Patents by Inventor Akihiro Uenishi

Akihiro Uenishi 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: 20220195556
    Abstract: A steel sheet including a steel micro-structure containing, in volume fraction, tempered martensite: 85% or more, retained austenite: 5% or more to less than 15%, and ferrite, pearlite, bainite, and as-quenched martensite being less than 10% in total, when contents of Mn and C in the retained austenite are denoted by MnA and CA, and when contents of Mn and C in a matrix are denoted by MnM and CM, respectively, following Formulas (1) to (3) are satisfied, and the number of carbides having an equivalent circle radius of 0.1 ?m or more is 100 or less in a region measuring 20000 ?m2, and the steel sheet has a tensile strength of 1100 MPa or more. The steel sheet is excellent in crash resistance and formability. MnA/MnM?1.2??(1) CA/CM?5.0??(2) CA?1.
    Type: Application
    Filed: June 26, 2020
    Publication date: June 23, 2022
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Katsuya NAKANO, Kengo TAKEDA, Hiroyuki KAWATA, Akihiro UENISHI
  • Patent number: 11365465
    Abstract: A steel sheet includes a predetermined chemical composition, and includes a steel microstructure represented by, in an area ratio, ferrite: 5% to 80%, a hard microstructure constituted of bainite, martensite or retained austenite or an arbitrary combination of the above: 20% to 95%, and a standard deviation of a line fraction of the hard microstructure on a line in a plane perpendicular to a thickness direction: 0.050 or less in a depth range where a depth from a surface when a thickness of a steel sheet is set as t is from 3t/8 to t/2.
    Type: Grant
    Filed: August 8, 2017
    Date of Patent: June 21, 2022
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Shohei Yabu, Akihiro Uenishi, Koutarou Hayashi
  • Publication number: 20220145415
    Abstract: The present invention relates to a cold rolled steel sheet containing C: 0.15% or more and 0.40% or less, Si: 0.50% or more and 4.00% or less, Mn: 1.00% or more and 4.00% or less, and sol. Al: 0.001% or more and 2.000% or less, having a metallic structure consisting of 35 to 65 area % of ferrite phases, 35 to 65 area % of hard second phases, and 0 to 5 area % of remaining phases, wherein 60% or more of the ferrite phases are recrystallized ferrite phases, an average crystal grain size defined by 15° grain boundaries is 5.0 ?m or less, a maximum connecting rate of the hard second phases is 10% or more, and a two-dimensional isoperimetric constant of the hard second phases is 0.20 or less.
    Type: Application
    Filed: March 31, 2020
    Publication date: May 12, 2022
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Shohei YABU, Koutarou HAYASHI, Akihiro UENISHI
  • Patent number: 11274356
    Abstract: A steel sheet having a chemical composition of the base metal including, in mass %, C: 0.17 to 0.40%, Si: 0.10 to 2.50%, Mn: 1.00 to 10.00%, P: 0.001 to 0.03%, S: 0.0001 to 0.02%, Al: 0.001 to 2.50%, N: 0.0001 to 0.010%, O: 0.0001 to 0.010%, Ti: 0 to 0.10%, Nb: 0 to 0.10%, V: 0 to 0.10%, B: 0 to 0.010%, Cr: 0 to 2.00%, Ni: 0 to 2.00%, Cu: 0 to 2.00%, Mo: 0 to 2.00%, Ca: 0 to 0.50%, Mg: 0 to 0.50%, REM: 0 to 0.50%, the balance: Fe and impurities, wherein the steel sheet has an internal oxidized layer in which at least one part of a crystal grain boundary is covered by oxides, and in which a grain boundary coverage ratio of oxides is 60% or more in a region from the surface of the base metal to a depth of 5.0 ?m.
    Type: Grant
    Filed: December 15, 2017
    Date of Patent: March 15, 2022
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kengo Takeda, Kunio Hayashi, Akihiro Uenishi, Hiroyuki Kawata, Chisato Yoshinaga, Yasunobu Miyazaki, Toyomitsu Nakamura
  • Patent number: 11242583
    Abstract: A steel sheet includes, as a chemical composition, by mass %: C: 0.05-0.30%; Si: 0.2-2.0%; Mn: 2.0-4.0%; Al: 0.001-2.000%; P: 0.100% or less; S: 0.010% or less; N: 0.010% or less; Ti: 0-0.100%; Nb: 0-0.100%; V: 0-0.100%; Cu: 0-1.00%; Ni: 0-1.00%; Mo: 0-1.00%; Cr: 0-1.00%; W: 0-0.005%; Ca: 0-0.005%; Mg: 0-0.005%; a rare earth element (REM): 0-0.010%; B: 0-0.0030%; and a remainder of Fe and impurities, in which a metallographic structure contains, by area ratio, 95% or more of a hard structure and 0-5% of residual austenite, by mass % in a cross section in a thickness direction, C1/C2 which is a ratio of an upper limit C1 of a Mn content to a lower limit C2 of the Mn content is 1.5 or less, and a bake-hardening amount BH is 150 MPa or less.
    Type: Grant
    Filed: November 8, 2018
    Date of Patent: February 8, 2022
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Mai Nagano, Koutarou Hayashi, Akihiro Uenishi
  • Publication number: 20220025497
    Abstract: A galvannealed steel sheet according to one aspect of the present invention has a hot-dip galvannealed layer on at least one surface of the steel sheet, and the steel sheet has a predetermined chemical composition, in which the steel sheet contains 10% or more and 90% or less of ferrite, and 10% or more of tempered martensite and tempered bainite in terms of an area ratio, a sum of the ferrite, the tempered martensite, and the tempered bainite is 90% or more, carbides having a major axis of 50 nm or more and 300 nm or less are contained in grains of the ferrite in a number density of 20/?m2 or more, and a two-dimensional homogeneous dispersion ratio S of Mn is 0.75 or more and 1.30 or less.
    Type: Application
    Filed: October 4, 2019
    Publication date: January 27, 2022
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Mai NAGANO, Koutarou HAYASHI, Akihiro UENISHI
  • Patent number: 11225701
    Abstract: A hot dip galvanized steel sheet and hot dip galvannealed steel sheet improved in uniform ductility and local ductility, yield strength and tensile strength, and low temperature impact property, characterized by having a predetermined chemical composition, having a metal structure containing, by volume %, retained austenite: over 5.0% and tempered martensite: over 5.0%, having retained austenite containing C: 0.85 mass % or more, and having a ratio [C]?gb/[P]?gb of an amount of segregation of C (number of atoms/nm2): [C]?gb to an amount of segregation of P (number of atoms/nm2): [P]?gb at prior austenite grain boundaries of 4.0 or more.
    Type: Grant
    Filed: March 30, 2018
    Date of Patent: January 18, 2022
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Jun Haga, Kohichi Sano, Koutarou Hayashi, Kunio Hayashi, Masaharu Kameda, Akihiro Uenishi, Hiroyuki Kawata
  • Patent number: 11208705
    Abstract: A high-strength cold-rolled steel sheet which is a steel sheet having a tensile strength of 980 MPa or more has a predetermined chemical component composition, a metallographic microstructure of the steel sheet contains, by area ratio, ferrite and granular bainite: 10% or more and 50% or less in total, one or both of upper bainite and lower bainite: 10% or more and 50% or less in total, tempered martensite: more than 0% and 30% or less, retained austenite: 5% or more, and one or more of pearlite, cementite, and martensite: 0% to 10% in total, and an area ratio of the ferrite with respect to a total area ratio of the ferrite and the granular bainite is 25% or less.
    Type: Grant
    Filed: November 15, 2017
    Date of Patent: December 28, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Yuri Toda, Kunio Hayashi, Katsuya Nakano, Eisaku Sakurada, Akihiro Uenishi, Kengo Takeda
  • Publication number: 20210269903
    Abstract: What is provided is a high-strength steel sheet including, by mass %: C: 0.05% to 0.15%; Si: 1.5% or less; Mn: 2.00% to 5.00%; P: 0.100% or less; S: 0.010% or less; Al: 0.001% to 2.000%; N: 0.010% or less; and a remainder of Fe and impurities, in which Ceq defined by Ceq=C+Si/90+Mn/100+1.5P+3S is less than 0.21, the high-strength steel sheet contains martensite in an area ratio of 98% or more, and a residual structure is in an area ratio of 2% or less, a two-dimensional homogeneous dispersion ratio S defined by S=Sy2/Sx2 (Sx2 is a dispersion value of Mn concentration profile data in a sheet width direction, and Sy2 is a dispersion value of the Mn concentration profile data in a sheet thickness direction) is 0.85 or more and 1.20 or less, and a tensile strength is 1200 MPa or more.
    Type: Application
    Filed: July 26, 2019
    Publication date: September 2, 2021
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Mai NAGANO, Koutarou HAYASHI, Akihiro UENISHI
  • Patent number: 11028458
    Abstract: When a zone surrounded by a grain boundary that is measured to be 5.0° or more by an EBSD analysis is assumed to be a grain, and when a K value is a value obtained by multiplying an average value of Image Qualities in a grain by 10?3, a Y value is an average crystal misorientation (°) in the grain, a metallic phase 1 is a metallic phase the K value of which is less than 4.000, a metallic phase 2 is a metallic phase the K value of which is 4.000 or more and the Y value of which is 0.5 to 1.0, a metallic phase 3 is a metallic phase the K value of which is 4.000 or more and the Y value of which is less than 0.5, and a metallic phase 4 is a metallic phase that falls under none of metallic phases 1 to 3, there is provided a steel sheet that has a predetermined chemical composition and includes a microstructure including, in area percent, a metallic phase 1: 1.0% or more and less than 35.0%, a metallic phase 2: 30.0% or more and 80.0% or less, a metallic phase 3: 5.0% or more and 50.
    Type: Grant
    Filed: January 27, 2017
    Date of Patent: June 8, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Yuri Toda, Masafumi Azuma, Akihiro Uenishi, Eisaku Sakurada, Tatsuo Yokoi, Genichi Shigesato
  • Publication number: 20210164082
    Abstract: What is provided is a high-strength steel sheet having a large bake hardening amount and a uniform bake hardenability is provided according to the present invention, the high-strength steel sheet comprising, by mass %: C: 0.13% to 0.40%; Si: 0.500% to 3.000%; Mn: 2.50% to 5.00%; P: 0.100% or less; S: 0.010% or less; Al: 0.001% to 2.000%; N: 0.010% or less; and a remainder consisting of Fe and impurities, wherein martensite is 95% or more in an area ratio, and residual structure is 5% or less in an area ratio, a ratio C1/C2 of an upper limit C1 (mass %) of Si concentrations to a lower limit C2 (mass %) of the Si concentrations in a cross section in a thickness direction is 1.25 or less, precipitates having a major axis of 0.05 ?m or more and 1.00 ?m or less and an aspect ratio of 1:3 or more are included in a number density of 30/?m2 or more, and a tensile strength is 1300 MPa or more.
    Type: Application
    Filed: July 26, 2019
    Publication date: June 3, 2021
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Mai NAGANO, Koutarou HAYASHI, Akihiro UENISHI
  • Publication number: 20210040588
    Abstract: A steel sheet has a predetermined chemical composition and a metal structure represented by, in area fraction, polygonal ferrite: 40% or less, martensite: 20% or less, bainitic ferrite: 50% to 95%, and retained austenite: 5% to 50%. In area fraction, 80% or more of the bainitic ferrite is composed of bainitic ferrite grains that have an aspect ratio of 0.1 to 1.0 and have a dislocation density of 8×102 (cm/cm3) or less in a region surrounded by a grain boundary with a misorientation angle of 15° or more. In area fraction, 80% or more of the retained austenite is composed of retained austenite grains that have an aspect ratio of 0.1 to 1.0, have a major axis length of 1.0 ?m to 28.0 ?m, and have a minor axis length of 0.1 ?m to 2.8 ?m.
    Type: Application
    Filed: March 30, 2018
    Publication date: February 11, 2021
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Yuri TODA, Eisaku SAKURADA, Kunio HAYASHI, Akihiro UENISHI
  • Patent number: 10907235
    Abstract: A steel sheet according to an aspect of the present invention has a chemical composition within a predetermined range; in which a metallographic structure at a thickness ¼ portion includes, by unit area %, ferrite: 10% or more and less than 50%, granular bainite: 5% or more and less than 50%, and martensite: 20% or more and less than 60%; in the metallographic structure at the thickness ¼ portion, a total of upper bainite, lower bainite, residual austenite, and pearlite is 0% or more and less than 15% by unit area %; at the thickness ¼ portion, a product of an area ratio Vm of the martensite and an average hardness Hv of the martensite is 12,000 to 34,000; and a tensile strength is 980 MPa or higher.
    Type: Grant
    Filed: September 13, 2016
    Date of Patent: February 2, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Yuri Toda, Kunio Hayashi, Katsuya Nakano, Hiroyuki Kawata, Akihiro Uenishi
  • Publication number: 20210017622
    Abstract: A hot dip galvanized steel sheet and hot dip galvannealed steel sheet improved in uniform ductility and local ductility, yield strength and tensile strength, and low temperature impact property, characterized by having a predetermined chemical composition, having a metal structure containing, by volume %, retained austenite: over 5.0% and tempered martensite: over 5.0%, having retained austenite containing C: 0.85 mass % or more, and having a ratio [C]?gb/[P]?gb of an amount of segregation of C (number of atoms/nm2): [C]?gb to an amount of segregation of P (number of atoms/nm2): [P]?gb at prior austenite grain boundaries of 4.0 or more.
    Type: Application
    Filed: March 30, 2018
    Publication date: January 21, 2021
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Jun HAGA, Kohichi SANO, Koutarou HAYASHI, Kunio HAYASHI, Masaharu KAMEDA, Akihiro UENISHI, Hiroyuki KAWATA
  • Patent number: 10895002
    Abstract: A steel sheet includes a predetermined chemical composition and a metal structure represented by, in area fraction, ferrite: 30% to 50%, granular bainite: 5% to 20%, martensite: 30% to 55%, bainite: less than 35%, and retained austenite and pearlite: 10% or less in total. Preferably, of the steel sheet, a tensile strength is 1180 MPa or more, elongation is 10% or more, and a hole expansion value is 20% or more. Further preferably, a VDA bending angle in the case where a thickness is set to t (mm) is “7.69t2?38.4t+109” or more.
    Type: Grant
    Filed: January 30, 2017
    Date of Patent: January 19, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Katsuya Nakano, Kunio Hayashi, Yuri Toda, Eisaku Sakurada, Akihiro Uenishi
  • Publication number: 20210002741
    Abstract: A steel sheet including, in mass %, C: 0.05% or more and 0.30% or less, Si: 0.05% or more and 6.00% or less, Mn: 1.50% or more and 10.00% or less, and the balance: Fe and impurities, a steel sheet structure is composed of, in area ratio, 15% or more and 80% or less of ferrite and 20% or more and 85% or less in total of a hard structure composed of any one of bainite, martensite, or retained austenite, or any combination thereof, and to a steel sheet thickness t, an area ratio of a maximum coupled ferrite region in a region from a t/2 position at the steel sheet thickness center to a position at a depth of 3t/8 from a surface is 80% or more in area ratio to a total ferrite area, and a two-dimensional isoperimetric constant of the maximum coupled ferrite region is 0.35 or less.
    Type: Application
    Filed: March 30, 2018
    Publication date: January 7, 2021
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Shohei YABU, Koutarou HAYASHI, Akihiro UENISHI
  • Patent number: 10876181
    Abstract: In a cold-rolled steel sheet having a predetermined chemical composition, a metallographic structure contains 40.0% or more and less than 60.0% of a polygonal ferrite, 30.0% or more of a bainitic ferrite, 10.0% to 25.0% of a residual austenite, and 15.0% or less of a martensite, by an area ratio, in the residual austenite, a proportion of the residual austenite in which an aspect ratio is 2.0 or less, a length of a long axis is 1.0 ?m or less, and a length of a short axis is 1.0 ?m or less, is 80.0% or more, in the bainitic ferrite, a proportion of the bainitic ferrite in which an aspect ratio is 1.7 or less and an average value of a crystal orientation difference in a region surrounded by a boundary in which a crystal orientation difference is 15° or more is 0.5° or more and less than 3.0°, is 80.0% or more, and a connection index D value of the martensite, the bainitic ferrite, and the residual austenite is 0.70 or less.
    Type: Grant
    Filed: February 24, 2016
    Date of Patent: December 29, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kengo Takeda, Kunio Hayashi, Akihiro Uenishi, Masafumi Azuma, Takayuki Nozaki, Yuri Toda
  • Patent number: 10822672
    Abstract: A steel sheet according to an aspect of the present invention has predetermined chemical composition, in which a structure at a thickness ¼ portion includes, in terms of volume ratios, tempered martensite: 30% to 70% and one or both of ferrite and bainite: a total of 20% to 70%, in the structure at the thickness ¼ portion, a volume ratio of residual austenite is less than 10%, a volume ratio of fresh martensite is 10% or less, a volume ratio of pearlite is 10% or less, and a total volume ratio of the residual austenite, the fresh martensite, and the pearlite is 15% or less, a number density of iron-based carbides having a major axis of 5 nm or more in the tempered martensite at the thickness ¼ portion is 5×107 particles/mm2 or more, a ratio of the number of ?-type carbides in the number of the iron-based carbides having the major axis of 5 nm or more at the thickness ¼ portion is 20% or more, and a tensile strength is 780 MPa or higher.
    Type: Grant
    Filed: July 13, 2015
    Date of Patent: November 3, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Yuri Toda, Masafumi Azuma, Akihiro Uenishi, Hiroyuki Kawata, Naoki Maruyama, Genichi Shigesato
  • Publication number: 20200332397
    Abstract: A steel sheet includes, as a chemical composition, by mass %: C: 0.05% to 0.30%; Si: 0.2% to 2.0%; Mn: 2.0% to 4.0%; Al: 0.001% to 2.000%; P: 0.100% or less; S: 0.010% or less; N: 0.010% or less; Ti: 0% to 0.100%; Nb: 0% to 0.100%; V: 0% to 0.100%; Cu: 0% to 1.00%; Ni: 0% to 1.00%; Mo: 0% to 1.00%; Cr: 0% to 1.00%; W: 0% to 0.005%; Ca: 0% to 0.005%; Mg: 0% to 0.005%; a rare earth element (REM): 0% to 0.010%; B: 0% to 0.0030%; and a remainder of Fe and impurities, in which a metallographic structure contains, by area ratio, 95% or more of a hard structure and 0% to 5% of residual austenite, by mass % in a cross section in a thickness direction, C1/C2 which is a ratio of an upper limit C1 of a Mn content to a lower limit C2 of the Mn content is 1.5 or less, and a bake-hardening amount BH is 150 MPa or less.
    Type: Application
    Filed: November 8, 2018
    Publication date: October 22, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Mai NAGANO, Koutarou HAYASHI, Akihiro UENISHI
  • Patent number: 10808291
    Abstract: A steel sheet according to an aspect of the present invention has predetermined chemical composition, in which a structure at a thickness ¼ portion includes, in terms of volume ratios, tempered martensite: 70% or more and one or both of ferrite and bainite: a total of less than 20%, in the structure at the thickness ¼ portion, a volume ratio of residual austenite is less than 10%, a volume ratio of fresh martensite is 10% or less, a volume ratio of pearlite is 10% or less, and a total volume ratio of the residual austenite, the fresh martensite, and the pearlite is 15% or less, a number density of iron-based carbides having a major axis of 5 nm or more in the tempered martensite at the thickness ¼ portion is 5×107 particles/mm2 or more, a ratio of the number of ?-type carbides in the number of the iron-based carbides having the major axis of 5 nm or more at the thickness ¼ portion is 20% or more, and a tensile strength is 780 MPa or higher.
    Type: Grant
    Filed: July 13, 2015
    Date of Patent: October 20, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Yuri Toda, Masafumi Azuma, Akihiro Uenishi, Hiroyuki Kawata, Naoki Maruyama, Genichi Shigesato