1979 Volume 87 Issue 1006 Pages 307-317
Thermal stress fracture behavior of various refractories was studied using an acoustic emission technique and a panel spalling method. Effects of thermal shock conditions such as heating rate on acoustic emission characteristics, that is, on crack propagation process were also studied.
As heating rate, specimen dimension or restraining force increased, magnesia refractory exhibited more and more unstable crack propagation. On the other hand, magnesia-dolomite refractories exhibited stable crack propagation and the propagation behavior was scarcely affected by the difference of the thermal shock conditions.
Measurements on magnesia, magnesia-dolomate, magnesia-chromite and high-alumina refractories have demonstrated that each specimen material exhibited different acoustic emission characteristics corresponding to the difference of thermal shock damage behavior. These acoustic emission characteristics were classified into five patterns in the present study.
Because good correlation was obtained among AE total rinddown count, service performance and thermal shock damage resistance parameter Rst for magnesia-dolomite refractories, it is effective to use the acoustic emission technique for evaluating thermal shock damage resistance of refractories such as magnesia-dolomite.
