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. 14, 1998
Filed:
Nov. 30, 1995
Shiho Fukumoto, Yasugi, JP;
Hideki Nakamura, Yonago, JP;
Hitachi Metals, Ltd., Tokyo, JP;
Abstract
There is disclosed a bearing member which is enhanced in toughness without lowering the hardness of a core portion so as to prevent an instantaneous rupture of the bearing member, and is excellent in rolling fatigue service life characteristics. Martensitic Fe-based bearing steel of the invention contains, by weight, not more than 0.4% carbon, not more than 2% silicon, not more than 2% manganese, not more than 5% nickel, 3.5 to 7.0% chromium, at least one of tungsten and molybdenum an tungsten equivalent defined by (�W!+2�Mo!) of which at least one is 3 to 15%, and not less than 0.5% but less than 1.1% vanadium. A ratio of Cv/Ceq is not more than 0.3 where Cv represents a carbon equivalent of vanadium defined by 0.2�V!, and Ceq represents a carbon equivalent of carbide-forming elements defined by (0.063�Cr!+0.06�Mo!+0.033�W!+0.2�V!). With this construction, the precipitation of MC carbides is suppressed, and M.sub.2 C-type carbides larger in morphology than MC-type carbides are dispersed in an appropriate amount, thereby enhancing a rupture toughness value.