What is the function of SAW flux regarding slag formation and shielding?

• A. Forms a protective slag covering
• B. Breaks down slag and exposes weld pool
• C. Increases arc energy
• D. Prevents any slag formation

Answer: (A)

The main idea is that SAW flux creates shielding by forming a protective slag layer on the weld. When the flux melts, it flows over the molten metal and solidifies as a slag covering that sits on top of the weld pool. This slag acts as a barrier to the atmosphere, preventing oxidation and contamination as the weld cools, since SAW relies on this slag rather than an external shielding gas. The flux also brings deoxidizers and alloying elements into the weld chemistry, helping to clean impurities and shape the bead. After welding, the slag becomes a solid layer that must be chipped away.