Patents by Inventor Norihiko Nakai

Norihiko Nakai 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).

  • Tool steel production method
    Patent number: 5458703
    Abstract: A tool steel production method and a tool steel are disclosed in this invention. The method consists of following two steps:1. Toughness (Ch) of the tool steel is evaluated from a formula:Ch=f(Vp, H, T)after estimating Vp, a square sum of output voltage of total Barkhausen noise signals which are produced in the process of magnetization of the tool steel sample, and measuring temperring hardness (H) and hardening temperature (T) of the tool steel sample.2. A tool steel having a required toughness is produced by adjusting temperring hardness (H) and/or hardening temperature (T) based on the toughness evaluation of the tool steel sample mentioned above.
    Type: Grant
    Filed: August 24, 1993
    Date of Patent: October 17, 1995
    Assignee: Nippon Koshuha Steel Co., Ltd.
    Inventor: Norihiko Nakai