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:
Jan. 11, 2022

Filed:

Jan. 16, 2018
Applicants:

Thyssenkrupp Steel Europe Ag, Duisburg, DE;

Thyssenkrupp Ag, Essen, DE;

Inventors:

Thorsten Rösler, Muelheim an der Ruhr, DE;

Liuyi Zhang, Ratingen, DE;

Jörg Mertens, Duisburg, DE;

Assignees:

THYSSENKRUPP STEEL EUROPE AG, Duisburg, DE;

THYSSENKRUPP AG, Essen, DE;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B32B 15/00 (2006.01); C21D 8/02 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (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); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/58 (2006.01);
U.S. Cl.
CPC ...
C21D 8/0226 (2013.01); C21D 8/0263 (2013.01); C21D 9/46 (2013.01); C22C 38/001 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (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 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/58 (2013.01); C21D 2211/001 (2013.01); C21D 2211/002 (2013.01); C21D 2211/003 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01);
Abstract

A flat steel product and a method of making a flat steel product having a hole expansion of at least 60%, a yield strength of at least 660 MPa, a tensile strength of at least 760 MPa, and an elongation at break of at least 10%. The flat steel product is made from a complex-phase steel, which includes (in wt %) C: 0.01-0.1%, Si: 0.1-0.45%, Mn: 1-2.5%, Al: 0.005-0.05%, Cr: 0.5-1%, Mo: 0.05-0.15%, Nb: 0.01-0.1%, Ti: 0.05-0.2%, N: 0.001-0.009%, P: <0.02%, S: <0.005%, Cu: ≤0.1 %, Mg: ≤0.0005 %, O: <0.01 %, optionally one or more of Ni, B, V, Ca, Zr, Ta, W, REM, and Co, where Ni: ≤1%, B: ≤0.005%, V: ≤0.3%, Ca: 0.0005-0.005%, Zr, Ta, W: in total ≤2%, REM: 0.0005-0.05%, and Co: <1%, and iron and unavoidable impurities as the remainder, where % Ti>(48/14)% N+(48/32)% S and % Nb<(93/12)% C+(45/14)% N+(45/32)% S. The structure of the flat steel product includes (in area %) ≥80% bainite, <15% ferrite, <15% martensite, <5% cementite, and <5 vol % retained austenite.


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