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. 17, 2020

Filed:

May. 26, 2016
Applicant:

Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;

Inventors:

Kazuo Hikida, Tokyo, JP;

Ken Takata, Tokyo, JP;

Kengo Takeda, Tokyo, JP;

Motonori Hashimoto, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22C 38/06 (2006.01); C21D 9/46 (2006.01); C22C 38/60 (2006.01); C22C 38/08 (2006.01); C22C 38/14 (2006.01); C22C 38/12 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/16 (2006.01); C22C 38/22 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C23G 1/00 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (2013.01); C21D 6/002 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0263 (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 38/08 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); C22C 38/22 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/60 (2013.01); C21D 2211/005 (2013.01); C21D 2211/009 (2013.01); C23G 1/00 (2013.01);
Abstract

The present invention provides steel sheet excellent in cold formability and ductility after heat treatment and a method for production thereof. The steel sheet of the present invention is steel sheet which has a chemical composition containing, by mass %, C: 0.10 to 0.40%, Si: 0.30 to 1.00%, Mn: 0.30 to 1.00%, Al: 0.001 to 0.10%, P: 0.0001 to 0.02%, and S: 0.0001 to 0.01% and having a balance of Fe and impurities, which steel sheet characterized in that a ratio (B/A) of the number of carbides at the ferrite grain boundaries (B) to the number of carbides inside the ferrite grains (A) is over 1, a ferrite grain size is 5 μm to 50 μm, an average grain size of carbides is 0.4 μm to 2.0 μm, a pearlite area ratio is 6% or less, and a Vicker's hardness is 120 HV to 170 HV.


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