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Why does aluminum oxide make aluminum difficult to weld?
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welding
Shielded metal arc welding.
Aluminum is difficult to weld primarily because of the tenacious oxide film that naturally forms on its surface. This layer acts as a barrier that prevents proper metal flow during the welding process.1
To achieve a sound weld, this film must be addressed. In gas welding, suitable fluxes are employed to manage the oxide. When using the gas-tungsten arc process, fusion welding is more effective when performed with alternating current, as the arc action helps to remove the oxide layer.1