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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 10196705 B1

PDFFull Text
Date of Patent:
Feb. 05, 2019

Filed:

Dec. 11, 2013

Martensitic steel with delayed fracture resistance and manufacturing method

Applicant:

Arcelormittal, Luxembourg, LU;

Inventors:

Rongjie Song, Munster, IN (US);

Narayan Pottore, Munster, IN (US);

Nina Fonstein, Chicago, IL (US);

Assignee:

ArcelorMittal, Luxembourg, LU;

Attorney:

Davidson, Davidson & Kappel, LLC

Primary Examiner:

Deborah Yee

Int. Cl.
CPC ...
C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C21D 9/46 (2006.01); C21D 8/02 (2006.01); C22C 38/40 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/34 (2006.01); C22C 38/08 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (2013.01); C21D 8/021 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 8/0263 (2013.01); C21D 8/0273 (2013.01); C21D 8/0278 (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 38/08 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/34 (2013.01); C22C 38/40 (2013.01); C21D 2211/008 (2013.01);
Abstract

A cold rolled and annealed martensitic steel sheet is provided. The steel sheet includes by weight percent, 0.30≤C≤0.5%, 0.2≤Mn≤1.5%, 0.5≤Si≤3.0%, 0.02≤Ti≤0.05%, 0.001≤N≤0.008%, 0.0010≤B≤0.0030%, 0.01≤Nb≤0.1%, 0.2≤Cr≤2.0%, P≤0.02%, S≤0.005%, Al≤1%, Mo≤1% and Ni≤0.5%. The remainder of the composition includes iron and unavoidable impurities resulting from melting. The microstructure is 100% martensitic and a prior austenite grain size is lower than 20 μm. The steel sheet has a delayed fracture resistance of at least 24 hours during an acid immersion U-bend test. A method, part, structural member and vehicle are also provided.

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