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: 10544474
    Abstract: A high-strength cold-rolled steel sheet includes, as a component composition, by mass %: C: 0.075% to 0.300%; Si: 0.30% to 2.50%; Mn: 1.30% to 3.50%; P: 0.001% to 0.050%; S: 0.0001% to 0.0100%; Al: 0.001% to 1.500%; and N: 0.0001% to 0.0100%, in which a surface microstructure contains residual austenite of 3% to 10% and ferrite of 90% or less by volume fraction, an inner microstructure at a depth of t/4 from the surface assuming that a sheet thickness is t contains residual austenite of 3% to 20% by volume fraction, a ratio Hvs/Hvb between a surface hardness Hvs of the steel sheet surface and a hardness Hvb at a depth of ¼ of the thickness is more than 0.75 to 0.90, and a maximum tensile strength is 700 MPa or more.
    Type: Grant
    Filed: February 4, 2013
    Date of Patent: January 28, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Masafumi Azuma, Takayuki Nozaki, Chisato Wakabayashi, Koichi Sato, Hiroyuki Kawata, Nobuhiro Fujita
  • Patent number: 10465272
    Abstract: Provided is a high-strength hot-dip galvanized steel sheet having excellent plating adhesion, formability, and hole expandability with an ultimate tensile strength of 980 MPa or more, the hot-dip galvanized steel sheet comprising a hot-dip galvanized layer formed on a surface of a base steel sheet. The base steel sheet contains, by mass %, C: 0.05% to 0.4%; Si: 0.01% to 3.0%; Mn: 0.1% to 3.0%; Al: 0.01 to 2.0%; in which Si+Al>0.5%, P: limited to 0.04% or less; S: limited to 0.05% or less; N: limited to 0.01% or less; and a balance including Fe and inevitable impurities, a microstructure of the base steel sheet contains 40% or more by total volume fraction of martensite and bainite, 8% or more by volume fraction of residual austenite, and a balance of the microstructure being ferrite or ferrite and 10% or less by volume fraction of pearlite.
    Type: Grant
    Filed: September 6, 2017
    Date of Patent: November 5, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Chisato Wakabayashi, Masafumi Azuma, Nobuhiro Fujita, Kohichi Sano
  • Patent number: 10407760
    Abstract: A hot-dip galvanized steel sheet includes: a steel sheet; and a plated layer on a surface of the steel sheet, a microstructure contains, by volume fraction, equal to or more than 20% and equal to or less than 99% in total of one or two of martensite and bainite, a residual structure contains one or two of ferrite, residual austenite of less than 8% by volume fraction, and pearlite of equal to or less than 10% by volume fraction, tensile strength is equal to or greater than 980 MPa, the plated layer is a hot-dip galvanized layer which contains oxides including one or two or more of Si, Mn, and Al, contains equal to or less than 15 mass % of Fe, and a remainder including Zn, Al, and unavoidable impurities, and when a cross section including the steel sheet and the hot-dip galvanized layer is seen in a sheet thickness direction, a projected area ratio is equal to or more than 10% and equal to or less than 90%.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: September 10, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Masafumi Azuma, Chisato Wakabayashi, Takayuki Nozaki, Manabu Takahashi, Nobuhiro Fujita
  • Patent number: 10364478
    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: January 20, 2017
    Date of Patent: July 30, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Tatsuo Yokoi, Hiroshi Shuto, Riki Okamoto, Nobuhiro Fujita, Kazuaki Nakano, Takeshi Yamamoto
  • Publication number: 20190211412
    Abstract: A hot-dip galvanized steel sheet includes a steel sheet and a hot-dip galvanized layer arranged on the steel sheet, in which the Si content and the Al content by mass % of components of the steel sheet satisfy a relationship 0.5<Si+Al<1.0, and a metallographic structure of the steel sheet satisfies a relationship of {(n2)2/3×d2}/{(n1)2/3×d1}×ln(H2/H1)<0.3 when the n1 is the number of a MnS of a surface portion of the steel sheet, the d1 ?m is an average equivalent circle diameter of the MnS in the surface portion of the steel sheet, the H1 GPa is a hardness of a martensite of the surface portion of the steel sheet, the n2 is the number of the MnS of a center portion of the steel sheet, the d2 ?m is an average equivalent circle diameter of the MnS in the center portion of the steel sheet, and the H2 GPa is the hardness of the martensite of the center portion of the steel sheet.
    Type: Application
    Filed: March 18, 2019
    Publication date: July 11, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Toshiki NONAKA, Toshio OGAWA, Nobuhiro FUJITA
  • Patent number: 10336037
    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: Grant
    Filed: April 28, 2014
    Date of Patent: July 2, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masaharu Oka, Nobuhiro Fujita, Manabu Takahashi, Riki Okamoto, Kenichiroh Matsumura
  • Patent number: 10303107
    Abstract: An image forming apparatus has an apparatus body having an image forming portion capable of forming an image based on an image information, an operation unit disposed as a separate body from the apparatus body and operating the apparatus body, and a cable connecting the apparatus body and the operation unit and capable of conducting power. The cable has a length set so that the operation unit does not contact an installation surface on which the apparatus body is supported, according to which a freedom of placement of the operation unit is improved compared to a case where the operation unit is connected via an arm.
    Type: Grant
    Filed: January 4, 2017
    Date of Patent: May 28, 2019
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takashi Fujita, Nobuhiro Tani
  • Patent number: 10294551
    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: Grant
    Filed: April 28, 2014
    Date of Patent: May 21, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masaharu Oka, Nobuhiro Fujita, Manabu Takahashi, Riki Okamoto, Chisato Wakabayashi
  • Patent number: 10280475
    Abstract: A hot-dip galvanized steel sheet includes a steel sheet and a hot-dip galvanized layer arranged on the steel sheet, in which the Si content and the Al content by mass % of components of the steel sheet satisfy a relationship 0.5<Si+Al<1.0, and a metallographic structure of the steel sheet satisfies a relationship of {(n2)2/3×d2}/{(n1)2/3×d1}×ln(H2/H1)<0.3 when the n1 is the number of a MnS of a surface portion of the steel sheet, the d1 ?m is an average equivalent circle diameter of the MnS in the surface portion of the steel sheet, the H1 GPa is a hardness of a martensite of the surface portion of the steel sheet, the n2 is the number of the MnS of a center portion of the steel sheet, the d2 ?m is an average equivalent circle diameter of the MnS in the center portion of the steel sheet, and the H2 GPa is the hardness of the martensite of the center portion of the steel sheet.
    Type: Grant
    Filed: December 15, 2011
    Date of Patent: May 7, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Toshiki Nonaka, Toshio Ogawa, Nobuhiro Fujita
  • Patent number: 10266928
    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: January 4, 2017
    Date of Patent: April 23, 2019
    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: 10167539
    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: Grant
    Filed: March 15, 2017
    Date of Patent: January 1, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kohichi Sano, Kunio Hayashi, Kazuaki Nakano, Riki Okamoto, Nobuhiro Fujita
  • Patent number: 10087499
    Abstract: There are provided a high-strength hot-rolled steel sheet securing low-temperature toughness and having excellent stretch flangeability by controlling a structural fraction and a hardness difference among structures, and a manufacturing method thereof. A hot-rolled steel sheet contains: C: 0.01 to 0.2%; Si: 0.001 to 2.5% or less; Mn: 0.10 to 4.0% or less; P: 0.10% or less; S: less than 0.03%; Al: 0.001 to 2.0%; N: less than 0.01%; Ti: (0.005+48/14[N]+48/32[S]) % or more and 0.3% or less; Nb: 0 to 0.06%; Cu: 0 to 1.2%; Ni: 0 to 0.6%; Mo: 0 to 1%; V: 0 to 0.2%; Cr: 0 to 2%; Mg: 0 to 0.01%; Ca: 0 to 0.01%; REM: 0 to 0.1%; and B: 0 to 0.002%, and has: an texture in which, at a central portion of a sheet thickness located between ? to ? thickness positions of the sheet thickness from a surface of the steel sheet, an average value of X-ray random intensity ratios of a group of {100}<011> to {223}<110> orientations of a sheet plane is 6.
    Type: Grant
    Filed: December 27, 2012
    Date of Patent: October 2, 2018
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Hiroshi Shuto, Tatsuo Yokoi, Yuuki Kanzawa, Nobuhiro Fujita, Ryohta Niiya, Shinya Saitoh
  • Patent number: 10066283
    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: August 29, 2016
    Date of Patent: September 4, 2018
    Assignee: NIPPON STEEL AND SUMITOMO METAL CORPORATION
    Inventors: Yuri Toda, Riki Okamoto, Nobuhiro Fujita, Kohichi Sano, Hiroshi Yoshida, Toshio Ogawa
  • Patent number: 10060006
    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 20, 2016
    Date of Patent: August 28, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yoshihiro Suwa, Kazuaki Nakano, Kunio Hayashi, Riki Okamoto, Nobuhiro Fujita, Kohichi Sano
  • Patent number: 9988697
    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 ? 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 10 ?m or less.
    Type: Grant
    Filed: April 12, 2012
    Date of Patent: June 5, 2018
    Assignee: NIPPON STEEL AND SUMITOMO METAL CORPORATION
    Inventors: Yoshihiro Suwa, Kazuaki Nakano, Kunio Hayashi, Riki Okamoto, Nobuhiro Fujita, Kohichi Sano
  • Patent number: 9970092
    Abstract: A galvanized steel sheet includes a steel sheet and a plating layer on the surface of the steel sheet, in which the steel sheet includes, as a steel chemical composition, by mass %, C: 0.05 to 0.40%, Si: 0.5 to 3.0% and Mn: 1.5 to 3.0%, a microstructure of the steel sheet includes ferrite, bainite, by volume fraction, 30% or more of a tempered martensite, and 8% or more of an austenite, and tensile strength of the steel sheet is 980 MPa or more, and the plating layer includes an oxide including at least one chemical element selected from Si, Mn and Al, and when seen at a cross section including the steel sheet and the plating layer in a plate thickness direction, a projection area fraction of the oxide is 10% or more.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: May 15, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takayuki Nozaki, Manabu Takahashi, Nobuhiro Fujita, Masafumi Azuma, Chisato Wakabayashi
  • Publication number: 20170369979
    Abstract: Provided is a high-strength hot-dip galvanized steel sheet having excellent plating adhesion, formability, and hole expandability with an ultimate tensile strength of 980 MPa or more, the hot-dip galvanized steel sheet comprising a hot-dip galvanized layer formed on a surface of a base steel sheet. The base steel sheet contains, by mass %, C: 0.05% to 0.4%; Si: 0.01% to 3.0%; Mn: 0.1% to 3.0%; Al: 0.01 to 2.0%; in which Si+Al>0.5%, P: limited to 0.04% or less; S: limited to 0.05% or less; N: limited to 0.01% or less; and a balance including Fe and inevitable impurities, a microstructure of the base steel sheet contains 40% or more by total volume fraction of martensite and bainite, 8% or more by volume fraction of residual austenite, and a balance of the microstructure being ferrite or ferrite and 10% or less by volume fraction of pearlite.
    Type: Application
    Filed: September 6, 2017
    Publication date: December 28, 2017
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Chisato WAKABAYASHI, Masafumi AZUMA, Nobuhiro FUJITA, Kohichi SANO
  • Patent number: 9797024
    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: August 17, 2016
    Date of Patent: October 24, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Tatsuo Yokoi, Hiroshi Shuto, Riki Okamoto, Nobuhiro Fujita, Kazuaki Nakano, Takeshi Yamamoto
  • Patent number: 9783878
    Abstract: Provided is a high-strength hot-dip galvanized steel sheet having excellent plating adhesion, formability, and hole expandability with an ultimate tensile strength of 980 MPa or more, the hot-dip galvanized steel sheet comprising a hot-dip galvanized layer formed on a surface of a base steel sheet. The base steel sheet contains, by mass %, C: 0.05% to 0.4 %; Si: 0.01% to 3.0%; Mn: 0.1% to 3.0%; Al: 0.01 to 2.0%; in which Si+Al >0.5%, P: limited to 0.04% or less; S: limited to 0.05% or less; N: limited to 0.01% or less; and a balance including Fe and inevitable impurities, a microstructure of the base steel sheet contains 40% or more by total volume fraction of martensite and bainite, 8% or more by volume fraction of residual austenite, and a balance of the microstructure being ferrite or ferrite and 10% or less by volume fraction of pearlite.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: October 10, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Chisato Wakabayashi, Masafumi Azuma, Nobuhiro Fujita, Kohichi Sano
  • 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