Introduction to welding aluminium

Published on 12 October 2023 Leestijd : 4 minutes

Base metals
Welding methods
Types of joint
Filler metals
Aluminium and its typical applications
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Introduction to welding Aluminium

Welding of Aluminium Aluminium is successfully welded only after careful thought and preparation. Through correct preparation, it is easier to avoid the pitfalls that can trap the unwary. Therefore, this introduction includes facts on base metals, welding methods, types of joint and filler metals. This introduction is just a general guideline. Please contact us for more information.

Base metals

Welding methods

Aluminium can be welded easily. Consideration must be given to both the welding method, the type of joint and the filler metal. The two dominating welding processes are GMAW (MIG) and GTAW (TIG) welding, but also gas, plasma and resistance welding are used, as well as welding with stick electrodes (SMAW). Determining the welding process depends on numerous factors. TIG welding is better for thin light-gauge materials, when there is a need for good surface finish and for single sided welding (such as when welding pipes) as well as repair welding. TIG welding is generally done on AC current.

MIG welding is used primarily in the case of thicker or heavy-gauge materials and when high speed is a priority in combination with long continuous welds. Due to the lower heat input, MIG welding results in less distortion in the welding zone. Pulse-arc welding with MIG is an interesting technology.

Stick electrodes are used mainly for repair jobs. The advantage of this process is the simple controllability, as well as the possibility to be flexible in any environment. Low investment costs can be a factor for choosing SMAW.

Types of joint

The type of joint depends on the thickness of the base materials and the type and shape of the workpiece. As a rule no preparation is required for thinner materials. An ordinary I-joint is recommended for single-sided TIG welding plates ≤ 4mm. plate thickness, a 50º V-joint with a 2 to 3 mm. bevelled edge is recommended for double-sided welding plates > 4 mm. thickness. Alternatively, a 90º double V-joint can be applied.

Good joint preparation makes welding easier, saves shielding gas and filler metals, and contributes to the quality of the weld.

A special characteristic of aluminium is the higher melting point of oxide that forms on its surface. To avoid welding defects the joint surface must be scraped or brushed using stainless steel wire brushes. Bear in mind that welding causes greater deformation in aluminium than it does in steel. It is therefore essential to give careful consideration to all aspects of the welding process.