Patents by Inventor Takaaki Fukushi

Takaaki Fukushi 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: 11028456
    Abstract: An electric resistance welded steel pipe for a torsion beam, in which a base metal portion includes, in terms of % by mass, 0.04 to 0.12% of C, 0.03 to 1.20% of Si, 0.30 to 2.50% of Mn, 0.08 to 0.24% of Ti, 0.005 to 0.500% of Al, 0.01 to 0.06% of Nb, and 0.0005 to 0.0100% of N, a balance including Fe and impurities, wherein Vc90, defined by the following Formulae (i) and (ii), is 200 or more, a mass ratio of Ti content to C content is from 0.85 to 5.00, an areal ratio of ferrite is 80% or more, an average crystal grain size of ferrite crystal grains is 10 ?m or less, and an average aspect ratio of ferrite crystal grains is 2.0 or less, in a metallographic microstructure of a central portion in a wall thickness direction of the base metal portion; log Vc90=2.94?0.75(?a?1)??Formula (i); ?a=2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo??Formula (ii).
    Type: Grant
    Filed: August 23, 2017
    Date of Patent: June 8, 2021
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takaaki Fukushi, Yasuhiro Shinohara, Hideki Hamatani
  • Patent number: 10738366
    Abstract: The present invention provides electric-resistance welded steel pipe optimal for applications such as production of shale gas which is comprised of steel having a chemical composition which contains, by mass %, respectively, C: 0.08 to 0.18%, Si: 0.01% to 0.50%, Mn: 1.30 to 2.1%, Al: 0.001 to 0.10%, Nb: 0.005 to 0.08%, and Ti: 0.005 to 0.03%, is limited to N 0.008% or less, P: 0.020% or less, and S: 0.010% or less, and has a balance of Fe and unavoidable impurities, wherein a structure at a center part of thickness is 40% to 70% by area of ferrite phase having a circle-equivalent diameter of 1.0 ?m to 10.0 ?m and a balance of a low temperature transformation phase comprising a bainite phase, and Ceq satisfies 0.32?Ceq?0.60.
    Type: Grant
    Filed: December 20, 2013
    Date of Patent: August 11, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Hideki Hamatani, Keinosuke Iguchi, Masakazu Ozaki, Takaaki Fukushi, Takuya Asano
  • Publication number: 20190217424
    Abstract: An electric resistance welded steel pipe for a torsion beam, in which a base metal portion includes, in terms of % by mass, 0.04 to 0.12% of C, 0.03 to 1.20% of Si, 0.30 to 2.50% of Mn, 0.08 to 0.24% of Ti, 0.005 to 0.500% of Al, 0.01 to 0.06% of Nb, and 0.0005 to 0.0100% of N, a balance including Fe and impurities, wherein Vc90, defined by the following Formulae (i) and (ii), is 200 or more, a mass ratio of Ti content to C content is from 0.85 to 5.00, an areal ratio of ferrite is 80% or more, an average crystal grain size of ferrite crystal grains is 10 ?m or less, and an average aspect ratio of ferrite crystal grains is 2.0 or less, in a metallographic microstructure of a central portion in a wall thickness direction of the base metal portion; log Vc90=2.94?0.75(?a?1)??Formula (i); ?a=2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo??Formula (ii).
    Type: Application
    Filed: August 23, 2017
    Publication date: July 18, 2019
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takaaki FUKUSHI, Yasuhiro SHINOHARA, Hideki HAMATANI
  • Patent number: 10196702
    Abstract: An electric resistance welded steel pipe for an oil well includes in terms of mass %: 0.02 to 0.14% of C, 0.05 to 0.50% of Si, 1.0 to 2.1% of Mn, 0.020% or less of P, 0.010% or less of S, 0.010 to 0.100% of Nb, 0.010 to 0.050% of Ti, 0.010 to 0.100% of Al, and 0.0100% or less of N. Contents of Cu, Ni, Cr, Mo, V, and B are 0 to 0.50%, 0 to 1.00%, 0 to 0.50%, 0 to 0.30%, 0 to 0.10%, and 0 to 0.0030%, respectively. Remainder consisting of Fe and unavoidable impurities. In a case that a full thickness specimen is subjected to a pipe axis direction tensile test, a tensile strength is 780 MPa or more, 0.2% proof stress/tensile strength is 0.80 or more, and 2% flow stress/tensile strength is from 0.85 to 0.98.
    Type: Grant
    Filed: December 11, 2014
    Date of Patent: February 5, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takaaki Fukushi, Hideki Hamatani, Masakazu Ozaki, Yuusuke Ichinose
  • Patent number: 10167538
    Abstract: A steel pipe, consisting of, in terms of mass %: from 0.06% to 0.25% of C, 0.50% or less of Si, 1.00% to 1.80% of Mn, 0.030% or less of P, 0.020% or less of S, 0.08% or less of Al, 0.008% or less of N, 0.080% or less of Nb, and a remainder consisting of Fe and unavoidable impurities, wherein a compressive residual stress at an outer surface measured by an X-ray method is 250 MPa or more, and a compressive residual stress at a position at a depth of 1 mm from the outer surface measured by the X-ray method is 70% or more of the compressive residual stress at the outer surface measured by the X-ray method.
    Type: Grant
    Filed: February 4, 2014
    Date of Patent: January 1, 2019
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yosuke Kiyota, Takaaki Fukushi, Hideyuki Nakamura
  • Patent number: 10081042
    Abstract: Electric resistance welded steel pipe excellent in weld zone quality suitable for oil country tubular goods and line pipe wherein steel plate forming the base metal of the electric resistance welded steel pipe has a predetermined chemical composition, the contents of Ca, O, S, Ce, La, and Al satisfy XCASO = ( Ca O + Ca S + 0.285 ? Ce + La O + 0.285 ? Ce + La S ) × ( Al Ca ) > 78 the oxide-based inclusions in the weld zone of the electric resistance welded steel pipe contains one or both of Ce and La, and the long axis/short axis of the oxide-based inclusions is 2.5 or less.
    Type: Grant
    Filed: August 7, 2014
    Date of Patent: September 25, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hideki Hamatani, Kenichi Yamamoto, Masafumi Miyazaki, Masaki Ina, Takaaki Fukushi
  • Patent number: 9702019
    Abstract: A quenched steel pipe member is formed of a GI galvanized steel pipe, in a middle section in a longitudinal direction of the GI galvanized steel pipe, a cross-section perpendicular to the longitudinal direction has a substantially V shape including a contact section at which opposite parts of an inner circumferential surface of the GI galvanized steel pipe come into contact with each other, the contact section is bonded using a Fe—Zn alloy phase, and a micro Vickers hardness at a location 50 ?m deep from a base material surface layer is 95% or more of a micro Vickers hardness at a location 200 ?m deep from the base material surface layer.
    Type: Grant
    Filed: September 12, 2013
    Date of Patent: July 11, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takaaki Fukushi, Koichi Sato, Satoshi Kato, Hideki Hamatani, Yoshiaki Hirota
  • Patent number: 9573436
    Abstract: A torsion beam which is used in a suspension system of an automobile which is provided with a pair of arm members which extend in a front-rear direction of the automobile and are designed to be connected to a chassis of the automobile so as to be able to swing and to have wheels attached rotably to them is disclosed. The torsion beam is formed with a recess which extends in the longitudinal direction whereby that torsion beam has first and second leg parts in a plane vertical to the longitudinal direction and exhibits a substantially V-shaped or substantially U-shaped cross-sectional shape. The torsion beam is provided with connection parts which are provided at the two ends of that torsion beam and are connected to the arm members, a fixed shape part which is provided at a center part in the longitudinal direction of that torsion beam, and asymmetric shape parts which are provided between that fixed shape part and the connection parts.
    Type: Grant
    Filed: January 30, 2013
    Date of Patent: February 21, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takeshi Kawachi, Eisaku Sakurada, Takaaki Fukushi
  • Publication number: 20160319404
    Abstract: The present invention provides a steel pipe, consisting of, in terms of mass %: from 0.06% to 0.25% of C, 0.50% or less of Si, 1.00% to 1.80% of Mn, 0.030% or less of P, 0.020% or less of S, 0.08% or less of Al, 0.008% or less of N, 0.080% or less of Nb, and a remainder consisting of Fe and unavoidable impurities, wherein a compressive residual stress at an outer surface measured by an X-ray method is 250 MPa or more, and a compressive residual stress at a position at a depth of 1 mm from the outer surface measured by the X-ray method is 70% or more of the compressive residual stress at the outer surface measured by the X-ray method.
    Type: Application
    Filed: February 4, 2014
    Publication date: November 3, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yosuke KIYOTA, Takaaki FUKUSHI, Hideyuki NAKAMURA
  • Publication number: 20160230241
    Abstract: An electric resistance welded steel pipe for an oil well includes in terms of mass %: 0.02 to 0.14% of C, 0.05 to 0.50% of Si, 1.0 to 2.1% of Mn, 0.020% or less of P, 0.010% or less of S, 0.010 to 0.100% of Nb, 0.010 to 0.050% of Ti, 0.010 to 0.100% of Al, and 0.0100% or less of N. Contents of Cu, Ni, Cr, Mo, V, and B are 0 to 0.50%, 0 to 1.00%, 0 to 0.50%, 0 to 0.30%, 0 to 0.10%, and 0 to 0.0030%, respectively. Remainder consisting of Fe and unavoidable impurities. In a case that a full thickness specimen is subjected to a pipe axis direction tensile test, a tensile strength is 780 MPa or more, 0.2% proof stress/tensile strength is 0.80 or more, and 2% flow stress/tensile strength is from 0.85 to 0.98.
    Type: Application
    Filed: December 11, 2014
    Publication date: August 11, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takaaki FUKUSHI, Hideki HAMATANI, Masakazu OZAKI, Yuusuke ICHINOSE
  • Publication number: 20160222480
    Abstract: The present invention provides electric-resistance welded steel pipe optimal for applications such as production of shale gas which is comprised of steel having a chemical composition which contains, by mass %, respectively, C: 0.08 to 0.18%, Si: 0.01% to 0.50%, Mn: 1.30 to 2.1%, Al: 0.001 to 0.10%, Nb: 0.005 to 0.08%, and Ti: 0.005 to 0.03%, is limited to N 0.008% or less, P: 0.020% or less, and S: 0.010% or less, and has a balance of Fe and unavoidable impurities, wherein a structure at a center part of thickness is 40% to 70% by area of ferrite phase having a circle-equivalent diameter of 1.0 ?m to 10.0 ?m and a balance of a low temperature transformation phase comprising a bainite phase, and Ceq satisfies 0.32?Ceq?0.60.
    Type: Application
    Filed: December 20, 2013
    Publication date: August 4, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hideki HAMATANI, Keinosuke IGUCHI, Masakazu OZAKI, Takaaki FUKUSHI, Takuya ASANO
  • Publication number: 20160193641
    Abstract: Electric resistance welded steel pipe excellent in weld zone quality suitable for oil country tubular goods and line pipe wherein steel plate forming the base metal of the electric resistance welded steel pipe has a predetermined chemical composition, the contents of Ca, O, S, Ce, La, and Al satisfy XCASO = ( Ca O + Ca S + 0.285 ? Ce + La O + 0.285 ? Ce + La S ) × ( Al Ca ) > 78 the oxide-based inclusions in the weld zone of the electric resistance welded steel pipe contains one or both of Ce and La, and the long axis/short axis of the oxide-based inclusions is 2.5 or less.
    Type: Application
    Filed: August 7, 2014
    Publication date: July 7, 2016
    Inventors: Hideki HAMATANI, Kenichi YAMAMOTO, Masafumi MIYAZAKI, Masaki INA, Takaaki Fukushi
  • Publication number: 20150352922
    Abstract: A torsion beam which is used in a suspension system of an automobile which is provided with a pair of arm members which extend in a front-rear direction of the automobile and are designed to be connected to a chassis of the automobile so as to be able to swing and to have wheels attached rotably to them is disclosed. The torsion beam is formed with a recess which extends in the longitudinal direction whereby that torsion beam has first and second leg parts in a plane vertical to the longitudinal direction and exhibits a substantially V-shaped or substantially U-shaped cross-sectional shape. The torsion beam is provided with connection parts which are provided at the two ends of that torsion beam and are connected to the arm members, a fixed shape part which is provided at a center part in the longitudinal direction of that torsion beam, and asymmetric shape parts which are provided between that fixed shape part and the connection parts.
    Type: Application
    Filed: January 30, 2013
    Publication date: December 10, 2015
    Inventors: Takaaki KAWACHI, Eisaku SAKURADA, Takaaki FUKUSHI
  • Patent number: 9050646
    Abstract: An automobile chassis part which is excellent in low cycle fatigue characteristics, characterized by being formed by steel which contains, by mass %, C: 0.02 to 0.10%, Si: 0.05 to 1.0%, Mn: 0.3 to 2.5%, P: 0.03% or less, S: 0.01% or less, Ti: 0.005 to 0.1%, Al: 0.005 to 0.1%, N: 0.0005 to 0.006%, and B: 0.0001 to 0.01 and has a balance of Fe and unavoidable impurities, in which 80% or more of the part structure comprises a bainite structure and in which a portion where a ratio R/t of the thickness “t” and external surface curvature radius R is 5 or less has an X-ray half width of an (211) plane of 5 (deg) or less.
    Type: Grant
    Filed: November 25, 2010
    Date of Patent: June 9, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takaaki Fukushi, Hideyuki Nakamura, Isao Anai
  • Publication number: 20150144228
    Abstract: A quenched steel pipe member is formed of a GI galvanized steel pipe, in a middle section in a longitudinal direction of the GI galvanized steel pipe, a cross-section perpendicular to the longitudinal direction has a substantially V shape including a contact section at which opposite parts of an inner circumferential surface of the GI galvanized steel pipe come into contact with each other, the contact section is bonded using a Fe—Zn alloy phase, and a micro Vickers hardness at a location 50 ?m deep from a base material surface layer is 95% or more of a micro Vickers hardness at a location 200 ?m deep from the base material surface layer.
    Type: Application
    Filed: September 12, 2013
    Publication date: May 28, 2015
    Applicant: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Takaaki Fukushi, Koichi Sato, Satoshi Kato, Hideki Hamatani, Yoshiaki Hirota
  • Patent number: 8894080
    Abstract: A method of press-forming a tubular part having a cross section of an irregular shape crushes a steel tube between an upper die and a lower die in order to form a V-shaped cross section. When the curvature radius of a tip of the upper die is defined as R1, the curvature radius of a bottom portion of the lower die corresponding to the tip of the upper die is defined as R2, and the wall thickness of the steel tube is defined as t; R1, R2, and t satisfy R1+2t=R2 and 1.5t?R1?3t.
    Type: Grant
    Filed: May 12, 2009
    Date of Patent: November 25, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Takaaki Fukushi, Isao Anai, Yasushi Yamamoto, Hideyuki Nakamura, Yoshiaki Kadoma, Naoki Hori
  • Patent number: 8828159
    Abstract: The present invention provides a steel material for automobile chassis parts which has high fatigue characteristics, does not require much cost for heat treatment, and further is superior in shapeability and a method of production of automobile chassis parts using this steel material, that is, one being a steel material to which Nb and Mo have been compositely added and having a difference 50 to 150 points between a Vicker's hardness of the center of plate thickness and a maximum value of Vicker's hardness within 0.5 mm from the surface after bending by a bending R of the plate outer surface of 2 to 5 times the plate thickness. The surface is high in hardness and the center part is low in hardness, so the fatigue characteristics and shapeability are superior. Note that if annealing under conditions giving a tempering parameter ? defined by ?=T(20+log(t)) of 14000 to 19000 (where T is the absolute temperature, t is the time (h), and the temperature rise is 660° C.
    Type: Grant
    Filed: August 8, 2007
    Date of Patent: September 9, 2014
    Assignees: Nippon Steel & Sumitomo Metal Corporation, Toyota Jidosha Kabushiki Kaisha
    Inventors: Hideyuki Nakamura, Isao Anai, Yasushi Yamamoto, Takaaki Fukushi, Izuru Yamamoto, Masaaki Kondo, Satoru Shimazu
  • Patent number: 8778261
    Abstract: The present invention provides a steel material for automobile chassis parts, having high fatigue characteristics, without a heat treatment, and superior shapeability, and a method of production of such automobile chassis parts. The surface of the steel has a high hardness and the center has a low hardness, providing the superior characteristics. With an annealing step of the invention, it is possible to relieve internal stress and further improve fatigue characteristics.
    Type: Grant
    Filed: November 21, 2011
    Date of Patent: July 15, 2014
    Assignees: Nippon Steel & Sumitomo Metal Corporation, Toyota Jidosha Kabushiki Kaisha
    Inventors: Hideyuki Nakamura, Isao Anai, Yasushi Yamamoto, Takaaki Fukushi, Izuru Yamamoto, Masaaki Kondo, Satoru Shimazu
  • Publication number: 20130056115
    Abstract: An automobile chassis part which is excellent in low cycle fatigue characteristics, characterized by being formed by steel which contains, by mass %, C: 0.02 to 0.10%, Si: 0.05 to 1.0%, Mn: 0.3 to 2.5%, P: 0.03% or less, S: 0.01% or less, Ti: 0.005 to 0.1%, Al: 0.005 to 0.1%, N: 0.0005 to 0.006%, and B: 0.0001 to 0.01 and has a balance of Fe and unavoidable impurities, in which 80% or more of the part structure comprises a bainite structure and in which a portion where a ratio R/t of the thickness “t” and external surface curvature radius R is 5 or less has an X-ray half width of an (211) plane of 5 (deg) or less.
    Type: Application
    Filed: November 25, 2010
    Publication date: March 7, 2013
    Inventors: Takaaki Fukushi, Hideyuki Nakamura, Isao Anai
  • Publication number: 20120093678
    Abstract: The present invention provides a steel material for automobile chassis parts, having high fatigue characteristics, without a heat treatment, and superior shapeability, and a method of production of such automobile chassis parts. The surface of the steel has a high hardness and the center has a low hardness, providing the superior characteristics. With an annealing step of the invention, it is possible to relieve internal stress and further improve fatigue characteristics.
    Type: Application
    Filed: November 21, 2011
    Publication date: April 19, 2012
    Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, NIPPON STEEL CORPORATION
    Inventors: Hideyuki NAKAMURA, Isao Anai, Yasushi Yamamoto, Takaaki Fukushi, Izuru Yamamoto, Masaaki Kondo, Satoru Shimazu