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:
May. 17, 2022

Filed:

May. 10, 2019
Applicant:

Komatsu Ltd., Tokyo, JP;

Inventors:

Kensuke Sato, Tokyo, JP;

Koji Yamamoto, Tokyo, JP;

Yusuke Hiratsuka, Himeji, JP;

Kazuya Hashimoto, Himeji, JP;

Assignee:

KOMATSU LTD., Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C22C 38/00 (2006.01); C23C 8/22 (2006.01); C21D 1/32 (2006.01); C21D 9/32 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); C22C 38/54 (2006.01); C23C 8/80 (2006.01);
U.S. Cl.
CPC ...
C23C 8/22 (2013.01); C21D 1/32 (2013.01); C21D 9/32 (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 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C22C 38/54 (2013.01); C23C 8/80 (2013.01); C21D 2211/003 (2013.01); Y10T 428/12458 (2015.01); Y10T 428/12771 (2015.01); Y10T 428/12861 (2015.01); Y10T 428/12951 (2015.01); Y10T 428/12972 (2015.01);
Abstract

A machine component includes a core made up of a steel for machine structural use, and a medium carbon-containing layer and a high carbon-containing layer formed of the steel for machine structural use, the medium carbon-containing layer covering the core, the high carbon-containing layer covering the medium carbon-containing layer and having a carbon concentration of 0.8-1.5%. The high carbon-containing layer is made up of a martensitic structure having carbides dispersed therein and a residual austenitic structure, wherein spheroidized carbides with an aspect ratio of 1.5 or less constitute 90% or more of a total number of the carbides, and the number of spheroidized carbides on prior austenite grain boundaries is 40% or less of the total number of the carbides.


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