| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method of an electroplated steel sheet or chemical conversion treated steel sheet having excellent appearance, and its apparatus. SOLUTION: The production method of the surface treated steel sheet having excellent appearance includes a pretreatment process of a continuous annealing line to subject a cold rolled steel sheet to cleaning treatment of either or both of alkaline cleaning and pickling, rinse cleaning treatment to remove the cleaning liquid adhering to the steel sheet in the rinse cleaning treatment from the steel sheet surface, and liquid draining treatment to remove the rinse cleaning liquid adhering to the steel sheet in the rinse cleaning treatment, an annealing process of subjecting the treated cold rolled steel sheet to continuous annealing, and a surface treatment process of subjecting the annealed steel sheet to surface treatment of either one or both of electroplating and chemical conversion treatment, in which a cleanliness evaluation process of collecting a sample from the steel sheet prior to the surface treatment, successively subjecting the sample to electrolytic degreasing treatment and electrolytic pickling treatment, and evaluating the cleanliness of the steel sheet surface according to whether a prescribed pattern appears on the sample surface or not is further included between the annealing process and the surface treatment process. COPYRIGHT: (C)2007,JPO&INPIT
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