Patents by Inventor Kiyomi Yasuura

Kiyomi Yasuura 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).

  • Method of ion nitriding steel workpieces
    Patent number: 5240514
    Abstract: In subjecting a steel workpiece to nitriding by glow discharge, formation of brittle nitrogen compound is restrained and the surface hardened layer with a nitrogen diffusion layer of high toughness is obtained by making the gas atmospheric condition the gas mixing ratio of N.sub.2 :H.sub.2 =1:2-40. By mixing Ar gas in the above gas atmospheric condition additionally, glow width is adjusted and glow discharge is allowed to enter into narrow concaves at the surface of a workpiece.
    Type: Grant
    Filed: September 30, 1991
    Date of Patent: August 31, 1993
    Assignee: NDK, Incorporated
    Inventors: Kiyomi Yasuura, Katunori Hanakawa, Yoshihisa Miwa