Patents by Inventor Riki Okamoto

Riki Okamoto 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: 9567658
    Abstract: A cold-rolled steel sheet satisfies that an average pole density of an orientation group of {100}<011> to {223}<110> is 1.0 to 5.0, a pole density of a crystal orientation {332}<113> is 1.0 to 4.0, a Lankford-value rC in a direction perpendicular to a rolling direction is 0.70 to 1.50, and a Lankford-value r30 in a direction making an angle of 30° with the rolling direction is 0.70 to 1.50. Moreover, the cold-rolled steel sheet includes, as a metallographic structure, by area %, a ferrite and a bainite of 30% to 99% in total and a martensite of 1% to 70%.
    Type: Grant
    Filed: May 24, 2012
    Date of Patent: February 14, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yuri Toda, Riki Okamoto, Nobuhiro Fujita, Kohichi Sano, Hiroshi Yoshida, Toshio Ogawa, Kunio Hayashi, Kazuaki Nakano
  • Patent number: 9546413
    Abstract: Disclosed is a hot-rolled steel sheet including, by mass %, C:0.02% to 0.5% of C, and the sum of the content of Si and the content of Al is 1.0% to 4.0%. An average pole density of an orientation group from {100}<011> to {223}<110> is 1.0 to 6.5, and a pole density of a crystal orientation {332}<113> is 1.0 to 5.0. A microstructure includes, by of an area ratio, 2% to 30% of retained austenite, 20% to 50% of ferrite, and 10% to 60% of bainite. rC that is a Lankford value in a direction orthogonal to a rolling direction is 0.70 to 1.10, and r30 that is a Lankford value in a direction forming an angle of 30° with the rolling direction is 0.70 to 1.10.
    Type: Grant
    Filed: March 28, 2012
    Date of Patent: January 17, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takayuki Nozaki, Manabu Takahashi, Nobuhiro Fujita, Hiroshi Yoshida, Shinichiro Watanabe, Takeshi Yamamoto, Chisato Wakabayashi, Riki Okamoto, Kohichi Sano
  • Publication number: 20160369383
    Abstract: This high-strength cold-rolled steel sheet having excellent uniform elongation and hole expandability contains, C: 0.01 to 0.4%; Si: 0.001 to 2.5%; Mn: 0.001 to 4.0%; P: 0.001 to 0.15%; S: 0.0005 to 0.03%; Al: 0.001 to 2.0%; N: 0.0005 to 0.01%; and O: 0.0005 to 0.01%; in which Si+Al is limited to less than 1.0%, and a balance being composed of iron and inevitable impurities, in which at a sheet thickness center portion, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 5.0 or less, and a pole density of the {332}<113> crystal orientation is 4.0 or less, a metal structure contains 5 to 80% of ferrite, 5 to 80% of bainite, and 1% or less of martensite in terms of an area ratio and the total of martensite, pearlite, and retained austenite is 5% or less, and an r value (rC) in a direction perpendicular to a rolling direction is 0.70 or more and an r value (r30) in a direction 30° from the rolling direction is 1.10 or less.
    Type: Application
    Filed: August 29, 2016
    Publication date: December 22, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yuri TODA, Riki OKAMOTO, Nobuhiro FUJITA, Kohichi SANO, Hiroshi YOSHIDA, Toshio OGAWA
  • Publication number: 20160355899
    Abstract: In a hot-rolled steel sheet, an average pole density of an orientation group of {100}<011> to {223}<110>, which is represented by an arithmetic average of pole density of each orientation of {100}<011>, {116}<110>, {114}<110>, {112}<110>, and {223}<110> in a center portion of a sheet thickness which is a range of the sheet thickness of ? to ? from a surface of the steel sheet, is 1.0 or more and 4.0 or less, the pole density of a crystal orientation of {332}<113> is 1.0 or more and 4.8 or less, an average grain size in a center in the sheet thickness is 10 ?m or less, and a microstructure includes, by a structural fraction, pearlite more than 6% and ferrite in the balance.
    Type: Application
    Filed: August 17, 2016
    Publication date: December 8, 2016
    Applicant: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Tatsuo YOKOI, Hiroshi SHUTO, Riki OKAMOTO, Nobuhiro FUJITA, Kazuaki NAKANO, Takeshi Yamamoto
  • Patent number: 9512508
    Abstract: A high-strength cold-rolled steel sheet having excellent stretch flangeability and precision punchability containing predetermined components and a balance being composed of iron and inevitable impurities, in which in a range of ? to ? in sheet thickness from the surface of the steel sheet, an average value of pole densities of the {100}<011> to {223}<110> orientation group represented by respective crystal orientations of {100}<011>, {116}<110>, {114}<110>, {113}<110>, {112}<110>, {335}<110>, and {223}<110> is 6.5 or less, and a pole density of the {332}<113> crystal orientation is 5.0 or less, and a metal structure contains, in terms of an area ratio, greater than 5% of pearlite, the sum of bainite and martensite limited to less than 5%, and a balance composed of ferrite.
    Type: Grant
    Filed: July 27, 2012
    Date of Patent: December 6, 2016
    Assignee: NIPPON STEEL AND SUMITOMO METAL CORPORATION
    Inventors: Hiroshi Shuto, Nobuhiro Fujita, Tatsuo Yokoi, Riki Okamoto, Kazuaki Nakano, Shinichiro Watanabe
  • Patent number: 9458520
    Abstract: This high-strength cold-rolled steel sheet having excellent uniform elongation and hole expandability contains, C: 0.01 to 0.4%; Si: 0.001 to 2.5%; Mn: 0.001 to 4.0%; P: 0.001 to 0.15%; S: 0.0005 to 0.03%; Al: 0.001 to 2.0%; N: 0.0005 to 0.01%; and O: 0.0005 to 0.01%; in which Si+Al is limited to less than 1.0%, and a balance being composed of iron and inevitable impurities, in which at a sheet thickness center portion, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 5.0 or less, and a pole density of the {332}<113> crystal orientation is 4.0 or less, a metal structure contains 5 to 80% of ferrite, 5 to 80% of bainite, and 1% or less of martensite in terms of an area ratio and the total of martensite, pearlite, and retained austenite is 5% or less, and an r value (rC) in a direction perpendicular to a rolling direction is 0.70 or more and an r value (r30) in a direction 30° from the rolling direction is 1.10 or less.
    Type: Grant
    Filed: April 19, 2012
    Date of Patent: October 4, 2016
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yuri Toda, Riki Okamoto, Nobuhiro Fujita, Kohichi Sano, Hiroshi Yoshida, Toshio Ogawa
  • Patent number: 9453269
    Abstract: In a hot-rolled steel sheet, an average pole density of an orientation group of {100}<011> to {223}<110>, which is represented by an arithmetic average of pole density of each orientation of {100}<011>, {116}<110>, {114}<110>, {112}<110>, and {223}<110> in a center portion of a sheet thickness which is a range of the sheet thickness of ? to ? from a surface of the steel sheet, is 1.0 or more and 4.0 or less, the pole density of a crystal orientation of {332}<113> is 1.0 or more and 4.8 or less, an average grain size in a center in the sheet thickness is 10 ?m or less, and a microstructure includes, by a structural fraction, pearlite more than 6% and ferrite in the balance.
    Type: Grant
    Filed: April 13, 2012
    Date of Patent: September 27, 2016
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Tatsuo Yokoi, Hiroshi Shuto, Riki Okamoto, Nobuhiro Fujita, Kazuaki Nakano, Takeshi Yamamoto
  • Publication number: 20160230245
    Abstract: This high-strength cold-rolled steel sheet contains, in mass %, C: 0.02% to 0.20%; Si: 0.001% to 2.5%; Mn: 0.01% to 4.0%; P: 0.001% to 0.15%; S: 0.0005% to 0.03%; Al: 0.001% to 2.0%; N: 0.0005% to 0.01%; and O: 0.0005% to 0.01%; in which Si+Al is limited to less than 1.0%, and a balance being composed of iron and inevitable impurities, in which an area ratio of bainite in a metal structure is 95% or more, at a sheet thickness center portion being a range of ? to ? in sheet thickness from the surface of the steel sheet, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 4.0 or less, and a pole density of the {332}<113> crystal orientation is 5.0 or less, and a mean volume diameter of crystal grains in the metal structure is 7 ?m or less.
    Type: Application
    Filed: April 20, 2016
    Publication date: August 11, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yoshihiro SUWA, Kazuaki NAKANO, Kunio HAYASHI, Riki OKAMOTO, Nobuhiro FUJITA, Kohichi SANO
  • Patent number: 9410231
    Abstract: A steel sheet, including: as chemical components, by mass %, 0.05% to 0.35% of C; 0.05% to 2.0% of Si; 0.8% to 3.0% of Mn; 0.01% to 2.0% of Al; equal to or less than 0.1% of P; equal to or less than 0.05% of S; equal to or less than 0.01% of N; and the balance including iron and inevitable impurities, wherein the steel sheet comprises 50% or more of a ferrite phase, a bainite phase, and a tempered martensite phase, 3% or more of a retained austenite phase, and 50% or more of the crystal grains of the retained austenite phase satisfy Expression 1, wherein a carbon concentration at a position of center of gravity is Cgc and a carbon concentration at a grain boundary is Cgb.
    Type: Grant
    Filed: January 31, 2011
    Date of Patent: August 9, 2016
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Riki Okamoto, Natsuko Sugiura, Kohichi Sano, Chisato Wakabayashi, Naoki Yoshinaga, Kaoru Kawasaki
  • Patent number: 9347122
    Abstract: This high-strength cold-rolled steel sheet contains, in mass %, C: 0.02% to 0.20%; Si: 0.001% to 2.5%; Mn: 0.01% to 4.0%; P: 0.001% to 0.15%; S: 0.0005% to 0.03%; Al: 0.001% to 2.0%; N: 0.0005% to 0.01%; and O: 0.0005% to 0.01%; in which Si+Al is limited to less than 1.0%, and a balance being composed of iron and inevitable impurities, in which an area ratio of bainite in a metal structure is 95% or more, at a sheet thickness center portion being a range of ? to ? in sheet thickness from the surface of the steel sheet, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 4.0 or less, and a pole density of the {332}<113> crystal orientation is 5.0 or less, and a mean volume diameter of crystal grains in the metal structure is 7 ?m or less.
    Type: Grant
    Filed: April 12, 2012
    Date of Patent: May 24, 2016
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yoshihiro Suwa, Kazuaki Nakano, Kunio Hayashi, Riki Okamoto, Nobuhiro Fujita, Kohichi Sano
  • Publication number: 20160130711
    Abstract: A hot-rolled steel sheet has an average value of the X-ray random intensity ratio of a {100}<011> to {223}<110> orientation group at least in a sheet thickness central portion that is in a sheet thickness range of ? to ? from a steel sheet surface of 1.0 to 6.0, an X-ray random intensity ratio of a {332}<113> crystal orientation of 1.0 to 5.0, rC which is an r value in a direction perpendicular to a rolling direction of 0.70 to 1.10, and r30 which is an r value in a direction that forms an angle of 30° with respect to the rolling direction of 0.70 to 1.10.
    Type: Application
    Filed: January 19, 2016
    Publication date: May 12, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Nobuhiro FUJITA, Kunio HAYASHI, Riki OKAMOTO, Manabu TAKAHASHI, Tetsuo KISHIMOTO, Hiroshi YOSHIDA
  • Publication number: 20160130680
    Abstract: A cold-rolled steel sheet includes a predetermined chemical composition, and includes a structure expressed by: an area fraction of ferrite: 95% or more; an area fraction of retained austenite and an area fraction of martensite: 1% to 3% in total; a product of the area fraction of retained austenite and a carbon concentration in retained austenite: 1 or more; a value of I(111)/{I(100)+I(110)} at a region where a depth from a surface is ¼ of a thickness of the cold-rolled steel sheet when intensity of a (hkl) plane is expressed by I(hkl): 2 or less.
    Type: Application
    Filed: July 1, 2014
    Publication date: May 12, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kaoru KAWASAKI, Masaharu KAMEDA, Kohichi SANO, Riki OKAMOTO
  • Publication number: 20160075109
    Abstract: A galvanized steel sheet according to the present invention includes a steel sheet and a galvanizing layer which is formed on a surface of the steel sheet. The steel sheet includes as a chemical component, by mass %, C: more than 0.100% to 0.500%, Si: 0.0001% to less than 0.20%, Mn: more than 0.20% to 3.00%, Al: 3.0% to 10.0%, N: 0.0030% to 0.0100%, Ti: more than 0.100% to 1.000%, P: 0.00001% to 0.0200%, S: 0.00001% to 0.0100% and a remainder including Fe and impurities. The galvanizing layer includes as a chemical composition, by mass %, Fe: 0.01% to 15% and a remainder including Zn and impurities. The galvanized steel sheet has a specific gravity of 5.5 to less than 7.5.
    Type: Application
    Filed: April 28, 2014
    Publication date: March 17, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masaharu OKA, Nobuhiro FUJITA, Manabu TAKAHASHI, Riki OKAMOTO, Kenichiroh MATSUMURA
  • Patent number: 9273370
    Abstract: A hot-rolled steel sheet has an average value of the X-ray random intensity ratio of a {100} <011> to {223} <110> orientation group at least in a sheet thickness central portion that is in a sheet thickness range of ? to ? from a steel sheet surface of 1.0 to 6.0, an X-ray random intensity ratio of a {332} <113> crystal orientation of 1.0 to 5.0, rC which is an r value in a direction perpendicular to a rolling direction of 0.70 to 1.10, and r30 which is an r value in a direction that forms an angle of 30° with respect to the rolling direction of 0.70 to 1.10.
    Type: Grant
    Filed: July 27, 2011
    Date of Patent: March 1, 2016
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Nobuhiro Fujita, Kunio Hayashi, Riki Okamoto, Manabu Takahashi, Tetsuo Kishimoto, Hiroshi Yoshida
  • Patent number: 9267196
    Abstract: In a hot-rolled sheet, an average value of pole densities of an orientation group {100}<011> to {223}<110>, which is represented by an arithmetic mean of pole densities of orientations {100}<011>, {116}<110>, {114}<110>, {112}<110>, and {223}<110> in a thickness center portion of a thickness range of ? to ? from a surface of the steel sheet, is 1.0 to 6.5 and a pole density of a crystal orientation {332}<113> is 1.0 to 5.0; and a Lankford value rC in a direction perpendicular to a rolling direction is 0.70 to 1.10 and a Lankford value r30 in a direction that forms 30° with respect to the rolling direction is 0.70 to 1.10.
    Type: Grant
    Filed: March 5, 2012
    Date of Patent: February 23, 2016
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Riki Okamoto, Nobuhiro Fujita, Manabu Takahashi, Kunio Hayashi, Tetsuo Kishimoto, Kazuaki Nakano, Takeshi Yamamoto
  • Publication number: 20160040273
    Abstract: A steel sheet including, by mass %, C: more than 0.100% and 0.500% or less, Si: 0.0001% or more and less than 0.20%, Mn: more than 0.20% and 0.50% or less, Al: 3.0% or more and 10.0% or less, N: 0.0030% or more and 0.0100% or less, Ti: more than 0.100% and 1.000% or less, P: 0.00001% or more and 0.0200% or less, S: 0.00001% or more and 0.0100% or less, and a remainder including Fe and impurities, in which a sum of a C content and a Ti content satisfies 0.200<C+Ti?1.500 by mass %, a product of an Al content and an Si content satisfies Al×Si?0.8 by mass %, and a specific gravity is 5.5 to less than 7.5.
    Type: Application
    Filed: April 28, 2014
    Publication date: February 11, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masaharu OKA, Nobuhiro FUJITA, Manabu TAKAHASHI, Riki OKAMOTO, Chisato WAKABAYASHI
  • Patent number: 8951366
    Abstract: A high-strength cold-rolled steel sheet includes, by mass %, C: 0.10% to 0.40%, Mn: 0.5% to 4.0%, Si: 0.005% to 2.5%, Al: 0.005% to 2.5%, Cr: 0% to 1.0%, and a balance of iron and inevitable impurities, in which an amount of P is limited to 0.05% or less, an amount of S is limited to 0.02% or less, an amount of N is limited to 0.006% or less, the microstructure includes 2% to 30% of retained austenite by area percentage, martensite is limited to 20% or less by area percentage in the microstructure, an average particle size of cementite is 0.01 ?m to 1 ?m, and 30% to 100% of the cementite has an aspect ratio of 1 to 3.
    Type: Grant
    Filed: January 26, 2011
    Date of Patent: February 10, 2015
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Kohichi Sano, Chisato Wakabayashi, Hiroyuki Kawata, Riki Okamoto, Naoki Yoshinaga, Kaoru Kawasaki, Natsuko Sugiura, Nobuhiro Fujita
  • Publication number: 20140193667
    Abstract: A high-strength cold-rolled steel sheet having excellent stretch flangeability and precision punchability containing predetermined components and a balance being composed of iron and inevitable impurities, in which in a range of ? to ? in sheet thickness from the surface of the steel sheet, an average value of pole densities of the {100}<011> to {223}<110> orientation group represented by respective crystal orientations of {100}<011>, {116}<110>, {114}<110>, {113}<110>, {112}<110>, {335}<110>, and {223}<110> is 6.5 or less, and a pole density of the {332}<113> crystal orientation is 5.0 or less, and a metal structure contains, in terms of an area ratio, greater than 5% of pearlite, the sum of bainite and martensite limited to less than 5%, and a balance composed of ferrite.
    Type: Application
    Filed: July 27, 2012
    Publication date: July 10, 2014
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hiroshi Shuto, Nobuhiro Fujita, Tatsuo Yokoi, Riki Okamoto, Kazuaki Nakano, Shinichiro Watanabe
  • Publication number: 20140124101
    Abstract: This high-strength hot-rolled steel sheet having excellent local deformability contains, in mass %, C: 0.07% to 0.20%; Si: 0.001% to 2.5%; Mn: 0.01% to 4.0%; P: 0.001% to 0.15%; S: 0.0005% to 0.03%; Al: 0.001% to 2.0%; N: 0.0005% to 0.01%; and O: 0.0005% to 0.01%; and a balance being composed of iron and inevitable impurities, in which an area ratio of bainite in a metal structure is 95% or more, at a sheet thickness center portion being a range of 5/8 to 3/8 in sheet thickness from the surface of the steel sheet, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 4.0 or less, and a pole density of the {332}<113> crystal orientation is 5.0 or less, and a mean volume diameter of crystal grains in the metal structure is 10 ?m or less.
    Type: Application
    Filed: April 12, 2012
    Publication date: May 8, 2014
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yoshihiro Suwa, Kazuaki Nakano, Kunio Hayashi, Riki Okamoto, Nobuhiro Fujita, Kohichi Sano
  • Publication number: 20140110022
    Abstract: A hot-rolled steel sheet satisfies that average pole density of orientation group of {100}<011> to {223}<110> is 1.0 to 5.0 and pole density of crystal orientation {332}<113> is 1.0 to 4.0. Moreover, the hot-rolled steel sheet includes, as a metallographic structure, by area %, ferrite and bainite of 30% to 99% in total and martensite of 1% to 70%. Moreover, the hot-rolled steel sheet satisfies following Expressions 1 and 2 when area fraction of the martensite is defined as fM in unit of area %, average size of the martensite is defined as dia in unit of ?m, average distance between the martensite is defined as dis in unit of ?m, and tensile strength of the steel sheet is defined as TS in unit of MPa.
    Type: Application
    Filed: May 24, 2012
    Publication date: April 24, 2014
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kohichi Sano, Kunio Hayashi, Kazuaki Nakano, Riki Okamoto, Nobuhiro Fujita