1. Weldability of Aluminium
Welding Technology/5.3 Weldability of Aluminium

2. Weldability of Aluminium
The most common commercial aluminium and aluminium alloy welding methods use an electric arc with either a continuously fed wire electrode [with DC current, with and without pulsed current] or a permanent tungsten electrode plus filler wire [with AC current].
The arc is protected by argon gas (or argon-helium gas mix) to shield the weld pool and the electrode from the surrounding atmosphere. Arc welding is easy to use, attains a high temperature, provides high heat input and is easy to regulate.
To ensure an acceptable weld quality, there are two basic factors to consider - breaking loose and removing the oxide film, and preventing the formation of new oxide during the weld process.
Welding Technology/5.3 Weldability of Aluminium

3. Weldability of Aluminium
One must consider what the most important characteristic is for a particular weld - and then carefully select the correct filler material accordingly.
When welding dissimilar alloys such careful selection becomes even more important as the required strength, ductility, corrosion resistance, low temperature service capability or colour match for anodizing may be the dominant factor in deciding which filler to use.
When a filler metal is used, the weld deposit alloy is a mixture of the filler metal and the base metal. The properties of this “new” alloy determine to some extent to properties of the joint - influenced by the degree of dilution of the weld metal by the base metal. Weld cracking is reduced by keeping base alloy dilution of the weld metal to a minimum.
Welding Technology/5.3 Weldability of Aluminium