Aluminum alloy die casting usually uses permanent mold casting. Both aluminum and its alloy have good rheology and plasticity. However, aluminum alloy blackens easily during usage.
Reasons causing black on surface of aluminum alloy die casting:
1. Unreasonable process design.
Aluminum alloy die casting is dealt with undeservedly after being cleaned or pressure tested, creating conditions for mildew and blackening and accelerating the generation of mildew.
2. Inadequate warehouse management
If the aluminum alloy die casting is stored at different heights in warehouse, the mildew differs.
3. Internal factor of aluminum alloy
Aluminum alloy die casting manufacturers do not carry out cleaning measurements after processes of die casting and machining. Or they just use water for washing. Completed washing is not realized. Corrosive materials such as release agents, cutting fluids and saponification solutions and other blots are remained on the surface of aluminum alloy die casting. Those blots accelerate die casting mildewing and blackening.
4. External environment factors of aluminum alloy
Aluminum is an active metal. It can easily mildew and blacken under particular temperature and humidity, which is decided by the properties of aluminum.
5. Inappropriate cleaning agents
Chosen cleaning agents have strong corrosivity, causing aluminum alloy die casting corrosion and oxidation.