Generalized gravity casting includes sand casting, metal casting, aluminum alloy casting, slurry casting, etc. Narrow gravity casting refers to metal casting.
The main advantages and disadvantages of gravity casting are introduced.
Gravity casting has a mold that can be reused many times. Each pouring of metal liquid can obtain one casting, which has long service life and high production efficiency. Metal castings not only have good dimensional accuracy and smooth surface but also have higher strength than sand mold and are not easy to be damaged. However, gravity casting also has some defects: due to the expensive processing of heat-resistant alloy and its hollow cavity, the mold manufacturing cost is expensive.
Therefore, for small batch production, the cost allocated to each product is obviously too high and generally unacceptable. Aluminum alloy gravity casting is an essential tool in the process of die casting. The die casting process is a production process of metal parts formed at one time, which involves the knowledge of mechanics, hydrodynamics, thermodynamics, and so on. There are many influencing factors, such as die-casting structure, injection speed, pressure, die-casting die temperature, liquid metal temperature, and so on. In short, the die casting process is a very complex processing process.
The work of aluminum alloy gravity casting is to carry the filling of liquid metal. This work can be divided into three stages.
In the first stage, the molten metal enters the mold cavity of aluminum alloy gravity casting through the inner gate, then diffuses around the wall and returns to the gate to form the shell of die casting.
Second, liquid metal enters the cavity of the aluminum profile die-casting die through the inner gate, expanding and merging around the core formed in the first stage, which is the stage of continuous flow and filling of liquid metal.
Third, the liquid metal completely fills the aluminum die-casting mold. The cavity, gating system, and pressure chamber are closed hydrodynamic systems.
The die-casting everywhere in the system is equal, and the injection force continues to act on the liquid metal through the center of the die-casting until the liquid metal solidifies and forms.