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.

Date of Patent:
May. 06, 2025

Filed:

Dec. 17, 2020
Applicant:

Nippon Steel Corporation, Tokyo, JP;

Inventors:

Yuya Suzuki, Tokyo, JP;

Kengo Takeda, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D 9/46 (2005.12); B32B 15/01 (2005.12); C21D 6/00 (2005.12); C21D 8/02 (2005.12); C22C 38/00 (2005.12); C22C 38/02 (2005.12); C22C 38/04 (2005.12); C22C 38/06 (2005.12); C22C 38/20 (2005.12); C22C 38/22 (2005.12); C22C 38/24 (2005.12); C22C 38/26 (2005.12); C22C 38/28 (2005.12); C22C 38/32 (2005.12); C23C 2/28 (2005.12); C23C 2/40 (2005.12);
U.S. Cl.
CPC ...
C21D 9/46 (2012.12); B32B 15/013 (2012.12); C21D 6/002 (2012.12); C21D 6/005 (2012.12); C21D 6/008 (2012.12); C21D 8/0205 (2012.12); C21D 8/0226 (2012.12); C21D 8/0263 (2012.12); C22C 38/001 (2012.12); C22C 38/002 (2012.12); C22C 38/02 (2012.12); C22C 38/04 (2012.12); C22C 38/06 (2012.12); C22C 38/20 (2012.12); C22C 38/22 (2012.12); C22C 38/24 (2012.12); C22C 38/26 (2012.12); C22C 38/28 (2012.12); C22C 38/32 (2012.12); C23C 2/28 (2012.12); C23C 2/40 (2012.12);
Abstract

This steel sheet has a specific chemical composition, the tensile strength is 1300 MPa or more, the ratio (R/t) of the limit bend radius to the sheet thickness is less than 3.5, when a depth position of 30 μm from the surface in the sheet thickness direction is defined as a position A and a depth position of ¼ of the sheet thickness from the surface in the sheet thickness direction is defined as a position B, the number density of AlN at the position A is 3000 pieces/mmor more and 6000 pieces/mmor less, a metallographic structure at the position B includes 90% or more of martensite by volume percentage, and the hardness at the position A is 1.20 times or higher than the hardness at the position B.


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