Which of the following is a common visual defect observed during VT of a weld?

• A. Porosity
• B. Overlap
• C. Lack of fusion
• D. Excessive reinforcement

Answer: (A)

Visual testing focuses on the weld bead’s surface for flaws that are visible without disassembling the joint. Porosity is a common defect to spot during VT because when gas pockets are near or break the surface, they show up as pits, a foamy or rough-looking weld face, or other surface irregularities. Those surface expressions are exactly what VT is designed to detect, making porosity a typical finding in a visual inspection. Other issues like overlap, lack of fusion, or excessive reinforcement are also visible, but porosity’s surface manifestation is the classic clue inspectors look for during VT.