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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 11447848 B1

PDFFull Text
Date of Patent:
Sep. 20, 2022

Filed:

Mar. 30, 2018

Steel sheet and manufacturing method of therefor

Applicant:

Nippon Steel Corporation, Tokyo, JP;

Inventors:

Takafumi Yokoyama, Tokyo, JP;

Kohichi Sano, Tokyo, JP;

Riki Okamoto, Tokyo, JP;

Hiroyuki Kawata, Tokyo, JP;

Eisaku Sakurada, Tokyo, JP;

Yuji Yamaguchi, Tokyo, JP;

Kazuki Shiokawa, Tokyo, JP;

Yuichi Nakahira, Tokyo, JP;

Kohei Ueda, Tokyo, JP;

Masahiro Nakata, Tokyo, JP;

Satoshi Uchida, Tokyo, JP;

Assignee:

NIPPON STEEL CORPORATION, Tokyo, JP;

Attorney:

Birch, Stewart, Kolasch & Birch, LLP

Primary Examiner:

Anthony M Liang

Assistant Examiner:

Danny N Kang

Int. Cl.
CPC ...
C21D 8/02 (2006.01); C21D 9/00 (2006.01); C22C 38/58 (2006.01); C21D 9/46 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/06 (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); C22C 38/52 (2006.01); C22C 38/54 (2006.01); C23C 2/06 (2006.01); C23C 2/40 (2006.01);
U.S. Cl.
CPC ...
C22C 38/58 (2013.01); C21D 8/0205 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 9/0081 (2013.01); C21D 9/46 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/008 (2013.01); C22C 38/02 (2013.01); C22C 38/06 (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); C22C 38/52 (2013.01); C22C 38/54 (2013.01); C23C 2/06 (2013.01); C23C 2/40 (2013.01); C21D 2211/001 (2013.01); C21D 2211/003 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01); C21D 2211/009 (2013.01);
Abstract

A steel sheet wherein a steel structure of an inside of the steel sheet contains, by volume fraction, soft ferrite: 0% to 30%, retained austenite: 3% to 40%, fresh martensite: 0% to 30%, a sum of pearlite and cementite: 0% to 10%, and a remainder including hard ferrite. In the steel sheet, in a ⅛ to ⅜ thickness range, a proportion of retained austenite having an aspect ratio of 2.0 or more is 50% or more, and a soft layer having a thickness of 1 to 100 μm from a surface in a sheet thickness direction is present. When an emission intensity at a wavelength indicating Si is analyzed in the sheet thickness direction from the surface by a radio-frequency glow discharge analysis method, a peak of the emission intensity appears in a range of more than 0.2 μm and 5.0 μm or less from the surface.

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