Of all the aluminum profiles and profiles made of alloys of the 6xxx series – alloys of Al-Mg-Si – have overwhelming popularity. It is due to their unique technological, structural and performance properties. To them, first of all, belong our aluminum alloys
- alloy AD31,
- abortion and AD33
- alloy AD35,
their foreign counterparts
- alloy 6060.
- alloy 6063,
- alloy 6061 and
- alloy 6082,
as well as alloys such as the
- Alloy 6005A and
- alloy 6106.
Viscosity aluminum alloys
Viscosity - a measure of the ability of the alloy to absorb mechanical energy and deform plastically before failure. This feature is particularly important for the structural elements, which must resist brittle fracture under the influence of shock. Unlike steel, aluminum alloys the temperature decrease are not transition from ductile to brittle fracture, typical steel. The viscosity of the aluminum alloy is most often judged by the results of the Charpy impact test and Izod, and, when it allows the product size, fracture toughness tests on.
Microstructure of High Viscosity
The toughness of 6xxx series aluminum alloys is controlled by three factors:
- precipitates at the grain boundaries and
- areas, free from precipitates near grain boundaries.
Provide the highest viscosity layered, unrecrystallized grain structure and uniform, intragranular distribution of magnesium silicide. On the other hand, low viscosity 6xxx series alloys commonly associated with coarse recrystallized structure, as well as with the presence of coarse particles of magnesium silicide particles and free silicon at the grain boundaries and boundary zones adjacent to the phase precipitates without excess.
Doping to increase the viscosity
Viscous properties improved by addition of manganese and chromium, low temperature of homogenization of ingots (for alloys, doped with manganese), low temperature profiles at the exit from the die and a high cooling rate during quenching to press.
The fracture toughness of the modified aluminum alloy 6005A twice, than that of its base alloy 6005. This is achieved in the alloy 6005A increased as compared with the alloy 6005 the content of manganese and chromium.
The fatigue strength of aluminum
The fatigue strength of the alloys is also important for the application profile as the structural elements. fatigue limit typically increases proportionally with the level of strength.
The ability of aluminum to the cold forming
The ability to cold forming, for example, bending, controlled chemical composition of the alloy, cooling rate during quenching and aging conditions. Usually forming ability increases with a decrease in the yield stress. Therefore, low doping, rapid cooling in the press, natural aging or artificial aging underaging to contribute to the improvement of formability characteristics. The most commonly used measure of formability is the minimum bending radius, achieved when bending at 180º.
All alloys 6xx seriesx satisfactorily welded by the MIG (semi-automatic) and TIG (manual) methods using a non-consumable (tungsten) electrode. The alloys are often used as the welding wire 4043 and 5356. The ratio of the weld strength and the base metal is usually about 0,6.
Aluminum Corrosion resistance
6xxx series aluminum alloys typically exhibit very high resistance to corrosion in rural, urban and industrial atmospheres. The natural oxide film on the extruded profile provides them with good protection. Increasing the thickness of the oxide film by anodization of aluminum profiles gives further improvement in corrosion resistance. Corrosion of these alloys is primarily manifested in the form of intergranular corrosion pitting. In most types of corrosive atmospheres, the maximum depth of corrosion "yazvinok" is about 100 m, and their growth rate slows with increasing depth.
The ability of aluminum to anodizing
On the ability of aluminum alloys to anodizing affect the density and size of the intermetallic alloy components – Magnesium silicide particles and iron particles. Reflective brightness anodized surface depends on the chemical composition. Generally, the higher the doping alloy, the more matte anodized surface looks.
copper supplements – for brilliant anodizing
The exception is copper alloying elements, which increases the reflective properties of the anodized surface by addition, it favors the formation of fine and uniform structure of salient magnesium silicide particles. Aluminium alloy 6463 specially formulated for a shiny anodized surface due to its low iron content (<0,15 %) and small additions of copper to crush the precipitates of magnesium silicide.
The use of aluminum profiles
Aluminum alloys 6060 and 6063 (and related 6463), possessing moderate strength properties most dominate in building enclosing structures (windows, doors, curtain facades) and decorative items, requiring shiny surface finish. Every year, expanding their application in various industries. for instance, of them are made with a variety of profiles of thin shelves for removing heat in electronic devices, by type of cross-section resembling a comb.
Aluminum Alloy 6005A is used in a variety of building products and ladders yacht masts to massive profiles for passenger cars bodywork.
Stronger aluminum alloys 6061, 6261 and 6082 used in the automotive industry, including, in the manufacture of chassis and bus bodies and trucks.