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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 10041158 B1

PDFFull Text
Date of Patent:
Aug. 07, 2018

Filed:

Apr. 07, 2011

Multi-phase hot-rolled steel sheet having improved dynamic strength and a method for its manufacture

Applicants:

Yasuaki Tanaka, Nishinomiya, JP;

Toshiro Tomida, Kobe, JP;

Kaori Kawano, Neyagawa, JP;

Inventors:

Yasuaki Tanaka, Nishinomiya, JP;

Toshiro Tomida, Kobe, JP;

Kaori Kawano, Neyagawa, JP;

Assignee:

NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;

Attorney:

Clark & Brody

Primary Examiner:

Colleen P Dunn

Assistant Examiner:

Jeremy C Jones

Int. Cl.
CPC ...
C22C 38/58 (2006.01); C22C 38/00 (2006.01); C22C 38/38 (2006.01); C22C 38/04 (2006.01); C22C 38/28 (2006.01); C22C 38/02 (2006.01); C21D 8/02 (2006.01); C21D 6/00 (2006.01); C21D 9/46 (2006.01); C22C 38/06 (2006.01); C22C 38/20 (2006.01); C22C 38/22 (2006.01); C22C 38/24 (2006.01); C22C 38/40 (2006.01); C22C 38/50 (2006.01);
U.S. Cl.
CPC ...
C22C 38/58 (2013.01); C21D 6/005 (2013.01); C21D 8/02 (2013.01); C21D 8/0226 (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 38/20 (2013.01); C22C 38/22 (2013.01); C22C 38/24 (2013.01); C22C 38/28 (2013.01); C22C 38/38 (2013.01); C22C 38/40 (2013.01); C22C 38/50 (2013.01); C21D 2211/002 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01);
Abstract

A multi-phase hot-rolled steel sheet having improved strength in an intermediate strain rate region has a chemical composition comprising, in mass percent, C: 0.07-0.2%, Si+Al: 0.3-1.5%, Mn: 1.0-3.0%, P: at most 0.02%, S: at most 0.005%, Cr: 0.1-0.5%, N: 0.001-0.008%, at least one of Ti: 0.002-0.05% and Nb: 0.002-0.05%, and a remainder of Fe and impurities. The area fraction of ferrite is 7-35%, the grain diameter of ferrite is in the range of 0.5-3.0 μm, and the nanohardness of ferrite is in the range of 3.5-4.5 GPa. A second phase which is the remainder other than ferrite contains martensite and bainitic ferrite and/or bainite. The average nanohardness of the second phase is 5-12 GPa, and the second phase contains a high-hardness phase of 8-12 GPa with an area fraction of 5-35% based on the overall structure.

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