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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 9970073 B1

PDFFull Text
Date of Patent:
May. 15, 2018

Filed:

Oct. 18, 2010

Hot-rolled, cold rolled, and plated steel sheet having improved uniform and local ductility at a high strain rate

Applicants:

Kaori Kawano, Osaka, JP;

Yasuaki Tanaka, Osaka, JP;

Toshiro Tomida, Osaka, JP;

Inventors:

Kaori Kawano, Osaka, JP;

Yasuaki Tanaka, Osaka, JP;

Toshiro Tomida, Osaka, JP;

Assignee:

NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;

Attorney:

Clark & Brody

Primary Examiner:

Christopher Kessler

Int. Cl.
CPC ...
C21D 8/02 (2006.01); C21D 8/04 (2006.01); C21D 9/46 (2006.01); C21D 9/48 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/06 (2006.01); C22C 38/38 (2006.01); C23C 2/02 (2006.01); C23C 2/28 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01);
U.S. Cl.
CPC ...
C21D 8/0221 (2013.01); C21D 8/04 (2013.01); C21D 8/0426 (2013.01); C21D 8/0436 (2013.01); C21D 8/0463 (2013.01); C21D 9/46 (2013.01); C21D 9/48 (2013.01); C22C 38/001 (2013.01); C22C 38/02 (2013.01); C22C 38/06 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/38 (2013.01); C23C 2/02 (2013.01); C23C 2/28 (2013.01); C21D 2211/001 (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 has a metallurgical structure having a main phase of ferrite with an average grain diameter of at most 3.0 μm and a second phase including at least one of martensite, bainite, and austenite. In the surface layer, the average grain diameter of the second phase is at most 2.0 μm, the difference (ΔnH) between the average nanohardness of the main phase (nH) and the average nanohardness of the second phase (nH) is 6.0-10.0 GPa, the difference (ΔσnH) of the standard deviation of the nanohardness of the second phase from the standard deviation of the nanohardness of the main phase is at most 1.5 GPa, and in the central portion, the difference (ΔnH) between the average nanohardnesses is at least 3.5 GPa to at most 6.0 GPa and the difference (ΔσnH) between the standard deviations of the nanohardnesses is at least 1.5 GPa.

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