Stress and Strain Evolution in Cast Refractory Blocks during Cooling

A computational model has been developed to study the stress and strain histories experienced by zirconia‐containing cast refractory blocks when they are cooled from the casting temperature. Incorporated into the model are strong temperature dependencies of the following material properties: elastic modulus, flow strength, thermal conductivity, and thermal expansion. The pressure‐sensitive Drucker‐Prager plasticity model has been used to account for the substantial difference between the tensile and compressive stress‐strain behaviors found in these refractories. The temperature‐induced phase transformation in the zirconia, as well as the overall thermal contraction, are united by introducing a coefficient of total dilatation. A nonuniform radial distribution of the transforming phase is also incorporated. The parameters that control the time‐dependent stress and strain responses are identified by performing calculations that span the range of expected variables. Process strategies for manufacturing crack‐free blocks are suggested.