Aluminum alloys are more difficult to weld as compare to steel as they have a lower melting point and are also better conductors leading to burnthroughs especially in sheets of aluminum that are thinner. It also has an oxide layer that is there for protection against corrosion and abrasion but also acts as an insulator that can cause problems during the welding process. When the service temperature decreases the strength of the aluminum also increases which is why it is used in applications where the temperature is colder such as the transportation of liquid nitrogen. When using best mig welder there are certain things that need to be taken into consideration such as the correct filler metal, proper storage and a thorough cleaning of the base material to allow for precise welding.
When the aluminum metal and filler metal are heated, they become liquid and absorb the soluble hydrogen in the mixture, this can cause pores to form in the solidifying material. This can be combatted using a mixture of argon as hydrogen gas. There are 3 different types of welding processes that are used with aluminum welders:
TIG (Tungsten inert gas) welding is the main method used as aluminum requires lot of heat to get to a temperature that allows the machine to weld it without causing burn through. It can hold the heat for a long time and this type of welding can be used in both thick and thin sheets or plates of aluminum. TIG welding requires a filler rod that is separate but needs to be a material that is close to the base material.
MIG (metal inert gas) welding is a process that can either use a spray arc or a pulse method, Pulse welding needs an inverter while spray arc needs a more constant voltage machine. MIG is better for aluminum sheets that are thinner.
Torch welding is more complex than TIG and MIG welding as it gets difficult to control the level of heat being applied by the torch and can lead to burns.
No matter the process used, there are certain things that should be kept in mind while welding aluminum. A stringer bead technique should be used instead of the weave technique as it allows better fusion and penetration. You should always clean the metal properly before welding to remove any dirt or moisture to achieve the best results and to avoid pores developing later on. Aluminum cleaners are used it remove any hydrocarbons that may be present on the surface. Also don’t used compresses air to remove any dirt as it can cause contamination. The oxide layer can also be removed using a stainless-steel brush to prevent problems in the welding process. Also make sure to store the material properly inside as storing it outdoors can cause water to get trapped and cause a layer of aluminum oxide to develop.