Important factors affecting the service life of aluminium sheets and coils

Important factors affecting the service life of aluminium sheets and coils

Corrosion has always been the primary factor affecting the service life of aluminium sheets and coils. After a certain process of treatment of the aluminium plate can be used in a complex environment, but because of the many factors that cause corrosion of the aluminium plate, and then the perfect treatment process can not guarantee that the aluminium plate will not occur corrosion. There are three main causes of corrosion in aluminium sheets: environmental factors, metallurgical factors and stress factors, all three of which interact with each other. Today we will first introduce the environmental factors that may lead to the corrosion of aluminium plates.

The main environmental factors affecting the stress corrosion of aluminium plates are: ion species, ion concentration, solution pH, oxygen and other gases, corrosion inhibitors, ambient temperature, ambient pressure, etc.

The stress corrosion of 2A12 and 7A04 aluminium plates in different atmospheric environments was studied, and it was found that the sensitivity of aluminium plates to stress corrosion in different environments is different, and the marine environment is more sensitive. The marine environment contains a large amount of salt, Cl- will pass through the maintenance film on the exterior of the aluminium plate into the interior, and produce corrosion on it.

Experiments show that when the mass concentration of HNO3 solution between 20% and 40%, the corrosion of aluminum plate increased, the concentration of about 35% when the corrosion rate of aluminum plate reached the highest point. In the concentrated HNO3 solution, the stress corrosion of the aluminium plate is not obvious, the reason for this phenomenon is due to the formation of a layer of dense oxide film on the exterior of the aluminium plate, preventing further corrosion of HNO3.