Patents by Inventor Tadamasa Yamada

Tadamasa Yamada 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 purifying a bearing steel
    Patent number: 4702767
    Abstract: A high-quality bearing steel contains 0.70 to 1.10% by weight of C, 0.15 to 1.60% by weight of Si, 0.15 to 1.15% by weight of Mn, 0.010% by weight or less of P, 0.002% by weight or less of S, 0.50 to 1.60% by weight of Cr, 0.015% by weight or less of Al, 0.0050% by weight or less of N, 0.0006% by weight or less of O, 0.0015% by weight or less of Ti, and the remainder of Fe together with impurities. The steel can further contain 0.05 to 0.50% by weight of Mo or a member or members selected from a group consisting of 0.05 to 0.30% by weight of V and 0.05 to 0.30% by weight of Nb. The bearing steel has an excellent durability life and cold workability.
    Type: Grant
    Filed: July 7, 1986
    Date of Patent: October 27, 1987
    Assignees: Aichi Steel Works, Ltd., Koyo Seiko Kabushiki Kaisha
    Inventors: Yatsuka Takata, Tadamasa Yamada, Eiki Kikuchi
  • Bearing steel and method of manufacturing the same
    Patent number: 4642219
    Abstract: A high-quality bearing steel contains 0.70 to 1.10% by weight of C, 0.15 to 1.60% by weight of Si, 0.15 to 1.15% by weight of Mn, 0.010% by weight or less of P, 0.002% by weight or less of S, 0.50 to 1.60% by weight of Cr, 0.015% by weight or less of Al, 0.0050% by weight or less of N, 0.0006% by weight or less of O, 0.0015% by weight or less of Ti, and the remainder of Fe together with impurities. The steel can further contain 0.05 to 0.50% by weight of Mo or a member or members selected from a group consisting of 0.05 to 0.30% by weight of V and 0.05 to 0.30% by weight of Nb. the bearing steel has an excellent durability life and cold workability.
    Type: Grant
    Filed: March 4, 1985
    Date of Patent: February 10, 1987
    Assignees: Aichi Steel Works, Ltd., Koyo Seiko Kabushiki Kaisha
    Inventors: Yatsuka Takata, Tadamasa Yamada, Eiki Kikuchi