In the surface treatment of aluminum alloy die castings, the common causes of mildew are as follows:
1. External environment elements. Aluminum is a living metal, which is easily oxidized to black or moldy under certain temperature and humidity conditions, which is the choice of its own characteristics.
2. Then there is the internal element of itself. After the die casting and machining processes of many manufacturers, they do not do any cleaning treatment, or simply wash with water, which can not be completely cleaned. There are corrosive substances such as mold release agent, cutting fluid, saponification fluid and other stains left on the surface of die-casting aluminum, which accelerate the growth of mould spots of aluminum alloy die-casting.
3. The process planning is unreasonable. Improper treatment of aluminum alloy die casting after cleaning or pressure inspection can make the mold of aluminum alloy die casting clear and accelerate the formation of mold.
4. Improper selection of cleaning agent. Cleaning has strong corrosiveness, forming die-casting aluminum corrosion oxidation.
5. The warehousing is not in place. When the height of the storage warehouse is different, the moldy condition is also different.
The methods to prevent mould of aluminum alloy casting are as follows:
1. No scouring and metamorphosis slagging agent containing Na salt or Mg salt, C2Cl6, Na2SiF6 and NaF components, or N2 gas refining.
2. Do not use the release agent containing plant fiber to replace the release agent with better quality;
3. Do not use cutting fluid containing plant fiber to replace oil-based antirust cutting fluid.
4. Products shall not be stored in the open air for a long time to prevent the accumulation of flying dust on the product surface.
5. The product packaging carton stacked on the lamp board needs to be wrapped with wrapping film.
6. After the product is stained with water, it needs to be placed in a ventilated place and dried.