Aluminum welding is one of the most technical jobs of welding and learning the intricacies
of aluminum welding is very important for those who are interested in making welding their full-fledged profession. It is very important to learn all the details of aluminum welding including how to choose welding equipment, preparing base material etc.
Aluminum welding is quite different from steel welding even if you are expert in steel welding handling aluminum welding could be a challenge for you. Because of higher thermal conductivity and low melting point welding of aluminum requires efficiency. Due to its lower column strength the aluminum wire tends to tangle at the drive roll and it is one of the biggest challenge is feeding aluminum welding wire during gas metal arc welding.
Once you are ready for the welding first and foremost step should be cleaning the base material and remove aluminum oxide and hydrocarbon contamination. One of the best methods to remove aluminum oxide is to use a stainless-steel bristle wire brush, move it in one direction with light hands. Degreaser is used for removing hydrocarbon from oil.
To avoid cracking during welding preheat the aluminum work piece. It is a good practice to preheat the thick piece of aluminum when welding it to a thin piece. Use run-on and run-off tabs to correct the cold lapping.
To reduce weld contamination use push the gun away technique from the weld puddle rather than pulling it. It will also improve shielding-gas coverage.
Aluminum welding procedure is hot and fast in comparison to steel welding. While working on thin-gage aluminum sheet one has to manage fast speed otherwise there are high chances of burn through on aluminum sheet.
Argon gas is highly recommendable for aluminum welding due to its good cleaning action and penetration profile. To minimize the formation of magnesium oxide in welding 5xxxseries aluminum alloy a shielding gas mixture combining argon with helium is used.
Always choose aluminum filler wire that has a melting temperature similar to base material as welding wire. Use 3/64- or 1/16- diameter wire, the larger the wire diameter you use the better and easier it feeds. For welding thin-gage material use 0.035 inch diameter wire combined with a pulsed- welding procedure at a low wire-feed speed -100 to 300 in./min.
Always use separate gun liner for welding aluminum.