What is a possible cause of "worm tracking" when using FCAW-GS wires?

What is a possible cause of "worm tracking" when using FCAW-GS wires?

• A. Voltage too high
• B. Low wire feed speed
• C. Insufficient shielding gas
• D. Too short arc length

Answer: (A)

Worm tracking is tied to how the arc length is controlled. In FCAW-GS, voltage largely sets the arc length; when voltage is too high, the arc becomes too long and can wander across the weld surface, leaving worm-like tracks. This instability of the arc causes the arc to follow the bead surface rather than staying steady, producing those characteristic worm tracks. Other issues, like a too short arc length or inadequate shielding gas, produce different defects such as instability in fusion or porosity, but they don’t create the wandering, worm-like traces along the bead.

Worm tracking is tied to how the arc length is controlled. In FCAW-GS, voltage largely sets the arc length; when voltage is too high, the arc becomes too long and can wander across the weld surface, leaving worm-like tracks. This instability of the arc causes the arc to follow the bead surface rather than staying steady, producing those characteristic worm tracks. Other issues, like a too short arc length or inadequate shielding gas, produce different defects such as instability in fusion or porosity, but they don’t create the wandering, worm-like traces along the bead.