Cold lap or lack of fusion is generally associated with which arc transfer?

• A. Short Circuit
• B. Spray
• C. Globular
• D. Pulsed

Answer: (A)

Cold lap and lack of fusion happen when the weld bead doesn’t properly fuse to the base metal or to the previous pass, usually due to not enough heat being delivered to the joint. This is most associated with short-circuit transfer because that mode delivers metal with lower heat input and rapid solidification. When the arc repeatedly shorts and the molten pool cools quickly, there isn’t enough heat to fully fuse the bead with the base metal, especially at the root or along edges, so you can see a distinct step or incomplete fusion.

To prevent it, you’d typically increase heat input enough to promote proper fusion—adjusting parameters like voltage, wire feed, or travel speed—without causing other defects. Other transfer modes behave differently: spray transfer uses continuous, small droplets with higher heat input and tends to weld with better fusion; globular transfer tends to produce irregular droplets and poorer fusion; pulsed transfer allows more controlled heat input to balance fusion and distortion.