Chemical Pretreatment of Galvanized Substrate Materials During Coil Coating.

The purpose of chemical pretreatment of galvanized steel strip prior to coil coating is to remove dirt, grease, oil, rolling debris and oxidation products from the metal surface, so that it more readily adheres to the subsequently deposited organic coating system. The author describes three methods of chemical pretreatment in a coil-coating line, namely, cleaning and subsequent rinsing, conversion treatment with subsequent rinsing and passivating final rinsing, and top coating by the NO-RINSE technique.