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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 12729420 B1

PDFFull Text
Date of Patent:
Sep. 08, 2026

Filed:

Apr. 27, 2021

Steel sheet and plated steel sheet

Applicant:

Nippon Steel Corporation, Tokyo, JP;

Inventors:

Keitaro Matsuda, Tokyo, JP;

Takuya Mitsunobu, Tokyo, JP;

Jun Maki, Tokyo, JP;

Hiroshi Takebayashi, Tokyo, JP;

Assignee:

NIPPON STEEL CORPORATION, Tokyo, JP;

Attorney:

Birch, Stewart, Kolasch & Birch, LLP

Primary Examiner:

Seth Dumbris

Int. Cl.
CPC ...
C22C 38/38 (2006.01); C21D 1/74 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C21D 8/0221 (2026.01); C21D 8/0247 (2026.01); C21D 8/0278 (2026.01); 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 38/08 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01); C22C 38/16 (2006.01); C22C 38/34 (2006.01); C23C 2/06 (2006.01);
U.S. Cl.
CPC ...
C22C 38/38 (2013.01); C21D 1/74 (2013.01); C21D 6/001 (2013.01); C21D 6/002 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/02 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 8/0252 (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 38/08 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/16 (2013.01); C22C 38/34 (2013.01); C23C 2/06 (2013.01);
Abstract

A steel sheet comprising, by mass %, C: 0.05 to 0.40%, Si: 0.2 to 3.0%, and Mn: 0.1 to 5.0%, wherein a surface layer of the steel sheet contains grain boundary oxides, a Ratio A of a length of the grain boundary oxides projected on a surface of the steel sheet to a length of the surface of the steel sheet is 50% or more and 100% or less, a number density of granular oxides is less than 4.0/μm, the steel sheet comprises an Si—Mn depleted layer having a thickness of 3.0 μm or more from the surface of the steel sheet, and Si and Mn contents of the Si—Mn depleted layer at the ½ position of the thickness and not containing oxides are respectively less than 10% of the Si and Mn contents at a sheet thickness center part of the steel sheet, and a plated steel sheet using the same are provided.

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