Structure Control and Evaluation of Effective Fracture Energy on Alumina-Magnesia Monolithic Refractories Prepared with CaO·6Al<sub>2</sub>O<sub>3</sub> Aggregate

Alumina-magnesium castable refractories are used for the inner walls of molten steel ladles. The main cause damage to these is thermal shock caused by rapid temperature changes during loading and unloading steel. Therefore, resistance coefficient R'''' a parameter that expresses shock, evaluation effective fracture energy important improving R''''. In this refractory, CaO·6Al2O3 (CA6) formed from raw materials alumina cement; CA6 has advantage inhibiting crack propagation mechanical properties. On other hand, disadvantage volumetric expansion formation. microstructural formation significantly affect properties refractories. study, was as material replaced with generated in-situ. amount coarse-grained added adjusted control microstructure. effect microstructure change on then evaluated. As result, improved in sample more added, due replacement aggregate.