Shell growth, surface quality and mould taper design for high-speed casting of stainless steel billets

An industrial plant trial was conducted on an operating billet casting mach ine at a Canadian minimill to determine mould wall temperature profiles for different stainless steel grades, a range of casting speeds, mould flux ty pes and oscillation frequencies. Samples of the billets cast at the trial w ere collected and process variables were recorded. An inverse heat-conducti on model was utilized to determine mould heat flux from measured mould-wall temperatures. Mathematical models were utilized to investigate mould/bille t interaction and mould taper using the heat flux as input. The results fro m plant measurements, mathematical models and billet sample evaluations wer e used to correlate mould thermal response with transverse and longitudinal depressions and oscillation-mark depths for austenitic and martensitic sta inless steels.