In welding aluminum, what is the primary purpose of using flux?

• A. To remove the oxide layer from the aluminum surface
• B. To increase the melting point of aluminum
• C. To act as a filler material during welding
• D. To prevent the formation of aluminum alloys

Answer: (A)

Verified step by step guidance

1. Understand that aluminum naturally forms a thin oxide layer (Al\_2O\_3) on its surface, which has a much higher melting point than pure aluminum and can interfere with the welding process.
2. Recognize that this oxide layer acts as a barrier, preventing proper fusion of the aluminum pieces during welding.
3. Know that flux is a chemical agent used in welding to remove or dissolve this oxide layer, allowing the base metal to melt and join properly.
4. Identify that the primary purpose of flux in aluminum welding is to clean the surface by removing the oxide layer, not to increase melting point, act as filler, or prevent alloy formation.
5. Conclude that using flux ensures a clean, oxide-free surface, which is essential for strong, defect-free welds in aluminum.