Which condition can be observed when a weld is subjected to a root bend test?

• A. Over penetration
• B. Incomplete fusion
• C. Excessive reinforcement
• D. Crater crack

Answer: (B)

Root bend testing specifically checks how well the weld fuses to the base metal at the root when the joint is bent. If the weld did not fuse properly at the root, stresses from bending reveal that lack of fusion as separation or a visible unbonded region along the weld root. That’s why incomplete fusion is the condition you observe in this test—the root isn’t fully fused to the base metal.

Over-penetration or excessive reinforcement describe excessive weld metal at the joint, not a fusion issue at the root, and crater cracks are cracks that can form at the weld crater but aren’t the primary defect this test targets.