During the visual inspection of welds, which type of defect is often overlooked?

• A. Porosity
• B. Lack of fusion at the wall of the weld
• C. Weld undercut
• D. Excessive spatter

Answer: (B)

During the visual inspection of welds, lack of fusion at the wall of the weld is often overlooked because it can be less visually apparent compared to other types of defects. This defect occurs when the weld metal does not properly bond with the base metal or with the adjoining layers of weld, resulting in a weak joint. Unlike visible surface defects such as excessive spatter or porosity, lack of fusion can occur at the interface and may not be evident without more detailed inspections like ultrasonic testing.

Inspectors typically focus on surface anomalies since these are more straightforward to identify visually. This can lead to an underestimation of the impact of internal bonding issues like lack of fusion, which may compromise the overall integrity and strength of the weld despite appearing superficially intact. Recognizing the subtle indicators of lack of fusion is essential to ensure a thorough evaluation and the reliability of the welded structure.