Aluminum is a very demanded metal as inconstruction, and in other spheres of human life. However, in its pure form it is used very rarely. Most often used aluminum alloys.
The properties of aluminum alloys can be divided intophysical, mechanical and chemical. As for physical properties, alloys have practically the same density as aluminum itself. They have high strength, which can compete with titanium and steel. But here it is necessary to take into account that the melting temperature of alloys is small (it is about 200 degrees). It is worth noting that aluminum alloys have good thermal conductivity, remarkably conduct electric current, are well welded and resistant to corrosion, although in pure aluminum these properties are much higher.
Since alloys must be used before useto process, and for the creation of certain structures, the elements of alloys have to be welded, attention should be paid to the fact that welding of aluminum alloys has certain characteristics. The process has some difficulties:
- Alloys are hard welded because of the oxide film that appears on the surface of the metal (it often pollutes the seam, which prevents normal fusion of the metal edges);
- since the casting expansion of aluminum is sufficiently high, then after welding, the metal can be seriously deformed;
- alloys have high fluidity, therefore, when welding on metal, flows may appear.
For welding alloys are mainly usedcarbon or metal electrodes. The process is carried out using a DC reverse polarity. Before starting work, the welded surface must be treated with acetone or gasoline and cleaned with a steel brush. To weld more qualitatively, the parts to be welded must be heated to a certain temperature (200 degrees). To get a good weld after welding, you should cool it slowly.</ p>