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:
Nov. 14, 2023

Filed:

Oct. 28, 2019
Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Masayuki Kasai, Tokyo, JP;

Naoya Ihara, Tokyo, JP;

Kimihiro Nishimura, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22C 38/60 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); C22C 38/42 (2006.01); C22C 38/54 (2006.01); C22C 38/00 (2006.01); C22C 38/06 (2006.01); C22C 38/52 (2006.01); C23C 12/00 (2006.01); C21D 9/00 (2006.01); C21D 8/00 (2006.01); C21D 7/13 (2006.01);
U.S. Cl.
CPC ...
C22C 38/60 (2013.01); C21D 7/13 (2013.01); C21D 8/005 (2013.01); C21D 9/00 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/06 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C22C 38/52 (2013.01); C22C 38/54 (2013.01); C23C 12/00 (2013.01); C21D 2211/002 (2013.01);
Abstract

Provided is a steel for nitrocarburizing that ensures mechanical workability before nitrocarburizing treatment. A steel for nitrocarburizing comprises: a chemical composition containing, in mass %, C: ≥0.02% and <0.15%, Si: ≤0.30%, Mn: 1.5-2.5%, P: ≤0.025%, S: ≤0.06%, Cr: 0.5-2.0%, Mo: 0.005-0.2%, V: 0.02-0.20%, Nb: 0.003-0.20%, Al: >0.020% and ≤1.0%, Ti: >0.0050% and ≤0.015%, N: ≤0.0200%, Sb: 0.0030-0.010%, with a balance being Fe and inevitable impurities, satisfying Expression (1) or (2); and a steel microstructure where an area ratio of bainite phase is >50%, a prior austenite grain size is ≤100 μm, ≥300/μmTi precipitates with an equivalent circular particle size of ≤30 nm disperse, Sb segregates to prior austenite grain boundaries.


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