Optimizing Copper Casting Processes: Preventing Common Defects and Enhancing Casting Quality

Copper casting is an ancient process known for its excellent electrical conductivity, thermal conductivity, ductility, and malleability. It is widely used in electronics, electrical appliances, machinery, and construction. However, the copper casting process can also result in various defects that affect the quality of the castings. Common defects include:

• Shrinkage: Caused by volume reduction after the casting solidifies.
• Porosity: Cavities formed inside or on the surface of the casting.
• Cold Shut: Incomplete fusion of the gating system with the casting.
• Cold Pour: Areas of the casting not filled with molten metal.
• Sand Inclusion: Adherence of sand to the casting surface.
• Incorrect Pouring Speed: Defects caused by too fast or too slow pouring speed of the molten metal.

These defects can reduce the mechanical properties, tightness, appearance, and dimensional accuracy of copper castings, affecting their performance. To produce high-quality copper castings, the following preventive measures should be taken:

1. Shrinkage
   • Increase Gating System Size: Increase the storage capacity of the gating system to accommodate the shrinkage during the solidification process.
   • Improve Casting System: Design a reasonable casting system to reduce flow resistance and ensure uniform filling of the molten metal.
   • Control Cooling Rate: Properly control the cooling rate to prevent stress during solidification.
2. Porosity
   • Improve Mold Permeability: Enhance the permeability of the mold to allow gases to escape smoothly.
   • Control Pouring Temperature: Maintain the pouring temperature within an appropriate range, approximately between 1100°C and 1300°C. This range provides sufficient heat to fully melt the copper alloy and ensure good fluidity while avoiding damage to the equipment and molds due to excessive temperature.
   • Add Degassing Agents: Add an appropriate amount of degassing agent to promote the release of gases.
3. Cold Shut
   • Optimize Gating System Design: Design a reasonable shape and size of the gating system to ensure sufficient molten metal filling.
   • Control Pouring Temperature: Increase the pouring temperature to improve the fluidity of the molten metal.
   • Preheat the Gating System: Preheat the gating system to increase its temperature.
4. Cold Pour
   • Increase Pouring Temperature: Raise the pouring temperature to enhance the fluidity of the molten metal.
   • Improve Casting System: Design a reasonable casting system to reduce flow resistance.
   • Control Pouring Speed: Control the pouring speed to ensure the complete filling of the molten metal.
5. Sand Inclusion
   • Increase Mold Surface Hardness: Enhance the surface hardness of the mold to reduce erosion by the molten metal.
   • Improve Coating Performance: Use coatings with good heat resistance and anti-sand inclusion properties.
   • Control Pouring Temperature: Maintain the pouring temperature within an appropriate range to reduce infiltration of the molten metal into the mold.
6. Incorrect Pouring Speed
   • Control Pouring Speed: Maintain the pouring speed within an appropriate range to ensure complete filling of the molten metal and form a good solidification structure.
   • Adjust Casting System: Adjust the design of the casting system to control the flow speed of the molten metal.

Copper casting is a complex process that requires comprehensive consideration of alloy composition, mold making, and casting processes to produce high-quality copper castings. By taking effective measures to prevent casting defects, the quality of castings can be improved to better meet customer requirements.