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.:
Date of Patent:
Jan. 26, 2016
Filed:
Mar. 26, 2012
Tomohiro Matsushima, Chiba, JP;
Masao Inose, Kawasaki, JP;
Masayasu Nagoshi, Chiba, JP;
Hiroyuki Masuoka, Fukuyama, JP;
Shigeyuki Aizawa, Chiba, JP;
Hisato Noro, Kawasaki, JP;
Tomohiro Matsushima, Chiba, JP;
Masao Inose, Kawasaki, JP;
Masayasu Nagoshi, Chiba, JP;
Hiroyuki Masuoka, Fukuyama, JP;
Shigeyuki Aizawa, Chiba, JP;
Hisato Noro, Kawasaki, JP;
JFE STEEL CORPORATION, Tokyo, JP;
Abstract
This invention provides methods and apparatuses which can manufacture Si-containing cold rolled steel sheets exhibiting excellent chemical conversion properties even if a chemical conversion treatment solution is used at a lower temperature while minimally suppressing the generation of sludge as well as reducing running costs. The method includes steps of cold rolling a steel containing 0.5 to 3.0 mass % Si, continuously annealing the cold rolled steel sheet, pickling the surface of the continuously annealed cold rolled steel sheet, and repickling the surface of the pickled steel sheet with a non-oxidative acid. The repickling is performed such that a repickling solution is sampled continuously or periodically, an acid concentration in the sampled solution is measured, and the acid concentration in the repickling solution is regularly controlled within a prescribed concentration range.