Which statement correctly describes the use of flux in FCAW and SMAW?

• A. Flux generates shielding for FCAW; in SMAW it provides slag and shielding.
• B. Gases shield both processes.
• C. No shielding is used.
• D. Only FCAW uses shielding.

Answer: (A)

Flux serves a protective role in welding by creating a shielding environment and, in many cases, a slag layer that guards the molten weld. In FCAW, the flux contained in the filler wire melts and releases shielding gases to shield the arc, and it often forms slag that floats on the weld to protect it as it cools. In SMAW, the flux coating on the electrode burns during welding, generating shielding gases and forming a protective slag on the weld surface that shields the molten metal until it solidifies and can be cleaned away. This description matches how flux functions in each process: providing shielding for FCAW and both slag formation and shielding for SMAW. The other statements don’t fit because shielding is indeed used in SMAW, and FCAW can rely on flux for shielding (even without external gas in self-shielded variants).