Patents by Inventor Masahiko Yasukawa

Masahiko Yasukawa 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 for producing a seamless steel tubular product
    Patent number: 5816087
    Abstract: A seamless steel tubular product is produced by hot-piercing an alloy-steel billet with a piercing plug to produce a hollow shell and then rolling the hollow shell. Prior to the hot-piercing, a steel sheet is joined to an end surface of the billet into which the plug is to be driven, such that the steel plate may not project beyond the periphery of the billet, the steel plate having a surface area (C) satisfying the equation:S.times.0.2.ltoreq.C.ltoreq.S.times.1.2where, S is represented (plug bottom radius).sup.2 .times.3.14.
    Type: Grant
    Filed: April 16, 1996
    Date of Patent: October 6, 1998
    Assignee: NKK Corporation
    Inventors: Tatsuro Katsumura, Yusuke Minami, Masahiko Yasukawa
  • Method for manufacturing seamless pipe
    Patent number: 5778714
    Abstract: A method for manufacturing a seamless pipe, comprises:preparing a billet made of an alloy steel or an alloy;joining a steel plate to an end surface at which piercing of the billet is commenced;preparing a piercing plug made of Mo, a Mo alloy or a heat-resisting steel;hot-piercing the billet by using the piercing plug to produce a hollow shell; androlling the hollow shell to produce a seamless pipe.
    Type: Grant
    Filed: May 13, 1996
    Date of Patent: July 14, 1998
    Assignee: NKK Corporation
    Inventors: Tatsuro Katsumura, Takashi Ariizumi, Motoharu Yamazaki, Masahiko Yasukawa