Iron is the main impurity element in aluminum alloys. In 6063 aluminum rod, the national standard stipulates that it is not more than 0.35. If a first-grade industrial aluminum ingot is used in production, the general iron content can be controlled below 0.25. However, if in order to reduce production costs, a large amount of recycled aluminum or other aluminum is used, iron will easily exceed the standard. There are two forms of Fe in aluminum, one is a β-phase (Al9Fe2Si2) with a needle-like (or sheet-like) structure, and one is an α-phase with a granular structure (Al12Fe3Si). Different phase structures have different effects on aluminum alloys. The β phase of the lamellar structure is much more destructive than the α phase of the granular structure. The β phase can make the surface of aluminum profile rough, mechanical properties and corrosion resistance worse. The surface of the oxidized profile is bluish, the gloss is reduced, and no true hue is obtained after coloring. Therefore, the iron content must be controlled.
Improve the Quality of 6063 Aluminum Rod
In order to reduce the harmful effects of iron, the following measures can be taken.
1) All tools for smelting and casting should be coated with lacquer before use to reduce the amount of iron melted aluminum liquid as much as possible.
2) Refine the grains, make the iron phase thinner and smaller, and reduce its harmful effects.
3) Add an appropriate amount of strontium modifier to transform the β phase into the α phase, reducing its harmful effects.
4) Carefully select waste and miscellaneous materials to reduce as much as possible such as iron wire, iron nails, iron filings and other debris entering the aluminum melting furnace to cause an increase in iron content.
Other impurity elements are very few in electrolytic aluminum ingots, which are far below the national standard, and may exceed the standard when using recycled aluminum. In production, not only must each element be exceeded, but also the total amount of impurity elements must not be exceeded. When the content of a single element does not exceed the standard, but the total amount exceeds the standard, these impurity elements also have a great influence on the quality of the profile. In particular, it needs to be emphasized that the practice has proved that when the zinc content reaches 0.05, white spots appear on the surface of the profile after oxidation, so the zinc content should be controlled below 0.05. AdTech offers ceramic foam filter（CFF） and plate filtering system for aluminum liquid. If you need it, please feel free to contact us.