Simulation using realistic spray cooling for the continuous casting of multi-component steel

A three-dimensional heat transfer model for continuous steel slab casting has been developed with realistic spray cooling patterns and microsegregation calculations to accurately determine the solidification path for multi-component steels. Temperature and composition dependent properties are implemented in a database for 15 chemical species. A considerable effort is made to accurately model the spray cooling heat transfer. Each spray nozzle position and distribution are considered, including variations of the spray patterns with flow rate, and spray overlap. Nozzle type, layout, nozzle-to-slab distance, and spray span and flux are variable. Natural convection, thermal radiation and contact cooling of individual rolls are computed. The present model provides more comprehensive information and realistic slab surface temperatures than results from a model using the "averaged" treatment of boundary conditions. Cooling operating conditions and parameters of individual spray nozzles can be analyzed to optimize the nozzle spray distribution, improve the product quality and troubleshoot issues such as nozzle clogging that may arise during production. By using a machine dependent calibration factor alpha of about 4, predicted and measured slab surface temperatures show good agreement with an error of 26 deg C for a variety of casting conditions, alloys, widths, casting speeds, and flow rate conditions.