Patents by Inventor Kohichi Sano

Kohichi Sano 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: 10501832
    Abstract: A base material (13) included in a plated steel sheet (1) includes a structure, at a ¼ sheet thickness position, represented by, in volume fraction: tempered martensite: 3.0% or more; ferrite: 4.0% or more; and retained austenite: 5.0% or more. An average hardness of the tempered martensite in the base material (13) is 5 GPa to 10 GPa, and a part or all of the tempered martensite and the retained austenite in the base material form an M-A. A volume fraction of ferrite in a decarburized ferrite layer (12) included in the plated steel sheet (1) is 120% or more of the volume fraction of the ferrite in the base material (13) at the ¼ sheet thickness position, an average grain diameter of the ferrite in the decarburized ferrite layer (12) is 20 ?m or less, a thickness of the decarburized ferrite layer (12) is 5 ?m to 200 ?m, a volume fraction of tempered martensite in the decarburized ferrite layer (12) is 1.0 volume% or more, a number density of the tempered martensite in the decarburized ferrite layer (12) is 0.
    Type: Grant
    Filed: April 22, 2016
    Date of Patent: December 10, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Koutarou Hayashi, Akihiro Uenishi, Masaharu Kameda, Jun Haga, Kunio Hayashi, Kohichi Sano, Hiroyuki Kawata
  • 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
  • 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: 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
  • Publication number: 20190218652
    Abstract: In a metal coated steel sheet, a chemical composition contains, in mass %, at least C: 0.03% to 0.70%, Si: 0.25% to 2.50%, Mn: 1.00% to 5.00%, P: 0.100% or less, S: 0.010% or less, sol. Al: 0.001% to 2.500, N: 0.020% or less, and a balance composed of iron and impurities, a metal structure contains greater than 5.0 vol % of retained austenite and greater than 5.0 vol % of tempered martensite, and satisfies a C content in the retained austenite being 0.85 mass % or more.
    Type: Application
    Filed: October 19, 2016
    Publication date: July 18, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Jun HAGA, Kohichi SANO, Koutarou HAYASHI, Kunio HAYASHI, Masaharu KAMEDA, Akihiro UENISHI, Hiroyuki KAWATA
  • Publication number: 20190211427
    Abstract: A steel sheet according to an aspect of the present invention includes a predetermined chemical composition; in which a metallographic structure in a ¼ t portion contains residual austenite of 4 volume % to 70 volume %; [Mn]?/[Mn]ave>1.5 is satisfied in the ¼ t portion; f?s/f??0.30 and [C]×[Mn]?0.15 are satisfied in the ¼ t portion.
    Type: Application
    Filed: September 21, 2016
    Publication date: July 11, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kohichi SANO, Masafumi AZUMA, Mutsumi SAKAKIBARA, Akihiro UENISHI, Koutarou HAYASHI
  • 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
  • Publication number: 20180298462
    Abstract: A steel sheet for galvannealed steel contains, by mass %, C: 0.25 to 0.70%, Si: 0.25 to 2.50%, Mn: 1.00 to 5.00%, Al: 0.005 to 3.50%, P: 0.15% or less, S: 0.03% or less, N £ 0.02%, O £ 0.01%, and optionally one or more selected from Ti, Nb, V, Cr, Mo, Cu, Ni, B, Ca, REM, Mg, W, Zr, Sb, Sn, As, Te, Y, Hf and Co, a balance being Fe and impurities. The microstructure consists of, by vol. %, retained g: 10.0 to 60.0%, high-temperature tempered martensite3 5.0%, low-temperature tempered martensite3 5.0%, fresh martensite £ 10.0%, a: 0 to 15.0%, P: 0 to 10.0%, a balance being bainite. Total volume ratio of tempered martensite and bainite is 30.0% or more, tensile strength is 1470 MPa or more, tensile strength×uniform elongation is 13000 MPa % or more, and tensile strength×local elongation is 5000 MPa % or more.
    Type: Application
    Filed: June 10, 2016
    Publication date: October 18, 2018
    Inventors: Kohichi SANO, Jun HAGA, Koutarou HAYASHI, Hiroyuki KAWATA, Riki OKAMOTO, Akihiro UENISHI
  • 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: 9970074
    Abstract: A cold-rolled steel sheet includes a predetermined chemical composition, and includes a structure expressed by: an area fraction of ferrite: 95% or more; an area fraction of retained austenite and an area fraction of martensite: 1% to 3% in total; a product of the area fraction of retained austenite and a carbon concentration in retained austenite: 1 or more; a value of I(111)/{I(100)+I(110)} at a region where a depth from a surface is ¼ of a thickness of the cold-rolled steel sheet when intensity of a (hkl) plane is expressed by I(hkl): 2 or less.
    Type: Grant
    Filed: July 1, 2014
    Date of Patent: May 15, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kaoru Kawasaki, Masaharu Kameda, Kohichi Sano, Riki Okamoto
  • Publication number: 20180105908
    Abstract: A base material (13) included in a plated steel sheet (1) includes a structure, at a ¼ sheet thickness position, represented by, in volume fraction: tempered martensite: 3.0% or more; ferrite: 4.0% or more; and retained austenite: 5.0% or more. An average hardness of the tempered martensite in the base material (13) is 5 GPa to 10 GPa, and a part or all of the tempered martensite and the retained austenite in the base material form an M-A. A volume fraction of ferrite in a decarburized ferrite layer (12) included in the plated steel sheet (1) is 120% or more of the volume fraction of the ferrite in the base material (13) at the ¼ sheet thickness position, an average grain diameter of the ferrite in the decarburized ferrite layer (12) is 20 ?m or less, a thickness of the decarburized ferrite layer (12) is 5 ?m to 200 ?m, a volume fraction of tempered martensite in the decarburized ferrite layer (12) is 1.
    Type: Application
    Filed: April 22, 2016
    Publication date: April 19, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Koutarou HAYASHI, Akihiro UENISHI, Masaharu KAMEDA, Jun HAGA, Kunio HAYASHI, Kohichi SANO, Hiroyuki KAWATA
  • 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: 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
  • Publication number: 20170191140
    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: Application
    Filed: March 15, 2017
    Publication date: July 6, 2017
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kohichi SANO, Kunio HAYASHI, Kazuaki NAKANO, Riki OKAMOTO, Nobuhiro FUJITA
  • Publication number: 20170183756
    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: Application
    Filed: January 4, 2017
    Publication date: June 29, 2017
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yuri TODA, Riki OKAMOTO, Nobuhiro FUJITA, Kohichi SANO, Hiroshi YOSHIDA, Toshio OGAWA, Kunio HAYASHI, Kazuaki NAKANO