Patents by Inventor Natsuko Sugiura

Natsuko Sugiura 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: 11028469
    Abstract: A hot press-formed part according to an aspect of the present invention contains a predetermined chemical composition; in which a microstructure in a thickness ¼ portion includes, by unit vol %, tempered martensite: 20% to 90%, bainite: 5% to 75%, and residual austenite: 5% to 25%, and ferrite is limited to 10% or less; and a pole density of an orientation {211}<011> in the thickness ¼ portion is 3.0 or higher.
    Type: Grant
    Filed: August 16, 2016
    Date of Patent: June 8, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Mutsumi Sakakibara, Natsuko Sugiura, Kunio Hayashi, Kaoru Kawasaki
  • Patent number: 10913988
    Abstract: A hot-rolled steel sheet includes a predetermined chemical composition, and a structure which include, by area ratio, ferrite and bainite in a range of 80% to 98% in total, and martensite in a range of 2% to 10%, in which in the structure, in a case where a boundary having an orientation difference of equal to or greater than 15° is defined as a grain boundary, and an area which is surrounded by the grain boundary, and has an equivalent circle diameter of equal to or greater than 0.3 ?m is defined as a grain, the ratio of the grains having an intragranular orientation difference in a range of 5° to 14° is, by area ratio, in a range of 10% to 60%.
    Type: Grant
    Filed: February 22, 2016
    Date of Patent: February 9, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Hiroshi Shuto, Natsuko Sugiura, Mitsuru Yoshida, Tatsuo Yokoi, Masayuki Wakita
  • Patent number: 10889879
    Abstract: A steel sheet having a specific chemical composition and structure represented by, by area ratio, ferrite: 5 to 95%, and bainite: 5 to 95%. The proportion of crystal grains having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. Hard crystal grains A in which precipitates or clusters with a maximum diameter of 8 nm or less are dispersed in the crystal grains with a number density of 1×1016 to 1×1019 pieces/cm3. Soft crystal grains B in which precipitates or clusters with a maximum diameter of 8 nm or less are dispersed in the crystal grains with a number density of 1×1015 pieces/cm3 or less are contained. The volume % of the hard crystal grains A/(the volume % of the hard crystal grains A+the volume % of the soft crystal grains B) is 0.1 to 0.9.
    Type: Grant
    Filed: August 4, 2017
    Date of Patent: January 12, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kohichi Sano, Makoto Uno, Ryoichi Nishiyama, Yuji Yamaguchi, Natsuko Sugiura, Masahiro Nakata
  • Patent number: 10752972
    Abstract: A hot-rolled steel sheet includes a predetermined chemical composition, and a structure which includes, by area ratio, a ferrite in a range of 5% to 60% and a bainite in a range of 30% to 95%, in which in the structure, in a case where a boundary having an orientation difference of equal to or greater than 15° is defined as a grain boundary, and an area which is surrounded by the grain boundary and has an equivalent circle diameter of equal to or greater than 0.3 ?m is defined as a grain, the ratio of the grains having an intragranular orientation difference in a range of 5° to 14° is, by area ratio, in a range of 20% to 100%.
    Type: Grant
    Filed: February 22, 2016
    Date of Patent: August 25, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Natsuko Sugiura, Mitsuru Yoshida, Hiroshi Shuto, Tatsuo Yokoi, Masayuki Wakita
  • Patent number: 10738384
    Abstract: A surface-treated steel sheet for fuel tanks, including a Zn—Ni alloy plating layer on one surface or both surfaces of a steel sheet; and a trivalent chromate covering layer or a chromate-free covering layer on the Zn—Ni alloy plating layer, wherein, in a surface outermost layer of the trivalent chromate covering layer or the chromate-free covering layer, concavities, of which a depth from an arithmetic average height of a cross-sectional curve of the surface outermost layer is more than or equal to 0.1 ?m, exist in a proportion of 50 to 1000 concavities/mm2 and at an area ratio of 20 to 80% to a surface area of the steel sheet.
    Type: Grant
    Filed: August 29, 2016
    Date of Patent: August 11, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Hiromasa Shoji, Taihei Kaneto, Masahiro Fuda, Hironori Sato, Natsuko Sugiura, Yuji Yamaguchi
  • Patent number: 10689724
    Abstract: There is provided a steel sheet with strain induced transformation type composite structure having a predetermined chemical composition in which a microstructure at the ¼ thickness of the steel sheet includes, by area ratio, 50% to 85% of a polygonal ferrite, 3% to 10% of a residual austenite, 5% to 47% of bainite and 1% or less of a fresh martensite and a tempered martensite in total and satisfies the equation of 0.01<Ex.C/fsd?0.015, the microstructure includes 1×1016 pieces/cm3 or more of precipitates containing TiC, an average grain diameter of the residual austenite 1.0 ?m to 5.0 ?m at an equivalent circle diameter, an average of closest distances of the austenite is 3.0 ?m to 10.0 ?m, and an average diameter of the precipitates is 3 nm or less.
    Type: Grant
    Filed: July 31, 2015
    Date of Patent: June 23, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Tatsuo Yokoi, Hiroshi Shuto, Yuuki Kanzawa, Natsuko Sugiura
  • Patent number: 10689737
    Abstract: A hot-rolled steel sheet includes a chemical composition represented by, in mass %, C: 0.010% to 0.100%, Si: 0.30% or less, Cr: 0.05% to 1.00%, Nb: 0.003% to 0.050%, Ti: 0.003% to 0.200% and others, wherein a proportion of grains having an intragranular misorientation of 5° to 14° in all grains is 20% or more by area ratio, the grain being defined as an area which is surrounded by a boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more.
    Type: Grant
    Filed: February 25, 2015
    Date of Patent: June 23, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Masayuki Wakita, Mitsuru Yoshida, Natsuko Sugiura, Hiroshi Shuto, Tatsuo Yokoi
  • Publication number: 20200157666
    Abstract: A hot press-formed part according to an aspect of the present invention contains a predetermined chemical composition; in which a microstructure in a thickness ¼ portion includes, by unit vol %, tempered martensite: 20% to 90%, bainite: 5% to 75%, and residual austenite: 5% to 25%, and ferrite is limited to 10% or less; and a pole density of an orientation {211}<011> in the thickness ¼ portion is 3.0 or higher.
    Type: Application
    Filed: August 16, 2016
    Publication date: May 21, 2020
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Mutsumi SAKAKIBARA, Natsuko SUGIURA, Kunio HAYASHI, Kaoru KAWASAKI
  • Publication number: 20200157650
    Abstract: A hot-rolled steel sheet has a chemical composition that contains, in mass %, C, Si, Mn, P, S, Al, N and Ti, and that satisfies Formula (1); and a microstructure containing bainite and ferrite. In the interior of the steel sheet an average value of pole densities of an orientation group {100}<011> to {223}<110> is 4 or less, and a pole density of a {332}<113> crystal orientation is 4.8 or less. In an outer layer of the steel sheet, a pole density of a {110}<001> crystal orientation is 2.5 or more. Furthermore, among Ti carbo-nitrides in the steel sheet, the number density of fine Ti carbo-nitrides having a particle diameter of 10 nm or less is 1.0×1017 per cm3 or less, and a bake hardening amount is 15 MPa or more.
    Type: Application
    Filed: January 28, 2020
    Publication date: May 21, 2020
    Inventors: Tatsuo Yokoi, Eisaku Sakurada, Natsuko Sugiura, Kiyoyuki Fukui
  • Patent number: 10590506
    Abstract: A hot-rolled steel sheet for a tailored rolled blank is provided that has high tensile strength and is excellent in cold formability. The hot-rolled steel sheet has: a chemical composition that contains, in mass %, C, Si, Mn, P, S, Al, N and Ti, with the balance being Fe and impurities, and that satisfies Formula (1); and a microstructure containing, in terms of area ratio, 20% or more of bainite, wherein 50% or more in terms of area ratio of the balance is ferrite. In the interior of the hot-rolled steel sheet an average value of pole densities of an orientation group {100}<011> to {223}<110> is 4 or less, and a pole density of a {332}<113> crystal orientation is 4.8 or less. In an outer layer of the hot-rolled steel sheet, a pole density of a {110}<001> crystal orientation is 2.5 or more. Furthermore, among Ti carbo-nitrides in the hot-rolled steel sheet, the number density of fine Ti carbo-nitrides having a particle diameter of 10 nm or less is 1.
    Type: Grant
    Filed: April 30, 2019
    Date of Patent: March 17, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Tatsuo Yokoi, Eisaku Sakurada, Natsuko Sugiura, Kiyoyuki Fukui
  • Publication number: 20190390294
    Abstract: A hot rolled steel sheet is provided, which is excellent in collision characteristics, excellent in anisotropy of toughness, and high in strength. The hot rolled steel sheet is characterized by containing, by mass %, C: 0.10% to 0.50%, Si: 0.10% to 3.00%, Mn: 0.5% to 3.0%, P: 0.100% or less, S: 0.010% or less, Al: 1.00% or less, N: 0.010% or less and a balance of Fe and impurities, wherein a metal structure at position of ¼ thickness from surface in L-cross-section of the steel sheet comprises prior austenite grains of average value of aspect ratios of 2.0 or less, average grain size of 0.1 ?m to 3.0 ?m, and coefficient of variation of a standard deviation of grain size distribution/average grain size of 0.40 or more, and a texture with X-ray diffraction intensity ratio of {001}<110> orientation for random samples of 2.0 or more, and the steel sheet has tensile strength of 1180 MPa or more.
    Type: Application
    Filed: February 16, 2018
    Publication date: December 26, 2019
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Takeshi TOYODA, Riki OKAMOTO, Natsuko SUGIURA, Tetsuya HIRASHIMA
  • Publication number: 20190309398
    Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 5 to 60%, and bainite: 40 to 95%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. A precipitate density of Ti(C,N) and Nb(C,N) each having a circle-equivalent diameter of 10 nm or less is 1010 precipitates/mm3 or more. A ratio (Hvs/Hvc) of a hardness at 20 ?m in depth from a surface (Hvs) to a hardness of the center of a sheet thickness (Hvc) is 0.85 or more.
    Type: Application
    Filed: August 4, 2017
    Publication date: October 10, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kohichi SANO, Makoto UNO, Ryoichi NISHIYAMA, Yuji YAMAGUCHI, Natsuko SUGIURA, Masahiro NAKATA
  • Publication number: 20190256941
    Abstract: A tailored rolled blank in which a plate thickness changes in a tapered shape in a rolling direction, comprises a thick-wall portion, and a thin-wall portion that is thinner than the thick-wall portion. In the tailored rolled blank, a ratio of an average hardness Htmax of a thickest wall portion at which the plate thickness is thickest to an average hardness Htmin of a thinnest wall portion at which the plate thickness is thinnest is in a range of more than 1.0 to 1.5. For the tailored rolled blank, an average dislocation density of the thinnest wall portion is 1×1014 m?2 or less, and a number density of fine Ti carbo-nitrides having a particle diameter of 10 nm or less is more than 2×1017 per cm3.
    Type: Application
    Filed: April 30, 2019
    Publication date: August 22, 2019
    Inventors: Tatsuo YOKOI, Eisaku SAKURADA, Natsuko SUGIURA, Kiyoyuki FUKUI
  • Publication number: 20190241996
    Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 0 to 30%, and bainite: 70 to 100%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. A grain boundary number density of solid-solution C or a grain boundary number density of the total of solid-solution C and solid-solution B is 1 piece/nm2 or more and 4.5 pieces/nm2 or less. An average grain size of cementite precipitated at grain boundaries is 2 ?m or less.
    Type: Application
    Filed: August 4, 2017
    Publication date: August 8, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kohichi SANO, Makoto UNO, Ryoichi NISHIYAMA, Yuji YAMAGUCHI, Natsuko SUGIURA, Masahiro NAKATA
  • Publication number: 20190233926
    Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 5 to 95%, and bainite: 5 to 95%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. Hard crystal grains A in which precipitates or clusters with a maximum diameter of 8 nm or less are dispersed in the crystal grains with a number density of 1×1016 to 1×1019 pieces/cm3 and soft crystal grains B in which precipitates or clusters with a maximum diameter of 8 nm or less are dispersed in the crystal grains with a number density of 1×1015 pieces/cm3 or less are contained, and the volume % of the hard crystal grains A/(the volume % of the hard crystal grains A +the volume % of the soft crystal grains B) is 0.1 to 0.9.
    Type: Application
    Filed: August 4, 2017
    Publication date: August 1, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kohichi SANO, Makoto UNO, Ryoichi NISHIYAMA, Yuji YAMAGUCHI, Natsuko SUGIURA, Masahiro NAKATA
  • Publication number: 20190226061
    Abstract: A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 30 to 95%, and bainite: 5 to 70%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. An average aspect ratio of ellipses equivalent to the crystal grains is 5 or less. An average distribution density of the total of Ti-based carbides and Nb-based carbides each having a grain size of 20 nm or more on ferrite grain boundaries is 10 carbides/?m or less.
    Type: Application
    Filed: August 4, 2017
    Publication date: July 25, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kohichi SANO, Makoto UNO, Ryoichi NISHIYAMA, Yuji YAMAGUCHI, Natsuko SUGIURA, Masahiro NAKATA
  • Patent number: 10329637
    Abstract: A heat-rolled steel plate has a chemical composition that contains, in mass %, C, Si, Mn, P, S, Al, N and Ti, and that satisfies Formula (1); and a microstructure containing bainite and ferrite. In the interior of the steel plate an average value of pole densities of an orientation group {100}<011> to {223}<110> is 4 or less, and a pole density of a {332}<113> crystal orientation is 4.8 or less. In an outer layer of the steel plate, a pole density of a {110}<001> crystal orientation is 2.5 or more. Furthermore, among Ti carbo-nitrides in the steel plate, the number density of fine Ti carbo-nitrides having a particle diameter of 10 nm or less is 1.0×1017 per cm3 or less, and a bake hardening amount is 15 MPa or more.
    Type: Grant
    Filed: April 23, 2015
    Date of Patent: June 25, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Tatsuo Yokoi, Eisaku Sakurada, Natsuko Sugiura, Kiyoyuki Fukui
  • Publication number: 20180216206
    Abstract: There is provided a steel sheet with strain induced transformation type composite structure having a predetermined chemical composition in which a microstructure at the ¼ thickness of the steel sheet includes, by area ratio, 50% to 85% of a polygonal ferrite, 3% to 10% of a residual austenite, 5% to 47% of bainite and 1% or less of a fresh martensite and a tempered martensite in total and satisfies the equation of 0.01<Ex.C/fsd?0.015, the microstructure includes 1×1016 pieces/cm3 or more of precipitates containing TiC, an average grain diameter of the residual austenite 1.0 ?m to 5.0 ?m at an equivalent circle diameter, an average of closest distances of the austenite is 3.0 ?m to 10.0 ?m, and an average diameter of the precipitates is 3 nm or less.
    Type: Application
    Filed: July 31, 2015
    Publication date: August 2, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Tatsuo YOKOI, Hiroshi SHUTO, Yuuki KANZAWA, Natsuko SUGIURA
  • Publication number: 20180209007
    Abstract: There is provided a high strength hot rolled steel sheet including a predetermined chemical composition. A structure includes, by area ratio, 80% or more of polygonal ferrite, a total of 5% or less of martensite and austenite, and a total of 5% or less of pearlite and cementite, and a remainder is at least one selected from bainitic ferrite and bainite. When a standard deviation of micro-hardness of 50 arbitrary pieces of the polygonal ferrite present within a range of ±100 ?m from a central plane in a sheet thickness direction is ?HV, the ?HV is 30 or smaller. A grain of the polygonal ferrite contains 5×107 pieces/mm2 or more of Ti-containing carbide, and in 50% or more of the Ti-containing carbide, the aspect ratio which is a ratio of a length of a long side to a length of a short side is less than 3. The tensile strength is 540 MPa or higher.
    Type: Application
    Filed: July 31, 2015
    Publication date: July 26, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Natsuko SUGIURA, Yasuaki TANAKA, Takafumi YOKOYAMA
  • Publication number: 20180187313
    Abstract: A surface-treated steel sheet for fuel tanks, including: a Zn—Ni alloy plating layer on one surface or both surfaces of a steel sheet; and a trivalent chromate covering layer or a chromate-free covering layer on the Zn—Ni alloy plating layer. The steel sheet consists of, in mass %, C: 0.0005 to 0.0050%, Si: 0.01 to 1.00%, Mn: 0.70 to 2.00%, P: less than or equal to 0.060%, S: less than or equal to 0.010%, Al: 0.01 to 0.30%, N: 0.001 to 0.010%, Ti: 0.010 to 0.050%, Nb: 0.010 to 0.040%, B: 0.0005 to 0.0030%, and the balance: Fe and unavoidable impurities. In a surface outermost layer of the trivalent chromate covering layer or the chromate-free covering layer, concavities, of which a depth from an arithmetic average height of a cross-sectional curve of the surface outermost layer is more than or equal to 0.1 ?m, exist in a proportion of 50 to 1000 concavities/mm2 and at an area ratio of 20 to 80% to a surface area of the steel sheet.
    Type: Application
    Filed: August 29, 2016
    Publication date: July 5, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hiromasa SHOJI, Taihei KANETO, Masahiro FUDA, Hironori SATO, Natsuko SUGIURA, Yuji YAMAGUCHI