What might very low current cause in FCAW?

What might very low current cause in FCAW?

• A. An unsatisfactory bead shape and unstable arc
• B. A strong, stable arc
• C. Excessive penetration
• D. No deposition

Answer: (A)

In FCAW, current controls heat input and arc stability. When current is very low, there isn’t enough heat to maintain a smooth, stable arc and to adequately melt the filler wire and fuse it to the base metal. The arc tends to wander and the molten pool isn’t held in place well, so the resulting bead is irregular and lacks proper wetting—producing an unsatisfactory bead shape and an unstable arc. The other outcomes come from different heat levels: a strong, stable arc is linked to sufficient current; excessive penetration happens with too much heat input; and deposition issues like “no deposition” would stem from problems beyond just low current, such as wire feed or power not delivering metal consistently.

In FCAW, current controls heat input and arc stability. When current is very low, there isn’t enough heat to maintain a smooth, stable arc and to adequately melt the filler wire and fuse it to the base metal. The arc tends to wander and the molten pool isn’t held in place well, so the resulting bead is irregular and lacks proper wetting—producing an unsatisfactory bead shape and an unstable arc.

The other outcomes come from different heat levels: a strong, stable arc is linked to sufficient current; excessive penetration happens with too much heat input; and deposition issues like “no deposition” would stem from problems beyond just low current, such as wire feed or power not delivering metal consistently.