FORMATION OF CASTINGS WITH COMPLEX-GEOMETRY - THERMOMECHANICAL EFFECTS, GROWTH AND INFLUENCE OF THE AIR-GAP

In previous works we have proposed a method for mathematical modelling of the processes of heat and mass transfer in castings, which includes the construction of a boundary fitted coordinate system in a Riemannian coordinate space. Within this approach we obtain the deformations, stresses and strains in the casting-mould system within a linear thermoelastic model. The equations for the stresses and deformations are derived from the corresponding laws of conservation in the coordinate space. Secondly, we consider the problem of heat transfer between the casting and the mould, while the boundary conditions change during the crystallization and formation of the crust due to the thermomechanical interaction there. We describe the evolution of the air gap and consider its influence on the process of crystallization. Some consequences from this model, which may allow a more subtle description of the casting formation, like the segregation behaviour in the two-phase region, are also discussed.