Signs of lack of fusion in a groove weld, and how can it be prevented?

• A. Signs include missing fusion at the root or between passes, visible seams along the joint, and inconsistent bead contour. Prevention: proper joint prep, cleaning, correct heat input, adequate root opening, and verification before filling.
• B. Signs include uniform bead and complete fusion; Prevention: overheating.
• C. Signs include excessive spatter; Prevention: use more gas.
• D. Signs include perfectly square joints.

Answer: (A)

Lack of fusion in a groove weld shows up when the weld metal does not bond with the base metal or with the previous weld bead. Signs include missing fusion at the root or between passes, visible seams along the joint, and an inconsistent bead contour that may look irregular or have gaps. Prevention focuses on getting the joint prepared and welded so fusion occurs: clean and fit-up the joint, maintain a proper root opening, and use the correct heat input and welding technique (appropriate current, voltage, travel speed, and arc length) so the molten metal fuses fully. Verify the root pass before proceeding to fill, ensuring there is proper fusion at the root and between passes. The other options describe conditions that don’t indicate lack of fusion—uniform, fully fused beads, excessive spatter, or perfectly square joints are not signs of this defect.