Casting soot is an essential part of casting in metallurgy. Its main function is to prevent molten metal from sticking to the wall of the mold and make it easy to remove the castings from the mold. Casting soot is also used to reduce surface defects of castings.
Casting soot is a mixture of various substances, such as coke, brick powder, quartz sand, zircon sand, clay and so on, which are formed by burning or calcination and made into a certain particle size. In the process of pouring and solidifying of casting, the casting soot forms a thin layer on the surface of the molten metal, and an isolation layer so that the molten metal does not stick to the cavity of the mould or the core of sand material.
The selection of casting soot is very important. Different casting soot is suitable for different mould and casting process. Generally, the coke powder is suitable for the production of large castings with thick wall. The quartz sand powder is suitable for those with thin and precise castings, and the clay powder is suitable for low temperature castings.
The casting soot is usually stirred into the molten metal before pouring or poured into the mold cavity. Then, the molten metal is poured into the cavity to form the castings.
The dosage of casting soot is affected by many factors, such as the type of casting material, the shape of the castings, the size of casting, the pouring speed and temperature of molten metal. Generally, the dosage should be adjusted according to the specific process and products to obtain a satisfactory effect.
In the casting process, the casting soot is homogeneous and evenly spread on the surface of the molten metal, and its layers are arranged in parallel. The central temperature of the casting core is the same as the temperature of the molten metal, and its heat is also provided by the molten metal. Therefore, the core of the casting also has lubricating and separating effects.
In addition, when the castings are taken out of the mold, the casting soot can also reduce the surface roughness of the castings, reduce casting defects such as burns and to the harm.
In the casting process, it is necessary to properly choose the casting soot and use it properly, so as to prevent sticking of castings and obtain idealcasting effects.
