Alumina-magnesia castable materials used mainly in steel ladles form spinel at high temperatures heated under free conditions results in large permanent linear change and the material texture becomes porous. The materials are used as a structure in actual use and are bi-axially restrained by the surrounding structural members. It is known that the textures and characteristics of the materials in actual use do not match the laboratory evaluations. This study investigated the influence of bi-axial restraint on the characteristics of alumina-magnesia castable refractories. The other castable material with high strength was cast to the surrounding area of the alumina-magnesia castable to prepare bi-axially restrained specimens. Densification of the specimen texture was observed after heating under restraint. The strength was greatly increased especially after heating at high temperature. This suggests that the difference in the strength between the working face and backside of actual ladles is significantly larger than the material evaluations carried out under non-restrained conditions.
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