Patents by Inventor Tatsuhiko Hiratani

Tatsuhiko Hiratani 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).

  • Silicon steel sheet and method thereof
    Patent number: 6045627
    Abstract: A silicon steel sheet contains 0.01 wt. % or less C, 4 to 10 wt. % Si, 0.5 wt. % or less Mn, 0.01 wt. % or less P, 0.01 wt. % or less S, 0.2 wt. % or less sol. Al, 0.01 wt. % or less N, 0.02 wt. % or less O and the balance being Fe. The silicon steel sheet has grain boundaries and carbides which are precipitated on the grain boundaries. The carbides have an area of 20% or less to an area of the grain boundaries. The steel sheet is cooled at a cooling speed of 5.degree. C./sec. or more in a temperature range of from 300 to 700.degree. C.
    Type: Grant
    Filed: June 4, 1998
    Date of Patent: April 4, 2000
    Assignee: NKK Corporation
    Inventors: Koichiro Fujita, Yasushi Tanaka, Hironori Ninomiya, Tatsuhiko Hiratani, Shoji Kasai
  • Soft magnetic alloy sheet having low residual magnetic flux density
    Patent number: 5993568
    Abstract: A soft magnetic alloy sheet has low residual magnetic flux density. The alloy sheet comprises a base element and an alloying element having a concentration gradient in a thickness direction of the alloy sheet. The alloying element is selected from Si, Al, Ni, Co and Fe.
    Type: Grant
    Filed: March 25, 1998
    Date of Patent: November 30, 1999
    Assignee: NKK Corporation
    Inventors: Yoshikazu Takada, Hironori Ninomiya, Misao Namikawa, Koichiro Fujita, Shoji Kasai, Tatsuhiko Hiratani
  • Silicon steel sheet and method thereof
    Patent number: 5902419
    Abstract: A silicon steel sheet contains 0.01 wt. % or less C, 4 to 10 wt. % Si, 0.5 wt. % or less Mn, 0.01 wt. % or less P, 0.01 wt. % or less S, 0.2 wt. % or less sol. Al, 0.01 wt. % or less N, 0.02 wt. % or less 0 and the balance being Fe. The silicon steel sheet has grain boundaries and carbides which are precipitated on the grain boundaries. The carbides have an area of 20% or less to an area of the grain boundaries. The steel sheet is cooled at a cooling speed of 5.degree. C./sec. or more in a temperature range of from 300 to 700.degree. C.
    Type: Grant
    Filed: September 23, 1996
    Date of Patent: May 11, 1999
    Assignee: NKK Corporation
    Inventors: Koichiro Fujita, Yasushi Tanaka, Hironori Ninomiya, Tatsuhiko Hiratani, Shoji Kasai