Castable, also known as refractory castable, is a kind of granular and powdery material made of refractory material and binder. It has high fluidity and is formed by pouring. Compared with other amorphous refractories, the binder and moisture content are higher and the fluidity is better. Therefore, the castable has a wide range of applications. The materials and binder used can be selected according to the service conditions. It can not only be directly poured into lining, but also be made into precast blocks by pouring or vibrating.
In the construction process of refractory castable, the key quality problems to be paid attention to are: the moisture content of castable during construction; Temperature at the construction site; Post maintenance; Baking of refractory castable.
In the process of adding water to mix castable, the amount of water is the key. If the amount of water added is too large, it will be thinner and the fluidity will increase, which will affect the exertion of the construction strength of the castable. However, if the water is added too little, it will make it difficult to mix the aggregate with the powder, resulting in a mountain of accumulation, resulting in loose structure and reduced construction quality.
Another important factor affecting the quality of castable is temperature. The sudden change of temperature in a short time will quickly damage the castable, resulting in a serious decline in quality, and even fall off before use. The thermal shock stability of castable is very weak before the completion of construction.
Cement dosage: cement is an important material to determine the strength of refractory castable. Generally, with the increase of cement dosage, the compressive strength at room temperature increases, the high-temperature strength decreases, the fire resistance and load softening temperature continue to decrease, and the linear shrinkage after burning also increases. Some manufacturers will shoddy, resulting in castable can not meet the use requirements.
Here are some common reasons for the decline of the performance of refractory castables. In addition to the above, the mixing time of the mixer, the vibration of the vibrator, the baking time, the demoulding time, etc. will affect the quality of castables.