Question

which shielding gas produces deeper penetration on aluminum?

argon
helium
oxygen
carbon dioxide

Explanation:

Analyze shielding gas requirements for aluminum

Using the Aluminum Welding Gases knowledge point

• Aluminum is a highly reactive metal that requires inert shielding gases (such as Argon or Helium) to prevent oxidation during welding.
• Active gases like Oxygen (\(\text{O}_2\)) and Carbon Dioxide (\(\text{CO}_2\)) cannot be used because they react aggressively with molten aluminum, causing severe oxidation and defects.

Compare penetration characteristics of inert gases

Using the Aluminum Welding Gases knowledge point

• Argon provides a stable arc, excellent cleaning action, and a shallower, finger-like penetration profile.
• Helium has a much higher thermal conductivity and ionization potential than Argon, which delivers more heat input to the base metal, resulting in a deeper and wider penetration profile on thick aluminum sections.

Answer:

• (A) Argon
• (B) Helium (Correct answer)
• (C) Oxygen
• (D) Carbon Dioxide