Issues in Thermal-Mechanical Modeling of Casting Processes

Mathematical modeling of stress generation in casting processes is a difficult, complex subject that is now receiving increased attention. This paper reviews the basic equations, solution methods and important phenomena associated with casting processes that require special numerical treatment. Stress modeling begins with a coupled, transient heat transfer analysis, including solidification, shrinkage-dependent interfacial heat transfer, and fluid flow effects. Further complicating phenomena include phase transformations, temperature, stress and structure-dependent plastic-creep, interaction between the casting and the mold, hydrostatic pressure from the liquid, the effects of fluid flow, and crack formation. Computational issues include numerical methods for handling these phenomena, mesh refinement, and two-dimensional stress state. Example applications are presented for the thermal-mechanical behavior of the solidifying steel shell in the mold region of a continuous slab caster, using a finite-element model, which accounts for many of these phenomena.