Integrated models for defect free casting (Deffree) : final report

The objective of the project was to develop a new modelling-based optimisation and quality control system for continuous casting. The concept was based on studying critical parameters affecting steel quality and finding safety ranges for them to ensure good quality in continuous casting. Several fundamental and semi-empirical models were developed in the project. The critical features affecting steel quality were defined through mathematical modelling and industrial casting trials. Both good quality casts and casts with some defects were simulated to find features which have an effect on steel quality. Cracking indices, fluid flow parameters in the mould and segregation severity parameters are examples of critical parameters defined in the project. Safety ranges inside which the critical parameters had to stay during casting were determined in steady-state casting conditions. If a critical feature could not be adjusted on-line during casting, for example, surface velocity of liquid in the mould, this feature was expressed as a function of casting parameter, e.g. casting speed, which can be controlled and modified during casting. For optimising and controlling steel quality during casting the following online models were developed in the project: transient 2D centreline segregation model, dynamic 3D heat transfer model and inverse mould heat flux difference model. These models can be applied also to other casters for online simulation, once the caster has been set up and casting process data is available.