Thermal shock resistance of andalusite based bricks

摘要

The influence of thermal cycling (1 cycle or 30 cycles) in the range 1510℃-970℃ has been studied on unfired or fired andalusite based bricks with the same composition. The main damaging effect of the first thermal cycle has been shown on the unfired andalusite based bricks. The successive dwell times at 1510℃ enable a partial recovery of the microstructure whatever the initial state of the brick (fired or unfired). After 30 cycles, both materials are still operational. However, the andalusite fired bricks, thanks to the composite microstructure of mullitised andalusite grains, shows a significant advantage towards unfired bricks in terms of homogeneity and reproducibility of the behaviour towards thermal cycling. The typical microstructure of andalusite fired bricks can partly explain their good performance during heating-cooling cycles of iron and steel ladles.