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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 12480173 B1

PDFFull Text
Date of Patent:
Nov. 25, 2025

Filed:

Nov. 30, 2018

Cold rolled annealed steel sheet with high hole expansion ratio and manufacturing process thereof

Applicant:

Arcelormittal, Luxembourg, LU;

Inventor:

Jean-Christophe Hell, Metz, FR;

Assignee:

ArcelorMittal, Luxembourg, LU;

Attorney:

Davidson Kappel LLC

Primary Examiner:

Jonathan Johnson

Int. Cl.
CPC ...
C21D 9/46 (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 38/06 (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 6/001 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (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); C21D 2211/001 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01);
Abstract

A cold rolled annealed steel sheet having a chemical composition including, in weight %: 0.30%≤C≤0.50%, 1.00%≤Mn≤2.50%, 1.00%≤Si≤2.00%, Al≤2.00%, Cr≤0.100%, 0.100%≤Mo≤0.500%, 0.020%≤Nb≤0.200%, B≤0.0005%, P≤0.02%, S≤0.005%, N≤0.01%, the remainder being Fe and unavoidable impurities, with the percentages in carbon, manganese, chromium, molybdenum and boron are such that the alloy satisfies the following condition: 250% C+120% Mn−200% Cr+200% Mo−10000% B≥320, and wherein the microstructure comprises in surface fraction, 35% to 45% of islands of martensite and retained austenite (M-A), the total retained austenite is higher than or equal to 24%, the remainder consisting of bainitic ferrite.

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