The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 15, 2003
Filed:
Jul. 31, 2001
Tatsuaki Sawai, Ibaraki, JP;
Saburo Matsuoka, Ibaraki, JP;
Takayuki Abe, Ibaraki, JP;
Etsuo Takeuchi, Ibaraki, JP;
Kensuke Miyahara, Ibaraki, JP;
Hisashi Hirukawa, Ibaraki, JP;
Kaneaki Tsuzaki, Ibaraki, JP;
Yuji Kimura, Ibaraki, JP;
National Institute for Materials Science, Ibaraki, JP;
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; (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; (unit thereof is MPa) of the steel satisfies either &sgr; ≧0.5 &sgr; or &sgr; ≧1.6 Hv, when a square root of the flaw area, (area) (unit thereof is m), contained in the steel is no larger than 45.8/&sgr; or 4.47/Hv . 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.