Welding is the process of joining two materials through fusion. Aluminium can be welded, and welding can for example provide air-and watertight joints relatively quickly. However, there are several factors to consider in welding in particular in order to be able to achieve a satisfactory welding result. This article describes some of the most important factors you should bear in mind when welding aluminium.
Aluminium forms an oxide layer
An oxide layer is formed on the aluminium surface when it comes in contact with oxygen. The oxide layer has a melting point of whole 2060 ºC, which is why the layer does not melt during welding. At the same time, the heat from the welding process speeds up the oxide layer formation, which is why it has to be removed before or during the welding process in order to make it possible to weld aluminium. There are different methods to remove the oxide layer as well as special fusion welding methods which break down the oxide layer, TIG and MIG welding.
Aluminium has a low melting point and high heat feel
The melting point of Aluminium is at approximately 660 °C, which is relatively low, if, for example, compared with steel which has a melting point of approximately 1500 ºC. However, a relatively high amount of heat must be applied during welding of aluminium because the specific heat of the metal is, for example, twice that of steel.
Hydrogen can cause pore formation
Welding of aluminium involves a risk of pore formation. Pore formation occurs when cooling the metal. It is the release of hydrogen that has been dissolved in the molten aluminium and that is removed during cooling, if too large quantities are present. The release of the gas can result in pore formation in the aluminium.
If you are in doubt about which alloys are suitable for welding, our skilled team assist with their extensive material knowledge will assist you, advising and guiding you in choosing suitable alloys for welding.