Patents by Inventor Koh-ichi Sugimoto

Koh-ichi Sugimoto 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: 20140230969
    Abstract: Provided is a TRIP-aided dual-phase martensitic steel which is excellent in terms of strength-elongation balance and Charpy impact value and has dual-phase martensite composed of a soft lath martensitic structure and a hard lath martensitic structure as a matrix phase, regardless of forging temperature or forging reduction ratio, by controlling heat treatment conditions. The dual-phase martensitic steel contains 0.1-0.7% C, 0.5-2.5% Si, 0.5-3.0% Mn, 0.5-2.0% Cr, 0.5% or less (including 0%) of Mo, 0.04-2.5% Al, and the balance Fe with incidental impurities; has its metallographic structure in which a matrix phase is composed of a soft lath martensitic structure and a hard lath martensitic structure; and obtained by heating its raw steel material to a ?-range, rapidly cooling the heated material to a temperature slightly above a martensite transformation starting temperature (Ms), and then performing an isothermal transformation process the cooled material in the temperature range from Mf to [(Mf)?100° C].
    Type: Application
    Filed: March 14, 2012
    Publication date: August 21, 2014
    Applicants: USUI KOKUSAI SANGYO KAISHA LIMITED, SHINSU UNIVERSITY
    Inventors: Koh-ichi Sugimoto, Junya Kobayashi, Nobuo Yoshikawa, Yuji Nakajima, Teruhisa Takahashi, Goro Arai
  • Patent number: 8585835
    Abstract: A high-strength steel machined product giving excellent hardenability has a metal microstructure with excellent balance of strength and toughness and high stability of retained austenite. The product is composed of an ultra-high low-alloy TRIP steel having a metal microstructure which contains an appropriate quantity of two or more of Cr, Mo, and Ni, and an appropriate quantity of one or more of Nb, Ti, and V, and having an appropriate value of carbon equivalent; the metal microstructure has a mother-phase structure composed mainly of lathy bainitic ferrite with a small amount of granular bainitic ferrite and polygonal ferrite, and has a secondary-phase structure composed of fine retained austenite and martensite.
    Type: Grant
    Filed: October 29, 2009
    Date of Patent: November 19, 2013
    Assignees: Usui Kokusai Sangyo Kaisha Limited, Shinshu University
    Inventors: Koh-ichi Sugimoto, Sho-hei Sato, Teruhisa Takahashi, Goro Arai
  • Publication number: 20110209803
    Abstract: A high-strength steel machined product giving excellent hardenability has a metal microstructure with excellent balance of strength and toughness and high stability of retained austenite. The product is composed of an ultra-high low-alloy TRIP steel having a metal microstructure which contains an appropriate quantity of two or more of Cr, Mo, and Ni, and an appropriate quantity of one or more of Nb, Ti, and V, and having an appropriate value of carbon equivalent; the metal microstructure has a mother-phase structure composed mainly of lathy bainitic ferrite with a small amount of granular bainitic ferrite and polygonal ferrite, and has a secondary-phase structure composed of fine retained austenite and martensite.
    Type: Application
    Filed: October 29, 2009
    Publication date: September 1, 2011
    Applicants: USUI KOKUSAI SANGYO KAISHA LIMITED, SHINSHU UNIVERSITY
    Inventors: Koh-ichi Sugimoto, Sho-hei Sato, Teruhisa Takahashi, Goro Arai
  • Patent number: 7833363
    Abstract: A high-strength forged part is disclosed which comprises a base phase structure, comprising 30% or more of ferrite in terms of a space factor, and a second phase structure, comprising bainite and/or martensite, and retained austenite having an average gain diameter of 5 ?m or less and a content represented by 50X[C]<[V?R]<150x[C], wherein [V?R] represents a space factor of the retained austenite (?R) and [C] represents the mass % of C in the forged part. Furthermore, a high-strength forged part is disclosed which comprises a base phase structure, comprising 50% or more of tempered bainite or tempered martensite in terms of a space factor, and a second phase structure, comprising martensite and 3% to 30% retained austenite in terms of a space factor, wherein the portion of the retained austenite and martensite having an aspect ratio of 2 or less is 25% or less in terms of a space factor.
    Type: Grant
    Filed: October 18, 2007
    Date of Patent: November 16, 2010
    Assignee: Kobe Steel, Ltd.
    Inventors: Shushi Ikeda, Koichi Makii, Hiroshi Akamizu, Yoichi Mukai, Koh-ichi Sugimoto
  • Publication number: 20080092996
    Abstract: A high-strength forged part is disclosed which comprises a base phase structure, comprising 30% or more of ferrite in terms of a space factor, and a second phase structure, comprising bainite and/or martensite, and retained austenite having an average grain diameter of 5 ?m or less and a content represented by 50X[C]<[V?R]<150x[C], wherein [V?R] represents a space factor of the retained austenite (?R) and [C] represents the mass % of C in the forged part. Furthermore, a high-strength forged part is disclosed which comprises a base phase structure, comprising 50% or more of tempered bainite or tempered martensite in terms of a space factor, and a second phase structure, comprising martensite and 3% to 30% retained austenite in terms of a space factor, wherein the portion of the retained austenite and martensite having an aspect ratio of 2 or less is 25% or less in terms of a space factor.
    Type: Application
    Filed: October 18, 2007
    Publication date: April 24, 2008
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO
    Inventors: Shushi Ikeda, Koichi Makii, Hiroshi Akamizu, Yoichi Mukai, Koh-ichi Sugimoto
  • Patent number: 7314532
    Abstract: A high-strength forged part is disclosed which comprises a base phase structure, comprising 30% or more of ferrite in terms of a space factor, and a second phase structure, comprising bainite and/or martensite, and retained austenite having an average grain diameter of 5 ?m or less and a content represented by 50×[C]<[V?R]<150×[C], wherein [V?R] represents a space factor of the retained austenite (?R) and [C] represents the mass % of C in the forged part. Furthermore, a high-strength forged part is disclosed which comprises a base phase structure, comprising 50% or more of tempered bainite or tempered martensite in terms of a space factor, and a second phase structure, comprising martensite and 3% to 30% retained austenite in terms of a space factor, wherein the portion of the retained austenite and martensite having an aspect ratio of 2 or less is 25% or less in terms of a space factor.
    Type: Grant
    Filed: February 25, 2004
    Date of Patent: January 1, 2008
    Assignee: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Shushi Ikeda, Koichi Makii, Hiroshi Akamizu, Yoichi Mukai, Koh-ichi Sugimoto
  • Patent number: 7090731
    Abstract: A high strength steel sheet having (2-1) a base phase structure, the base phase structure being tempered martensite or tempered bainite and accounting for 50% or more in terms of a space factor relative to the whole structure, or the base phase structure comprising tempered martensite or tempered bainite which accounts for 15% or more in terms of a space factor relative to the whole structure and further comprising ferrite, the tempered martensite or the tempered bainite having a hardness which satisfies the relation of Vickers hardness (Hv)?500[C]+30[Si]+3[Mn]+50 where [ ] represents the content (mass %) of each element, and (2-2) a second phase structure comprising retained austenite which accounts for 3 to 30% in terms of a space factor relative to the whole structure and optionally further comprising bainite and/or martensite, the retained austenite having a C concentration (C?R) of 0.8% or more.
    Type: Grant
    Filed: January 31, 2002
    Date of Patent: August 15, 2006
    Assignee: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Takahiro Kashima, Shunichi Hashimoto, Shushi Ikeda, Hiroshi Akamizu, Koh-ichi Sugimoto, Akihiko Nagasaka, Akinobu Kanda, Ryo Kikuchi
  • Publication number: 20040226635
    Abstract: A high-strength forged part is disclosed which comprises a base phase structure, comprising 30% or more of ferrite in terms of a space factor, and a second phase structure, comprising bainite and/or martensite, and retained austenite having an average grain diameter of 5 &mgr;m or less and a content represented by 50×[C]<[V&ggr;R]<150×[C], wherein [V&ggr;R] represents a space factor of the retained austenite (&ggr;R) and [C] represents the mass % of C in the forged part. Furthermore, a high-strength forged part is disclosed which comprises a base phase structure, comprising 50% or more of tempered bainite or tempered martensite in terms of a space factor, and a second phase structure, comprising martensite and 3% to 30% retained austenite in terms of a space factor, wherein the portion of the retained austenite and martensite having an aspect ratio of 2 or less is 25% or less in terms of a space factor.
    Type: Application
    Filed: February 25, 2004
    Publication date: November 18, 2004
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO
    Inventors: Shushi Ikeda, Koichi Makii, Hiroshi Akamizu, Yoichi Mukai, Koh-ichi Sugimoto
  • Publication number: 20040074575
    Abstract: A high strength steel sheet having (2-1) a base phase structure, the base phase structure being tempered martensite or tempered bainite and accounting for 50% or more in terms of a space factor relative to the whole structure, or the base phase structure comprising tempered martensite or tempered bainite which accounts for 15% or more in terms of a space factor relative to the whole structure and further comprising ferrite, the tempered martensite or the tempered bainite having a hardness which satisfies the relation of Vickers hardness (Hv)≧500[C]+30[Si]+3[Mn]+50 where [ ] represents the content (mass %) of each element, and (2-2) a second phase structure comprising retained austenite which accounts for 3 to 30% in terms of a space factor relative to the whole structure and optionally further comprising bainite and/or martensite, the retained austenite having a C concentration (C&ggr;R) of 0.8% or more.
    Type: Application
    Filed: July 31, 2003
    Publication date: April 22, 2004
    Inventors: Takahiro Kashima, Shunichi Hashimoto, Shushi Ikeda, Hiroshi Akamizu, Koh-ichi Sugimoto, Akihiko Nagasaka, Akinobu Kanda, Ryo Kikuchi