High-temperature operations require refractory materials to withstand high-temperature heat load performance, but due to different operating sectors, even in the same furnace in different parts of the working conditions are not consistent. Therefore, the requirements for refractory materials are also different. Is based on the general working conditions of ordinary industrial furnaces as the basis for the performance of refractory materials to the following requirements:
Resistant to high temperature heat load, do not soften, do not melt. Requiring refractory material with a very high refractoriness. Resistance to high temperature heat load, the volume does not shrink and only uniform expansion. Requiring material with high volume stability, residual shrinkage and residual swelling is small, no crystalline transformation and severe volume effect. Resistance to high temperature heat load and heavy load of the combined effect, do not lose strength, no creep and collapse. Requirements of the material has a very high room temperature strength and high temperature thermal strength, high load softening temperature, high creep resistance. Resistance to sudden changes in temperature or uneven heating, no cracking, no flaking. Require material with good thermal shock resistance. Resistance to molten chemical, dust and gas chemical erosion, no deterioration, no erosion. Require material with good slag resistance. Resistance to flames and charge, dust erosion, impact and wear, the surface does not wear. Requirements of the material has a very high density and room temperature, high temperature wear resistance.
Vacuum casting equipment by the high temperature vacuum operation and the impact of changes in the atmosphere, non-volatile, not damaged. The material is required to have low vapor pressure and high chemical stability. In addition, in order to ensure the overall quality of the structure or lining made of bulk refractory masonry. Slag resistance and air tightness, and easy to construction, but also requires the appearance of the material neat, accurate size, to ensure a certain tolerance, and to prevent the defects are not allowed. In order to withstand the impact of handling and possible mechanical vibration and extrusion, the material must have a very high room temperature strength. For some special requirements, sometimes also consider its thermal conductivity and conductivity. It should be noted that although the above points can be used as a basis for evaluating the quality of refractories, none of the refractories satisfies all of the above requirements. In the selection or evaluation of refractories, the material must be the characteristics of the protrusion and the use of conditions to adapt to make the best use. Taking into account economic accounting.