Title:
STEEL SHAFT COMPONENT
Document Type and Number:
WIPO Patent Application WO/2020/209320
Kind Code:
A1
Abstract:
Provided is a steel shaft component having excellent fatigue strength. The steel shaft component has a chemical composition comprising C: 0.40-0.60%, Si: 0.05-1.00%, Mn: 1.00-2.00%, P: 0.030% or less, S: 0.005-0.100%, Cr: 0.10-0.50%, V: 0.10-0.30%, Al: 0.005-0.050%, N: 0.0050-0.0200%, Ti: 0-0.050%, and the balance: Fe and impurities. Vickers hardness Hs of the surface of a shaft section is 620 HV or higher, Vickers hardness Hb at R/2 position satisfies expression (1), and the depth Hr (mm) of a hardened layer having a Vickers hardness of 620 HV or higher satisfies expression (2). A microstructure at the R/2 position comprises ferrite and perlite. Within the hardened layer, the number of V-containing deposits having an equivalent circle diameter exceeding 100 nm is 10 deposits/276 μm2. (1) Hs/2.3 ≤ Hb ≤ 350
(2) 0.05 ≤ Hr/R ≤ 0.40
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Inventors:
NISHIHARA KISON (JP)
TAHIRA HIROAKI (JP)
SUEYASU YOKO (JP)
TAHIRA HIROAKI (JP)
SUEYASU YOKO (JP)
Application Number:
PCT/JP2020/015917
Publication Date:
October 15, 2020
Filing Date:
April 09, 2020
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
International Classes:
C21D8/06; C21D9/30; C22C38/00; C22C38/60; F16C3/08
Domestic Patent References:
| WO2015174088A1 | 2015-11-19 |
Foreign References:
| JP2017171977A | 2017-09-28 | |||
| JPS62199750A | 1987-09-03 |
Attorney, Agent or Firm:
ASCEND IP LAW FIRM (JP)
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