Which statement best describes groove welds?

• A. It joins two members at their surfaces with no groove.
• B. It is formed using a fillet cross-section only.
• C. It joins two members along a groove, often requiring a root pass for fusion.
• D. It uses a partial penetration with a triangular cross-section.

Answer: (C)

Groove welds involve preparing a groove in the edges of the pieces to be joined and filling that groove with weld metal, so the weld runs along the joint. Because fusion must occur at the bottom of the groove, a root pass is often required to ensure proper penetration and complete fusion at the joint root before the rest of the weld is built up. This is different from fillet welds, which are deposited on the intersection of two surfaces and do not involve a groove or a root fusion. So the description that best fits groove welds is that they join two members along a groove, often requiring a root pass for fusion.