The use of graphite molds is mainly that its high temperature resistance is better. The casting temperature of pure copper casting is about 1200 degrees. The performance of graphite molds is still stable at the temperature. The amount of heat and cold shrinkage is small, which can be ignored. On the other hand, the lubrication is better. During the solidification process, the metal solution is not easy to stick to the graphite mold. Although the thermal conductivity is poor, it is not necessary to cool down in casting, so this may become a strength. Graphite molds are generally used in horizontal casting, because the gravity of this casting method has a greater impact on solidification, and the lubrication is not good and cannot be cast horizontally.
The main disadvantage is that it can only be used for 1 to 2 weeks, because the metal liquid will be residial on the mold, and it will affect the crystallization to a certain extent, which will endure the surface quality of the ingot. High -quality ingots even use new boards, which are high. Most manufacturers rely on imports, generally more in Japan and the United States, and expensive.
There are also iron mold casting in the current production. However, in order to improve lubrication, generally lubricants such as carbon black and oil are generally added. Generally, it is only used in the vertical semi -linked casting.