For a critical structural weld connection, the engineering drawing specifies that the finished weld profile must be flush or slightly convex, with a maximum reinforce of 1.5 mm. During visual inspection, the inspector finds an area where the weld surface is below the adjacent plate surface. This condition is known as:

Question: For a critical structural weld connection, the engineering drawing specifies that the finished weld profile must be flush or slightly convex, with a maximum reinforce of 1.5 mm. During visual inspection, the inspector finds an area where the weld surface is below the adjacent plate surface. This condition is known as:

Answer options:

• Overfill
• Concave root
• Incomplete root penetration ✅ Underfill

Correct answer: Underfill

Explanation: Underfill describes a condition where the weld metal surface is below the adjacent surface of the base metal. This is a common discontinuity and can reduce the effective cross-sectional area of the weld. Overfill is excessive reinforcement, while concave root and incomplete root penetration refer to issues specifically at the root of a groove weld.