Filed: September 29, 2016
    Date of Patent: August 27, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Nobuyuki Shimoda, Kohei Tokuda, Kenichiro Matsumura, Yasuto Goto
  • Patent number: 10351943
    Abstract: A Mg-containing Zn alloy coated steel including a steel and a metallic coating layer placed on a surface of the steel, in which the metallic coating layer is a layered structure of plural flat-form metal particles having a particle diameter of from 5 to 100 ?m, and a thickness of from 0.5 to 30 ?m, the composition of the metal particles include Zn from 11 to 80 mass %, Al from 3 to 80 mass %, Mg from 8 to 45 mass %, and Ca from 1 to 5 mass %, and the Zn, Al, and Mg content satisfy Zn+Al>Mg, and in which the metal particles include a quasicrystalline phase, an MgZn2 phase, and optionally a balance structure.
    Type: Grant
    Filed: September 29, 2016
    Date of Patent: July 16, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Nobuyuki Shimoda, Kohei Tokuda, Kenichiro Matsumura, Yasuto Goto
  • Patent number: 10232589
    Abstract: A plated steel sheet with a quasicrystal includes a steel sheet and a plated-metal-layer arranged on a surface of the steel sheet. The plated-metal-layer includes, as a chemical composition, Mg, Zn. The plated-metal-layer includes, as a metallographic structure, a quasicrystal phase. A Mg content, a Zn content, and an Al content in the quasicrystal phase satisfy 0.5?Mg/(Zn+Al)?0.83 in atomic %. In addition, an average equivalent circle diameter of the quasicrystal phase is equal to or larger than 0.01 ?m and equal to or smaller than 1 ?m.
    Type: Grant
    Filed: March 28, 2014
    Date of Patent: March 19, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventor: Kohei Tokuda
  • Patent number: 10232590
    Abstract: A plated steel sheet with a quasicrystal includes a steel sheet and a plated-metal-layer arranged on a surface of the steel sheet. The plated-metal-layer includes, as a chemical composition, Mg, Zn, and Al, and satisfies 25%?Zn+Al in atomic %. The plated-metal-layer includes, as a metallographic structure, a quasicrystal phase. A Mg content, a Zn content, and an Al content in the quasicrystal phase satisfy 0.5?Mg/(Zn+Al)?0.83 in atomic %. In addition, an average equivalent circle diameter of the quasicrystal phase is larger than 1 ?m and equal to or smaller than 200 ?m.
    Type: Grant
    Filed: March 28, 2014
    Date of Patent: March 19, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventor: Kohei Tokuda
  • Publication number: 20180265955
    Abstract: An Mg-containing Zn alloy coated steel including a steel and a metallic coating layer placed on a surface of the steel, in which the metallic coating layer is a layered structure of a flat-form metal particle having a particle diameter of from 5 to 100 ?m, and a thickness of from 0.5 to 30 ?m, the composition of the metal particles include, in terms of % by mass, Zn from 11 to 80%, Al from 3 to 80%, Mg from 8 to 45%, and Ca from 1 to 5%, while the balance is impurities, and the Zn content, the Al content, and the Mg content in terms of % by mass satisfy Zn+Al>Mg, and in which the metal particles include a quasicrystalline phase, an MgZn2 phase, and a balance structure, in which the total area fraction of the quasicrystalline phase and the MgZn2 phase is 45% or more, the area fraction of the balance structure is from 0 to 55%, the area fraction of the quasicrystalline phase is 20% or more, and the area fraction of the MgZn2 phase is 3% or more.
    Type: Application
    Filed: September 29, 2016
    Publication date: September 20, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Nobuyuki SHIMODA, Kohei TOKUDA, Kenichiro MATSUMURA, Yasuto GOTO
  • Publication number: 20180237900
    Abstract: The invention provides a coated steel including a steel, a coated metal layer coated on a surface of the steel, and an interfacial alloy layer formed at the boundary between the steel and the coated metal layer, in which the composition of the coated metal layer includes in terms of % by mass Zn from 20 to 83%, and Al from 2.5 to 46.5% as well as Mg and impurities as the balance, in which the Mg content is 10% or more, in which the structure of the coated metal layer includes a quasicrystalline phase, a MgZn2 phase, and a balance structure, in which the area fraction of the quasicrystalline phase is from 30 to 60%, and not less than 90 number-% of the quasicrystalline phases are a quasicrystalline phase having a particle diameter in the major axis direction of from 0.05 to 1.0 ?m, and in which the thickness of the coated metal layer is 0.1 ?m or more, and the thickness of the interfacial alloy layer is 500 nm or less.
    Type: Application
    Filed: September 29, 2016
    Publication date: August 23, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Akinobu KOBAYASHI, Kohei TOKUDA, Nobuyuki SHIMODA, Yasuto GOTO, Kenichiro MATSUMURA
  • Publication number: 20180171460
    Abstract: [Object] To provide a quasicrystal-containing plated steel sheet having a good balance between corrosion resistance and chipping resistance and a method for producing the quasicrystal-containing plated steel sheet. [Solution] Provided is a quasicrystal-containing plated steel sheet including: a plating layer positioned on at least one surface of a steel sheet; and an alloy layer positioned at an interface between the plating layer and the steel sheet and composed of an Al—Fe intermetallic compound. A chemical composition of the plating layer contains at least, in atom %, Zn: 28.5% to 50%, Al: 0.3% to 12%, and the balance: Mg and impurities, and the plating layer includes, in order from the steel sheet side, a first plating layer which is composed of a structure containing an MgZn phase, an Mg phase, and a quasicrystal phase, and a second plating layer which is positioned on the first plating layer and is composed of a structure containing an Mg51Zn20 phase, a Zn phase, and a quasicrystal phase.
    Type: Application
    Filed: September 5, 2014
    Publication date: June 21, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventor: Kohei TOKUDA
  • Publication number: 20170100915
    Abstract: A plated steel sheet with a quasicrystal includes a steel sheet and a plated-metal-layer arranged on a surface of the steel sheet. The plated-metal-layer includes, as a chemical composition, Mg, Zn, and Al, and satisfies 25%?Zn+Al in atomic %. The plated-metal-layer includes, as a metallographic structure, a quasicrystal phase. A Mg content, a Zn content, and an Al content in the quasicrystal phase satisfy 0.5?Mg/(Zn+Al)?0.83 in atomic %. In addition, an average equivalent circle diameter of the quasicrystal phase is larger than 1 ?m and equal to or smaller than 200 ?m.
    Type: Application
    Filed: March 28, 2014
    Publication date: April 13, 2017
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventor: Kohei TOKUDA
  • Publication number: 20170095995
    Abstract: A plated steel sheet with a quasicrystal includes a steel sheet and a plated-metal-layer arranged on a surface of the steel sheet. The plated-metal-layer includes, as a chemical composition, Mg, Zn. The plated-metal-layer includes, as a metallographic structure, a quasicrystal phase. A Mg content, a Zn content, and an Al content in the quasicrystal phase satisfy 0.5?Mg/(Zn+Al)?0.83 in atomic %. In addition, an average equivalent circle diameter of the quasicrystal phase is equal to or larger than 0.01 ?m and equal to or smaller than 1 ?m.
    Type: Application
    Filed: March 28, 2014
    Publication date: April 6, 2017
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventor: Kohei TOKUDA
  • Patent number: 9187814
    Abstract: The hot-dip aluminum alloy plated steel has a base steel and a plated layer, in which the composition of the plated layer contains, by % by mass, Fe: 25% to 75%, Mg: 2% to 20%, and Ca: 0.02% to 2% with a remainder of Al and inevitable impurities, the plated layer contains one or both of an ?-Mg phase and an Al3Mg2 phase, and the sum of the partial volume fraction of the ?-Mg phase and the partial volume fraction of the Al3Mg2 phase in a range of a depth of 5 ?m from a surface of the plated layer is 1% to 40%.
    Type: Grant
    Filed: May 31, 2011
    Date of Patent: November 17, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Koichi Nose, Yasuhide Morimoto, Kohei Tokuda
  • Patent number: 8663818
    Abstract: The present invention provides a high corrosion resistance hot dip galvannealed steel material comprised of a Zn-based hot dip plated steel material achieving both a higher corrosion resistance of the plated layer itself by the added elements and sacrificial protection of iron metal by the plated layer or workability free of degradation caused of formation of intermetallic compounds by added elements, that is, a high corrosion resistance hot dip Zn plated steel material characterized in that an alloy plated layer containing Zn: 35 mass % or more, preferably 40 mass % or more, contains a non-equilibrium phase having a heat capacity by differential scanning calorimetry of 1 J/g or more. Furthermore, 5% or more, preferably 50% or more in terms of vol % is an amorphous phase. The alloy layer may contain, by mass %, Mg: 1 to 60% and Al: 0.07 to 59%, may further contain one or more elements selected from Cr, Mn, Fe, Co, Ni, and Cu in a total of 0.1 to 10%, and may in addition contain one or more elements of 0.
    Type: Grant
    Filed: March 14, 2007
    Date of Patent: March 4, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Koichi Nose, Kohei Tokuda, Yuichi Sato, Makoto Nakazawa
  • Patent number: 8637163
    Abstract: An alloy with a high glass forming ability characterized by containing a group of elements A with atomic radii of less than 0.145 nm of a total of 20 to 85 atm %, a group of elements B with atomic radii of 0.145 nm to less than 0.17 nm of a total of 10 to 79.7 atm %, and a group of elements C with atomic radii of 0.17 nm or more of a total of 0.3 to 15 atm %; when the elements with the greatest contents in the group of elements A, group of elements B, and group of elements C are respectively designated as the “element a”, “element b”, and “element c”, by the ratio of the content of the element a in the group of elements A (for example, Zn and/or Al), the ratio of the content of the element b in the group of elements B (for example, Mg), and the ratio of the content of the element c in the group of elements C (for example, Ca) all being 70 atm % or more; and by the liquid forming enthalpy between any two elements selected from the element a, element b, and element c being negative.
    Type: Grant
    Filed: July 19, 2007
    Date of Patent: January 28, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Kohei Tokuda, Koichi Nose, Yuichi Sato, Makoto Nakazawa