Nozzle design for ArcelorMittal Dofasco's No. 1 continuous caster for minimizing sliver defects

A study was conducted at ArcelorMlttal Dofasco to evaluate fluid flow patterns generated in the No. 1 continuous caster mold by using computational fluid flow and heat transfer models. Single-phase (liquid steel without argon co-flow), three-dimensional, computational fluid dynamics (CFD) and heat transfer models were developed using ANSYS CFXTM for a 220-mm-thick mold and a two-port SEN with a nozzle well used at the No. 1 CC to produce ULC steel slabs at various caster throughput rates. Based on these models, the predicted fluid flow conditions that might contribute to alumina and/ or mold powder entrapment at extreme caster throughput rates were identified. Meniscus velocities greater than 0.35 m/second in a 900-mm-wide mold at extremely high throughput rate resulted in excessive meniscus activity, contributing to the entrapment of mold powder, and meniscus velocities less than 0.20 m/second in a 1,600-mm- wide mold at extremely low throughput rate may result in minimal meniscus activity and formation of deep hooks and oscillation marks, contributing to entrapment of alumina inclusions.