Aluminium - the metal is very high demand in construction and in other spheres of human activity.However in its pure form it is used very rarely.The most commonly used aluminum alloys.
All alloys can be divided into casting and wrought.The first kind is made by melting and for the manufacture of alloys, the second type of pressure is applied.Casting aluminum alloys often presented a compound of aluminum with silicon.Such metals are durable, have high corrosion resistance, good cut.As for wrought alloys known among them is Duralumin, which is composed of aluminum, magnesium and copper.This produced metal wire profile, sheet, tape.Handle the alloy can be submitted by any means.
properties of aluminum alloys can be divided into physical, mechanical and chemical.With regard to physical properties, the alloys have nearly the same density as the aluminum itself.They have high strength, which can compete with titanium and steel.But it should be noted that the melting temperature of the alloys is small (it is about 200 degrees).It is noteworthy that the aluminum alloys have good thermal conductivity, remarkably conduct electricity well welded and resistant to corrosion, although pure aluminum, these properties are much higher.
For mechanical properties, they become higher with increasing degree of doping.Presented aluminum alloys are used for the construction of structures of small and medium loading.It should be noted that the properties of the alloys are largely changed after heating to a certain temperature, which determines and uses.
Since the alloys must be treated before use, and for the creation of certain elements of the designs alloys have to be welded, you should pay attention to the fact that the welding of aluminum alloys has certain peculiarities.The process has some difficulties:
- hard alloy welded because the oxide film that appears on the surface of the metal (which often pollute the seam, and this prevents the normal alloying metal edges);
- oxide film alloy itself have different melting points, the difference can be substantial;
- as the expansion of the aluminum foundry is high enough, after sealing the metal can seriously deformed;
- alloys have high fluidity, so when welding on the metal flow may occur.
for welding alloys are mainly used carbon or metal electrodes.The process is carried out using a direct current of reverse polarity.Before you start welding surface must be treated with acetone or gasoline, and clean with a steel brush.To better quality welding held must be welded parts to warm up to a certain temperature (200 degrees).To get a good post weld should cool it slowly.
