Patents by Inventor Takuya Kochi

Takuya Kochi 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: 10570478
    Abstract: Provided is a steel for a mechanical structure for cold working, which contains C, Si, Mn, P, S, Al and N and in which the metal structure includes pearlite and ferrite, the total areal proportion of pearlite and ferrite relative to the overall structure is 90% or higher, the average circle-equivalent diameter of bcc-Fe crystal grains surrounded by large angle grain boundaries is 5-15 ?m, the average aspect ratio of pro-eutectoid ferrite crystal grains is 3.0 or lower, and the average spacing at the narrowest pearlite lamellar spacing is 0.20 ?m or less.
    Type: Grant
    Filed: June 8, 2015
    Date of Patent: February 25, 2020
    Assignee: KOBE STEEL, LTD.
    Inventors: Yuki Sasaki, Takehiro Tsuchida, Takuya Kochi, Koji Yamashita, Masamichi Chiba, Kei Masumoto, Masayuki Sakata
  • Patent number: 10526675
    Abstract: A method for manufacturing steel, by quenching and tempering a seamless pipe for use as a material of a hollow spring, where the seamless pipe including predetermined components is subjected to a heat treatment which is performed to satisfy quenching conditions (1) and tempering conditions (2), (1) quenching conditions: 26,000?(T1+273)×(log(t1)+20)?29,000 900° C.?T1?1,050° C., 10 seconds?t1?1,800 seconds,??formula (1) where T1 is a quenching temperature (° C.), and t1 is a holding time (seconds) in a temperature range of 900° C. or higher, and (2) tempering conditions: 13,000?(T2+273)×(log(t2)+20)?15,500 T2?550° C., and t2?3,600 seconds,??formula (2) where T2 is a tempering temperature (° C.), and t2 is a total time (seconds) from start of heating to completion of cooling.
    Type: Grant
    Filed: October 26, 2015
    Date of Patent: January 7, 2020
    Assignees: Kobe Steel, Ltd., NHK SPRING CO., LTD.
    Inventors: Takuya Kochi, Hitoshi Hatano, Akira Tange, Kiyoshi Kurimoto, Yurika Goto
  • Publication number: 20180265952
    Abstract: Provided is a hollow seamless steel pipe for a spring, including by mass %, C: 0.2 to 0.7%; Si: 0.5 to 3%; Mn: 0.1 to 2%; Cr: more than 0% and 3% or less; Al: more than 0% and 0.1% or less; P: more than 0% and 0.02% or less; S: more than 0% and 0.02% or less; and N: more than 0% and 0.02%: or less, with the balance being iron and inevitable impurities, wherein, an uneven thickness ratio calculated by formula (1) below is 7.0% or less.
    Type: Application
    Filed: January 5, 2016
    Publication date: September 20, 2018
    Applicants: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.), Shinko Metal Products Co., Ltd.
    Inventors: Takuya KOCHI, Hitoshi HATANO, Kotaro TOYOTAKE
  • Publication number: 20180251876
    Abstract: Disclosed herein is a mechanical structure steel for cold-working that includes C, Si, Mn, P, S, Al, and N and has a metal microstructure including proeutectoid ferrite and pearlite, in which a total area ratio of the proeutectoid ferrite and the pearlite with respect to the entire microstructure is 90% or more, while an area ratio Af of the proeutectoid ferrite with respect to the entire microstructure satisfies a relationship of Af?A where an A value is represented by formula (1) below, an average circle equivalent diameter of a bcc-Fe crystal grain is in a range of 15 to 30 ?m, and a pearlite lamellar spacing is 0.20 ?m or less on average: A=(103?128×[C(%)])×0.80(%)??(1) where [C (%)] in the formula (1) indicates the C content in percent by mass.
    Type: Application
    Filed: August 12, 2016
    Publication date: September 6, 2018
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Yuki SASAKI, Takuya KOCHI, Masamichi CHIBA, Masayuki SAKATA, Shogo MURAKAMI
  • Patent number: 9956650
    Abstract: The present invention is a weld metal formed by gas shielded arc welding using a flux cored wire, the welded metal having a predetermined chemical composition, residual austenite particles being present in an amount of at least 2500 particles/mm2, and the volume fraction of residual austenite particles being at least 4.0%.
    Type: Grant
    Filed: February 25, 2013
    Date of Patent: May 1, 2018
    Assignee: Kobe Steel, Ltd.
    Inventors: Hidenori Nako, Takuya Kochi, Wataru Urushihara, Munenobu Sato, Yoshihiko Kitagawa
  • Publication number: 20180105894
    Abstract: An object of the present invention is to provide a steel wire for mechanical structural parts that is reduced in deformation resistance and improved in crack resistance during cold working, and thus exhibits excellent cold workability. The steel wire for mechanical structural parts of the present invention is a steel wire containing, in mass %, 0.3 to 0.6% of C, (105 to 0.5% of Si, 0.2 to 1.7% of Mn, more than 0% and 0.03% or less of P, 0.001 to 0.05% of S, 0.005 to 0.1% of Al, and 0 to 0.015% of N, the balance being iron and inevitable impurities, wherein steel of the steel wire has a metal structure formed of ferrite and cementite, and the number proportion of cementite particles present in ferrite grain boundaries is 40% or more based on the total number of cementite particles.
    Type: Application
    Filed: March 16, 2016
    Publication date: April 19, 2018
    Applicant: Kabushiki Kaisha Kobe Seiko Sho {Kobe Steel, Ltd.)
    Inventors: Yuki SASAKI, Takuya KOCHI, Masamichi CHIBA, Masayuki SAKATA
  • Publication number: 20170306432
    Abstract: A method for manufacturing steel, by quenching and tempering a seamless pipe for use as a material of a hollow spring, where the seamless pipe including predetermined components is subjected to a heat treatment which is performed to satisfy quenching conditions (1) and tempering conditions (2), (1) quenching conditions: 26,000?(T1+273)×(log(t1)+20)?29,000??formula (1) 900° C.?T1?1,050° C., 10 seconds?t1?1,800 seconds, where T1 is a quenching temperature (° C.), and t1 is a holding time (seconds) in a temperature range of 900° C. or higher, and (2) tempering conditions: 13,000?(T2+273)×(log(t2)+20)?15,500??formula (2) T2?550° C., and t2?3,600 seconds, where T2 is a tempering temperature (° C.), and t2 is a total time (seconds) from start of heating to completion of cooling.
    Type: Application
    Filed: October 26, 2015
    Publication date: October 26, 2017
    Applicants: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.), NHK SPRING CO., LTD.
    Inventors: Takuya KOCHI, Hitoshi HATANO, Akira TANGE, Kiyoshi KURIMOTO, Yurika GOTO
  • Publication number: 20170274482
    Abstract: A flux cored wire, which is obtained by filling the inside of a steel outer skin with a flux, is configured to have a composition that contains, in mass % relative to the total mass of the wire, 0.01-0.12% of C, 0.05% or more but less than 0.30% of Si, 1.0-3.5% of Mn, 0.1% or more but less than 1.0% of Ni, 0.10-0.30% of Mo, 0.1-0.9% of Cr, 4.5-8.5% of TiO2, 0.10-0.40% of SiO2, 0.03-0.23% of Al2O3 and 80% or more of Fe.
    Type: Application
    Filed: September 2, 2015
    Publication date: September 28, 2017
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Peng HAN, Hiroyuki KAWASAKI, Yoshihiko KITAGAWA, Hidenori NAKO, Takuya KOCHI, Wataru URUSHIHARA, Yoshitomi OKAZAKI
  • Patent number: 9718150
    Abstract: Disclosed is a weld metal which is formed by gas-shielded arc welding using a flux-cored wire, and which has a specific chemical composition, in which retained austenite particles are present in a number density of 2500 per square millimeter or more and in a total volume fraction of 4.0% or more based on the total volume of entire structures of the weld metal. The weld metal has excellent hydrogen embrittlement resistance and is resistant to cracking at low temperatures even when the weld metal has a high strength.
    Type: Grant
    Filed: February 1, 2012
    Date of Patent: August 1, 2017
    Assignee: Kobe Steel, Ltd.
    Inventors: Hidenori Nako, Takuya Kochi, Wataru Urushihara, Munenobu Sato, Yoshihiko Kitagawa
  • Patent number: 9650704
    Abstract: A seamless steel pipe for a hollow spring includes C: 0.2 to 0.7 mass %, Si: 0.5 to 3 mass %, Mn: 0.1 to 2 mass %, Cr: 3 mass % or less (excluding 0 mass %), Al: 0.1 mass % or less (excluding 0 mass %), P: 0.02 mass % or less (excluding 0 mass %), S: 0.02 mass % or less (excluding 0 mass %) and N: 0.02 mass % or less (excluding 0 mass %). A residual austenite content in an inner surface layer part of the steel pipe is 5 vol. % or less. An average grain size of a ferrite-pearlite structure in the inner surface layer part of the steel pipe is 18 ?m or less. A number density of a carbide having a circle equivalent diameter of 500 nm or more and being present in the inner surface layer part of the steel pipe is 1.8×10?2 particles/?m2 or less.
    Type: Grant
    Filed: June 11, 2013
    Date of Patent: May 16, 2017
    Assignees: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.), SHINKO METAL PRODUCTS CO., LTD.
    Inventors: Takuya Kochi, Hitoshi Hatano, Eiichi Tamura, Kotaro Toyotake
  • Publication number: 20170130295
    Abstract: Provided is a steel for a mechanical structure for cold working, which contains C, Si, Mn, P, S, Al and N and in which the metal structure includes pearlite and ferrite, the total areal proportion of pearlite and ferrite relative to the overall structure is 90% or higher, the average circle-equivalent diameter of bcc-Fe crystal grains surrounded by large angle grain boundaries is 5-15 ?m, the average aspect ratio of pro-eutectoid ferrite crystal grains is 3.0 or lower, and the average spacing at the narrowest pearlite lamellar spacing is 0.20 ?m or less.
    Type: Application
    Filed: June 8, 2015
    Publication date: May 11, 2017
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.)
    Inventors: Yuki SASAKI, Takehiro TSUCHIDA, Takuya KOCHI, Koji YAMASHITA, Masamichi CHIBA, Kei MASUMOTO, Masayuki SAKATA
  • Patent number: 9592575
    Abstract: The weld metal of the present invention is formed by gas shield arc welding using a flux-cored wire, has a predetermined chemical component composition, and contains 20% or more of Ti. The amount of Ti-containing oxide particles having a circle-equivalent diameter of 0.15-1.0 ?m is at least 5000 per square mm, the amount of V per total mass of weld metal present as a compound within the weld metal is 0.002% or more, and the average circle equivalent diameter of V-containing carbide present in the weld metal is 15 nm or less.
    Type: Grant
    Filed: April 6, 2012
    Date of Patent: March 14, 2017
    Assignee: Kobe Steel, Ltd.
    Inventors: Hidenori Nako, Takuya Kochi, Wataru Urushihara, Munenobu Sato, Yoshihiko Kitagawa
  • Patent number: 9429255
    Abstract: A hollow seamless pipe for a high-strength spring in the present invention includes a steel material in which chemical component compositions are properly adjusted, wherein a depth of a whole decarburized layer in an inner surface layer part is 100 ?m or less, a depth of a flaw which is present in an inner surface is 40 ?m or less, a width of the flaw is 60 ?m or less, and a number density of a carbide which has a circle equivalent diameter of 500 nm or more and is present in the inner surface layer part is 1.8×10?2 particles/?m2 or less.
    Type: Grant
    Filed: April 2, 2013
    Date of Patent: August 30, 2016
    Assignees: KOBE STEEL, LTD., SHINKO METAL PRODUCTS CO., LTD., NHK SPRING CO., LTD.
    Inventors: Takuya Kochi, Hitoshi Hatano, Eiichi Tamura, Kotaro Toyotake, Takashi Yajima, Akira Tange
  • Publication number: 20160201172
    Abstract: A hot-rolled steel sheet which has a thickness of 3-20 mm and contains specific amounts of C, Si, Mn, P, S, Al and N, with the balance made up of iron and unavoidable impurities. This hot-rolled steel sheet contains a specific amount of solid-solved N, and the contents of C and N satisfy the relation 10C+N?3.0. This hot-rolled steel sheet contains bainitic ferrite and pearlite, respectively in an area ratio of 5% or more and in an area ratio of less than 20% relative to the whole structure, with the balance made up of polygonal ferrite. The average crystal grain size of the bainitic ferrite is 3-50 ?m.
    Type: Application
    Filed: September 2, 2014
    Publication date: July 14, 2016
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.)
    Inventors: Katsura KAJIHARA, Takuya KOCHI
  • Patent number: 9267183
    Abstract: A hot-rolled wire rod excelling in wire drawability is provided, in which breakage can be suppressed even in heavy work from a large diameter. A hot-rolled wire rod contains C: 0.35 to 0.65% (percent by mass, hereinafter expressed as well), Si: 1.4 to 3.0%, Mn: 0.10 to 1.0%, Cr: 0.1 to 2.0%, P: 0.025% or less (exclusive of 0%), S: 0.025% or less (exclusive of 0%), N: 0.006% or less (exclusive of 0%), Al: 0.1% or less (exclusive of 0%), and O: 0.0030% or less (exclusive of 0%), with the remnant consisting of Fe and inevitable impurities; wherein the content of hydrogen in steel is 2.50 ppm (ppm by mass, hereinafter expressed as well) or less, and hardness (HV) is 460×C00.1 or less (C0 indicates the content of C (percent by mass) in a position of depth of D/4 (D: diameter of the wire rod)).
    Type: Grant
    Filed: November 7, 2006
    Date of Patent: February 23, 2016
    Assignee: Kobe Steel, Ltd.
    Inventors: Takuya Kochi, Shogo Murakami, Shoji Miyazaki, Ken Ishida, Masao Toyama, Fujio Koizumi
  • Publication number: 20160008931
    Abstract: This welded metal contains 0.02-0.10% of C, 0.10-0.60% of Si, 0.90-2.5% of Mn, 0.20-2.00% of Ni, 0.05-1.0% of Cr, 0.10-1.50% of Mo, 0.040-0.15% of Ti, 0.0010-0.0050% of B, 0.030-0.100% of O and 0.015% or less (excluding 0%) of N, with the balance made up of iron and unavoidable impurities. The average circle-equivalent diameter of carbides having a circle-equivalent diameter of 0.40 ?m or more among the carbides present in the grain boundary of this welded metal is 0.75 ?m or less. Consequently, the present invention provides: a welded metal which exhibits excellent low-temperature toughness at lower temperatures, while having high strength after SR annealing, even in cases where gas sealed arc welding using a flux cored wire and having excellent work efficiency is applied; and a welded structure which is provided with this welded metal.
    Type: Application
    Filed: February 24, 2014
    Publication date: January 14, 2016
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Hidenori NAKO, Takuya KOCHI, Wataru URUSHIHARA, Hiroyuki KAWASAKI, Peng HAN, Yoshihiko KITAGAWA, Yoshitomi OKAZAKI
  • Publication number: 20150314400
    Abstract: The weld metal of the present invention has a given chemical composition, contains retained austenite particles in an amount of 2,500 grains/mm2 or more, and has a volume fraction of the retained austenite particles of 4.3 vol % or more and a content ratio of Cr and Mn, [Cr]/[Mn], of 0.20 or more. The weld metal has excellent resistance to hydrogen embrittlement even when the weld metal has a high tensile strength of more than 780 MPa.
    Type: Application
    Filed: January 10, 2014
    Publication date: November 5, 2015
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD)
    Inventors: Hidenori NAKO, Takuya KOCHI, Wataru URUSHIHARA, Hiroyuki KAWASAKI, Peng HAN, Yoshihiko KITAGAWA
  • Publication number: 20150285410
    Abstract: A hollow seamless pipe for a high-strength spring in the present invention includes a steel material in which chemical component compositions are properly adjusted, wherein a depth of a whole decarburized layer in an inner surface layer part is 100 ?m or less, a depth of a flaw which is present in an inner surface is 40 ?m or less, a width of the flaw is 60 ?m or less, and a number density of a carbide which has a circle equivalent diameter of 500 nm or more and is present in the inner surface layer part is 1.8×10?2 particles/?m2 or less.
    Type: Application
    Filed: April 2, 2013
    Publication date: October 8, 2015
    Applicants: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD), SHINKO METAL PRODUCTS CO., LTD., NHK SPING CO., LTD.
    Inventors: Takuya Kochi, Hitoshi Hatano, Eiichi Tamura, Kotaro Toyotake, Takashi Yajima, Akira Tange
  • Publication number: 20150159245
    Abstract: A seamless steel pipe for a hollow spring includes C: 0.2 to 0.7 mass %, Si: 0.5 to 3 mass %, Mn: 0.1 to 2 mass %, Cr: 3 mass % or less (excluding 0 mass %), Al: 0.1 mass % or less (excluding 0 mass %), P: 0.02 mass % or less (excluding 0 mass %), S: 0.02 mass % or less (excluding 0 mass %) and N: 0.02 mass % or less (excluding 0 mass %). A residual austenite content in an inner surface layer part of the steel pipe is 5 vol. % or less. An average grain size of a ferrite-pearlite structure in the inner surface layer part of the steel pipe is 18 ?m or less. A number density of a carbide having a circle equivalent diameter of 500 nm or more and being present in the inner surface layer part of the steel pipe is 1.8×10?2 particles/?m2 or less.
    Type: Application
    Filed: June 11, 2013
    Publication date: June 11, 2015
    Applicants: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.), SHINKO METAL PRODUCTS CO., LTD.
    Inventors: Takuya Kochi, Hitoshi Hatano, Eiichi Tamura, Kotaro Toyotake
  • Patent number: 9023159
    Abstract: A steel for heat treatment, which exhibits high strength and high toughness even when the heat treatment (such as quenching and tempering) of the steel is conducted under conventional conditions in an after stage. The steel for heat treatment contains C: 0.10 to 0.70 mass %, Mn: 0.1 to 3.0 mass %, Al: 0.005 to 2.0 mass %, P: 0.050 mass % or less, S: 0.50 mass % or less, O: 0.0030 mass or less, N: 0.0200 mass % or less, and one or more selected from the group consisting of Ti: 0.30 mass % or less and Nb: 0.30 mass or less with the balance being Fe and unavoidable impurities, and has a TH value of 1.0 or above as calculated according to the formula: ({Ti}/48+{Nb}/93) 104 and grain diameters of 10 ?m or below. {Ti} and {Nb} refer respectively to the contents of Ti and Nb in precipitates of 5 to 100 nm in size as determined about their respective extraction residues.
    Type: Grant
    Filed: June 17, 2009
    Date of Patent: May 5, 2015
    Assignee: Kobe Steel, Ltd.
    Inventors: Hitoshi Hatano, Takuya Kochi