Welder Red Seal · Question
When performing GTAW on aluminum, why is Alternating Current (AC) the most commonly used current type?
AC provides a balance for welding aluminum. The electrode positive (EP) portion of the cycle breaks up the refractory aluminum oxide layer (cleaning action), wh
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Question: When performing GTAW on aluminum, why is Alternating Current (AC) the most commonly used current type?
Answer options:
- It provides the deepest penetration with minimal risk of tungsten contamination. ✅ It offers a balance of cathodic cleaning action and good penetration.
- It minimizes the size of the heat-affected zone compared to DC.
- It is the only current type that can create a stable arc on aluminum.
Correct answer: It offers a balance of cathodic cleaning action and good penetration.
Explanation: AC provides a balance for welding aluminum. The electrode positive (EP) portion of the cycle breaks up the refractory aluminum oxide layer (cleaning action), while the electrode negative (EN) portion provides heat and penetration into the base metal.
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