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.

Date of Patent:
Apr. 14, 2025

Filed:

Apr. 08, 2020
Applicant:

Nippon Steel Corporation, Tokyo, JP;

Inventors:

Kison Nishihara, Tokyo, JP;

Hiroaki Tahira, Tokyo, JP;

Yoko Sueyasu, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D 9/30 (2005.12); C22C 38/00 (2005.12); C22C 38/02 (2005.12); C22C 38/04 (2005.12); C22C 38/06 (2005.12); C22C 38/24 (2005.12); C22C 38/28 (2005.12);
U.S. Cl.
CPC ...
C21D 9/30 (2012.12); C22C 38/001 (2012.12); C22C 38/002 (2012.12); C22C 38/02 (2012.12); C22C 38/04 (2012.12); C22C 38/06 (2012.12); C22C 38/24 (2012.12); C22C 38/28 (2012.12); C21D 2211/005 (2012.12); C21D 2211/009 (2012.12);
Abstract

The steel shaft component consists of C: 0.40 to 0.60%, Si: 0.05 to 1.00%, Mn: 1.00 to 2.00%, P: 0.030% or less, S: 0.005 to 0.100%, Cr: 0.10 to 0.50%, V: 0.10 to 0.30%, Al: 0.005 to 0.050%, N: 0.0050 to 0.0200%, Ti: 0 to 0.050%, and the balance: Fe and impurities. A Vickers hardness Hs of the surface of the shaft part is 620 HV or more. A Vickers hardness Hb at an R/2 position satisfies Formula (1). A depth of the hardened layer Hr (mm) having a Vickers hardness of 620 HV or more satisfies Formula (2). The microstructure at the R/2 position is composed of ferrite and pearlite. Within the hardened layer, the number of density of V-containing precipitates having an equivalent circular diameter of more than 100 nm is 10 particles/276 μmor less./2.3≤≤350  (1)0.05≤≤0.40  (2)


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