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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 9322088 B1

PDFFull Text
Date of Patent:
Apr. 26, 2016

Filed:

Dec. 06, 2013

High-strength steel sheet and method for producing the same

Applicant:

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

Inventors:

Sae Mizuta, Kakogawa, JP;

Yukihiro Utsumi, Kakogawa, JP;

Assignee:

Kabushiki Kaisha Kobe Seiko Sho (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 9/06 (2006.01); C21D 6/00 (2006.01); C22C 38/58 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/60 (2006.01); C22C 38/08 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); C22C 38/36 (2006.01); C22C 38/38 (2006.01); C23C 2/06 (2006.01); C23C 2/28 (2006.01); C23C 2/40 (2006.01); C25D 5/50 (2006.01); C25D 7/06 (2006.01); C21D 8/02 (2006.01); B32B 15/01 (2006.01); C22C 38/28 (2006.01); C22C 38/34 (2006.01); C22C 38/50 (2006.01); C22C 38/54 (2006.01); C23C 2/04 (2006.01); C25D 7/00 (2006.01); C21D 1/22 (2006.01);
U.S. Cl.
CPC ...
C22C 38/58 (2013.01); B32B 15/013 (2013.01); C21D 6/001 (2013.01); C21D 6/002 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0247 (2013.01); C21D 9/46 (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 38/28 (2013.01); C22C 38/34 (2013.01); C22C 38/36 (2013.01); C22C 38/38 (2013.01); C22C 38/50 (2013.01); C22C 38/54 (2013.01); C22C 38/60 (2013.01); C23C 2/04 (2013.01); C23C 2/06 (2013.01); C23C 2/28 (2013.01); C23C 2/40 (2013.01); C23C 2/405 (2013.01); C25D 5/50 (2013.01); C25D 7/00 (2013.01); C25D 7/0614 (2013.01); C21D 1/22 (2013.01); C21D 2211/001 (2013.01); C21D 2211/002 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01);
Abstract

Provided is a high-strength steel sheet having a tensile strength of 1180 MPa or more. The high-strength steel sheet has a specific chemical composition, includes a microstructure meeting all conditions (1) to (4) as measured by specific methods at a position corresponding to one-fourth the thickness of the steel sheet, has excellent workability and low-temperature toughness, and has a tensile strength of 1180 MPa or more. (1) The microstructure includes ferrite in a volume fraction of 5% to 35% and at least one of bainitic ferrite and tempered martensite in a volume fraction of 50% or more relative to the entire microstructure. (2) The microstructure includes MA constituent in a volume fraction of 20% or less (excluding 0%) relative to the entire microstructure, where the MA constituent is a mixed phase of fresh martensite and retained austenite. (3) The microstructure includes retained austenite in a volume fraction of 5% or more relative to the entire microstructure. (4) The microstructure has an amount of stacking faults in the retained austenite of 10.0×10(nm/nm) or less.

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