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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 9580782 B1

PDFFull Text
Date of Patent:
Feb. 28, 2017

Filed:

Jan. 31, 2014

Thick high-tensile-strength hot-rolled steel sheet having excellent low-temperature toughness and manufacturing method thereof

Applicant:

Jfe Steel Corporation, Chiyoda-ku, Tokyo, JP;

Inventors:

Chikara Kami, Kurashiki, JP;

Hiroshi Nakata, Kurashiki, JP;

Kinya Nakagawa, Fukuyama, JP;

Assignee:

JFE Steel Corporation, Tokyo, JP;

Attorney:

RatnerPrestia

Primary Examiner:

Deborah Yee

Int. Cl.
CPC ...
C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C21D 8/02 (2006.01); C22C 38/58 (2006.01); C21D 8/10 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/06 (2006.01); C22C 38/08 (2006.01); C22C 38/16 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/38 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01); B21B 3/00 (2006.01);
U.S. Cl.
CPC ...
C22C 38/58 (2013.01); C21D 8/0205 (2013.01); C21D 8/0263 (2013.01); C21D 8/105 (2013.01); C21D 9/46 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (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 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/38 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); B21B 3/00 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01);
Abstract

A high-tensile-strength hot-rolled steel sheet is provided having a composition which contains 0.02 to 0.08% C, 0.01 to 0.10% Nb, 0.001 to 0.05% Ti and Fe and unavoidable impurities as a balance, wherein the steel sheet contains C, Ti and Nb in such a manner that (Ti+(Nb/2))/C<4 is satisfied, and the steel sheet has a structure where a primary phase of the structure at a position 1 mm away from a surface in a sheet thickness direction is one selected from a group consisting of a ferrite phase, tempered martensite and a mixture structure of a ferrite phase and tempered martensite, a primary phase of the structure at a sheet thickness center position is formed of a ferrite phase, and a difference ΔV between a structural fraction (volume %) of a secondary phase at the position 1 mm away from the surface in the sheet thickness direction and a structural fraction (volume %) of a secondary phase at the sheet thickness center position is 2% or less.

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