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. 09, 2021
Filed:
Aug. 24, 2018
Nippon Steel Corporation, Tokyo, JP;
Jtekt Corporation, Osaka, JP;
Tomohiro Yamashita, Tokyo, JP;
Takahisa Suzuki, Tokyo, JP;
Yutaka Neishi, Tokyo, JP;
Daisuke Hirakami, Tokyo, JP;
Kohei Kanetani, Osaka, JP;
Takashi Sada, Osaka, JP;
Nippon Steel Corporation, Tokyo, JP;
JTEKT Corporation, Osaka, JP;
Abstract
The steel material for a carburized bearing part according to the present invention contains, by mass %, C: 0.25 to 0.45%, Si: 0.15 to 0.45%, Mn: 0.40 to 1.50%, P: 0.015% or less, S: 0.005% or less, Cr: 0.60 to 2.00%, Mo: 0.10 to 0.35%, V: 0.20 to 0.40%, Al: 0.005 to 0.100%, Ca: 0.0002 to 0.0010%, N: 0.0300% or less and O: 0.0015% or less, with the balance being Fe and impurities, and satisfies Formulae (1) to (3).1.20<0.4Cr+0.4Mo+4.5V<2.75  (1)A1/A2>0.50  (2)2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo+V>2.55  (3)Formula (2) shows an area fraction of sulfides containing Ca in an amount of 1 mol % or more among sulfides having an equivalent circular diameter of 1 μm or more.