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:
Oct. 15, 2024

Filed:

Mar. 20, 2019
Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Hiroyuki Masuoka, Tokyo, JP;

Shinichi Furuya, Tokyo, JP;

Akira Matsuzaki, Tokyo, JP;

Hayato Takeyama, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D 9/46 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C23C 28/04 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/0205 (2013.01); C21D 8/0236 (2013.01); C21D 8/0273 (2013.01); C22C 38/002 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C23C 28/04 (2013.01);
Abstract

An object is to provide a cold-rolled steel sheet having excellent phosphatability, even in the case where a phosphating solution has a low temperature, and a method for manufacturing the steel sheet, and a cold-rolled steel sheet for annealing. A cold-rolled steel sheet for annealing has a chemical composition containing C: 0.01 mass % to 0.30 mass %, Si: less than 0.10 mass % (including 0.0 mass %), Mn: 2.0 mass % to 3.5 mass %, P: 0.05 mass % or less, S: 0.01 mass % or less, and Al: 0.15 mass % or less, the balance being Fe and inevitable impurities, in which Si and/or Si oxide exists on a surface of the steel sheet with an average coating thickness of 1 nm to 20 nm.


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