Patents by Inventor Yusaku Maruno

Yusaku Maruno 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: 11634805
    Abstract: An austenitic stainless steel includes a mixed grain structure composed of a columnar crystal having an average crystal grain size of 20 ?m or less and an equiaxed crystal having an average crystal grain size of 5.0 ?m or less, in which an area proportion of the columnar crystal in the mixed grain structure is 20% or more, and an average crystal grain size of the whole mixed grain structure is 5.0 ?m or less. Accordingly, it is possible to provide a material having excellent irradiation resistance and mechanical properties.
    Type: Grant
    Filed: March 11, 2019
    Date of Patent: April 25, 2023
    Assignee: Hitachi, Ltd.
    Inventors: Takahiro Ishizaki, Yusaku Maruno, Kinya Aota, Yingjuan Yang
  • Patent number: 11053562
    Abstract: An objective of the invention is to provide an austenitic stainless steel article having superior irradiation resistance and stress corrosion cracking resistance than before while maintaining mechanical properties equivalent to those of conventional ones. There is provided a dispersion strengthened austenitic stainless steel article, including: 16-26 mass % of Cr; 8-22 mass % of Ni; 0.005-0.08 mass % of C; 0.002-0.1 mass % of N; 0.02-0.4 mass % of O; at least one of 0.2-2.8 mass % of Zr, 0.4-5 mass % of Ta, and 0.2-2.6 mass % of Ti; and a balance consisting of Fe and inevitable impurities. The Zr, Ta and Ti components form inclusion particles in the stainless steel article by combining with the C, N and O components. The stainless steel article has an average grain size of 1 ?m or less and a maximum grain size of 5 ?m or less.
    Type: Grant
    Filed: October 19, 2016
    Date of Patent: July 6, 2021
    Assignee: HITACHI, LTD.
    Inventors: Takahiro Ishizaki, Yusaku Maruno
  • Publication number: 20210189537
    Abstract: An austenitic stainless steel includes a mixed grain structure composed of a columnar crystal having an average crystal grain size of 20 ?m or less and an equiaxed crystal having an average crystal grain size of 5.0 ?m or less, in which an area proportion of the columnar crystal in the mixed grain structure is 20% or more, and an average crystal grain size of the whole mixed grain structure is 5.0 ?m or less. Accordingly, it is possible to provide a material having excellent irradiation resistance and mechanical properties.
    Type: Application
    Filed: March 11, 2019
    Publication date: June 24, 2021
    Inventors: Takahiro ISHIZAKI, Yusaku MARUNO, Kinya AOTA, Yingjuan YANG
  • Patent number: 10718038
    Abstract: An object of the invention is to provide: a two-phase alloy as a metal material that can be preferably utilized under circumstances of a temperature range and a high corrosion as in an oil well, the two-phase alloy having a high corrosion resistance and good mechanical properties that are equivalent or more than those of conventional ones, and saving a cost; a product of the two-phase alloy; and a method for producing the product. There is provided a two-phase alloy containing Cr as a major component and including two phases of an austenite phase and a ferrite phase in a mixed state. The alloy has a chemical composition containing: 34-70 mass % of Cr; 17-45 mass % of Ni; 10-35 mass % of Fe; 0.1-2 mass % of Mn; 0.1-1 mass % of Si; and impurities. The total content of the Ni and the Fe is 30-65 mass %.
    Type: Grant
    Filed: September 28, 2015
    Date of Patent: July 21, 2020
    Assignee: HITACHI, LTD.
    Inventors: Masafumi Noujima, Yasuhisa Aono, Naoya Okizaki, Yusaku Maruno, Tomonori Kimura, Makoto Ogata
  • Publication number: 20180274053
    Abstract: An objective of the invention is to provide an austenitic stainless steel article having superior irradiation resistance and stress corrosion cracking resistance than before while maintaining mechanical properties equivalent to those of conventional ones. There is provided a dispersion strengthened austenitic stainless steel article, including: 16-26 mass % of Cr; 8-22 mass % of Ni; 0.005-0.08 mass % of C; 0.002-0.1 mass % of N; 0.02-0.4 mass % of O; at least one of 0.2-2.8 mass % of Zr, 0.4-5 mass % of Ta, and 0.2-2.6 mass % of Ti; and a balance consisting of Fe and inevitable impurities. The Zr, Ta and Ti components form inclusion particles in the stainless steel article by combining with the C, N and O components. The stainless steel article has an average grain size of 1 ?m or less and a maximum grain size of 5 ?m or less.
    Type: Application
    Filed: October 19, 2016
    Publication date: September 27, 2018
    Inventors: Takahiro ISHIZAKI, Yusaku MARUNO
  • Publication number: 20170292175
    Abstract: An object of the invention is to provide: a two-phase alloy as a metal material that can be preferably utilized under circumstances of a temperature range and a high corrosion as in an oil well, the two-phase alloy having a high corrosion resistance and good mechanical properties that are equivalent or more than those of conventional ones, and saving a cost; a product of the two-phase alloy; and a method for producing the product. There is provided a two-phase alloy containing Cr as a major component and including two phases of an austenite phase and a ferrite phase in a mixed state. The alloy has a chemical composition containing: 34-70 mass % of Cr; 17-45 mass % of Ni; 10-35 mass % of Fe; 0.1-2 mass % of Mn; 0.1-1 mass % of Si; and impurities. The total content of the Ni and the Fe is 30-65 mass %.
    Type: Application
    Filed: September 28, 2015
    Publication date: October 12, 2017
    Applicant: HITACHI, LTD.
    Inventors: Masafumi NOUJIMA, Yasuhisa AONO, Naoya OKIZAKI, Yusaku MARUNO, Tomonori KIMURA, Makoto OGATA
  • Patent number: 8888069
    Abstract: The invention provides a valve which suppresses a continuous corrosion of a chemical compound phase such as an eutectic carbide or the like in a valve seat, and improves a corrosion resistance, an impact resistance and an erosion resistance of the valve seat. The invention disperses a chemical compound phase such as the eutectic carbide or the like crystallizing in a dendrite gap as a granular shape or a blocky shape which is equal to or less than about 100 ?m, by moving a tool rotating in a crimped state by a load application to a vertical direction to a surface of the valve seat so as to carry out a friction stir processing, and forming a weld metallographic structure of a surface layer portion of the valve seat as a cubic.
    Type: Grant
    Filed: March 30, 2011
    Date of Patent: November 18, 2014
    Assignee: Hitachi-GE Nuclear Energy, Ltd.
    Inventors: Yusaku Maruno, Seunghwan Park, Yoshihisa Kiyotoki, Shin Kumagai
  • Publication number: 20110278490
    Abstract: The invention provides a valve which suppresses a continuous corrosion of a chemical compound phase such as an eutectic carbide or the like in a valve seat, and improves a corrosion resistance, an impact resistance and an erosion resistance of the valve seat. The invention disperses a chemical compound phase such as the eutectic carbide or the like crystallizing in a dendrite gap as a granular shape or a blocky shape which is equal to or less than about 100 ?m, by moving a tool rotating in a crimped state by a load application to a vertical direction to a surface of the valve seat so as to carry out a friction stir processing, and forming a weld metallographic structure of a surface layer portion of the valve seat as a cubic.
    Type: Application
    Filed: March 30, 2011
    Publication date: November 17, 2011
    Inventors: Yusaku Maruno, Seunghwan Park, Yoshihisa Kiyotoki, Shin Kumagai
  • Patent number: 7619332
    Abstract: A permanent magnet type electric rotating machine comprises a stator having a distributed winding and a permanent magnet rotor, wherein the permanent magnet rotor is provided with a wind passage in an axial direction thereof.
    Type: Grant
    Filed: September 30, 2005
    Date of Patent: November 17, 2009
    Assignee: Hitachi, Ltd.
    Inventors: Mamoruo Kimura, Kazumasa Ide, Motonobu Iizuka, Shuji Mizutani, Tetsuo Fujigaki, Kengo Iwashige, Hisato Tagawa, Yusaku Maruno
  • Publication number: 20060071568
    Abstract: A permanent magnet type electric rotating machine comprises a stator having a distributed winding and a permanent magnet rotor, wherein the permanent magnet rotor is provided with a wind passage in an axial direction thereof.
    Type: Application
    Filed: September 30, 2005
    Publication date: April 6, 2006
    Inventors: Mamoruo Kimura, Kazumasa Ide, Motonobu Iizuka, Shuji Mizutani, Tetsuo Fujigaki, Kengo Iwashige, Hisato Tagawa, Yusaku Maruno