Question

what two shielding gases can be used on aluminum?

• oxygen
• helium
• carbon dioxide
• argon

Explanation:

Analyze aluminum chemical reactivity

Aluminum is a highly reactive metal that readily combines with oxygen at high temperatures to form aluminum oxide, which interferes with the welding process. Therefore, welding aluminum requires completely inert shielding gases to protect the weld pool from atmospheric contamination.

Evaluate the gas options

Using the Shielding Gas Function knowledge point

• Oxygen: Highly reactive; causes severe oxidation.
• Carbon Dioxide: Reactive; dissociates in the arc and oxidizes aluminum.
• Argon: Inert gas; provides excellent arc stability and cleaning action.
• Helium: Inert gas; provides high heat input for thick sections.

Select the correct inert gases

Both Argon and Helium are inert gases that do not react with the molten aluminum, making them the only suitable choices among the options.

Answer:

• Oxygen
• Helium (Correct answer)
• Carbon Dioxide
• Argon (Correct answer)