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).
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Patent number: 11649531Abstract: 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: GrantFiled: August 4, 2017Date of Patent: May 16, 2023Assignee: NIPPON STEEL CORPORATIONInventors: Kohichi Sano, Makoto Uno, Ryoichi Nishiyama, Yuji Yamaguchi, Natsuko Sugiura, Masahiro Nakata
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Publication number: 20230141963Abstract: There is provided a steel sheet including a chemical composition consisting of, in mass %: C: 0.03 to 0.25%, Si: 0.1 to 2.0%, Mn: 1.0 to 3.0%, P: 0.200% or less, S: 0.0500% or less, Al: 0.01 to 1.00%, N: 0.0100% or less, and Ti: 0.01 to 0.25%, with the balance: Fe and impurities, and a steel micro-structure containing, in area %: ferrite: 50 to 85%, the balance being one or more kinds selected from martensite, bainite, and retained austenite, and an intensity of ?-fiber is more than 4.0 times in terms of random intensity ratio, and an average KAM value of grains having crystal orientations that form angles within 10° from ?-fiber is 1.30° or less.Type: ApplicationFiled: March 30, 2021Publication date: May 11, 2023Applicant: NIPPON STEEL CORPORATIONInventors: Yasuaki TANAKA, Hitoshi NIKAIDO, Hiroyuki KAWATA, Natsuko SUGIURA
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Patent number: 11401571Abstract: 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: GrantFiled: February 20, 2015Date of Patent: August 2, 2022Assignee: NIPPON STEEL CORPORATIONInventors: Tatsuo Yokoi, Mitsuru Yoshida, Natsuko Sugiura, Hiroshi Shuto, Masayuki Wakita
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Patent number: 11274355Abstract: 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: GrantFiled: February 16, 2018Date of Patent: March 15, 2022Assignee: NIPPON STEEL CORPORATIONInventors: Takeshi Toyoda, Riki Okamoto, Natsuko Sugiura, Tetsuya Hirashima
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Patent number: 11236412Abstract: 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: GrantFiled: August 4, 2017Date of Patent: February 1, 2022Assignee: NIPPON STEEL CORPORATIONInventors: Kohichi Sano, Makoto Uno, Ryoichi Nishiyama, Yuji Yamaguchi, Natsuko Sugiura, Masahiro Nakata
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Patent number: 11230755Abstract: 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: GrantFiled: August 4, 2017Date of Patent: January 25, 2022Assignee: NIPPON STEEL CORPORATIONInventors: Kohichi Sano, Makoto Uno, Ryoichi Nishiyama, Yuji Yamaguchi, Natsuko Sugiura, Masahiro Nakata
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Patent number: 11028469Abstract: 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: GrantFiled: August 16, 2016Date of Patent: June 8, 2021Assignee: NIPPON STEEL CORPORATIONInventors: Mutsumi Sakakibara, Natsuko Sugiura, Kunio Hayashi, Kaoru Kawasaki
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Patent number: 10913988Abstract: 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: GrantFiled: February 22, 2016Date of Patent: February 9, 2021Assignee: NIPPON STEEL CORPORATIONInventors: Hiroshi Shuto, Natsuko Sugiura, Mitsuru Yoshida, Tatsuo Yokoi, Masayuki Wakita
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Patent number: 10889879Abstract: 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: GrantFiled: August 4, 2017Date of Patent: January 12, 2021Assignee: NIPPON STEEL CORPORATIONInventors: Kohichi Sano, Makoto Uno, Ryoichi Nishiyama, Yuji Yamaguchi, Natsuko Sugiura, Masahiro Nakata
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Patent number: 10752972Abstract: 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: GrantFiled: February 22, 2016Date of Patent: August 25, 2020Assignee: NIPPON STEEL CORPORATIONInventors: Natsuko Sugiura, Mitsuru Yoshida, Hiroshi Shuto, Tatsuo Yokoi, Masayuki Wakita
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Patent number: 10738384Abstract: 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: GrantFiled: August 29, 2016Date of Patent: August 11, 2020Assignee: NIPPON STEEL CORPORATIONInventors: Hiromasa Shoji, Taihei Kaneto, Masahiro Fuda, Hironori Sato, Natsuko Sugiura, Yuji Yamaguchi
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Patent number: 10689724Abstract: 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: GrantFiled: July 31, 2015Date of Patent: June 23, 2020Assignee: NIPPON STEEL CORPORATIONInventors: Tatsuo Yokoi, Hiroshi Shuto, Yuuki Kanzawa, Natsuko Sugiura
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Patent number: 10689737Abstract: 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: GrantFiled: February 25, 2015Date of Patent: June 23, 2020Assignee: NIPPON STEEL CORPORATIONInventors: Masayuki Wakita, Mitsuru Yoshida, Natsuko Sugiura, Hiroshi Shuto, Tatsuo Yokoi
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Publication number: 20200157666Abstract: 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: ApplicationFiled: August 16, 2016Publication date: May 21, 2020Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Mutsumi SAKAKIBARA, Natsuko SUGIURA, Kunio HAYASHI, Kaoru KAWASAKI
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Publication number: 20200157650Abstract: 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: ApplicationFiled: January 28, 2020Publication date: May 21, 2020Inventors: Tatsuo Yokoi, Eisaku Sakurada, Natsuko Sugiura, Kiyoyuki Fukui
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Patent number: 10590506Abstract: 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: GrantFiled: April 30, 2019Date of Patent: March 17, 2020Assignee: NIPPON STEEL CORPORATIONInventors: Tatsuo Yokoi, Eisaku Sakurada, Natsuko Sugiura, Kiyoyuki Fukui
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Publication number: 20190390294Abstract: 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: ApplicationFiled: February 16, 2018Publication date: December 26, 2019Applicant: NIPPON STEEL CORPORATIONInventors: Takeshi TOYODA, Riki OKAMOTO, Natsuko SUGIURA, Tetsuya HIRASHIMA
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Publication number: 20190309398Abstract: 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: ApplicationFiled: August 4, 2017Publication date: October 10, 2019Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kohichi SANO, Makoto UNO, Ryoichi NISHIYAMA, Yuji YAMAGUCHI, Natsuko SUGIURA, Masahiro NAKATA
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Publication number: 20190256941Abstract: 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: ApplicationFiled: April 30, 2019Publication date: August 22, 2019Inventors: Tatsuo YOKOI, Eisaku SAKURADA, Natsuko SUGIURA, Kiyoyuki FUKUI
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Publication number: 20190241996Abstract: 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: ApplicationFiled: August 4, 2017Publication date: August 8, 2019Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kohichi SANO, Makoto UNO, Ryoichi NISHIYAMA, Yuji YAMAGUCHI, Natsuko SUGIURA, Masahiro NAKATA