Patents by Inventor Shunsuke Toyoda

Shunsuke Toyoda 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: 20210129491
    Abstract: Provided is a high-strength hot-rolled coated steel sheet with excellent formability, A high-strength hot-rolled coated steel sheet has a constituent composition containing, in a mass percent, C: 0.03% to 0.15%, Si: 0.4% or less, Mn: 1.2% to 1.9%, Ti: 0.05% to 0.25%, B: 0.0005% to 0.0050%, P: 0.03% or less, S: 0.005% or less, Al: 0.005% to 0.4%, and N: 0.01% or less, the balance being Fe and incidental impurities. The total area fraction of one or more of ferrite and tempered bainite is 90% or more. The steel sheet has a structure in which the volume fraction of Ti carbides having particle sizes of 20 nm or less is 0.05 vol % or more.
    Type: Application
    Filed: February 26, 2018
    Publication date: May 6, 2021
    Applicant: JFE Steel Corporation
    Inventors: Sota Goto, Kazuhiko Yamazaki, Taro Kizu, Shunsuke Toyoda
  • Patent number: 10815547
    Abstract: A high strength steel sheet having high strength such as a tensile strength of 780 MPa or more and having excellent blanking workability and stretch flangeability and a manufacturing method therefor are provided. A high strength steel sheet comprises: a chemical composition containing, in mass %, C: 0.05% to 0.30%, Si: 0.6% to 2.0%, Mn: 1.3% to 3.0%, P: 0.10% or less, S: 0.030% or less, Al: 2.0% or less, N: 0.010% or less, and one or more of Ti, Nb, and V: 0.01% to 1.0% each, with a balance being Fe and incidental impurities; a ferrite microstructure of 50% or more in area ratio; an amount of precipitated Fe of 0.04 mass % or more; and a precipitate with a particle size of less than 20 nm, wherein C* and C*p satisfy specific conditions.
    Type: Grant
    Filed: March 1, 2016
    Date of Patent: October 27, 2020
    Assignee: JFE STEEL CORPORATION
    Inventors: Taro Kizu, Shunsuke Toyoda, Akimasa Kido, Tetsushi Tadani
  • Publication number: 20200232074
    Abstract: Provided are a high-carbon hot-rolled steel sheet with excellent formability and hardenability and a method for manufacturing the same. The high-carbon hot-rolled steel sheet has a composition containing, on a mass basis, C: 0.10% to 0.33%, Si: 0.15% to 0.35%, Mn: 0.5% to 0.9%, P: 0.03% or less, S: 0.010% or less, sol. Al: 0.10% or less, N: 0.0065% or less, and Cr: 0.90% to 1.5%, the remainder being Fe and inevitable impurities, has a microstructure containing ferrite and cementite, a cementite density being 0.25 grains/?m2 or less, and has a hardness of 110 HV to 160 HV and a total elongation of 40% or more.
    Type: Application
    Filed: February 13, 2018
    Publication date: July 23, 2020
    Applicant: JFE Steel Corporation
    Inventors: Yuka Miyamoto, Yasuhiro Sakurai, Takashi Kobayashi, Shunsuke Toyoda
  • Publication number: 20200190618
    Abstract: A steel member, a hot-rolled steel sheet to be used as a material thereof, and production methods therefor are provided. A steel member contains 0.031% to 0.200% Ti, in which 0.005% or more of Ti is precipitated as a precipitate having a particle size of 20 nm or less in the microstructure. A hot-rolled steel sheet contains 0.031% to 0.200% Ti, in which 0.005% or more of Ti is present as dissolved Ti in the microstructure. A method for producing the steel member includes subjecting a hot-rolled steel sheet to forming processing and then performing heat treatment including heating to a temperature of higher than 550° C. and 1,050° C. or lower and then cooling at an average cooling rate of 10° C./s or more in the temperature range of 550° C. to 400° C.
    Type: Application
    Filed: March 29, 2018
    Publication date: June 18, 2020
    Applicant: JFE Steel Corporation
    Inventors: Shunsuke Toyoda, Ichiro Sugimoto, Shuji Kawamura
  • Publication number: 20200190615
    Abstract: A steel member, a hot-rolled steel sheet to be used as a material thereof, and production methods therefor are provided. A steel member contains 0.010% to 0.120% Ti, in which 0.005% or more of Ti is precipitated as a precipitate having a particle size of 20 nm or less in the microstructure. A hot-rolled steel sheet for the steel member contains 0.010% to 0.120% Ti, in which 0.005% or more of Ti is present as dissolved Ti in the microstructure. A method for producing the steel member includes subjecting a hot-rolled steel sheet to forming processing and then performing heat treatment including heating to a temperature of higher than 550° C. and 1,050° C. or lower and then cooling at an average cooling rate of 10° C./s or more in the temperature range of 550° C. to 400° C.
    Type: Application
    Filed: March 29, 2018
    Publication date: June 18, 2020
    Applicant: JFE Steel Corporation
    Inventors: Shunsuke Toyoda, Ichiro Sugimoto, Shuji Kawamura
  • Patent number: 10584405
    Abstract: A resistance welded steel pipe is provided. A hot-rolled steel sheet having a composition containing, in mass %, C: 0.025 to 0.168%, Si: 0.10 to 0.30%, Mn: 0.60 to 1.90%, and one or at least two selected from Ca, Nb, V, and Ti such that Pcm is 0.20 or less is subjected to continuous cold roll forming to obtain a pipe-shaped body. Tapered grooves are formed in the steel sheet such that the ratio of the tapered portions to the wall thickness of the steel sheet is 10 to 80%. Then end surfaces of the pipe-shaped body are butted against each other and subjected to electric resistance welding. Ultrasonic waves are transmitted toward the electric resistance weld surface such that a beam width is within the range of 0.1 to 4.0 mm, and the reflected waves are used for ultrasonic flaw detection using an ultrasonic flaw detector.
    Type: Grant
    Filed: November 17, 2015
    Date of Patent: March 10, 2020
    Assignee: JFE Steel Corporation
    Inventors: Shunsuke Toyoda, Takatoshi Okabe, Sota Goto, Yutaka Matsui, Satoru Yabumoto
  • Publication number: 20200063227
    Abstract: There are provided a high-strength hot-rolled steel sheet having a tensile strength of 980 MPa or more and a production method therefor. The high-strength hot-rolled steel sheet has a predetermined component composition and a microstructure containing 75.0% or more by area and less than 97.0% by area of a primary phase composed of an upper bainite phase, the primary phase having an average grain size of 12.0 ?m or less, and more than 3.0% by area and 25.0% or less by area of a secondary phase that is a structure composed of one or two of a lower bainite phase and/or a tempered martensite phase, and a martensite phase, in which the number density of grains of the secondary phase having an equivalent circular diameter of 0.5 ?m or more is 150,000 grains/mm2 or less, and the steel sheet has an arithmetic mean surface roughness of 2.00 ?m or less.
    Type: Application
    Filed: February 6, 2018
    Publication date: February 27, 2020
    Applicant: JFE Steel Corporation
    Inventors: Kazuhiko Yamazaki, Shunsuke Toyoda, Noriaki Moriyasu, Sumio Kaiho
  • Patent number: 10526678
    Abstract: This disclosure provides a predetermined composition, where a conversion value C* of total carbon contents in Ti, Nb and V precipitates whose grain sizes are less than 20 nm is 0.010 mass % to 0.100 mass %, Fe content in Fe precipitates is 0.03 mass % to 0.50 mass %, and an average grain size of ferrite grains whose grain sizes are top 5 % large in ferrite grain size distribution of rolling direction cross section is (4000/TS)2 ?m or less, the TS indicating tensile strength in unit of MPa.
    Type: Grant
    Filed: July 5, 2016
    Date of Patent: January 7, 2020
    Assignee: JFE STEEL CORPORATION
    Inventors: Taro Kizu, Shunsuke Toyoda, Akimasa Kido, Tetsushi Tadani
  • Publication number: 20190390311
    Abstract: There is provided a hot-rolled steel sheet suitable for manufacturing an electric resistance welded steel tube, having workability necessary for roll forming and high yield strength, for coiled tubing without performing whole-tube quenching treatment and reheating-tempering treatment after electric resistance welding. The steel sheet includes, by mass %, C, Si, Mn, P, S, Al, Cr, Cu, Ni, Mo, Nb, V, Ti, and N contained at a specific content. The steel sheet has a microstructure containing 3% to 20% martensite and 10% or less retained austenite on a volume fraction basis, the remainder being bainite. The yield strength is set to 600 MPa or more, the tensile strength is set to 950 MPa or more, and the uniform elongation is set to 7.0% or more.
    Type: Application
    Filed: December 14, 2017
    Publication date: December 26, 2019
    Applicant: JFE STEEL CORPORATION
    Inventors: Akihide MATSUMOTO, Hiroshi NAKATA, Shunsuke TOYODA
  • Publication number: 20190390296
    Abstract: There is provided an electric resistance welded steel tube having a yield strength of 896 MPa or more, and excellent low-cycle fatigue resistance, for coiled tubing without performing whole-tube quenching treatment and reheating-tempering treatment after performing electric resistance welding and a method for manufacturing the same. The steel tube includes, by mass %, C, Si, Mn, P, S, Al, Cr, Cu, Ni, Mo, Nb, V, Ti, and N at a specific content. The steel tube has a microstructure that contains 2% to 10% retained austenite and 20% or less martensite on a volume fraction basis, and the remainder being bainite. The yield strength is set to 896 MPa or more and the uniform elongation is set to 9.0% or more.
    Type: Application
    Filed: December 14, 2017
    Publication date: December 26, 2019
    Applicant: JFE STEEL CORPORATION
    Inventors: Akihide MATSUMOTO, Hiroshi NAKATA, Shunsuke TOYODA
  • Patent number: 10385417
    Abstract: By using, as a raw material, a thick hot-rolled steel sheet having a chemical composition containing, by mass %, C: 0.02% or more and 0.10% or less, Si: 0.05% or more and 0.30% or less, Mn: 0.80% or more and 2.00% or less, and Nb: 0.010% or more and 0.100% or less and satisfying the condition that a carbon equivalent Ceq is 0.25% or more and 0.50% or less, a microstructure including a bainitic ferrite phase and/or a bainite phase, a high strength of 52 ksi or more in terms of yield strength and a high toughness of ?45° C. or lower in terms of fracture transition temperature vTrs, and satisfying the condition that the ratio of the average crystal grain size of the coarsest-grain portion to the average crystal grain size of the finest-grain portion is 2.0 or less in every portion in the wall thickness direction is obtained.
    Type: Grant
    Filed: July 8, 2014
    Date of Patent: August 20, 2019
    Assignee: JFE Steel Corporation
    Inventors: Sota Goto, Shunsuke Toyoda, Takatoshi Okabe
  • Publication number: 20180371574
    Abstract: This disclosure provides a predetermined composition, where a conversion value C* of total carbon contents in Ti, Nb and V precipitates whose grain sizes are less than 20 nm is 0.010 mass % to 0.100 mass %, Fe content in Fe precipitates is 0.03 mass % to 0.50 mass %, and an average grain size of ferrite grains whose grain sizes are top 5 % large in ferrite grain size distribution of rolling direction cross section is (4000/TS)2 ?m or less, the TS indicating tensile strength in unit of MPa.
    Type: Application
    Filed: July 5, 2016
    Publication date: December 27, 2018
    Applicant: JFE STEEL CORPORATION
    Inventors: Taro KIZU, Shunsuke TOYODA, Akimasa KIDO, Tetsushi TADANI
  • Publication number: 20180237874
    Abstract: A high-strength hot-rolled steel sheet that has excellent punching workability and hole expandability, and a method for manufacturing the same. The hot-rolled steel sheet has a tensile strength of 980 MPa or more. The hot-rolled steel sheet has a chemical composition containing C, Si, Mn, P, S, Al, N, Ti, Cr, and B, and has a microstructure including a bainite phase having an area ratio of 85% or more as a main phase, and a martensite phase or martensite-austenite constituent having an area ratio of 15% or less as a second phase, the balance being a ferrite phase. The second phase has an average grain diameter of 3.0 ?m or less, prior-austenite grains have an average aspect ratio of 1.3 or more and 5.0 or less, and recrystallized prior-austenite grains have an area ratio of 15% or less relative to non-recrystallized prior-austenite grains.
    Type: Application
    Filed: July 20, 2016
    Publication date: August 23, 2018
    Applicant: JFE STEEL CORPORATION
    Inventors: Kazuhiko YAMAZAKI, Shunsuke TOYODA, Noriaki MORIYASU, Kentaro IRISA
  • Publication number: 20180155806
    Abstract: This disclosure provides a predetermined composition, where a conversion value C* of total carbon contents in Ti, Nb and V precipitates whose grain sizes are less than 20 nm is 0.010 mass % to 0.100 mass %, Fe content in Fe precipitates is 0.03 mass % to 0.50 mass %, and an average grain size of ferrite grains whose grain sizes are top 5 % large in ferrite grain size distribution of rolling direction cross section is (4000/TS)2 ?m or less, the TS indicating tensile strength in unit of MPa.
    Type: Application
    Filed: July 5, 2016
    Publication date: June 7, 2018
    Applicant: JFE STEEL CORPORATION
    Inventors: Taro KIZU, Shunsuke TOYODA, Akimasa KIDO, Tetsushi TADANI
  • Publication number: 20180119240
    Abstract: A hot rolled steel sheet comprises: a predetermined chemical composition; a microstructure in which a total area ratio of a tempered bainite phase and a tempered martensite phase is 70% or more, a total area ratio of a coarse pearlite phase, a martensite phase, and a retained austenite phase is 10% or less, the tempered bainite phase and the tempered martensite phase have laths with an average width of 1.0 ?m or less as a substructure, a proportion of Fe-based carbides with an aspect ratio of 5 or less in Fe-based carbides precipitated inside and at boundaries of the laths is 80% or more, and MC-type carbides with an average particle size of 20 nm or less are dispersed and precipitated inside and at the boundaries of the laths; and an average dislocation density of 1.0×1014 m?2 or more and 5.0×1015 m?2 or less.
    Type: Application
    Filed: March 30, 2016
    Publication date: May 3, 2018
    Applicant: JFE Steel Corporation
    Inventors: Takaaki TANAKA, Taro KIZU, Shunsuke TOYODA
  • Publication number: 20180030557
    Abstract: Provided is a high-strength electric resistance welded steel pipe having excellent bendability and which includes a composition containing, on a mass % basis, C: 0.04% to 0.15%, Si: 0.10% to 0.50%, Mn: 1.0% to 2.2%, P: 0.050% or less, S: 0.005% or less, Cr: 0.2% to 1.0%, Ti: 0.005% to 0.030%, and Al: 0.010% to 0.050%, the balance being Fe and unavoidable impurities, and a microstructure including polygonal ferrite with a volume fraction of 70% or more and retained austenite with a volume fraction of 3% to 20%, the balance being at least one selected from martensite, bainite, and pearlite, wherein the polygonal ferrite has an average grain size of 5 ?m or more and an aspect ratio of 1.40 or less.
    Type: Application
    Filed: February 18, 2016
    Publication date: February 1, 2018
    Applicant: JFE STEEL CORPORATION
    Inventors: Sota Goto, Shunsuke Toyoda, Takatoshi Okabe
  • Patent number: 9873164
    Abstract: Electric resistance welded steel pipes or steel tubes with a tensile property TS of not less than 434 MPa which have electric resistance welded parts exhibiting both excellent HIC resistance and excellent low-temperature toughness, and methods for manufacturing such steel pipes or steel tubes.
    Type: Grant
    Filed: September 20, 2013
    Date of Patent: January 23, 2018
    Assignee: JFE STEEL CORPORATION
    Inventors: Shunsuke Toyoda, Sota Goto, Takatoshi Okabe, Atsushi Yonemoto
  • Publication number: 20180016657
    Abstract: A high strength steel sheet having high strength such as a tensile strength of 780 MPa or more and having excellent blanking workability and stretch flangeability and a manufacturing method therefor are provided. A high strength steel sheet comprises: a chemical composition containing, in mass %, C: 0.05% to 0.30%, Si: 0.6% to 2.0%, Mn: 1.3% to 3.0%, P: 0.10% or less, S: 0.030% or less, Al: 2.0% or less, N: 0.010% or less, and one or more of Ti, Nb, and V: 0.01% to 1.0% each, with a balance being Fe and incidental impurities; a ferrite microstructure of 50% or more in area ratio; an amount of precipitated Fe of 0.04 mass % or more; and a precipitate with a particle size of less than 20 nm, wherein C* and C*p satisfy specific conditions.
    Type: Application
    Filed: March 1, 2016
    Publication date: January 18, 2018
    Applicant: JFE STEEL CORPORATION
    Inventors: Taro KIZU, Shunsuke TOYODA, Akimasa KIDO, Tetsushi TADANI
  • Publication number: 20170356071
    Abstract: A resistance welded steel pipe is provided. A hot-rolled steel sheet having a composition containing, in mass %, C: 0.025 to 0.168%, Si: 0.10 to 0.30%, Mn: 0.60 to 1.90%, and one or at least two selected from Ca, Nb, V, and Ti such that Pcm is 0.20 or less is subjected to continuous cold roll forming to obtain a pipe-shaped body. Tapered grooves are formed in the steel sheet such that the ratio of the tapered portions to the wall thickness of the steel sheet is 10 to 80%. Then end surfaces of the pipe-shaped body are butted against each other and subjected to electric resistance welding. Ultrasonic waves are transmitted toward the electric resistance weld surface such that a beam width is within the range of 0.1 to 4.0 mm, and the reflected waves are used for ultrasonic flaw detection using an ultrasonic flaw detector.
    Type: Application
    Filed: November 17, 2015
    Publication date: December 14, 2017
    Applicant: JFE STEEL CORPORATION
    Inventors: Shunsuke TOYODA, Takatoshi OKABE, Sota GOTO, Yutaka MATSUI, Satoru YABUMOTO
  • Patent number: 9841124
    Abstract: A high-strength thick-walled electric resistance welded steel pipe has excellent low-temperature toughness and excellent HIC resistance and a yield strength of 400 MPa or more. The steel has a chemical composition consisting of C: 0.025% to 0.084%, Si: 0.10% to 0.30%, Mn: 0.70% to 1.80%, controlled amounts of P, S, Al, N, and O, Nb: 0.001% to 0.065%, V: 0.001% to 0.065%, Ti: 0.001% to 0.033%, and Ca: 0.0001% to 0.0035% on a mass percent basis and the remainder being Fe and incidental impurities, and satisfies Pcm of 0.20 or less.
    Type: Grant
    Filed: April 11, 2013
    Date of Patent: December 12, 2017
    Assignee: JFE Steel Corporation
    Inventors: Shunsuke Toyoda, Sota Goto, Takatoshi Okabe, Tomohiro Inoue, Motoharu Egi, Atsushi Yonemoto