The reason we choose aluminum for decoration is because its structure is more stable, and it has corrosion resistance in the long-term use. However, some aluminum profiles will have corrosion on the surface, which is mainly due to the wrong material compostion during the manufacturing.
1. In the process of casting, the proportion of magnesium and silicon is not appropriate, such as the existence of some surplus silicon, which has a small amount of silicon in a free state, will form ternary compounds in aluminum alloy at the same time. These insoluble impurity phases or free impurity phases formed in the alloy tend to gather on the grain boundary, and weaken the strength and toughness of the grain boundary at the same time, become the weakest link of corrosion resistance, and corrosion firstly starts from there.
2. In the process of smelting, although the proportion of magnesium and silicon is within the standard, but sometimes due to uneven and inadequate mixing, resulting in uneven distribution of silicon in the melt, there are rich areas and poor areas. A small amount of free silicon in the aluminum matrix will not only reduce the corrosion resistance of the alloy, but also coarse the grain size of the alloy.
3. The control of various technological parameters during extrusion, such as the bar preheating temperature is too high, the metal extrusion flow rate, the air cooling strength during extrusion, aging temperature and holding time and other improper control are easy to produce silicon segregation and dissociation, so that magnesium and silicon do not completely become Mg2Si, some free silicon exists.
In short, if the surface of the aluminum profile is easy to corrode in use, it’s because the quality standard of the aluminum profile is too low in production, so we should find a professional manufacturer when choosing the aluminum profile, thus the aluminum profile you choose will be more secure.
Post time: May-10-2022
