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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 11230755 B1

PDFFull Text
Date of Patent:
Jan. 25, 2022

Filed:

Aug. 04, 2017

Steel sheet and plated steel sheet

Applicant:

Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;

Inventors:

Kohichi Sano, Tokyo, JP;

Makoto Uno, Tokyo, JP;

Ryoichi Nishiyama, Tokyo, JP;

Yuji Yamaguchi, Tokyo, JP;

Natsuko Sugiura, Tokyo, JP;

Masahiro Nakata, Tokyo, JP;

Assignee:

NIPPON STEEL CORPORATION, Tokyo, JP;

Attorney:

Birch, Stewart, Kolasch & Birch, LLP

Primary Examiner:

Jophy S Koshy

Int. Cl.
CPC ...
C21D 9/46 (2006.01); C22C 38/38 (2006.01); C22C 38/58 (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 38/26 (2006.01); C22C 38/28 (2006.01); C23C 2/06 (2006.01); C23C 2/40 (2006.01);
U.S. Cl.
CPC ...
C22C 38/38 (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 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/58 (2013.01); C23C 2/06 (2013.01); C23C 2/40 (2013.01); C21D 9/46 (2013.01); C21D 2211/002 (2013.01); C21D 2211/005 (2013.01);
Abstract

A steel sheet has a specific chemical composition and has a structure represented by, by area ratio, ferrite: 0 to 30%, and bainite: 70 to 100%. When a region that is surrounded by a grain boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 μm or more is defined as a crystal grain, the proportion of crystal grains each having an intragranular misorientation of 5 to 14° to all crystal grains is 20 to 100% by area ratio. A grain boundary number density of solid-solution C or a grain boundary number density of the total of solid-solution C and solid-solution B is 1 piece/nmor more and 4.5 pieces/nmor less. An average grain size of cementite precipitated at grain boundaries is 2 μm or less.

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