Electroslag remelting (ESR) is widely used for the production of high-value-added alloys such as special steels or nickel-based superalloys. Because of high trial costs and the complexity of the mechanisms involved, trial-and-error-based approaches are not well suited for fundamental studies or for optimization of the process. Consequently, a transient-state numerical model has been developed that accounts for electromagnetic phenomena and coupled heat and momentum transfers in an axisymmetrical geometry. The model simulates the continuous growth of the electroslag-remelted ingot through a mesh-splitting method. In addition, solidification of the metal is modeled by an enthalpy-based technique. A turbulence model is implemented to compute the motion of liquid phases (slag and metal), while the mushy zone is described as a porous medium the permeability of which varies with the liquid fraction, thus enabling accurate calculation of solid/liquid interaction. The coupled partial differential equations (PDEs) are solved using a finite-volume technique. The computed results are compared to the experimental observation of an industrial remelted ingot; the melt pool depth and shape, in particular, are investigated, in order to validate the model. These results provide valuable information about the process performance and the influence of the operating parameters. In this way, we present an example of a model used as a support in analyzing the influence of the electrode fill ratio.

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:Macro-and meso-segregations correspond to heterogeneities of composition at the scale of a casting. They develop during the solidification. One of the parameters that has an essential effect on these segregations is the mush permeability which varies over a wide range of magnitude. We present simulation results for solidification of Sn-Pb alloy in a two-dimensional cavity. The role of discretization schemes and mesh size on the formation of channel segregates and macrosegregation is discussed.

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The treatment of liquid metal in gas-stirred ladles has long been identified as the main process responsible for the inclusion cleanness in special steels. Four university teams and three steels developers have combined their efforts through a project, supported by French National Research Agency, in order to improve the understanding of the complex mechanisms involved during the ladle treatment. In this paper, the contribution of the Institut Jean Lamour to this program, that bears the acronym CIREM, is presented. Using a commercial CFD code as a basis, a three-dimensional simulation model is developed that includes the geometry and industrial operating conditions. The hydrodynamics of the turbulent metal/bubbles mixture is well represented along with the coupled mechanisms of transport, aggregation and surface entrapment of inclusions.