Multiple-Scale Thermomechanical Analysis of a Forced-Cooled Aluminum Reduction Pot

Abstract

Accurate prediction of the thermomechanical behavior of the aluminum reduction pot, in aluminum smelters, is critical in ensuring the pot’s mechanical integrity is maintained during forced-cooling procedures. To that effect, this study investigates the microstructural and macrostructural behavior of the steel potshell under different forced-cooling techniques. In the microscale analyses, tensile and microhardness tests are followed by scanning electron microscope (SEM) imaging of the potshell material cooled at different rates. In this scale, the effect of various cooling rates on the potshell’s microstructural evolution is investigated. Thermal and mechanical experimental characterizations of the potshell material are performed to facilitate the development of a three-dimensional (3-D) thermomechanical (TM) finite-element model of the pot. Using the commercial code ANSYS, a macroscale TM model of the pot is developed, validated, and used to estimate thermal-induced stresses during different cooling techniques. Tensile tests and microscale measurements show that cooling rates between 0°C/s and 50°C/s does not significantly affect the microstructural integrity of the potshell material. The TM model depicted a good correlation with practical measurements. The results from the model show that the metal-pad forced-cooling technique presents no danger to the mechanical integrity of the potshell.