Patents by Inventor Tatsuaki Sawai

Tatsuaki Sawai 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 evaluating high fatigue strength material in high tensile strength steel and creation of high fatigue strength material
    Patent number: 6546808
    Abstract: The present invention provides a method of designing a high fatigue strength in high tensile strength steel, comprising: obtaining values of tensile strength &sgr;B (unit thereof is MPa) and Vickers hardness Hv of the steel; measuring a flaw area of an inclusion, when a fracture origin is located only at a surface of the steel; and estimating, in designing the high fatigue strength steel, that a fatigue limit &sgr;w (unit thereof is MPa) of the steel satisfies either &sgr;w≧0.5 &sgr;B or &sgr;w≧1.6 Hv, when a square root of the flaw area, (area)½ (unit thereof is m), contained in the steel is no larger than 45.8/&sgr;B2 or 4.47/Hv2. According to the present invention, a method of evaluating high fatigue strength in high tensile strength steel, in which method a relationship between a flaw dimension (area) of ODA and the fatigue strength is considered, and a high fatigue strength material can be provided.
    Type: Grant
    Filed: July 31, 2001
    Date of Patent: April 15, 2003
    Assignee: National Institute for Materials Science
    Inventors: Tatsuaki Sawai, Saburo Matsuoka, Takayuki Abe, Etsuo Takeuchi, Kensuke Miyahara, Hisashi Hirukawa, Kaneaki Tsuzaki, Yuji Kimura
  • Method of evaluating high fatigue strength material in high tensile strength steel and creation of high fatigue strength material
    Publication number: 20020033053
    Abstract: The present invention provides a method of designing a high fatigue strength material in high tensile strength steel, comprising the steps of: obtaining the values of tensile strength &sgr;B (unit thereof is MPa) and Vickers hardness Hv of the steel; measuring the flaw area of inclusion, when the fracture origin is located only at the surface of the steel; and estimating, in designing the high fatigue strength material, that the fatigue limit &sgr;w (unit thereof is MPa) of the steel satisfies either &sgr;w≧0.5&sgr;B or &sgr;w≧1.6 Hv, when a square root of the flaw area, (area)½ (unit thereof is m), contained in the steel is no larger than 45.8/&sgr;B2 or 4.47/Hv2. According to the present invention, a method of evaluating high fatigue strength material in high tensile strength steel, in which method the relationship between the flaw dimension (area) of ODA and the fatigue strength is considered, as well as a high fatigue strength material, can be Provided.
    Type: Application
    Filed: July 31, 2001
    Publication date: March 21, 2002
    Inventors: Tatsuaki Sawai, Saburo Matsuoka, Takayuki Abe, Etsuo Takeuchi, Kensuke Miyahara, Hisashi Hirukawa, Kaneaki Tsuzaki, Yuji Kimura