Hot elastic modulus of Al2O3–SiC–SiO2–C castables

This work discusses an investigation of the hot elastic modulus and crack generation of two Al2O3–SiC–SiO2–C castable compositions throughout two thermal cycles in an oxidizing atmosphere. A high temperature ultrasonic technique carried out using a long bar mode, thermogravimetric, X-ray diffraction, apparent porosity analyses and thermodynamic calculations were evaluated in order to understand the results. Significant changes in the castables’ elastic modulus values were observed with temperature, which were related to the decomposition of hydrated phases, antioxidant reactions, changes in the liquid phase viscosity, and formation and closure of microcracks in the castable microstructure. The results attained are fundamental for providing data for thermo-mechanical computing simulations by finite element analyses and for the design of large refractory structures, such as blast furnace runners for the steel industry.