Mechanism of Roll Coating Molten Zinc onto Steel Strip

The mechanism of roll coating molten zinc onto steel strip was studied with horizontal and vertical roll coating apparatus, while varying the strip speed, roll speed, line tension and roll-to-strip contact arc length. Roll coating is a process in which the coating roll is wetted with molten zinc and brings it into the contact arc, where the molten zinc reacts with the steel, wetting it and resulting in the transfer of the molten zinc to the steel surface. The amount of zinc entering the contact arc is limited by the amount of zinc supplied on the coating roll, but when sufficient zinc is supplied, the amount entering the contact arc is determined by strip speed and line tension. The distribution ratio of zinc between the strip and the roll at the outlet and the amount of zinc entering the contact arc are considered related to the roughness of the roll surface.