What indicates proper root fusion when inspecting a groove weld non-destructively?

• A. Root reinforcement should be heavily oversized.
• B. Root fusion is not observable visually.
• C. Root fusion progress appears uneven across the joint.
• D. Consistent root fusion along the weld indicating proper fusion.

Answer: (D)

When inspecting a groove weld non-destructively, the telltale sign of proper root fusion is a consistent, uniform fusion along the entire root of the weld. This means the molten metal has completely fused with the base metal along the length of the joint, with no gaps or areas where fusion is missing. Visual cues should show a smooth, continuous root without irregularities that would indicate incomplete fusion. Heavy root reinforcement can hide these issues and doesn’t guarantee good fusion at the root, while uneven fusion or progression suggests inconsistent bonding and potential flaws. So, a weld that shows a uniform, continuous root fusion along its length best indicates proper fusion.