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:
Jul. 05, 2005
Filed:
Mar. 11, 2002
Yukitaka Murakami, Fukuoka, JP;
Yukitaka Murakami, Fukuoka, JP;
Kyushu TLO Company Limited, Fukuoka, JP;
NSK Ltd., Tokyo, JP;
Abstract
A long life fatigue strength design method for a metallic material is capable of allowing design of an optimum mechanical part according to a set service life by considering an increase in ODA (area affected by hydrogen observed blackish by a metallurgical microscope) size according to the assumed service life of the mechanical part. The method includes obtaining, from the results of a fatigue test, a functional relation between the number of stress cycles to failure and the size of a hydrogen affected area around an inclusion affected by trapped hydrogen. From the functional relation, equivalent defect sizes as the sizes of the inclusions after growth corresponding to the assumed number of cycles of working stress on the mechanical part using the metallic material are obtained, and the mechanical part is designed using the equivalent defect sizes in the calculation of a long life fatigue strength such as allowable stress, whereby a failure life design can be performed with the ODA size growth taken into account according to the assumed service life of the mechanical part.