WELD-301C Practice Test

For a root pass in a 2G weld, the goal is to fuse the root edge evenly along the groove. Sawtooth motion achieves this by guiding the electrode in small, overlapping diagonal sweeps along the root. This pattern keeps the arc dwelling at the root, distributing heat and filler gradually so the root opening fills consistently without concentrating heat in one spot. It helps ensure complete fusion at the root and along both groove faces, reducing the risk of lack of fusion or slag-related defects that can occur with simpler, non-moving passes.

Using a circular or linear weaving pattern tends to widen or misalign the bead, which isn’t ideal for the narrow root area in a 2G root pass. Holding the electrode steady without movement can lead to insufficient root fill and poor fusion at the sides of the groove.