Increasing sequence length: process development and optimisation at the slab caster of Columbus Stainless

Abstract

The present paper discusses the process development and optimisation conducted over a two-year period at the continuous caster at Columbus Stainless to allow an increased sequence length, thereby satisfying the continual drive for increased throughput, lower cost of production and higher quality. Increased sequence length results in longer exposure of refractory to steel or slag resulting in more erosion and chemical attack. The refractory system in use at Columbus Stainless was initially designed and optimised for 6 h of casting and the focus of the development was to increase this time to 14 h. This objective was achieved by modifications to tundish design and lining, optimisation of the tundish cover, modifications to stopper and SEN design, composition and operating practise. After these changes, the original objective of increasing the sequence length to 14 h was achieved with a concomitant saving in refractory cost per ton of up to 35%.