Refractory products; determination of refractoriness-under-load (differential - with rising temperature)

This technical specification establishes a standardized procedure for evaluating the softening behavior of refractory products under load. The method is designed to determine the temperature at which a specimen deforms to a specified extent when subjected to a constant compressive stress. By simulating conditions where materials bear mechanical loads at elevated temperatures, the test provides critical data on the structural integrity of refractory materials used in high-temperature industrial applications. The procedure involves preparing standardized specimens and subjecting them to a defined load within a controlled furnace environment. As the temperature is gradually increased, the deformation of the specimen is continuously monitored. The temperature corresponding to a specific deformation limit is recorded as the load softening temperature. This metric serves as a fundamental indicator of the material's ability to maintain shape and function under operational stress in furnaces or kilns. The detailed steps cover specimen preparation, apparatus setup, heating rates, and the calculation of results, ensuring consistency and comparability across different testing facilities and material batches.