The poor filling conditions of aluminum alloy castings indicate that the metal at the bottom of the castings solidifies irregularly. The reasons are as follows:
1. When the existing aluminum cast iron solidifies prematurely, the wedge shape, deep groove, thin wall (even thinner than the intermediate wall), cylindrical hole wall and other parts of the aluminum alloy casting will be discarded.
2. The temperature of the casting mold is too low;
3. Aluminum alloy casting temperature is too low;
4. The gate position of the casting mold is not good, and the movement resistance is large.
There is gas in the mold cavity, which is characterized by the lubrication of the lower surface of the casting, but the shape is irregular. The reasons are as follows:
1. The overflow system is difficult to adjust. where the gas collects;
2. The weld metal is turbulent, and the gas is wrapped when it is active.
3. Die casting residual cavity.
4. The local coating deposition of the mold is caused by improper coating amount or improper spraying method.
5. The insertion gap or sliding fit gap of the aluminum alloy die casting is too large, and the metal contacts when filling. After the aluminum alloy is cast, the aluminum alloy is not completely pulled out, but clamped in the space.
Note that when the pouring part of the aluminum alloy casting is serious, it can be considered that the shape of the aluminum alloy die casting does not meet the requirements of the drawing. Downcasting is generally not allowed.