APPARATUS AND PROCESS FOR PRODUCING STEEL SHEET PLATED BY HOT DIPPING WITH ALLOYED ZINC

摘要

An apparatus for producing a steel sheet plated by hot dipping with alloyed zinc. It can conform to abrupt changes in the kind of steel, deposit amount, and other external factors to enable a steel plate plated by hot dipping with alloyed zinc to be produced always under optimal production conditions. The apparatus (1) for producing a steel sheet plated by hot dipping with alloyed zinc is equipped with an oven (7) for both heat retention and cooling where a steel sheet (I) which has been discharged from a rapidly heating oven (6) and is passing through the oven (7) is subjected to at least either of heating for heat retention and cooling.The oven (7) for both heat retention and cooling is constituted so that it has a heat retention zone (15) where the steel sheet (I) is kept hot at a temperature of 500-650°C with heating means (21) and a cooling zone (16) where the steel sheet (I) is cooled with spray nozzles (22) at an average cooling rate of 5 °C/sec or higher and that the proportion of the zone (15) to the zone (16) in the oven is changeable.