Two-phase thermo-mechanical and macrosegregation modelling of binary alloys solidification with emphasis on the secondary cooling stage of steel slab continuous casting processes

Abstract

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

Simulation Model for Solidification Process in Planar Flow Casting Using the Multi-zone Method

“…This seems to be because an elaborate model requires elaborate material data and solution techniques; rare intermediate material data on free surfaces have been published. Fachinotti et al 17) solved semi-solidified slab deformation in continuous casting with the mobile mesh model; only 100 % solid area constitutes a free surface in this study.…”

Review on Modeling and Simulation of Continuous Casting

“…Because the liquid level at the top free surface in the mold is free to rise and fall, the mass contained in the computational domain for the mechanical analysis can change with time during the process, and it is usually too expensive to include this free surface in the model domain. This issue can be addressed in several other ways, such as by introducing another strain component for the fluid flow, leaving space for shrinkage in the central portion of the domain, or by adopting an Arbitrary Lagrangian–Eulerian (ALE) formulation, where the internal fluid flow region is solved with an Eulerian methodology and the exterior mechanical behavior of the moving solid shell is solved with a Lagrangian method …”

Using a Two-Phase Columnar Solidification Model to Study the Principle of Mechanical Soft Reduction in Slab Casting

“…Another issue is the volume change of the solid-state phase transition (from d ferrite to c austenite), which may play an important role in the mechanical deformation as well. For future development, incorporating the thermomechanical model in the multiphase solidification model as suggested by Bellet or Fachinotti [32,33] is desirable. Otherwise, the one-way coupling as suggested by Kajitani et al [17] is also an intermediate solution.…”