What type of defects pose a higher potential for failure in welding?

Planar defects are those that occur in a flat or planar configuration within the material, such as cracks or inclusions that can extend over a significant area. These defects can propagate during service under stress, leading to mechanical failure. Because they can create stress concentrations, planar defects significantly increase the likelihood of catastrophic failure, particularly in welded joints where integrity is critical.

Rounded defects, smooth defects, and minor surface discrepancies generally do not share the same level of risk as planar defects. Rounded defects may disperse stress more evenly, and smooth defects are less likely to create points of stress concentration. Minor surface discrepancies are often considered tolerable in many applications and usually do not compromise the structural integrity of the weld. In contrast, planar defects can be sources of weakness that allow cracks to develop, compromising the overall strength of the welded structure.