Aluminum is the go-to material to reduce weight and maintain stability and strength. Properly welded aluminum can also be a beautiful thing. For all of its wonderful attributes, there are still some tricky aspects to processing this metal the right way. Welding this material requires special skill and knowledge. This quick guide will provide you with more information on welding aluminum.
How Hard Is Welding Aluminum?
Welding aluminum can be difficult because it has unique properties. One of these properties is the oxide layer that is formed on the metal as soon as it comes in contact with ambient air. This thin layer of oxide gives the metal its silver-gray color. It also makes the material corrosion resistant to water, oxygen, and many other chemicals. It acts as a protection for the metal. When it comes to welding, though, this layer of protection must be cracked. Otherwise, the oxide layer will prevent the arc and the weld pool from connecting.
This oxide layer has an extreme melting temp of 2050 C. This is fascinating when you consider that the aluminum itself has a melting point of only 660 C. So, to crack this oxide layer you must first use extremely high temps. The tricky part is that these high temps can burn a hole through the aluminum.
For this reason, aluminum must first be prepared for welding. During this preparation process, the oxide layer is removed. This allows the aluminum to be welded without damage.
Steps to Welding Aluminum
Prepare – Even before removing the oxide layer, there are also other steps in the preparation process. Any kind of dirt or debris must be removed from the surfaces.
The oxide layer can be removed with a brush or a fleece. Remember, the oxide layer will reform rather quickly, so you must be prepared to remove the layer and begin welding quickly.
Select Torch – There are different processes that can be used to effectively weld aluminum. TIG, MIG, and Plasma are all processes that can be used.
TIG is recommended for thinner sheets of material. It is also recommended for butt joints.
When welding thicker sheets of material, it is recommended to use MIG welding processes.
Plasma welding processes using direct current are beneficial when introduced to the workpiece in a targeted way. Keep in mind that plasma welding can be a difficult process.