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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 9115415 B1

PDFFull Text
Date of Patent:
Aug. 25, 2015

Filed:

Aug. 10, 2011

Case hardened steel and method for producing same

Applicants:

Nariaki Okamoto, Kobe, JP;

Mutsuhisa Nagahama, Kobe, JP;

Inventors:

Nariaki Okamoto, Kobe, JP;

Mutsuhisa Nagahama, Kobe, JP;

Assignee:

Kobe Steel, Ltd., Kobe-shi, JP;

Attorney:

Oblon, McClelland, Maier & Neustadt, L.L.P.

Primary Examiner:

Deborah Yee

Int. Cl.
CPC ...
C21D 8/00 (2006.01); C21D 1/06 (2006.01); C21D 9/28 (2006.01); C21D 9/40 (2006.01); C22C 38/32 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/22 (2006.01); C22C 38/20 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); C22C 38/54 (2006.01); C21D 8/02 (2006.01); B22D 11/22 (2006.01);
U.S. Cl.
CPC ...
C21D 8/005 (2013.01); B22D 11/225 (2013.01); C21D 1/06 (2013.01); C21D 8/0226 (2013.01); C21D 8/0247 (2013.01); C21D 9/28 (2013.01); C21D 9/40 (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 38/20 (2013.01); C22C 38/22 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C22C 38/54 (2013.01); C21D 2211/004 (2013.01);
Abstract

A case hardened steel with excellent cold forgeability and excellent impact properties after case hardening processing contains C, Si, Mn, S, Cr, Al, Ti, Nb, B, and N, with the balance being iron and unavoidable impurities. Of precipitates containing Ti and/or Nb, precipitates having a size of not less than 20 μmare at a number density of not more than 1.0/mm. Of precipitates containing Ti and/or Nb, precipitates having a size of more than 5 μmand less than 20 μmand containing Mn and S are at a number density of more than 0.7/mmand not more than 3.0/mm. The ferrite fraction is more than 77% by area.

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