Pure aluminum is very soft, and has good ductility. It can be drawn into thin wires and rolled into foil. Therefore, pure aluminum is the best choice for making cold storage aluminum platoon. There are many kinds of surface treatment technology for aluminum. Among them, the most commonly used products are acid washing, sandblasting, caustic corrosion, acid sand and so on. Sandblasting is a physical process, while others belong to chemical process.
Acid pickling is the way to remove oxide scale and rust from metal surface by acid solution. Acid washing takes a long time, resulting in high processing cost. The effect of thick oxide scale is not ideal, especially the black slag at the welding site can not be eliminated. And its corrosion resistance is difficult to reach the national standard of ISO, because its aluminum fluoride is attached to the surface of aluminum, and the oxidation hole after oxidation is relatively large, and it is easy to appear uneven surface treatment.
Therefore, the surface of the aluminum row produced by this process is not neat, the air tightness is poor, and it is easy to produce the hidden danger of natural leakage. If the leakage problem is produced, the service life of the aluminum platoon will be shortened greatly, thus more cost burden will be brought to the cold storage.
The sand blasting technology uses compressed air as the motive force to form high speed jet beam (copper ore, quartz sand, Jin Gang sand, iron sand, Hainan sand) to the surface of the workpiece to be treated, so that the exterior surface or shape of the surface of the workpiece is changed. Because sandblasting is not able to deal with corners and turning points evenly, the technology is also defective in aluminum fabrication.
Alkali etching process is high quality requirement for aluminum material, and it can only be applied to pure aluminum ingot. Due to the high requirement of alkali etching process, if the alkali corrosion is not good, it will cause long surface pit and spot on the surface of aluminum. If the producer uses recycled aluminum plus this technology, the aluminum row produced will produce a lot of harmful substances, which will directly cause health risks.
In the introduction of acid sand technology, aluminum is a very electronegative metal, which has a strong affinity for oxygen atoms. Aluminum will produce a thin and dense layer of oxide film in the air. This layer of oxide film has a certain protective effect. However, this protective film will take more than 48 days in the natural environment, and it is not uniform. Therefore, the anticorrosion and air tightness of the aluminum platoon under natural environment is not good, which can easily lead to the leakage of refrigerant. The technology of acid sand is to make the aluminum oxide produce 8 to 12 wire oxide film evenly in a very short time, and play a protective role for aluminum row.
Because the conductivity of the oxide film is very low, it can prevent the cathode reaction and make the aluminum do not corrode. The anticorrosion layer produced by this process is uniform in thickness and stable in chemical properties, and can effectively reduce the problem of refrigerant leakage. Therefore, to a certain extent, the service life of the aluminum production product produced by this process will be far longer than that of other process products.