A hot pass may be used to correct which issues?

• A. Incomplete root fusion
• B. Excessive concavity
• C. Both A and B
• D. Poor fit-up

Answer: (C)

A hot pass is used to re-melt the root area to improve fusion and to adjust the root profile of the weld. By applying extra heat and sometimes additional filler, it can complete incomplete root fusion where the initial passes didn’t fully fuse the base metals at the root, eliminating voids in that region. It also helps fill and shape the root, reducing excessive concavity so the weld sits closer to the desired contour.

However, heat alone can’t fix a poor fit-up between parts. If the joint doesn’t fit properly, gaps or misalignment must be addressed before or during welding; a hot pass may not reliably correct the underlying fit issues.