Aluminum is ideal for welding. They can be welded to a variety of methods, but, in practice, is dominated by a few of them. When welding aluminum metal to be incorporated into the reaction with oxygen and then rising at a rapid pace oxide. Note that the oxide is hard and has a high melting point (about 2050 °C), and therefore may easily cause defects in the weld.
The oxide is heavier than the molten metal therein, and can create inclusions. Therefore, the first welding of aluminum oxide to remove all the bonded surface. You can either use a stainless steel brush. Well cleaned and free from oxide surfaces are subject to the joint free from defects.
During the solidification of molten material is separated in the form of hydrogen gas bubbles which can retain the metal cooling down causing porosity.
Welding aluminium methods
Methods currently dominate arc welding gas, particularly MIG and TIG. With TIG welding and MIG shielding gas as used argon (Ar) and helium (He). They are so called. noble gases (inert), which means that they are not considered chemical compounds with other elements. The blend of argon and helium can be used for MIG welding in the case when a high degree of penetration for example by fillet welds or by welding the material with a very large thickness.
Since aluminum is susceptible to inclusions in the form of aluminum oxide and hydrogen (porosity), the shielding gas must have a certain purity, which in the case of argon and helium should be above 99.5%. The purpose of the gas, in addition to participate in the creation of the electric arc, is to protect the electrode and molten metal from oxidation, and cooling the electrode.
MIG (Metal Inert Gas) is usually used when the material thickness of 1 mm and more, but it is possible to weld thinner materials MIG pulsed with a hook. The binder is added in the form of a wire through the electrode holder. TIG (Tungsten Metal Gas) welding or tungsten inert gas is used in small thickness of the material, even less than 1 mm. The upper practical limit is about 10 mm. TIG welding can be used in all places, and it guarantees the correct execution of joint with the best quality.