A comprehensive slice model for continuous casting of steel

A simple Lagrangean travelling slice model has been successfully used in the past to predict the relations between the process parameters and the temperature field as well as grain structure, macrosegregation assessment, optimisation of process parameters and calculation of caster regulation coefficients. The present paper aims to include also the mechanical stress and deformation model into the slice framework. The basis of all the mentioned models is the slice heat-conduction model that takes into account the complex heat extraction mechanisms in the mould, with the sprays, rolls and through the radiation. Its main advantage is very fast calculation time, amenable for use also in the caster's online control. The macroscopic model used in this study is based on the continuum mixture theory, calculating enthalpy and mixture composition as input parameters for microscopic calculations. The grain structure model is based on the cellular automata concept, replaced by a random node point automata concept. The macrosegregation model is based on the lever rule microsegregation model. The liquid phase's thermal conductivity and species diffusivity are artificially enhanced to consider the convection of the melt. The calculated thermal field is used to estimate the thermal contraction of the solid shell, which, in combination with the metallostatic pressure, drives the elastic-viscoplastic model of solid mechanics. The results of the model are used to estimate the areas susceptible to crack nucleation using several hot-tearing and damage models. The solution procedure of all the models is based on the meshless local radial basis function collocation method on the macroscopic scale and the point automata concept on the grain structure scale. A sensitivity study on the recently introduced standard continuous casting geometry is performed as well as on the realistic conditions in Store-Steel billet caster. Possible additional refinements of the model are discussed.