What is the purpose of slag removal between passes in SMAW?

• A. It exposes clean metal for subsequent passes and prevents slag inclusions, improving fusion
• B. The slag is necessary to improve ductility
• C. Removing slag increases weld hardness
• D. The slag layer protects the weld from contamination during cooling

Answer: (A)

In SMAW, slag removal between passes is done to expose clean metal for the next weld pass so the new bead can fuse properly. The flux creates a slag layer on top of the weld as it deposits, and this layer acts as a barrier. If you leave it in place, the next weld pass won’t wet the underlying metal well, which can cause lack of fusion and slag inclusions where slag gets trapped in the weld. By removing the slag, you ensure a clean metal surface for good bonding, a smooth bead, and easier inspection for defects. Slag does protect the weld while it cools, but that protective role is during cooling, not the reason to leave slag on between passes. Slag removal does not make the weld more ductile or harder; its main purpose between passes is to permit proper fusion.