The most common methods for welding aluminium are MIG welding (metal inert gas) and TIG welding (tungsten inert gas). TIG welding is particularly suitable for thinner materials, while MIG welding is more efficient for thicker aluminium sections.

Aluminium has a high thermal conductivity and forms an oxide layer that has a higher melting point than the actual aluminium. This can lead to problems such as uneven melting and porosity, which requires special techniques and equipment.

Removing the oxide layer is crucial as it makes welding more difficult. This can be achieved by chemical cleaning or mechanical processing (e.g. stainless steel brushes). It may also be necessary to preheat the material to reduce stresses.

Argon or an argon-helium mixture is usually used to create a shielding gas atmosphere that prevents oxygen and nitrogen from entering the weld pool and thus minimises oxidation.

Typical problems include porosity, distortion, cracking and difficulties when joining aluminium with other metals such as steel. These can be minimised by preparing the material correctly and selecting the right welding process.

Joining aluminium with other metals, especially steel, is complex and requires special processes such as cold metal transfer (CMT) welding or friction stir welding (FSW) to avoid the formation of brittle intermetallic joints.

Quality is ensured by selecting the right filler material, controlling the heat input and using suitable welding techniques. Preheating and precise control of the welding parameters are also crucial.

Alloys from the 5xxx and 6xxx series are frequently used. 5356 cored wire, for example, is a common choice for welding 5xxx alloys as it offers high strength and good workability.

Thinner aluminium sheets require precise TIG welding to avoid distortion and burn-through, while thicker materials tend to benefit from MIG welding, which allows for greater penetration and faster processing.

It is important that the service provider has experience in working with aluminium, offers the right welding processes and has the necessary equipment. They should also be able to fulfil specific requirements in terms of material, thickness and area of application.