The Secondary Cooling Technology of Continuous Casting for Production of High Temperature and High Quality Slab

Abstract

Delivery of sound slabs at high temperature is one of the most important conditions for the caster to realize the direct rolling (HDR) practice. Secondary cooling system was to be modified to make plan of Fukuyama No. 5 machine for HDR practice. To improve the uniformity and the controllability of cooling intensity, an air-mist cooling nozzle was newly developed. The developed nozzle has several features such as small amount of air consumption, stable spray pattern, easy maintenance, and others. Empirical equation to describe the cooling intensity of the air-mist cooling nozzle was obtained as a function of its operational factors. Evaluation of the nozzle performance in the secondary cooling zone was carried out through plant test with existing casters prior to the installation of No. 5 machine. Improvement of surface qualities of slabs was confirmed as the results of the test. Average heat transfer coefficient of the secondary cooling zone was also determined. Based on the knowledge, the secondary cooling zone and the reheating zone of No. 5 machine was designed and operated. Sound and high temperature slabs are delivered by the caster to realize the smooth HDR operation.