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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.:

US 11332799 B1

PDFFull Text
Date of Patent:
May. 17, 2022

Filed:

Sep. 08, 2017

Case hardening steel, method of producing the same, and method of producing gear parts

Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Keisuke Ando, Tokyo, JP;

Takashi Iwamoto, Tokyo, JP;

Kimihiro Nishimura, Tokyo, JP;

Katsuyuki Ichimiya, Tokyo, JP;

Assignee:

JFE STEEL CORPORATION, Tokyo, JP;

Attorney:

Kenja IP Law PC

Primary Examiner:

Humera N Sheikh

Assistant Examiner:

Katherine A Christy

Int. Cl.
CPC ...
C21D 1/06 (2006.01); C21D 9/32 (2006.01); C22C 38/00 (2006.01); C21D 9/00 (2006.01); C21D 8/06 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/22 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C22C 38/26 (2006.01); C22C 38/60 (2006.01); C22C 38/44 (2006.01); C22C 38/24 (2006.01); C22C 38/54 (2006.01); C22C 38/50 (2006.01); C22C 38/06 (2006.01); C22C 38/20 (2006.01);
U.S. Cl.
CPC ...
C21D 1/06 (2013.01); C21D 8/065 (2013.01); C21D 9/0075 (2013.01); C21D 9/32 (2013.01); C22C 38/00 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/008 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/22 (2013.01); C22C 38/24 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/44 (2013.01); C22C 38/50 (2013.01); C22C 38/54 (2013.01); C22C 38/60 (2013.01); C22C 38/20 (2013.01); C22C 38/26 (2013.01);
Abstract

Disclosed are a case hardened steel which is suitable as a material for producing mechanical structural parts having high rotating bending fatigue strength and impact fatigue strength at a relatively low cost, and a method of producing the same. The case hardening steel has a chemical composition containing, by mass %, C, Si, Mn, P, S, Cr, Mo, B, Ti, N, and O within a range satisfying a predetermined relationship, and Al in at least a predetermined amount in relation to the B, N, and Ti contents, with the balance being Fe and inevitable impurities, wherein √I≤80 is satisfied, where I represents an area in μmof an oxide-based inclusion located at the center of a fish-eye on a fracture surface of the case hardening steel after being subjected to carburizing-quenching and tempering and subsequently to a rotating bending fatigue test.

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