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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 12497677 B1

PDFFull Text
Date of Patent:
Dec. 16, 2025

Filed:

Jul. 12, 2022

High strength steel sheet

Applicant:

Nippon Steel Corporation, Tokyo, JP;

Inventor:

Kyohei Ishikawa, Tokyo, JP;

Assignee:

NIPPON STEEL CORPORATION, Tokyo, JP;

Attorney:

Birch, Stewart, Kolasch & Birch, LLP

Primary Examiner:

Katherine A Christy

Int. Cl.
CPC ...
C22C 38/54 (2006.01); C21D 1/18 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); C22C 38/22 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C22C 38/34 (2006.01); C22C 38/38 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/48 (2006.01);
U.S. Cl.
CPC ...
C22C 38/54 (2013.01); C21D 1/18 (2013.01); C21D 6/002 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 8/0257 (2013.01); C21D 8/0263 (2013.01); C21D 8/0278 (2013.01); C21D 9/46 (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 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); C22C 38/22 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/34 (2013.01); C22C 38/38 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/48 (2013.01); C21D 2211/001 (2013.01); C21D 2211/002 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01); C21D 2211/009 (2013.01);
Abstract

A high strength steel sheet including a sheet thickness center part and a surface layer soft part formed at one side or both sides of the sheet thickness center part, wherein the sheet thickness center part has a predetermined chemical composition and has a microstructure comprising tempered martensite: 85% or more, the surface layer soft part has a thickness of more than 10 μm to 5.0% or less of the sheet thickness, a microstructure comprising ferrite: 80% or more, and an internal oxide layer having a thickness of 3 μm or more from the surface, an average Vickers hardness (Hc) of the sheet thickness center part and an average Vickers hardness (Hs) of the surface layer soft part satisfy Hs/Hc≤0.50, and a void area ratio in a region from the surface down to a 10 μm depth position is 3.0% or less.

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