Patents by Inventor Yukio Arimi

Yukio Arimi 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: 5595610
    Abstract: A manufacturing method of case-hardened parts whose chemical components comprising especially Fe, C, Si, Mn, S, Ni, Mo, Al, V and N including a step of the heat treatment 1 in which, after carburizing, carbonitriding or carburizing followed by carbonitriding steel is cooled gradually at a temperature less than 100.degree. C./minute, by another step of the heat treatment 2, in which steel is heated to a temperature higher than the Ac.sub.3 transformation point and less than 850.degree. C. and kept at the above temperature before quenching, or after keeping at the temperature, is cooled down to a level not below 600.degree. C. before quenching, or quenching is done after cooling down to and keeping the temperature not below 600.degree. C. is disclosed. This method makes the surface layer a mixture of martensite and retained austenite. Thus the case hardened steel products of high precision and high strength are obtainable.
    Type: Grant
    Filed: January 22, 1996
    Date of Patent: January 21, 1997
    Assignees: Kabushiki Kaisha Kobe Seiko Sho, Mazda Motor Corporation
    Inventors: Hisao Maeda, Yoshitake Matsushima, Morifumi Nakamura, Akito Shiina, Mikio Hirahara, Yukio Arimi, Yoshihiko Kojima
  • Patent number: 5019182
    Abstract: A method of manufacturing a steel member comprising the steps of: carburizing and quenching or carbo-nitriding and quenching a steel material; shot-peening the steel material quenched in the first step without tempering; and aging the steel material shot-peened in the second step. Preferably the steel material comprises 0.1 to 0.4 wt. % C, 0.06 to 0.15 wt. % Si, 0.3 to 1.0 wt. % Mn, 0.9 to 1.2 wt. % Cr, 0.3 to 0.5 wt. % Mo, and the remainder Fe. The steel member is preferably used in transmission gears for automobiles, which require superior strength.
    Type: Grant
    Filed: September 26, 1989
    Date of Patent: May 28, 1991
    Assignee: Mazda Motor Corporation
    Inventor: Yukio Arimi
  • Patent number: 4971634
    Abstract: A method of carburizing and quenching involves the following three steps of: pre-carburizing a steel member containing Cr with precipitating carbide by heating to achieve a surface carbon concentration of not less than 1%; spheroidizing the carbide obtained by alternately holding the steel member at a temperature slightly above and slightly below the A.sub.1 transformation temperature under a carbon potential of from 0.5 to 1.0%; and carburizing and quenching or carbo-nitriding and quenching the steel member followed by reheating at not more than the heating temperature of pre-carburizing.
    Type: Grant
    Filed: July 25, 1989
    Date of Patent: November 20, 1990
    Assignee: Mazda Motor Corporation
    Inventors: Shinya Shibata, Yoshihisa Miwa, Yoshihiko Kojima, Yukio Arimi