Low pressure casting is a method to make liquid metal fill the mold cavity under pressure to form castings. Known for its low pressure, what are the specifications for this casting process?
1. Mold filling and pressurization of low pressure casting
Lifting pressure refers to the pressure required when the metal level rises to the gate. The rising speed of the liquid metal in the riser shall be as slow as possible, so as to facilitate the discharge of gas in the mold cavity and prevent the liquid metal from splashing when entering the gate.
2. Pressurization and pressurization speed of low pressure casting
After the molten metal fills the mold cavity, continue to pressurize to make the crystallization and solidification of the casting proceed under a certain pressure. The pressure at this time is called crystallization pressure. The higher the crystallization pressure, the better the feeding effect and the denser the casting structure.
3. Mold temperature and pouring temperature of low pressure casting
Low pressure casting can adopt various molds. The working temperature of non-metallic mold is generally room temperature, while there are certain requirements for the working temperature of metal mold. For example, when low-pressure casting aluminum alloy, the working temperature of metal mold is generally controlled at 200 ~ 250 ° C, and when pouring thin-walled complex parts, it can be as high as 300 ~ 350 ° C.
If the metal mold is used for low-pressure casting, in order to improve its service life and casting quality, the coating shall be applied evenly, and the coating thickness shall be determined according to the surface finish and casting structure of the casting.
Editing: xyq