Common methods include Manual Metal Arc welding (MMA), Metal Inert Gas (MIG)/Metal Active Gas (MAG) welding, and Tungsten Inert Gas (TIG) welding.

Method 1: Manual Welding

Extensively used and easy to operate, manual welding relies heavily on human adjustment and uses welding rods as the weld filling material. It can nearly weld all materials, including outdoor conditions, making it highly adaptable. Typically, direct current is used during the manual welding process.

Welding rods can be either titanium-type or inert. Titanium-type welding rods are easier to weld, resulting in aesthetically pleasing welds with slag that's easy to remove. However, the downside is that if they're not used for a long time and then put back into use, they must be re-baked to prevent moisture accumulation.

Method Two: Metal Inert Gas (MIG) Welding

It falls under gas shielded welding, which is also a type of arc welding, where the welding rod is melted by an electric arc under a protective gas. Metal inert gas (MIG) welding is suitable for materials such as steel, non-alloy steel, low-alloy steel, and high-alloy metals, and is widely used. However, it is important to note that the protective gas must be an active gas, such as carbon dioxide or a mixed gas. One drawback is that if welding is done outdoors, the workpiece cannot be damp, as this would affect the protective effect of the gas.

Method Three: Tungsten Inert Gas (TIG) Welding

An arc is formed between the tungsten welding wire and the workpiece, requiring a pure argon shielding gas. Since the wire is uncharged, it can be manually or mechanically fed, or even not fed at all, depending on the welding material. Whether it uses DC or AC current then depends on the welding material.

Tungsten inert gas (TIG) welding is primarily used for joining thin and medium-thickness workpieces, with a wide range of materials, including alloy steel, aluminum, magnesium, copper, gray cast iron, nickel, silver, titanium, and lead.