Patents by Inventor Chisato Wakabayashi

Chisato Wakabayashi 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: 10544474
    Abstract: A high-strength cold-rolled steel sheet includes, as a component composition, by mass %: C: 0.075% to 0.300%; Si: 0.30% to 2.50%; Mn: 1.30% to 3.50%; P: 0.001% to 0.050%; S: 0.0001% to 0.0100%; Al: 0.001% to 1.500%; and N: 0.0001% to 0.0100%, in which a surface microstructure contains residual austenite of 3% to 10% and ferrite of 90% or less by volume fraction, an inner microstructure at a depth of t/4 from the surface assuming that a sheet thickness is t contains residual austenite of 3% to 20% by volume fraction, a ratio Hvs/Hvb between a surface hardness Hvs of the steel sheet surface and a hardness Hvb at a depth of ¼ of the thickness is more than 0.75 to 0.90, and a maximum tensile strength is 700 MPa or more.
    Type: Grant
    Filed: February 4, 2013
    Date of Patent: January 28, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Masafumi Azuma, Takayuki Nozaki, Chisato Wakabayashi, Koichi Sato, Hiroyuki Kawata, Nobuhiro Fujita
  • 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
  • Patent number: 10407760
    Abstract: A hot-dip galvanized steel sheet includes: a steel sheet; and a plated layer on a surface of the steel sheet, a microstructure contains, by volume fraction, equal to or more than 20% and equal to or less than 99% in total of one or two of martensite and bainite, a residual structure contains one or two of ferrite, residual austenite of less than 8% by volume fraction, and pearlite of equal to or less than 10% by volume fraction, tensile strength is equal to or greater than 980 MPa, the plated layer is a hot-dip galvanized layer which contains oxides including one or two or more of Si, Mn, and Al, contains equal to or less than 15 mass % of Fe, and a remainder including Zn, Al, and unavoidable impurities, and when a cross section including the steel sheet and the hot-dip galvanized layer is seen in a sheet thickness direction, a projected area ratio is equal to or more than 10% and equal to or less than 90%.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: September 10, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Masafumi Azuma, Chisato Wakabayashi, Takayuki Nozaki, Manabu Takahashi, Nobuhiro Fujita
  • Patent number: 10350701
    Abstract: A spot welding method able to simply prevent liquid metal embrittlement cracks in spot welding of plated steel sheets, comprising, before spot welding, removing the plating at least in a zone including the inside of a circle centered at a scheduled location where the center of the nugget is formed and having an outer circumference of the inside of the outer edge of a weld affected zone or a zone at the mated surfaces of the steel sheets to be welded at the inside of a circle sharing a center of a scheduled location becoming the center of the nugget formed at the mated surfaces of the steel sheets and having an outer circumference of the inside of the outer edge of a weld affected zone.
    Type: Grant
    Filed: March 30, 2016
    Date of Patent: July 16, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Yasunobu Miyazaki, Fuminori Watanabe, Chisato Wakabayashi, Kunio Hayashi, Hiroyuki Kawata, Seiji Furusako, Sho Matsui
  • Patent number: 10351937
    Abstract: The present invention provides a high-strength steel sheet excellent in impact resistance. The high-strength steel sheet contains predetermined contents of C, Si, Mn, P, S, Al, Ti, N, and O, with the balance being iron and inevitable impurities, and has a steel sheet structure in which, in a ? thickness to ? thickness region across ¼ of a sheet thickness, 1 to 8% retained austenite is contained in volume fraction, an average aspect ratio of the retained austenite is 2.0 or less, an amount of solid-solution Mn in the retained austenite is 1.1 times an average amount of Mn or more, and TiN grains having a 0.5 ?m average grain diameter or less are contained, and a density of AlN grains with a 1 ?m grain diameter or more is 1.0 pieces/mm2 or less, wherein a maximum tensile strength is 900 MPa or more.
    Type: Grant
    Filed: July 27, 2012
    Date of Patent: July 16, 2019
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Hiroyuki Kawata, Naoki Maruyama, Akinobu Murasato, Akinobu Minami, Hajime Hasegawa, Chisato Wakabayashi, Tsuyoshi Oki
  • Patent number: 10294551
    Abstract: A steel sheet including, by mass %, C: more than 0.100% and 0.500% or less, Si: 0.0001% or more and less than 0.20%, Mn: more than 0.20% and 0.50% or less, Al: 3.0% or more and 10.0% or less, N: 0.0030% or more and 0.0100% or less, Ti: more than 0.100% and 1.000% or less, P: 0.00001% or more and 0.0200% or less, S: 0.00001% or more and 0.0100% or less, and a remainder including Fe and impurities, in which a sum of a C content and a Ti content satisfies 0.200<C+Ti?1.500 by mass %, a product of an Al content and an Si content satisfies Al×Si?0.8 by mass %, and a specific gravity is 5.5 to less than 7.5.
    Type: Grant
    Filed: April 28, 2014
    Date of Patent: May 21, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masaharu Oka, Nobuhiro Fujita, Manabu Takahashi, Riki Okamoto, Chisato Wakabayashi
  • Publication number: 20190030637
    Abstract: By obtaining a spot-welded joint being a spot-welded joint formed by overlapping a plurality of pieces of steel plates (1A, 1B) and performing spot welding on the steel plates, including a high-strength steel plate whose tensile strength is 750 (MPa) to 2500 (MPa), being at least one piece of steel plate out of the plurality of pieces of steel plates, in which a carbon equivalent Ceq of the high-strength steel plate is 0.20 mass % to 0.55 mass %, and ten or more of iron-based carbides in each of which a length of a longest portion is 0.1 (?m) or more exist in a square region 103 within a heat-affected zone 4 of a cross section that passes through a center of a welding mark, and is cut along a plate thickness direction of the steel plates (1A, 1B), a cross tensile strength of the spot-welded joint to be formed is improved.
    Type: Application
    Filed: September 28, 2018
    Publication date: January 31, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Chisato WAKABAYASHI, Fuminori WATANABE, Seiji FURUSAKO, Yasunobu MIYAZAKI, Hiroyuki KAWATA, Tohru OKADA, Hideki HAMATANI
  • Patent number: 10023947
    Abstract: High strength steel plate with an ultimate tensile strength of 900 MPa or more which is excellent in hydrogen embrittlement resistance characterized in that, in the structure of the steel plate, (a) by volume fraction, ferrite is present in 10 to 50%, bainitic ferrite and/or bainite in 10 to 60%, and tempered martensite in 10 to 50%, and (b) iron-based carbides which contain Si or Si and Al in 0.1% or more are present in 4×108 (particles/mm3) or more.
    Type: Grant
    Filed: November 30, 2010
    Date of Patent: July 17, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masafumi Azuma, Noriyuki Suzuki, Naoki Maruyama, Akinobu Murasato, Yasuharu Sakuma, Hiroyuki Kawata, Chisato Wakabayashi
  • Publication number: 20180186887
    Abstract: The present invention provides a novel therapeutic agent for mental illness. The therapeutic agent for mental illness comprises an IL-6 inhibitor as an active ingredient.
    Type: Application
    Filed: June 3, 2016
    Publication date: July 5, 2018
    Applicants: NATIONAL CENTER OF NEUROLOGY AND PSYCHIATRY, CHUGAI SEIYAKU KABUSHIKI KAISHA
    Inventors: Hiroshi KUNUGI, Chisato WAKABAYASHI
  • Patent number: 9970092
    Abstract: A galvanized steel sheet includes a steel sheet and a plating layer on the surface of the steel sheet, in which the steel sheet includes, as a steel chemical composition, by mass %, C: 0.05 to 0.40%, Si: 0.5 to 3.0% and Mn: 1.5 to 3.0%, a microstructure of the steel sheet includes ferrite, bainite, by volume fraction, 30% or more of a tempered martensite, and 8% or more of an austenite, and tensile strength of the steel sheet is 980 MPa or more, and the plating layer includes an oxide including at least one chemical element selected from Si, Mn and Al, and when seen at a cross section including the steel sheet and the plating layer in a plate thickness direction, a projection area fraction of the oxide is 10% or more.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: May 15, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takayuki Nozaki, Manabu Takahashi, Nobuhiro Fujita, Masafumi Azuma, Chisato Wakabayashi
  • Publication number: 20180079026
    Abstract: A spot welding method able to simply prevent liquid metal embrittlement cracks in spot welding of plated steel sheets, comprising, before spot welding, removing the plating at least in a zone including the inside of a circle centered at a scheduled location where the center of the nugget is formed and having an outer circumference of the inside of the outer edge of a weld affected zone or a zone at the mated surfaces of the steel sheets to be welded at the inside of a circle sharing a center of a scheduled location becoming the center of the nugget formed at the mated surfaces of the steel sheets and having an outer circumference of the inside of the outer edge of a weld affected zone
    Type: Application
    Filed: March 30, 2016
    Publication date: March 22, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yasunobu MIYAZAKI, Fuminori WATANABE, Chisato WAKABAYASHI, Kunio HAYASHI, Hiroyuki KAWATA, Seiji FURUSAKO, Sho MATSUI
  • 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
  • Publication number: 20170348798
    Abstract: There is provided a power supply device that supplies an output current to an electric processing device which performs electric processing on workpieces. The device includes: a first power supply; a magnetic energy recovery switch that receives a current supplied from the first power supply, and converts the received current into the output current; and a control unit that controls the magnetic energy recovery switch such that an electric current frequency of the output current includes a first electric current frequency and a second electric current frequency which are different from each other within a one-time electric processing time using the electric processing device.
    Type: Application
    Filed: December 11, 2015
    Publication date: December 7, 2017
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Fuminori WATANABE, Kazuhiko FUKUTANI, Seiji FURUSAKO, Chisato WAKABAYASHI, Tohru OKADA
  • 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
  • Patent number: 9546413
    Abstract: Disclosed is a hot-rolled steel sheet including, by mass %, C:0.02% to 0.5% of C, and the sum of the content of Si and the content of Al is 1.0% to 4.0%. An average pole density of an orientation group from {100}<011> to {223}<110> is 1.0 to 6.5, and a pole density of a crystal orientation {332}<113> is 1.0 to 5.0. A microstructure includes, by of an area ratio, 2% to 30% of retained austenite, 20% to 50% of ferrite, and 10% to 60% of bainite. rC that is a Lankford value in a direction orthogonal to a rolling direction is 0.70 to 1.10, and r30 that is a Lankford value in a direction forming an angle of 30° with the rolling direction is 0.70 to 1.10.
    Type: Grant
    Filed: March 28, 2012
    Date of Patent: January 17, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takayuki Nozaki, Manabu Takahashi, Nobuhiro Fujita, Hiroshi Yoshida, Shinichiro Watanabe, Takeshi Yamamoto, Chisato Wakabayashi, Riki Okamoto, Kohichi Sano
  • Patent number: 9540720
    Abstract: Disclosed is a high-strength hot-dip galvanized steel sheet having small material anisotropy and excellent formability with an ultimate tensile strength of 980 MPa or more. The hot-dip galvanized steel sheet includes a hot-dip galvanized layer formed on a surface of a base steel plate. The base steel plate contains C, Si, Mn, O, P, S, Al and N within predetermined ranges and a balance including Fe and inevitable impurities. The hot-dip galvanized layer contains Fe at less than 7 mass % or 7 to 15 mass % and a balance including Zn, Al, and inevitable impurities.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: January 10, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masafumi Azuma, Chisato Wakabayashi, Takayuki Nozaki, Nobuhiro Fujita, Manabu Takahashi
  • Patent number: 9410231
    Abstract: A steel sheet, including: as chemical components, by mass %, 0.05% to 0.35% of C; 0.05% to 2.0% of Si; 0.8% to 3.0% of Mn; 0.01% to 2.0% of Al; equal to or less than 0.1% of P; equal to or less than 0.05% of S; equal to or less than 0.01% of N; and the balance including iron and inevitable impurities, wherein the steel sheet comprises 50% or more of a ferrite phase, a bainite phase, and a tempered martensite phase, 3% or more of a retained austenite phase, and 50% or more of the crystal grains of the retained austenite phase satisfy Expression 1, wherein a carbon concentration at a position of center of gravity is Cgc and a carbon concentration at a grain boundary is Cgb.
    Type: Grant
    Filed: January 31, 2011
    Date of Patent: August 9, 2016
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Riki Okamoto, Natsuko Sugiura, Kohichi Sano, Chisato Wakabayashi, Naoki Yoshinaga, Kaoru Kawasaki
  • Publication number: 20160082543
    Abstract: By obtaining a spot-welded joint being a spot-welded joint formed by overlapping a plurality of pieces of steel plates (1A, 1B) and performing spot welding on the steel plates, including a high-strength steel plate whose tensile strength is 750 (MPa) to 2500 (MPa), being at least one piece of steel plate out of the plurality of pieces of steel plates, in which a carbon equivalent Ceq of the high-strength steel plate is 0.20 mass % to 0.55 mass %, and ten or more of iron-based carbides in each of which a length of a longest portion is 0.1 (?m) or more exist in a square region 103 within a heat-affected zone 4 of a cross section that passes through a center of a welding mark, and is cut along a plate thickness direction of the steel plates (1A, 1B), a cross tensile strength of the spot-welded joint to be formed is improved.
    Type: Application
    Filed: June 2, 2014
    Publication date: March 24, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Chisato WAKABAYASHI, Fuminori WATANABE, Seiji FURUSAKO, Yasunobu MIYAZAKI, Hiroyuki KAWATA, Tohru OKADA, Hideki HAMATANI
  • Publication number: 20160040273
    Abstract: A steel sheet including, by mass %, C: more than 0.100% and 0.500% or less, Si: 0.0001% or more and less than 0.20%, Mn: more than 0.20% and 0.50% or less, Al: 3.0% or more and 10.0% or less, N: 0.0030% or more and 0.0100% or less, Ti: more than 0.100% and 1.000% or less, P: 0.00001% or more and 0.0200% or less, S: 0.00001% or more and 0.0100% or less, and a remainder including Fe and impurities, in which a sum of a C content and a Ti content satisfies 0.200<C+Ti?1.500 by mass %, a product of an Al content and an Si content satisfies Al×Si?0.8 by mass %, and a specific gravity is 5.5 to less than 7.5.
    Type: Application
    Filed: April 28, 2014
    Publication date: February 11, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Masaharu OKA, Nobuhiro FUJITA, Manabu TAKAHASHI, Riki OKAMOTO, Chisato WAKABAYASHI
  • Patent number: 9139885
    Abstract: This high-strength steel sheet includes by mass percentage: 0.05 to 0.4% of C; 0.1 to 2.5% of Si; 1.0 to 3.5% of Mn; 0.001 to 0.03% of P; 0.0001 to 0.01% of S; 0.001 to 2.5% of Al; 0.0001 to 0.01% of N; 0.0001 to 0.008% of O; and a remainder composed of iron and inevitable impurities, wherein a steel sheet structure contains by volume fraction 10 to 50% of a ferrite phase, 10 to 50% of a tempered martensite phase, and a remaining hard phase, wherein a 98% hardness is 1.5 or more times as high as a 2% hardness in a range from ? to ? of a thickness of the steel sheet, wherein a kurtosis K* of the hardness distribution between the 2% hardness and the 98% hardness is ?1.2 to ?0.4, and wherein an average crystal grain size in the steel sheet structure is 10 ?m or less.
    Type: Grant
    Filed: September 16, 2011
    Date of Patent: September 22, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hiroyuki Kawata, Naoki Maruyama, Akinobu Murasato, Naoki Yoshinaga, Chisato Wakabayashi, Noriyuki Suzuki