International audienceAs an approach towards a better modelling of solidification problems, we introduce a thermo-mechanical and macrosegregation model that considers a solidifying alloy as a binary mixture made of a liquid and a solid phase. Macroscopic conservation laws for mass, momentum and solute are obtained by spatial averaging of the respective microscopic conservation equations. Assuming local thermal equilibrium, a single equation for the conservation of the mixture energy is then written. A single equation can be obtained for the solute as well by invoking a proper microsegregation rule. The numerical implementation in a 2D finite element code is then detailed. Lastly, some examples of simulations of academic tests as well as industrial applications for continuous casting of steel slabs are discussed. They particularly enlighten the ability of the formulation to describe the formation of central macrosegregation during the secondary cooling of slab continuous casting processes

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Subject of a presentation at the 2004 ATS International Steelmaking Conference (Paris, December 9-10, 2004, Session 14). La publication originale est disponible sur le site http://www.revue-metallurgie.orgInternational audienceThe development of high tensile strength steels with higher levels of alloying elements needs the implementation of operating means in the continuous casting machine to master slabs internal soundness and surface quality. In order to define optimal process parameters according to the characteristics of the different continuous casting machines and to optimize the revamping of older equipment, thermomechanical modelling of the steel slab behaviour during casting has been carried out. This paper presents the results of simulations performed to check the potential of this modelling