In the process of machining copper, the crystallization characteristics of copper alloys with different compositions are different, the casting performance is different, and the casting process characteristics are also different.
1. Tin bronze: The crystallization characteristic is that the crystallization temperature range is wide and the solidification area is wide. Poor fluidity in casting performance, easy to produce shrinkage, not easy to oxidize. The process is characterized by directional solidification (sequential solidification) of thick-walled parts, and simultaneous solidification of complex thin-walled parts and general thick-walled parts.
2. Aluminum bronze and aluminum brass: The crystallization characteristic is that the crystallization temperature range is small, which is the characteristic of layer-by-layer solidification. In terms of casting performance, it has good fluidity, easily forms concentrated shrinkage cavities, and is easily oxidized. The characteristic of the process is that the aluminum bronze casting system is a bottom injection type, and the aluminum brass casting system is an open type.
3. Silicon brass: The crystalline feature is between tin bronze and aluminum bronze. Casting performance is the best (in special brass). The characteristic of the process is the sequential solidification process, the middle injection type pouring system, and the size of the dark riser is small.