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:
Nov. 04, 2014
Filed:
Sep. 10, 2010
Yuuji Kimura, Tsukuba, JP;
Tadanobu Inoue, Tsukuba, JP;
Shuji Murasaki, Takatsuki, JP;
Mataichi Fukuda, Komatsu, JP;
Yuuji Kimura, Tsukuba, JP;
Tadanobu Inoue, Tsukuba, JP;
Shuji Murasaki, Takatsuki, JP;
Mataichi Fukuda, Komatsu, JP;
National Institute for Materials Science, Ibaraki, JP;
Fusokiko Co., Ltd., Osaka, JP;
Kyowa Kogyosyo Co., Ltd., Ishikawa, JP;
Abstract
Provided is a high-strength bolt which has a tensile strength of 1,200 MPa or more while exhibiting excellent ductility and delayed facture resistance, and further has an excellent impact toughness which had not been obtained in the conventional high-strength bolt. The high-strength bolt has a tensile strength of 1.2 GPa or more and includes a threaded portion and cylindrical neck portion. The bolt has K of 0.8 or more and satisfies Ho<Hs, where K is defined by the equation: (Ao×Ho)/(As×Hs)=K, in which Ao is an effective cross-sectional area of the cylindrical neck portion with a diameter larger than that of the threaded portion, Ho is a Vickers hardness of a portion at which Ao is measured, As is an effective cross-sectional area of the threaded portion, and Hs is a Vickers hardness of the threaded portion.