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:
Feb. 21, 2012
Filed:
Jan. 27, 2010
Takashi Iwamoto, Tokyo, JP;
Kunikazu Tomita, Tokyo, JP;
Hideto Kimura, Tokyo, JP;
Takaaki Toyooka, Tokyo, JP;
Hisato Nishisaka, Osaka, JP;
Masao Goto, Osaka, JP;
Hisashi Harada, Osaka, JP;
Takashi Iwamoto, Tokyo, JP;
Kunikazu Tomita, Tokyo, JP;
Hideto Kimura, Tokyo, JP;
Takaaki Toyooka, Tokyo, JP;
Hisato Nishisaka, Osaka, JP;
Masao Goto, Osaka, JP;
Hisashi Harada, Osaka, JP;
JFE Steel Corporation, , JP;
JTEKT Corporation, , JP;
Abstract
A steel part having a long rolling contact fatigue life and capable of further increasing the life of a bearing under severer using condition than usual conditions. The steel part includes steel having a composition containing 0.7% by mass to 1.1% by mass of C, 0.5% by mass to 2.0% by mass of Si, 0.4% by mass to 2.5% by mass of Mn, 1.6% by mass to 5.0% by mass of Cr, 0.1% by mass to less than 0.5% by mass of Mo, 0.010% by mass to 0.050% by mass of Al, less than 0.0015% by mass of Sb as an impurity, and the balance composed of Fe and inevitable impurities, the steel being hardened and tempered. In the steel structure of a portion from the surface to a depth of 5 mm, residual cementite has a grain diameter of 0.05 to 1.5 μm, prior austenite has a grain diameter of 30 μm or less, and the ratio by volume of the residual austenite is less than 25%.