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).

  • 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
  • Patent number: 9988700
    Abstract: The present invention provides a high-strength steel sheet excellent in shape fixability. The high-strength steel sheet contains C, Si, Mn, P, S, Al, N, and O with predetermined contents, in which a retained austenite phase of 5 to 20% in volume fraction is contained, an amount of solid-solution C contained in the retained austenite phase is 0.80 to 1.00% in mass %, WSi? is 1.10 times or more WSi*, WMn? is 1.10 times or more WMn*, and when a frequency distribution is measured with respect to a sum of a ratio between WSi and WSi* and a ratio between WAl and WAl*, a mode value of the frequency distribution is 1.95 to 2.05, and a kurtosis is 2.00 or more.
    Type: Grant
    Filed: July 27, 2012
    Date of Patent: June 5, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Akinobu Minami, Hiroyuki Kawata, Akinobu Murasato, Yuji Yamaguchi, Natsuko Sugiura, Takuya Kuwayama, Naoki Maruyama, Takamasa Suzuki
  • Publication number: 20180100213
    Abstract: A hot-rolled steel sheet according to the present embodiment has a chemical composition containing, in mass %: C: 0.07 to 0.30%, Si: more than 1.0 to 2.8%, Mn: 2.0 to 3.5%, P: 0.030% or less, S: 0.010% or less, Al: 0.01 to less than 1.0%, N: 0.01% or less, O: 0.01% or less, and one or more types selected from the group consisting of Sb, Sn and Te in a total amount of 0.03 to 0.30%, with a balance being Fe and impurities, and satisfying Formula (1). The micro-structure of the hot-rolled steel sheet includes ferrite and pearlite in a total amount of 50 area % or more. The tensile strength of the hot-rolled steel sheet is 900 MPa or less. Si+Mn?3.20??(1) Where, a content (mass %) of a corresponding element is substituted for each symbol of an element in Formula (1).
    Type: Application
    Filed: April 14, 2016
    Publication date: April 12, 2018
    Inventors: Yasuaki TANAKA, Mutsumi SAKAKIBARA, Takafumi YOKOYAMA, Hiroyuki KAWATA, Natsuko SUGIURA, Yasumitsu KONDO
  • Patent number: 9896751
    Abstract: High strength steel sheet and high strength galvanized steel sheet which are excellent in shapeability which secure a tensile maximum strength 900 MPa or more high strength while obtaining excellent ductility and stretch flangeability, which sheets have predetermined compositions of ingredients, have steel sheet structures which contain volume fraction 1 to 20% of residual austenite phases, and which have martensite transformation points of the residual austenite phases of ?60° C. or less.
    Type: Grant
    Filed: July 27, 2012
    Date of Patent: February 20, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hiroyuki Kawata, Naoki Maruyama, Akinobu Murasato, Akinobu Minami, Takeshi Yasui, Yuji Yamaguchi, Natsuko Sugiura
  • Publication number: 20180044749
    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: Application
    Filed: February 22, 2016
    Publication date: February 15, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hiroshi SHUTO, Natsuko SUGIURA, Mitsuru YOSHIDA, Tatsuo YOKOI, Masayuki WAKITA
  • Publication number: 20180037980
    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: Application
    Filed: February 25, 2015
    Publication date: February 8, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masayuki WAKITA, Mitsuru YOSHIDA, Natsuko SUGIURA, Hiroshi SHUTO, Tatsuo YOKOI
  • Publication number: 20180037967
    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: Application
    Filed: February 22, 2016
    Publication date: February 8, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Natsuko SUGIURA, Mitsuru YOSHIDA, Hiroshi SHUTO, Tatsuo YOKOI, Masayuki WAKITA
  • Patent number: 9879336
    Abstract: A cold-rolled steel sheet containing: in mass %, C: 0.0005 to 0.0045%; Mn: 0.80 to 2.50%; Ti: 0.002 to 0.150%; B: 0.0005 to 0.01%, in which (1) Expression is satisfied, and a balance being composed of iron and impurities, in which at the position of ¼ thickness of a sheet thickness, a random intensity ratio (A) of the {332}<110> orientation is 3 or less, a random intensity ratio (B) of the {557}<9 16 5> orientation and a random intensity ratio (C) of the {111}<112> orientation are both 7 or more, and {(B)/(A)?5} and {(B)>(C)} are satisfied.
    Type: Grant
    Filed: July 31, 2013
    Date of Patent: January 30, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Natsuko Sugiura, Shigeru Yonemura, Naoki Maruyama
  • Publication number: 20180023162
    Abstract: A hot-rolled steel sheet includes a predetermined chemical composition, and a structure which includes, by area ratio, ferrite and bainite in a range of 75% to 95% in total, and martensite in a range of 5% to 20%, in which in the structure, in a case where a boundary having an orientation difference of equal to or greater than 15° is set 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: Application
    Filed: February 20, 2015
    Publication date: January 25, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Natsuko SUGIURA, Mitsuru YOSHIDA, Hiroshi SHUTO, Tatsuo YOKOI, Masayuki WAKITA
  • Publication number: 20170349967
    Abstract: A hot-rolled steel sheet includes a specific chemical composition, and includes a microstructure represented by, in vol %: retained austenite: 2% to 30%; ferrite: 20% to 85%; bainite: 10% to 60%; pearlite: 5% or less; and martensite: 10% or less. A proportion of grains having an intragranular misorientation of 5° to 14° in all grains is 5% to 50% 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: Application
    Filed: February 20, 2015
    Publication date: December 7, 2017
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Tatsuo YOKOI, Mitsuru YOSHIDA, Natsuko SUGIURA, Hiroshi SHUTO, Masayuki WAKITA
  • Patent number: 9758892
    Abstract: A steel sheet for electroplating includes, by mass %, C: 0.0005% to 0.0050%, Si: 0.20% to 1.0%, Mn: 0.40% to 2.5%, P: 0.05% or less, Ti: 0.010% to 0.050%, Nb: 0.010% to 0.040%, B: 0.0005% to 0.0030%, S: 0.02% or less, Al: 0.01% to 0.30%, N: 0.0010% to 0.01%, and the balance including Fe and impurities, in which when Si content is represented by [Si] and Mn content is represented by [Mn], “[Mn]+5[Si]” is 2.0 to 7.0, and the steel sheet has surface property in which an average of displacements of a measurement point obtained based on a moving average of continuous 31 points in total including 15 front points and 15 back points in a cross-sectional profile of a surface obtained by measuring the average of displacements in an evaluation length of 10 ?m or more at an interval of 0.07 ?m, is 0.005 ?m to 0.10 ?m.
    Type: Grant
    Filed: April 12, 2013
    Date of Patent: September 12, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hironori Sato, Masao Kurosaki, Masahiro Fuda, Natsuko Sugiura, Yuji Yamaguchi