Modeling of Thermal Expansion and Metallurgical Phases of a Material during its Cooling

In metallurgy, the use of numerical models is popular because of the many coupled physical phenomena that occur during the various processes. For instance, the resulting shape and metallurgical state of a material are very sensitive to changes in temperature.

The ingot cooling leads to thermal contraction : the thermal exchanges are drastically affected by the quality of contact between the metallic ingot and the crucible. To better understand these phenomena, a 2D axisymmetric model is developed using COMSOL Multiphysics® to simulate the casting and cooling of an ingot in a crucible.

The casting process is carried out until the ingot has reached its final height, and then the ingot is cooled for several hours by water flowing over the crucible walls. By using a moving mesh method to describe the growth of the ingot, a thermo-mechanical model is built which includes the metallurgic phases evolution. After numerical validation, this model can be used to predict the influence of thermal contact resistances at the external walls of the ingot on the temperature and shape evolution of a material during casting.

The metallurgical phase composition of the metal ingot is directly influenced by its thermal history over time and the properties of each potential phase change : this model can be used to describe the evolution of the different metallurgical phases during the cooling.