Welding aluminium can be a daunting task for the inexperienced welder. However, with the proper knowledge and equipment, welding aluminium can be a relatively easy process.
In this article, we will discuss the basics of welding aluminium, including the different types of aluminium alloys, welding equipment, and welding techniques.
Welding Aluminum Alloys
Aluminium alloys are classified into four categories: casting alloys, wrought alloys, heat-treatable alloys, and non-heat-treatable alloys. Casting alloys are used to make castings from molten metal. Wrought alloys are formed by rolling or forging metal into shapes.
Heat-treatable alloys are subjected to a thermal treatment to change the alloy’s microstructure. Non-heat-treatable alloys are not subjected to a thermal treatment.
The most common welding techniques for aluminium alloys are gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), flux-cored arc welding (FCAW), and shielded metal arc welding (SMAW). GTAW is the most commonly used technique for welding aluminium alloys because it produces the highest quality welds.
GMAW is the second most popular technique, followed by FCAW and SMAW.
When welding aluminium, you will need a welder, a torch, a shielding gas, and a welding filler metal. You should also have proper ventilation, a helmet with a dark shade to protect your eyes from the bright light of the welding arc, and gloves for protection against heat and sparks.
A welder is any machine that applies concentrated force to bend or mould metal into desired forms. Generally speaking, aluminium alloys can be welded using an AC welder with a minimum rating of 150 amps and either a gas tungsten arc welding process (GTAW) or a gas metal arc welding process (GMAW).
A torch is used as an interface between the welder and the workpieces. The main function of the torch is to ignite the wire-feed mechanism by producing an electrical spark inside it.
Shielding gas is a gas that is used to protect the weld from contamination. The most common shielding gases for welding aluminium are argon and helium. Argon is a heavier gas than helium and provides better shield protection, but it is more expensive.
Helium is a lighter gas than argon and does not provide as good of a shield, but it is less expensive.
Welding filler metal is a metal wire or rod that is used to fill the joint between the two workpieces. The type of welding filler metal you use will depend on the type of aluminium alloy you are welding.
There are four basic welding techniques: shielded metal arc welding (SMAW), flux-cored arc welding (FCAW), gas metal arc welding (GMAW), and gas tungsten arc welding (GTAW). Of these, GTAW is the most commonly used technique for welding aluminium alloys.
SMAW is a manual process in which an electrode is used to weld the workpieces. The electrode is a metal wire that is covered with a flux coating. When the electrode is melted by the welding arc, the flux coating forms a protective shield around the weld puddle.
FCAW is similar to SMAW, but instead of using an electrode, FCAW uses a self-shielding flux-cored wire. The flux-cored wire contains both the electrode and the flux necessary to protect the weld.
GMAW is an automatic process that uses a continuously feeding wire electrode. The electrode is made of metal alloys that are compatible with aluminium alloys. GMAW produces high-quality welds, and it is the most popular welding technique for welding aluminium alloys.
GTAW is a manual process that uses a non-consumable tungsten electrode to weld the workpieces. GTAW produces the highest quality welds, and it is the most commonly used technique for welding aluminium alloys.
Welding aluminium can be a challenging task for inexperienced welders. However, with the proper knowledge and equipment, welding aluminium can be a relatively easy process.