Causes Of Blowhole In Copper Casting
Copper casting is an ideal mechanical accessory after die casting. When copper products are used in the assembly process, many people are interested in the smelting principle of copper castings. Copper castings in the production process will appear blowholes, let's look at the causes of copper castings blowholes and solutions.
The causes of porosity in copper castings are as follows
1. The preheating temperature of the mould is too low, and the liquid metal is cooled too fast through the gating system;
2. The exhaust function of the mould is not perfect and the gas can not be discharged smoothly;
3. Poor coating, poor self exhaust, and even self volatilization or decomposition gas;
4. There are holes and pits on the surface of die cavity. After the liquid metal is injected, the gas in the holes and pits expands rapidly and compresses the liquid metal to form a plug hole.
5. The surface of die cavity was rusted and not cleaned up.
6. Raw materials (sand cores) are not properly stored and not preheated before use.
7. Deoxidizer is not good, or the dosage is not good or the operation is improper.
The solution to blowhole of copper casting is as follows:
1. The mold should be fully preheated, the particle size of coating (graphite) should not be too fine, and the air permeability should be good.
2. The skew pouring method is used.
3. Raw materials should be stored in a ventilated and dry place, and should be preheated when using.
4. A good deoxidizer (magnesium) was selected.
5. The pouring temperature should not be too high.
The above is the cause of copper casting porosity and solutions, I hope to help you.