Which type of SAW flux can change weld properties or add small amounts of alloy depending on welding variables?

• A. Active flux
• B. Reactive flux
• C. Passive flux
• D. Neutral flux

Answer: (A)

Active flux is designed to modify the weld metal chemistry by releasing alloying elements into the molten pool. As the flux melts and reacts during welding, those elements enter the weld and can change properties such as hardness, strength, or microstructure. The amount and type of alloying added depend on welding variables like current, heat input, and travel speed, so adjusting these parameters can dial in how much the weld chemistry changes. This is different from neutral or passive flux, which mainly shield and deoxidize without adding significant alloying elements. Reactive fluxes may influence chemistry as well, but active flux is the one specifically intended to alter weld properties by controllably introducing small amounts of alloying elements.