PREVENTING EDGE OVERCOAT IN CONTINUOUS GALVANIZING

摘要

PURPOSE:In continuous galvanizing line, immediately after steel plate is passed through plating rolls, inert gas is jetted through wide-opened, elongated nozzle onto the both sides of the plated steel, thereby preventing the generation of edge overcoat, and enhancing the quality of the plated steel. CONSTITUTION:Steel plate 5 is passed through the pair of rolls 3 dipped into molten zinc 4, the both side of galvanized plate 5 is immediately jetted with inert gas such as N2 at both edge sides. The edge nozzles 6 having wide-opened elongated opening 7 are directed at the center of the plating rolls 3, jetting the gas at a pressure of 1500 to 2500 mm H2O which is 2 to 3 times greater than the usual value. As a result, molten zinc pool between the roll 3 and the plate 5 is blown toward inside, rendering plating layer uniformly distributed, thereby to eliminate the overcoat at the edge portions. The process thus enhance the quality of the products and reduces production cost as well as the consumption of corrugated board to be used for preventing build up when winding the steel plate.