Impact of preheating on the mechanical performance of different MgO-C bricks?Intermediate temperature range

This work analyses the mechanical behavior of MgO-C refractories at an intermediate temperature of 1000 ?C. Conditions similar to those occurring during the in-service pre-heating of steelmaking ladles are simulated by thermal treatment before the mechanical testing. Stress-strain curves were determined under compressive loading at RT and 1000 ?C. The impact of the thermally activated physicochemical transformations on the mechanical response of the materials was evaluated in terms of parameters such as strength, fracture deformation, secant modulus and yield strength. The presence of Al seems to be deleterious when longer soaking times at 1000 ?C were applied, which was attributed to the progressive damage related to in situ phase formation. On the other hand, when heating these types of refractories simultaneously with the application of a low compressive load, the closure of previously formed microcracks (self-healing) was considered to be mainly responsible for their mechanical behavior.