The application of refractory materials at high temperatures necessitates special material properties, which influences the material wear, the energy consumption, and the production cost. Therefore, the failure mechanism investigation of refractory materials is of great importance. The current study aimed to investigate the possible thermomechanical failure of the refractory lining used in a steel ladle with the help of finite element analysis. As different material parameters are required for the FE-simulations, an experimental study was designed to obtain them. Therefore, the outline of this study consists of two main parts, i.e., mechanical characterization and thermomechanical simulation.
In the first part, high-temperature mechanical tests were applied to investigate the necessary material properties of a shaped alumina spinel refractory, which is used in the working lining of the investigated steel ladle. The experimental study included Young’s modulus measurements, uniaxial compressive and tensile creep tests, modified shear test and wedge splitting test. In this part of the study, several improvements were implemented in the material characterization methods. Firstly, a statistical study was introduced in the creep behavior investigation since a high scatter was received in the creep results due to the material heterogeneity. The second improvement was applied in tensile failure characterization. A novel material constitutive model was developed to be employed together with wedge splitting test and evaluate the refractory fracture parameters at high temperatures. The model overcomes the limitations of the concrete damaged plasticity model in Abaqus. It could deliver more accurate results by considering simultaneously creep and fracture behaviour.
In the second part of the research study, the evaluated material parameters were employed in the thermomechanical simulation of the steel ladle. A unit-cell modeling approach was applied, and three different constitutive material models were considered, each corresponding to an irreversible deformation mechanism. Creep behavior was simulated using the Norton-Bailey creep model, shear failure using the Drucker-Prager yield criterion, and tensile failure using the concrete damaged plasticity. The results of the three models were compared to observe the influence of each failure phenomenon on the stress-strain responses of the lining and the steel shell.