- Patent Title: Bearing steel component, and steel bar for bearing steel component
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Application No.: US16962153Application Date: 2019-01-22
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Publication No.: US11459630B2Publication Date: 2022-10-04
- Inventor: Tatsuya Koyama , Kei Miyanishi , Yutaka Neishi
- Applicant: NIPPON STEEL CORPORATION
- Applicant Address: JP Tokyo
- Assignee: NIPPON STEEL CORPORATION
- Current Assignee: NIPPON STEEL CORPORATION
- Current Assignee Address: JP Tokyo
- Agency: Solaris Intellectual Property Group, PLLC
- Priority: JPJP2018-008180 20180122
- International Application: PCT/JP2019/001915 WO 20190122
- International Announcement: WO2019/142946 WO 20190725
- Main IPC: C22C38/00
- IPC: C22C38/00 ; C22C38/02 ; C22C38/06 ; C21D9/40 ; C21D6/00 ; C21D7/06 ; C22C38/20 ; C22C38/24 ; C22C38/26 ; C22C38/28 ; C22C38/30 ; C22C38/32 ; C22C38/38 ; C22C38/44

Abstract:
A bearing steel part having a predetermined chemical composition, in which the number density of oxide particles having an equivalent circle diameter of 5 μm or more, and containing CaO, Al2O3 and SiO2, such that the content ratio of Al2O3 with respect to the total mass of CaO, Al2O3, and SiO2 is 50% by mass or more, is 3.0/cm2 or less in an arbitrary cross section of the part, and in which the Vickers hardness at a depth of 50 μm from a rolling surface is 750 or more, and in which the compressive residual stress at the rolling surface is 900 MPa or more. Also provided is a steel bar for a bearing steel part that is suitable for obtaining the foregoing bearing steel part.
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