Crack Growth in Castable Refractory due to Thermal Shock Fatigue: An Acousto-Ultrasonic Study

Thermal shock fatigue crack growth in an alumino-silicate castable refractory has been studied using the non-destructive method of acousto-uitrasonic signal analysis. Acousto-ultra- sonic signal parameters supported by strength measurement studies and microscopic observations, indicated initiation, growth and interlinking of microcracks with increasing cycles of thermal shock fatigue. Equations have been proposed to monitor degradation of strength from acousto-uitrasonic measurements. The study reveals that acousto-ultrasonics is a very useful approach for non-destructive qualitative as well as quantitative evaluation of thermal shock damage in refractories.