Which of the following is a common defect categorized as a discontinuity?

A common defect categorized as a discontinuity can encompass various types of imperfections that interrupt the continuity of a material. In the case of weld spatter, this occurs when molten metal unintentionally splatters onto the surrounding areas during the welding process, creating an unwanted surface feature.

Undercut is another defect where the base metal is removed from the sides of the weld, creating a groove that can weaken the joint and affect its structural integrity. This is also regarded as a discontinuity because it disrupts the intended profile of the weld.

Porosity involves the formation of small voids or gas pockets within a weld bead, which can compromise the quality and strength of the weld. The presence of such holes indicates a lack of complete fusion and continuity within the weld material.

All these defects—weld spatter, undercut, and porosity—demonstrate how discontinuities can arise in welding processes, making them collectively significant as common defects in the context of visual testing and quality assurance in welds. Therefore, recognizing that each of these defects represents a type of discontinuity is critical for ensuring the integrity of welded structures.