Patents by Inventor Kazuo Hikida

Kazuo Hikida 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: 20210102270
    Abstract: A hot stamped article excellent in strength having a predetermined composition, having an average crystal grain size of prior austenite of 3 ?m or less, containing at least one of lower bainite, martensite, and tempered martensite in an area rate of 90% or more, and having a grain boundary solid solution ratio Z, defined by Z=(mass % of one or both of Nb and Mo at the grain boundaries)/(mass % of one or more of Nb and Mo at time of dissolution) of 0.3 or more.
    Type: Application
    Filed: March 29, 2018
    Publication date: April 8, 2021
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuri TODA, Kazuo HIKIDA, Shingo FUJINAKA, Tomohito TANAKA
  • Patent number: 10934609
    Abstract: [Object] To provide a steel sheet for carburizing that demonstrates improved extreme deformability prior to carburizing, and a method for manufacturing the same. [Solution] A steel sheet consisting of, in mass %, C: more than or equal to 0.02%, and less than 0.30%, Si: more than or equal to 0.005%, and less than 0.5%, Mn: more than or equal to 0.01%, and less than 3.0%, P: less than or equal to 0.1%, S: less than or equal to 0.1%, sol. Al: more than or equal to 0.0002%, and less than or equal to 3.0%, N: less than or equal to 0.2%, and the balance: Fe and impurities, in which average value of X-ray random intensity ratio, assignable to an orientation group of ferrite crystal grain ranging from {100}<011> to {223}<110>, is 7.0 or smaller, average equivalent circle diameter of carbide is 5.0 ?m or smaller, percentage of number of carbides with an aspect ratio of 2.
    Type: Grant
    Filed: August 30, 2018
    Date of Patent: March 2, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Yuri Toda, Kazuo Hikida, Motonori Hashimoto
  • Publication number: 20210040592
    Abstract: A hot stamped article having excellent shock absorption having a predetermined chemical composition, having a microstructure containing prior austenite having an average grain size of 3 ?m or less and further containing at least one of lower bainite, martensite, and tempered martensite in an area ratio of 90% or more, and having a grain boundary solid solution ratio Z defined by Z=(mass % of one or both of Nb and Mo at grain boundaries)/(mass % of one or both of Nb and Mo at time of melting) of 0.3 or more.
    Type: Application
    Filed: March 29, 2018
    Publication date: February 11, 2021
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuri TODA, Kazuo HIKIDA, Shingo FUJINAKA, Tomohito TANAKA
  • Publication number: 20210010118
    Abstract: A hot stamped article of high strength steel sheet excellent in bending deformability having a predetermined chemical composition, having an area rate of 90% or more of the microstructures of the steel sheet comprised of one or more of lower bainite, martensite, and tempered martensite, and having a ratio of the length of grain boundaries with a rotational angle about a rotational axis of the <011> direction of the crystal grains of the lower bainite, martensite, and tempered martensite of 15 or more with respect to the length of grain boundaries with a rotational angle of 5° to 75° of 80% or more.
    Type: Application
    Filed: March 29, 2018
    Publication date: January 14, 2021
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuri TODA, Kazuo HIKIDA, Shingo FUJINAKA, Tomohito TANAKA
  • Patent number: 10837077
    Abstract: The present invention provides steel sheet excellent in cold formability and ductility after heat treatment and a method for production thereof. The steel sheet of the present invention is steel sheet which has a chemical composition containing, by mass %, C: 0.10 to 0.40%, Si: 0.30 to 1.00%, Mn: 0.30 to 1.00%, Al: 0.001 to 0.10%, P: 0.0001 to 0.02%, and S: 0.0001 to 0.01% and having a balance of Fe and impurities, which steel sheet characterized in that a ratio (B/A) of the number of carbides at the ferrite grain boundaries (B) to the number of carbides inside the ferrite grains (A) is over 1, a ferrite grain size is 5 ?m to 50 ?m, an average grain size of carbides is 0.4 ?m to 2.0 ?m, a pearlite area ratio is 6% or less, and a Vicker's hardness is 120 HV to 170 HV.
    Type: Grant
    Filed: May 26, 2016
    Date of Patent: November 17, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kazuo Hikida, Ken Takata, Kengo Takeda, Motonori Hashimoto
  • Patent number: 10822680
    Abstract: A steel sheet for heat treatment having a chemical composition including, by mass %: C: 0.05 to 0.50%; Si: 0.50 to 5.0%; Mn; 1.5 to 4.0%; P: 0.05% or less; S: 0.05% or less; N: 0.01% or less; Ti: 0.01 to 0.10%; B: 0.0005 to 0.010%; Cr: 0 to 1.0%; Ni: 0 to 2.0%; Cu: 0 to 1.0%; Mo: 0 to 1.0%; V: 0 to 1.0%; Ca: 0 to 0.01%; Al: 0 to 1.0%; Nb: 0 to 1.0%; REM: 0 to 0.1%; and the balance: Fe and impurities, wherein a maximum height roughness Rz on a surface of the steel sheet is 3.0 to 10.0 ?m, and a number density of carbide being present in the steel sheet and having circle-equivalent diameters of 0.1 ?m or larger is 8.0×103/mm2 or lower.
    Type: Grant
    Filed: April 7, 2016
    Date of Patent: November 3, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Yoshihiro Suwa, Shinichiro Tabata, Masafumi Azuma, Kazuo Hikida
  • Publication number: 20200306812
    Abstract: The entirety or a part of this hot stamped product includes, as a chemical composition, by mass %, C: 0.001% or more and less than 0.080%, Si: 2.50% or less, Mn: 0.01% or more and less than 0.50%, P: 0.200% or less, S: 0.0200% or less, sol.Al: 0.001% to 2.500%, N: 0.0200% or less, Cr: 0.30% or more and less than 2.00%, and a remainder: Fe and impurities, in which a metallographic structure contains, by vol %, ferrite: more than 60.0%, martensite: 0% or more and less than 10.0%, and bainite: 0% or more and less than 20.0%, a tensile strength is less than 700 MPa, and ?TS, which is a decrease in the tensile strength after a heat treatment at 170° C. for 20 minutes, is 100 MPa or less.
    Type: Application
    Filed: October 2, 2018
    Publication date: October 1, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Jun HAGA, Kazuo HIKIDA
  • Publication number: 20200230681
    Abstract: The present invention, in consideration of the problems in the prior art, provides a hot stamped body simultaneously achieving the high bendability and high ductility for realizing impact resistance and also hydrogen embrittlement resistance and kept down in scattering in hardness. The hot stamped body according to the present invention is provided with a middle part in sheet thickness and a softened layer arranged at both sides or one side of the middle part in sheet thickness.
    Type: Application
    Filed: February 20, 2018
    Publication date: July 23, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuri TODA, Genki ABUKAWA, Daisuke MAEDA, Kazuo HIKIDA, Shingo FUJINAKA
  • Publication number: 20200232058
    Abstract: There is provided a steel sheet including an inner layer and a hard layer formed on one or both surfaces of the inner layer, wherein each content of C and Mn in the hard layer is more than each content of C and Mn in the inner layer, a thickness of the hard layer is 20 ?m or more and a total of the thickness of the hard layer is ? or less of the entire sheet thickness, an average micro-Vickers hardness of the hard layer is 400 HV or more and less than 800 HV, an average micro-Vickers hardness of the inner layer is 350 HV or more and is 50 HV or more smaller than a hardness of the hard layer, and a screw dislocation density of the inner layer is 2.0×1013 m/m3 or more.
    Type: Application
    Filed: February 20, 2018
    Publication date: July 23, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Kengo TAKEDA, Riki OKAMOTO, Kazuo HIKIDA, Katsuya NAKANO, Yuya SUZUKI, Genki ABUKAWA
  • Publication number: 20200232056
    Abstract: The present invention provides a hot stamped body excellent in bendability, ductility, impact resistance, and hydrogen embrittlement resistance and small in scattering in hardness. The hot stamped body according to the present invention is provided with a middle part in sheet thickness and a softened layer arranged at both sides or one side of the middle part in sheet thickness.
    Type: Application
    Filed: February 20, 2018
    Publication date: July 23, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuri TODA, Genki ABUKAWA, Daisuke MAEDA, Kazuo HIKIDA
  • Patent number: 10718033
    Abstract: A heat-treated steel material is provided having strength of 2.000 GPa or more. The heat-treated steel material includes a chemical composition represented by, in mass %: C: 0.05% to 0.30%; Si: 0.50% to 5.00%; Mn: 2.0% to 10.0%; Cr: 0.01% to 1.00%; Ti: 0.010% to 0.100%; B: 0.0020% to 0.0100%; P: 0.050% or less; S: 0.0500% or less; N: 0.0100% or less; Ni: 0% to 2.0%; each of Cu, Mo, and V: 0% to 1.0%; each of Al and Nb: 0% to 1.00%; and the balance: Fe and impurities. “4612×[C]+51×[Si]+102×[Mn]+605>2000” is satisfied. The heat-treated steel material includes a microstructure in which 90 volume % or more is formed of martensite, and a dislocation density in the martensite is equal to or more than 1.2×1016 m?2.
    Type: Grant
    Filed: May 26, 2015
    Date of Patent: July 21, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Shinichiro Tabata, Kazuo Hikida, Nobusato Kojima
  • Publication number: 20200181728
    Abstract: [Object] To provide a steel sheet for carburizing that demonstrates improved ductility, and a method for manufacturing the same. [Solution] A steel sheet consisting of, in mass %, C: more than or equal to 0.02%, and less than 0.30%, Si: more than or equal to 0.005%, and less than 0.5%, Mn: more than or equal to 0.01%, and less than 3.0%, P: less than or equal to 0.1%, S: less than or equal to 0.1%, sol. Al: more than or equal to 0.0002%, and less than or equal to 3.0%, N: less than or equal to 0.2%, Ti: more than or equal to 0.010%, and less than or equal to 0.150%, and the balance: Fe and impurities, in which the number of carbides per 1000 ?m2 is 100 or less, percentage of number of carbides with an aspect ratio of 2.0 or smaller is 10% or larger relative to the total carbides, average equivalent circle diameter of carbide is 5.0 ?m or smaller, and average crystal grain size of ferrite is 10 ?m or smaller.
    Type: Application
    Filed: August 30, 2018
    Publication date: June 11, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Motonori HASHIMOTO, Kazuo HIKIDA, Yuri TODA
  • Publication number: 20200181744
    Abstract: [Object] To provide a steel sheet for carburizing that demonstrates improved extreme deformability prior to carburizing, and a method for manufacturing the same. [Solution] A steel sheet consisting of, in mass %, C: more than or equal to 0.02%, and less than 0.30%, Si: more than or equal to 0.005%, and less than 0.5%, Mn: more than or equal to 0.01%, and less than 3.0%, P: less than or equal to 0.1%, S: less than or equal to 0.1%, sol. Al: more than or equal to 0.0002%, and less than or equal to 3.0%, N: less than or equal to 0.2%, and the balance: Fe and impurities, in which average value of X-ray random intensity ratio, assignable to an orientation group of ferrite crystal grain ranging from {100}<011> to {223}<110>, is 7.0 or smaller, average equivalent circle diameter of carbide is 5.0 ?m or smaller, percentage of number of carbides with an aspect ratio of 2.
    Type: Application
    Filed: August 30, 2018
    Publication date: June 11, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuri TODA, Kazuo HIKIDA, Motonori HASHIMOTO
  • Patent number: 10662494
    Abstract: A heat-treated steel material is provided having strength of 1.800 GPa or more. The heat-treated steel material includes a chemical composition represented by, in mass %: C: 0.05% to 0.30%; Mn: 2.0% to 10.0%; Cr: 0.01% to 1.00%; Ti: 0.010% to 0.100%; B: 0.0010% to 0.0100%; Si: 0.08% or less; P: 0.050% or less; S: 0.0500% or less; N: 0.0100% or less; Ni: 0% to 2.0%; each of Cu, Mo, and V: 0% to 1.0%; each of Al and Nb: 0% to 1.00%; and the balance: Fe and impurities. “4612×[C]+102×[Mn]+605?1800” is satisfied where [C] denotes a C content and [Mn] denotes a Mn content. The heat-treated steel material includes a microstructure in which 90 volume % or more is formed of martensite, and a dislocation density in the martensite is equal to or more than 9.0×1015 m?2.
    Type: Grant
    Filed: May 26, 2015
    Date of Patent: May 26, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Shinichiro Tabata, Kazuo Hikida, Nobusato Kojima
  • Publication number: 20200094525
    Abstract: A steel sheet for hot stamping includes a steel structure represented by an area fraction of bainite, fresh martensite and tempered martensite: 80% or more in total, and a product of a number density (pieces/?m2) of carbides and a proportion of carbides precipitated into prior austenite grains in carbides: 0.50 or more.
    Type: Application
    Filed: January 17, 2017
    Publication date: March 26, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Genki ABUKAWA, Kunio HAYASHI, Kazuo HIKIDA, Kaoru KAWASAKI
  • Publication number: 20200071799
    Abstract: Steel sheet low in cost and improved in fatigue characteristics without causing a drop in the cold formability, characterized in that it comprises an inner layer and a hard layer on one or both surfaces of the inner layer, a thickness of the hard layer is 20 ?m or more and 40% or less of the thickness of the steel sheet, an average micro-Vickers hardness of the hard layer is 240 HV or more and less than 400 HV, an amount of C of the hard layer is 0.4 mass % or less, an amount of N is 0.02 mass % or less, a variation of hardness measured by a nanoindenter at a depth of 10 from the surface of the hard layer is a standard deviation of 2.0 or less, an average micro-Vickers hardness of the inner layer is 80 HV or more and less than 400 HV, a volume rate of carbides contained in the inner layer is less than 2.00%, and the average micro-Vickers hardness of the hard layer is 1.05 times or more the average micro-Vickers hardness of the inner layer.
    Type: Application
    Filed: February 20, 2018
    Publication date: March 5, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Kengo TAKEDA, Riki OKAMOTO, Kazuo HIKIDA, Katsuya NAKANO, Yuya SUZUKI, Genki ABUKAWA
  • Patent number: 10570470
    Abstract: A steel sheet for hot stamping includes a predetermined chemical composition containing: C: 0.08% or more and less than 0.20%; Si: 0.003% to 0.2%; Mn: 1.6% to 3.5%, and others, and further includes a steel structure expressed by, in an area ratio: bainite: 1% to 95%; ferrite: 5% to 94%; and balance: one or more selected from the group consisting of pearlite, martensite and retained austenite. When an Mn content is represented by [Mn], a C content is represented by [C], an expression of “[Mn]+6.67×[C]?2.73?0” is satisfied.
    Type: Grant
    Filed: August 15, 2013
    Date of Patent: February 25, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Akari Tamaki, Kazuo Hikida
  • Patent number: 10563281
    Abstract: A heat-treated steel sheet member having a composition including, by mass %: C: 0.05 to 0.50%; Si: 0.50 to 5.0%; Mn: 1.5 to 4.0%; P: 0.05% or less; S: 0.05% or less; N: 0.01% or less; Ti: 0.01 to 0.10%; B: 0.0005 to 0.010%; Cr: 0 to 1.0%; Ni: 0 to 2.0%; Cu; 0 to 1.0%; Mo: 0 to 1.0%; V: 0 to 1.0%; Ca: 0 to 0.01%; Al: 0 to 1.0%; Nb: 0 to 1.0%; REM: 0 to 0.1%; and the balance: Fe and impurities. The steel sheet member has a microstructure comprising mainly martensite and retained austenite of which a volume ratio is 0.2 to 1.0%, a number density of retained carbide in the steel sheet member having circle-equivalent diameters of 0.1 mm or larger is 4.0×103/mm2 or lower, a tensile strength is 1.4 GPa or higher, and a yield ratio is 0.65 or higher.
    Type: Grant
    Filed: April 7, 2016
    Date of Patent: February 18, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Yoshihiro Suwa, Shinichiro Tabata, Masafumi Azuma, Kazuo Hikida
  • Publication number: 20200016866
    Abstract: There is provided a hot stamped body including a middle part in sheet thickness and a surface layer arranged at both sides or one side of the middle part in sheet thickness, further including an intermediate layer formed between the middle part in sheet thickness and each surface layer so as to adjoin them, wherein the middle part in sheet thickness has a predetermined composition, the middle part in sheet thickness has a hardness of 500 Hv or more and 800 Hv or less, the surface layer has a hardness change ?H1 in the sheet thickness direction of 100 Hv or more and less than 200 Hv, and the intermediate layer has a hardness change ?H2 in the sheet thickness direction of 10 Hv or more and less than 50 Hv.
    Type: Application
    Filed: February 20, 2018
    Publication date: January 16, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuri TODA, Genki ABUKAWA, Daisuke MAEDA, Kazuo HIKIDA
  • Publication number: 20200001342
    Abstract: There is provided a hot stamped body including a middle part in sheet thickness and a surface layer arranged at both sides or one side of the middle part in sheet thickness, further including an intermediate layer formed between the middle part in sheet thickness and each surface layer so as to adjoin them, wherein the middle part in sheet thickness has a predetermined composition, the middle part in sheet thickness has a hardness of 500 Hv or more and 800 Hv or less, the surface layer has a hardness change ?H1 in the sheet thickness direction of 10 Hv or more and less than 200 Hv, and the intermediate layer has a hardness change ?H2 in the sheet thickness direction of 50 Hv or more and less than 200 Hv.
    Type: Application
    Filed: February 20, 2018
    Publication date: January 2, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuri TODA, Genki ABUKAWA, Daisuke MAEDA, Kazuo HIKIDA, Shingo FUJINAKA