How to choose materials for processing graphite crucible? What kind of graphite crucible is durable?

Graphite crucibles are mainly used to smelt non-ferrous metals such as copper, brass, gold, silver, zinc and lead and their alloys. Graphite crucible is made of natural flake graphite as the main raw material and plastic refractory clay or carbon as binder. It has the characteristics of high temperature resistance, strong thermal conductivity, good corrosion resistance and long service life. In the process of high temperature use, the coefficient of thermal expansion is small, and it has certain strain resistance to rapid cooling and rapid heating. It has strong corrosion resistance to acidic and alkaline solutions, has excellent chemical stability, and does not participate in any chemical reactions during the smelting process.
In addition, the inner wall of the graphite crucible is smooth, and the molten metal liquid is not easy to leak and adhere to the inner wall of the crucible, so that the metal liquid has good fluidity and castability, and is suitable for various mold casting. Due to the above excellent characteristics, graphite crucibles are widely used in the smelting of alloy tool steel and non-ferrous metals and their alloys.
For the selection of graphite crucibles, in general, the raw materials for making crucibles should have high refractoriness, have a strong high temperature resistance coefficient, and the crucible raw materials should have sufficient strength, and will be subject to high temperature impact during the smelting process, which will cause wear and tear. , so if the raw material strength is not high, it is likely to cause the crucible to become more broken and less tough as it is used. At the same time, the shrinkage coefficient of the crucible should be small, and it can withstand rapid changes in temperature without deformation and fracture. In addition, in the selection of materials, attention should be paid to not having a chemical reaction with the molten metal, and the high temperature resistance of the chemical metal should also be high, so it cannot be caused by burning the crucible. loss occurs. High temperature is required when smelting metals, and the selection of crucible materials should ensure chemical stability at high temperatures. It can be seen that a lot of attention should be paid to the selection of crucible materials, and different materials should be used for different purposes. For example: graphite crucible should be used for smelting aluminum and aluminum alloy.