Patents by Inventor Yukio Numakura

Yukio Numakura 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).

  • Galvannealed steel sheet with distinguished anti-powdering and anti-flaking properties and process for producing the same
    Patent number: 5049453
    Abstract: A galvannealed steel sheet having distinguished anti-powdering property and anti-flaking property is disclosed. The steel sheet comprises a matrix steel sheet and a galvannealed coating layer having a coating weight of 45 to 90 g/m.sup.2, composed of 8.about.12 wt. % Fe and 0.05.about.0.35 wt. %, preferably 0.05.about.0.30 wt. % Al, the balance being Zn, provided on at least one side of the matrix steel sheet, the galvannealed coating layer having a .GAMMA. phase with a thickness of not more than 1.3 .mu.m, preferably not more than 1.0 .mu.m in the region at the boundary to the matrix steel sheet, and the surface region of galvannealed coating layer has a structure either (1) .eta. and .zeta. phases do not exist in the surface region of the galvannealed coating layer, or, (2) when at least one of .eta. and .zeta. phases exist therein, the total amount of the at least one of .eta. and .zeta. phases in the galvannealed coating layer is not more than 1.5 g/m.sup.2.
    Type: Grant
    Filed: February 22, 1990
    Date of Patent: September 17, 1991
    Assignee: Nippon Steel Corporation
    Inventors: Yukimasa Suemitsu, Motohiro Nakayama, Yukio Numakura, Tatsuya Kanamaru, Hisao Hayashi, Tadafumi Honda