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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 11174543 B1

PDFFull Text
Date of Patent:
Nov. 16, 2021

Filed:

May. 31, 2017

Case hardening steel, method of producing case hardening steel, and method of producing gear part

Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Keisuke Ando, Tokyo, JP;

Takashi Iwamoto, Tokyo, JP;

Kunikazu Tomita, Tokyo, JP;

Kazukuni Hase, Tokyo, JP;

Kimihiro Nishimura, Tokyo, JP;

Assignee:

JFE STEEL CORPORATION, Tokyo, JP;

Attorney:

Kenja IP Law PC

Primary Examiner:

Jessee R Roe

Int. Cl.
CPC ...
C23C 8/22 (2006.01); C21D 1/06 (2006.01); C21D 8/06 (2006.01); C21D 9/32 (2006.01); C21D 9/52 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/22 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C23C 8/02 (2006.01); C23C 8/80 (2006.01); F16H 55/06 (2006.01);
U.S. Cl.
CPC ...
C23C 8/22 (2013.01); C21D 1/06 (2013.01); C21D 8/065 (2013.01); C21D 9/32 (2013.01); C21D 9/525 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/22 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C23C 8/02 (2013.01); C23C 8/80 (2013.01); F16H 55/06 (2013.01);
Abstract

A case hardening steel suitable as raw material for producing a mechanical structural part having high rotating bending fatigue strength and pitting fatigue strength at relatively low cost and a method of producing the case hardening steel are provided. A case hardening steel comprises a chemical composition containing, in mass %, C, Si, Mn, P, S, Cr, Mo, Al, N, and O in a predetermined relationship, with a balance being Fe and inevitable impurities, wherein √I≤80 (where I denotes an area (μm) of an oxide-based inclusion located in a fish eye central portion at a fracture surface after subjecting the case hardening steel to carburizing-quenching and tempering and then performing a rotating bending fatigue test).

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