What are the characteristics of firebricks? What is the refractory limit of firebricks?
Publish Time:
2023-07-11
I. What are the characteristics of refractory bricks?
1. Chemical Composition: The main components of refractory bricks determine the quality and refractory properties of the brick body.
2. Bulk Density: The higher the bulk density, the better the density of the refractory brick, the higher the strength, and the higher the thermal conductivity; conversely, the lower the density, the lower the strength, and the better the insulation effect.
3. Apparent Porosity: The apparent porosity of high-density refractory bricks is generally 3%-10%, that of ordinary dense refractory bricks is 20%-30%, and that of lightweight refractory bricks is 45%-48%.
4. Load Softening Temperature: This is the temperature at which a refractory brick deforms under a constant load and heating conditions at a certain heating rate. It indicates the resistance of the refractory material to the simultaneous action of high temperature and load.
5. Thermal Shock Resistance: Refractory bricks can withstand extreme temperature changes without being damaged, such as clay bricks, which can be used for molten iron storage and transportation in iron tanks.
6. Compressive Strength: The ultimate load that a refractory brick can withstand per unit area at a certain temperature (generally at room temperature) without being damaged.
7. Flexural Strength: Refers to the ability of refractory bricks to withstand shear stress. This is generally achievable for refractory bricks, and is generally much smaller than the compressive strength.
8. Re-burning Linear Change Rate: The residual shrinkage or expansion of the brick body length after the refractory brick is heated to a specified temperature and kept warm for a certain period of time and cooled to room temperature. A plus sign indicates expansion, and a minus sign indicates shrinkage. The linear change rate is an aspect that indicates the high-temperature volume stability of refractory bricks. If the shrinkage is too large, it will cause the refractory bricks to fall off, etc.
The characteristics of refractory bricks are directly related to the content of raw materials. Different content of raw materials will lead to different characteristics. Different refractory brick usage environments require different refractory brick characteristics.
II. What is the refractory limit of refractory bricks?
Refractory bricks, depending on their material and content, can be used for a long time at high temperatures of more than 1000 degrees to over 2000 degrees. The refractory limit is a fire test conducted on building components according to the time-temperature standard curve for fire prevention and fire isolation. The refractory limit refers to the time of the fire test on building components according to the time-temperature standard curve, from the time when it is affected by fire to the time when it loses its supporting ability or its integrity is damaged or catches fire. Isolation loss, expressed in hours.
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