What are the effects of increasing welding current in FCAW?

• A. Increases max voltage, melt-off rate, deposition rate, heat input, and penetration
• B. Reduces deposition rate
• C. Eliminates spatter
• D. Decreases heat input

Answer: (A)

In FCAW, the amount of energy delivered by the arc is governed primarily by the welding current. When you raise the current, the arc becomes hotter, delivering more energy to the wire and the weld pool. That extra energy melts a larger portion of the wire per unit time (melt-off rate), so more filler metal is available to deposit in the weld (deposition rate).

With more heat in the weld area, the heat input to the workpiece increases (for the same arc voltage and travel speed, or with a higher voltage to sustain the arc). That higher heat input promotes greater fusion and flow of molten metal, resulting in deeper penetration into the base metal.

Additionally, maintaining a stable arc at higher current often requires a higher arc voltage, so the voltage observed at the arc can increase as current goes up. Put together, increasing current in FCAW raises voltage under these conditions, increases melt-off and deposition rates, and enhances heat input and penetration.