Which statement about groove welds is true?

• A. Groove welds do not require root fusion for full strength.
• B. Groove welds join two members along a groove, often requiring proper root fusion.
• C. Groove welds are only used for cosmetic purposes.
• D. Groove welds cannot be used with root passes.

Answer: (B)

Groove welds join two pieces along a prepared groove and fill that gap with weld metal to create a continuous joint. The root fusion at the bottom of the groove is crucial because it ensures the weld metal actually fuses with the base metal at the joint’s root, providing the foundational strength of the weld. In practice, a root pass (or passes) is often made first to establish this fusion, followed by additional passes to fill and cap the joint. This is what makes groove welds structural, not cosmetic. The other statements are not correct because groove welds do rely on root fusion for strength, they’re not just for appearance, and they can be used with root passes to achieve proper weld integrity.