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:
Jan. 28, 2020

Filed:

Jun. 09, 2015
Applicant:

Jfe Steel Corporation, Tokyo, JP;

Inventors:

Hideyuki Kimura, Fukuyama, JP;

Koichiro Fujita, Nagoya, JP;

Hiroshi Hasegawa, Fukuyama, JP;

Mai Aoyama, Fukuyama, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C21D 9/46 (2006.01); B21B 1/26 (2006.01); B21B 3/00 (2006.01); C23C 2/06 (2006.01); C23C 2/40 (2006.01); C22C 38/14 (2006.01); C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/12 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/38 (2006.01); C23G 1/08 (2006.01);
U.S. Cl.
CPC ...
C21D 9/46 (2013.01); B21B 1/26 (2013.01); B21B 3/00 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01); C21D 8/0263 (2013.01); C21D 8/0278 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/38 (2013.01); C23C 2/06 (2013.01); C23C 2/40 (2013.01); C23G 1/081 (2013.01); C23G 1/085 (2013.01); C21D 2211/001 (2013.01); C21D 2211/002 (2013.01); C21D 2211/005 (2013.01); C21D 2211/008 (2013.01);
Abstract

A method for manufacturing a high-strength galvanized steel sheet includes performing hot rolling, cold rolling, first annealing, pickling, and second annealing. The first annealing is performed to obtain a steel sheet having a steel microstructure including ferrite in an amount of 10% or more and 60% or less in terms of area ratio, and martensite, bainite, and retained austenite in a total amount of 40% or more and 90% or less in terms of area ratio. The second annealing includes heating to an annealing temperature of 750° C. or higher and 850° C. or lower, holding at the annealing temperature for 10 seconds or more and 500 seconds or less, cooling at an average cooling rate of 1° C./s or more and 15° C./s or less, performing a galvanizing treatment, and cooling to a temperature of 150° C. or lower at an average cooling rate of 5° C./s or more and 100° C./s or less.


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