Patents by Inventor Yoshikazu Kawabata
Yoshikazu Kawabata 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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Publication number: 20230079323Abstract: An electric resistance welded steel pipe or tube comprises: a base metal being a steel sheet having a specific chemical composition and an electric resistance weld portion having a bond width of 40×10?6 m or more and 120×10?6 m or less, wherein C0-C1 is 0.05 mass % or less, where C0-C1 is a difference between C1 in mass % which is a minimum C content of the electric resistance weld portion and Co in mass % which is a C content of the steel sheet, and a depth of a total decarburized layer in each of an inner surface layer and an outer surface layer of the electric resistance welded steel pipe or tube is 50×10?6 m or less.Type: ApplicationFiled: October 18, 2022Publication date: March 16, 2023Applicants: JFE STEEL CORPORATION, JFE Welded Pipe Manufacturing Co.,Ltd.Inventors: Yoshikazu KAWABATA, Makio GUNJI
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Patent number: 11512361Abstract: Provided is an electric resistance welded steel pipe or tube having excellent fatigue durability after rapid and short-time heating quenching treatment. An electric resistance welded steel pipe or tube comprises: a base metal being a steel sheet having a specific chemical composition and an electric resistance weld portion having a bond width of 40×10?6 m or more and 120×10?6 m or less, wherein C0-C1 is 0.05 mass % or less, where C0-C1 is a difference between C1 in mass % which is a minimum C content of the electric resistance weld portion and C0 in mass % which is a C content of the steel sheet, and a depth of a total decarburized layer in each of an inner surface layer and an outer surface layer of the electric resistance welded steel pipe or tube is 50×10?6 m or less.Type: GrantFiled: December 26, 2018Date of Patent: November 29, 2022Assignees: JFE STEEL CORPORATION, JFE Welded Pipe Manufacturing Co., Ltd.Inventors: Yoshikazu Kawabata, Makio Gunji
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Patent number: 11332812Abstract: A method for manufacturing an electric resistance welded steel tube for high-strength thin hollow stabilizers is provided. A steel with a certain chemical composition is heated to a temperature of 1000 to 1300° C., hot rolled under conditions where the rolling finish temperature is 750 to 950° C., cooled, coiled into a coil at 500 to 650° C., and skin pass rolled with a rolling reduction ratio of not less than 0.3%. The resultant hot rolled sheet is electric resistance welded into an electric resistance welded steel tube, which is then reheated to a temperature of 800 to 1100° C. and hot stretch-reducing rolled under conditions where the rolling finish temperature is not more than 850° C. and the cumulative diameter reduction is not more than 75%. Consequently, a thin electric resistance welded steel tube is produced.Type: GrantFiled: October 19, 2017Date of Patent: May 17, 2022Assignee: JFE Steel CorporationInventors: Masatoshi Aratani, Shinsaku Kokubo, Hiromichi Hori, Yoshikazu Kawabata, Ryoji Matsui
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Publication number: 20210277507Abstract: A method for manufacturing an electric resistance welded steel tube for high-strength thin hollow stabilizers is provided. A steel with a certain chemical composition is heated to a temperature of 1000 to 1300° C., hot rolled under conditions where the rolling finish temperature is 750 to 950° C., cooled, coiled into a coil at 500 to 650° C., and skin pass rolled with a rolling reduction ratio of not less than 0.3%. The resultant hot rolled sheet is electric resistance welded into an electric resistance welded steel tube, which is then reheated to a temperature of 800 to 1100° C. and hot stretch-reducing rolled under conditions where the rolling finish temperature is not more than 850° C. and the cumulative diameter reduction is not more than 75%. Consequently, a thin electric resistance welded steel tube is produced.Type: ApplicationFiled: October 19, 2017Publication date: September 9, 2021Applicant: JFE Steel CorporationInventors: Masatoshi Aratani, Shinsaku Kokubo, Hiromichi Hori, Yoshikazu Kawabata, Ryoji Matsui
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Publication number: 20200332381Abstract: Provided is an electric resistance welded steel pipe or tube having excellent fatigue durability after rapid and short-time heating quenching treatment. An electric resistance welded steel pipe or tube comprises: a base metal being a steel sheet having a specific chemical composition and an electric resistance weld portion having a bond width of 40×10?6 m or more and 120×10?6 m or less, wherein C0-C1 is 0.05 mass % or less, where C0-C1 is a difference between C1 in mass % which is a minimum C content of the electric resistance weld portion and C0 in mass % which is a C content of the steel sheet, and a depth of a total decarburized layer in each of an inner surface layer and an outer surface layer of the electric resistance welded steel pipe or tube is 50×10?6 m or less.Type: ApplicationFiled: December 26, 2018Publication date: October 22, 2020Applicants: JFE STEEL CORPORATION, JFE Welded Pipe Manufacturing Co.,Ltd.Inventors: Yoshikazu KAWABATA, Makio GUNJI
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Patent number: 10308994Abstract: A seamless steel tube has a particular composition and a structure with an average prior ? grain size of 150 ?m or less in an axial cross-section after cold drawing and heat treatment. The structure retards the growth of a fatigue crack. The steel tube has a tensile strength TS of 500 MPa or more and good internal pressure fatigue resistance and is suitable for use as a fuel injection tube under high injection pressures. The composition of the steel tube may further contain at least one of Cu, Ni, Cr, Mo, and B; at least one of Ti, Nb, and V; and/or Ca.Type: GrantFiled: March 20, 2015Date of Patent: June 4, 2019Assignee: JFE Steel CorporationInventors: Yoshikazu Kawabata, Manabu Nishino, Makio Gunji
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Patent number: 10301703Abstract: Disclosed is a high-strength welded steel pipe for airbag inflators that has high toughness and workability. A base material portion of the steel pipe has a composition containing, in mass %, C: 0.02 to 0.08%, Si: 0.001 to 1.0%, Mn: 0.1 to 2.0%, P: 0.1% or less, Al: 0.01 to 0.1%, N: 0.01% or less, Ti: 0.01 to 0.20%, and V: 0.01 to 0.50%, with the balance being Fe and incidental impurities. The base material portion has a structure that includes a ferrite phase having an average grain size of 10 ?m or less at an area fraction of 90% or more and a Ti, V-based carbide having an average grain size of 10 nm or less and dispersed in the ferrite phase. The welded steel pipe has a high tensile strength TS of 780 MPa or more and a strength-elongation balance TS×El of 15,000 MPa % or more. The difference ?HV in Vickers hardness between the base material portion and the welded portion is 60 points or less.Type: GrantFiled: October 19, 2015Date of Patent: May 28, 2019Assignee: JFE STEEL CORPORATIONInventors: Masatoshi Aratani, Yoshikazu Kawabata, Kenichi Iwazaki, Ryoji Matsui
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Publication number: 20180023163Abstract: Disclosed is a high-strength welded steel pipe for airbag inflators that has high toughness and workability. A base material portion of the steel pipe has a composition containing, in mass %, C: 0.02 to 0.08%, Si: 0.001 to 1.0%, Mn: 0.1 to 2.0%, P: 0.1% or less, Al: 0.01 to 0.1%, N: 0.01% or less, Ti: 0.01 to 0.20%, and V: 0.01 to 0.50%, with the balance being Fe and incidental impurities. The base material portion has a structure that includes a ferrite phase having an average grain size of 10 ?m or less at an area fraction of 90% or more and a Ti, V-based carbide having an average grain size of 10 nm or less and dispersed in the ferrite phase. The welded steel pipe has a high tensile strength TS of 780 MPa or more and a strength-elongation balance TS×El of 15,000 MPa % or more. The difference ?HV in Vickers hardness between the base material portion and the welded portion is 60 points or less.Type: ApplicationFiled: October 19, 2015Publication date: January 25, 2018Applicant: JFE STEEL CORPORATIONInventors: Masatoshi Aratani, Yoshikazu Kawabata, Kenichi Iwazaki, Ryoji Matsui
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Patent number: 9862014Abstract: A method for manufacturing an electric resistance welded steel tube including: forming a steel tube material into an almost cylindrical open pipe, the steel tube material being a steel sheet wherein Ti and N satisfy (N/14)<(Ti/47.9); forming an electric resistance welded steel tube by bonding ends of the open pipe to each other by induction resistance welding with heat input controlled so that the bond width is 30 to 65 ?m; heating the electric resistance welded steel tube to a temperature equal to or higher than the Ac3 transformation temperature; and diameter-reducing rolling the heated electric resistance welded steel tube with rolling reduction expressed by an outer diameter ratio greater than (1?25/the bond width before diameter-reducing rolling (?m))×100% such that the bond width is 25 ?m or less.Type: GrantFiled: December 12, 2012Date of Patent: January 9, 2018Assignee: JFE Steel CorporationInventors: Yoshikazu Kawabata, Masayuki Sakaguchi, Kei Sakata
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Publication number: 20170022581Abstract: A seamless steel tube has a particular composition and a structure with an average prior ? grain size of 150 ?m or less in an axial cross-section after cold drawing and heat treatment. The structure retards the growth of a fatigue crack. The steel tube has a tensile strength TS of 500 MPa or more and good internal pressure fatigue resistance and is suitable for use as a fuel injection tube under high injection pressures. The composition of the steel tube may further contain at least one of Cu, Ni, Cr, Mo, and B; at least one of Ti, Nb, and V; and/or Ca.Type: ApplicationFiled: March 20, 2015Publication date: January 26, 2017Inventors: Yoshikazu Kawabata, Manabu Nishino, Makio Gunji
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Publication number: 20150368768Abstract: An electric resistance welded steel pipe excellent in terms of fatigue strength. The steel pipe including a chemical composition containing, by mass %, C: 0.35% or more and 0.55% or less, Si: 0.01% or more and 1.0% or less, Mn: 1.0% or more and 3.0% or less, P: 0.02% or less, S: 0.01% or less, Al: 0.005% or less, N: 0.0050% or less, Cr: 0.1% or more and 0.5% or less, and the balance being Fe and inevitable impurities and a metallic microstructure including pearlite, ferrite, and bainite, in which the area ratio of the pearlite is 85% or more, the total of the area ratios (including 0) of the ferrite and the bainite is 15% or less, and in which a prior austenite grain size is 25 ?m or more.Type: ApplicationFiled: January 30, 2014Publication date: December 24, 2015Applicant: JFE STEEL CORPORATIONInventors: Masatoshi ARATANI, Takatoshi OKABE, Shunsuke TOYODA, Yoshikazu KAWABATA, Hiromichi HORI
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Publication number: 20150275339Abstract: A raw steel tube has a composition containing, by mass, 0.25% to 0.60% carbon, 0.01% to 2.0% silicon, 0.2% to 3.0% manganese, 0.001% to 0.1% aluminum, 0.001% to 0.05% phosphorus, 0.02% or less sulfur, 0.0010% to 0.0100% nitrogen, 0.0003% to 0.0050% boron, and 0.0001% to 0.0050% calcium, the balance being iron and incidental impurities. The raw steel tube is heated to and soaked at an Ac3 transformation point or higher and is then subjected to stretch-reducing rolling at a finishing temperature of rolling of 900° C. to (Ac1 transformation point) with a cumulative reduction in diameter of 30% to 70% within the temperature range of 900° C. or lower.Type: ApplicationFiled: June 28, 2012Publication date: October 1, 2015Applicant: JFE Steel CorporationInventors: Masatoshi Aratani, Shunsuke Toyoda, Takatoshi Okabe, Yoshikazu Kawabata, Kenichi Iwazaki
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Patent number: 8505941Abstract: A method enhances fatigue strength of ear portions which are high fatigue risk parts in a torsion beam almost without bringing about disadvantages in terms of productivity and cost. A torsion beam is formed with a portion of the tubular body into an approximately U-shape in cross section by crushing the portion of the tubular body in the radial direction and, thereafter, due to bending with a bottom line set as a belly side of bending, a bending strain of 2 to 6% in the tube longitudinal direction on a tensile side is imparted to the ear portions.Type: GrantFiled: March 31, 2010Date of Patent: August 13, 2013Assignee: JFE Steel CorporationInventors: Yuji Hashimoto, Shunsuke Toyoda, Kinya Nakagawa, Koji Suzuki, Yoshikazu Kawabata, Osamu Sonobe, Akio Sato
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Publication number: 20130160889Abstract: A high-strength electric resistance welded steel tube has a composition including, in terms of percent by mass, C: 0.05 to 0.20%, Si: 0.5 to 2.0%, Mn: 1.0 to 3.0%, P: 0.1% or less, S: 0.01% or less, Al: 0.01 to 0.1%, N: 0.005% or less, and the balance being Fe and unavoidable impurities; and a structure which is a dual phase structure including a ferrite phase and a martensite phase, with a volume ratio of the martensite phase being 20 to 60%, wherein a tensile strength TS is 1180 MPa or more, an elongation El in a tube axis direction is 10% or more, and a yield ratio is less than 90%; and after application of a 2% prestrain and baking finishing that includes a heat treatment of 170° C.×10 min, a strength increase (BH value) is 100 MPa or more and a yield ratio is 90% or more.Type: ApplicationFiled: March 23, 2011Publication date: June 27, 2013Applicant: JFE STEEL CORPORATIONInventors: Masatoshi Aratani, Yoshikazu Kawabata, Saiji Matsuoka, Norimasa Hirata
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Publication number: 20130126036Abstract: A base material portion of an electric resistance welded steel pipe has a composition including C at 0.25 to 0.55%, Si at 0.01 to 1.0%, Mn at 0.2 to 3.0%, Al at not more than 0.1% and N at 0.0010 to 0.0100%, with the balance being represented by Fe and inevitable impurities, and the weld defect area, which is a projected area of a weld defect in an electric resistance weld zone, is less than 40000 ?m2.Type: ApplicationFiled: May 23, 2011Publication date: May 23, 2013Applicant: JFE STEEL CORPORATIONInventors: Masatoshi Aratani, Yoshikazu Kawabata, Takatoshi Okabe, Yukinori Iizuka, Hiromichi Hori, Gunji Makio, Kenichi Iwazaki
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Publication number: 20120104717Abstract: A method enhances fatigue strength of ear portions which are high fatigue risk parts in a torsion beam almost without bringing about disadvantages in terms of productivity and cost. A torsion beam is formed with a portion of the tubular body into an approximately U-shape in cross section by crushing the portion of the tubular body in the radial direction and, thereafter, due to bending with a bottom line set as a belly side of bending, a bending strain of 2 to 6% in the tube longitudinal direction on a tensile side is imparted to the ear portions.Type: ApplicationFiled: March 31, 2010Publication date: May 3, 2012Applicant: JFE STEEL CORPORATIONInventors: Yuji Hashimoto, Shunsuke Toyoda, Kinya Nakagawa, Koji Suzuki, Yoshikazu Kawabata, Osamu Sonobe, Akio Sato
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Patent number: 7992762Abstract: A frictionally press-bonded member includes a steel pipe, and a stab. The steel pipe has opposite ends. The stab is frictionally press-bonded to at least one of the opposite ends of the steel pipe. The steel pipe is subjected to a normalizing treatment before being frictionally press-bonded to the stab.Type: GrantFiled: September 13, 2007Date of Patent: August 9, 2011Assignees: Toyota Jidosha Kabushiki Kaisha, JTEKT Corporation, JFE Steel CorporationInventors: Tomohiko Sato, Takeo Yamamoto, Kaname Onoda, Yoshikazu Kawabata
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Patent number: 7942984Abstract: A steel pipe blank having a composition containing 0.5% or less C and 85% or more Fe in terms of mass percent is heated, and stretch-reducing is then performed so that the diameter decrease ratio is 15% or more and the rolling finishing temperature is (the Ar3 transformation point?10)° C. or lower. Consequently, a structure in which the ratio of X-ray diffraction intensity obtained from the plane in which the <100> direction of crystal grains is preferentially oriented parallel to the circumference direction and the <011> direction of crystal grains is preferentially oriented parallel to the rolling direction of the steel pipe to that obtained for a three-dimensionally randomly oriented sample is 3.0 or more is formed, and the r-value is increased, thereby improving the magnetic properties of the steel pipe.Type: GrantFiled: September 1, 2005Date of Patent: May 17, 2011Assignee: JFE Steel CorporationInventors: Yasuhide Ishiguro, Yoshikazu Kawabata, Kei Sakata, Masayuki Sakaguchi, Masayoshi Ishida, Motoaki Itadani, Yasue Koyama
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Patent number: 7887649Abstract: A high-tensile strength welded steel tube has excellent formability and torsional fatigue endurance after being formed into cross-sectional shape and then stress-relief annealed. A steel material used has a composition which contains C, Si, Al, 1.01% to 1.99% Mn, 0.041% to 0.150% Ti, 0.017% to 0.150% Nb, P, S, N, and O such that the sum of the content of Ti and that of Nb is 0.08% or more, the content of each of C, Si, and Al being within an appropriate range, the content of each of P, S, N, and O being adjusted to a predetermined value or less.Type: GrantFiled: June 19, 2007Date of Patent: February 15, 2011Assignee: JFE Steel CorporationInventors: Shunsuke Toyoda, Masatoshi Aratani, Yoshikazu Kawabata, Yuji Hashimoto, Koji Suzuki, Kei Sakata, Makio Gunji, Akio Sato, Tetsuro Sawaki
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Publication number: 20100062277Abstract: A frictionally press-bonded member includes a steel pipe, and a stab. The steel pipe has opposite ends. The stab is frictionally press-bonded to at least one of the opposite ends of the steel pipe. The steel pipe is subjected to a normalizing treatment before being frictionally press-bonded to the stab.Type: ApplicationFiled: September 13, 2007Publication date: March 11, 2010Inventors: Tomohiko Sato, Takeo Yamamoto, Kaname Onoda, Yoshikazu Kawabata