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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 10066274 B1

PDFFull Text
Date of Patent:
Sep. 04, 2018

Filed:

Sep. 25, 2014

High-strength steel sheet having excellent ductility and low-temperature toughness, and method for producing same

Applicant:

Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.), Kobe-shi, JP;

Inventors:

Koji Kasuya, Kakogawa, JP;

Tadao Murata, Kakogawa, JP;

Sae Mizuta, Kakogawa, JP;

Yuichi Futamura, Kakogawa, JP;

Assignee:

Kobe Steel, Ltd., Kobe-shi, JP;

Attorney:

Oblon, McClelland, Maier & Neustadt, L.L.P.

Primary Examiner:

Deborah Yee

Int. Cl.
CPC ...
C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C21D 8/02 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/08 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); C22C 38/38 (2006.01); C22C 38/18 (2006.01); C23C 2/02 (2006.01); C23C 2/28 (2006.01); C23C 2/06 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (2013.01); C21D 8/0205 (2013.01); C21D 8/0247 (2013.01); C22C 38/00 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (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 38/18 (2013.01); C22C 38/38 (2013.01); C23C 2/02 (2013.01); C23C 2/06 (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 high-strength steel sheet of the present invention is a steel sheet satisfying a predetermined component composition. A metal structure of the steel sheet is composed of polygonal ferrite, high-temperature region generated bainite, low-temperature region generated bainite and retained austenite each having a predetermined area percent, and a distribution using each average IQ of predetermined crystal grains determined by electron backscatter diffraction satisfies Equations (1) and (2) below. According to the present invention, a high-strength steel sheet having excellent ductility and low-temperature toughness can be realized even at a tensile strength of 780 MPa or more.(IQave−IQmin)/(IQmax−IQmin)≥0.40  (1)(σIQ)/(IQmax−IQmin)≤0.25  (2)

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