One-side Galvanizing of a Steel Strip by Electromagnetic Pump

Abstract

Design and construction have been made on a new hot galvanizing apparatus which successfully galvanizes one-side of a steel strip by spouting molten zinc upwards through an electromagnetic pump. This apparatus also has a gas-wiping device to control the weight of coated zinc just after galvanizing. The results obtained are as follows :
(1) The electromagnetic pump can easily spout up molten zinc to sufficient height to perform one-side galvanizing.
(2) The spouting nozzle should be wider than the width of the steel strip to ensure galvanizing of the whole surface.
(3) The uncoated side was contaminated by molten zinc stuck to the guide roll surface on the outer side of the steel strip in case the guide roll was wholly made of steel. This contamination, however, could be avoided by covering the guide roll with a graphite or ceramics, to which molten zinc does not stick.
(4) The weight of coated zinc decreased drastically with an increase in the flow rate of the wiping gas, so that the weight of coated zinc could be minimized to 20 g /m².
(5) The zinc coating obtained showed good quality and the oxide film on uncoated side was very thin.