Patents by Inventor Nobuhiro Fujita

Nobuhiro Fujita 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: 9752217
    Abstract: In a hot-rolled steel sheet, an average pole density 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> is 1.0 to 4.0 and a pole density of a crystal orientation {332}<113> is 1.0 to 4.8, in a thickness center portion which is a thickness range of ? to ? from the surface of the steel sheet; an average grain size in the thickness center portion is less than or equal to 10 ?m and a grain size of cementite precipitating in a grain boundary of the steel sheet is less than or equal to 2 ?m; and an average grain size of precipitates containing TiC in grains is less than or equal to 3 nm and a number density per unit volume is greater than or equal to 1×1016 grains/cm3.
    Type: Grant
    Filed: April 13, 2012
    Date of Patent: September 5, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Tatsuo Yokoi, Hiroshi Shuto, Riki Okamoto, Nobuhiro Fujita, Kazuaki Nakano, Takeshi Yamamoto
  • Publication number: 20170191140
    Abstract: A hot-rolled steel sheet wherein an 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. The hot-rolled steel sheet includes, as a metallographic structure, by area %, 30% to 99% ferrite and bainite in total, and 1% to 70% martensite. The hot-rolled steel sheet satisfies Expression 1: dia?13 ?m, and also satisfies Expression 2: TS/fM×dis/dia?500, wherein an area fraction of the martensite is defined as fM in unit of area %, an average size of the martensite is defined as dia in unit of ?m, an 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: March 15, 2017
    Publication date: July 6, 2017
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kohichi SANO, Kunio HAYASHI, Kazuaki NAKANO, Riki OKAMOTO, Nobuhiro FUJITA
  • Publication number: 20170183756
    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: Application
    Filed: January 4, 2017
    Publication date: June 29, 2017
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yuri TODA, Riki OKAMOTO, Nobuhiro FUJITA, Kohichi SANO, Hiroshi YOSHIDA, Toshio OGAWA, Kunio HAYASHI, Kazuaki NAKANO
  • Patent number: 9670569
    Abstract: This is a cold-rolled steel sheet includes, by mass %, C: 0.02% to 0.4%, Si: 0.001% to 2.5%, Mn: 0.001% to 4.0%, and Al: 0.001% to 2.0%. The sum of the Si content and the Al content is 1.0% to 4.5%. 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 an area ratio %, 5% to 80% of ferrite, 5% to 80% of bainite, and 2% to 30% of retained austenite. In the microstructure, by an area ratio %, martensite is limited to 20% or less, pearlite is limited to 10% or less, and tempered martensite is limited to 60% or less.
    Type: Grant
    Filed: March 28, 2012
    Date of Patent: June 6, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takayuki Nozaki, Manabu Takahashi, Nobuhiro Fujita, Hiroshi Yoshida, Shinichiro Watanabe, Takeshi Yamamoto
  • Publication number: 20170130294
    Abstract: The present invention provides a bainite-containing-type high-strength hot-rolled steel sheet. The steel sheet, containing C: greater than 0.07 to 0.2%, Si: 0.001 to 2.5%, Mn: 0.01 to 4%, P: 0.15% or less, S: 0.03% or less, N: 0.01% or less, Al: 0.001 to 2% and a balance being composed of Fe and impurities, has an average value of pole densities of the {100}<011> to {223}<110> orientation group at a sheet thickness center portion being a range of ? to ? in sheet thickness from the surface of the steel sheet is 4.0 or less, and a pole density of the {332}<113> crystal orientation is 4.8 or less, an average crystal grain diameter is 10 ?m or less and vTrs is ?20° C. or lower, and a microstructure is composed of 35% or less in a structural fraction of pro-eutectoid ferrite and a balance of a low-temperature transformation generating phase.
    Type: Application
    Filed: January 20, 2017
    Publication date: May 11, 2017
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Tatsuo YOKOI, Hiroshi SHUTO, Riki OKAMOTO, Nobuhiro FUJITA, Kazuaki NAKANO, Takeshi YAMAMOTO
  • Patent number: 9631265
    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: Grant
    Filed: May 24, 2012
    Date of Patent: April 25, 2017
    Assignees: NIPPON STEEL, SUMITOMO METAL CORPORATION
    Inventors: Kohichi Sano, Kunio Hayashi, Kazuaki Nakano, Riki Okamoto, Nobuhiro Fujita
  • Patent number: 9587287
    Abstract: The present invention provides a bainite-containing-type high-strength hot-rolled steel sheet. The steel sheet, containing C: greater than 0.07 to 0.2%, Si: 0.001 to 2.5%, Mn: 0.01 to 4%, P: 0.15% or less, S: 0.03% or less, N: 0.01% or less, Al: 0.001 to 2% and a balance being composed of Fe and impurities, has an average value of pole densities of the {100}<011> to {223}<110> orientation group at a sheet thickness center portion being a range of ? to ? in sheet thickness from the surface of the steel sheet is 4.0 or less, and a pole density of the {332}<113> crystal orientation is 4.8 or less, an average crystal grain diameter is 10 ?m or less and vTrs is ?20° C. or lower, and a microstructure is composed of 35% or less in a structural fraction of pro-eutectoid ferrite and a balance of a low-temperature transformation generating phase.
    Type: Grant
    Filed: March 29, 2012
    Date of Patent: March 7, 2017
    Assignee: NIPPON STEEL AND SUMITOMO METAL CORPORATION
    Inventors: Tatsuo Yokoi, Hiroshi Shuto, Riki Okamoto, Nobuhiro Fujita, Kazuaki Nakano, Takeshi Yamamoto
  • Patent number: 9587319
    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: January 19, 2016
    Date of Patent: March 7, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Nobuhiro Fujita, Kunio Hayashi, Riki Okamoto, Manabu Takahashi, Tetsuo Kishimoto, Hiroshi Yoshida
  • 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
  • Patent number: 9540720
    Abstract: Disclosed is a high-strength hot-dip galvanized steel sheet having small material anisotropy and excellent formability with an ultimate tensile strength of 980 MPa or more. The hot-dip galvanized steel sheet includes a hot-dip galvanized layer formed on a surface of a base steel plate. The base steel plate contains C, Si, Mn, O, P, S, Al and N within predetermined ranges and a balance including Fe and inevitable impurities. The hot-dip galvanized layer contains Fe at less than 7 mass % or 7 to 15 mass % and a balance including Zn, Al, and inevitable impurities.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: January 10, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masafumi Azuma, Chisato Wakabayashi, Takayuki Nozaki, Nobuhiro Fujita, Manabu Takahashi
  • 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
  • Patent number: 9523134
    Abstract: This high strength hot-rolled steel sheet includes: in terms of percent by mass, C: 0.05 to 0.12%; Si: 0.8 to 1.2%; Mn: 1.6 to 2.2%; Al: 0.30 to 0.6%; P: 0.05% or less; S: 0.005% or less; and N: 0.01% or less, with the remainder being Fe and unavoidable impurities, wherein a microstructure includes specific ranges (in area %) of ferrite phases as well as martensite phases, and a maximum concentration of Al detected by a glow discharge emission spectroscopic analysis is in a range of 0.75 mass % or less in a region from a surface of the steel sheet to a thickness of 500 nm after being acid-pickled.
    Type: Grant
    Filed: August 27, 2014
    Date of Patent: December 20, 2016
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hiroyuki Tanahashi, Shinya Saitoh, Masashi Fukuda, Hiroyuki Okada, Kunio Hayashi, Toshimasa Tomokiyo, Nobuhiro Fujita
  • 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: 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