If spherical indications are present on a part during penetrant testing, what could they indicate?

Spherical indications observed during penetrant testing typically point to the presence of porosity within the material. Porosity refers to tiny voids or pores that can occur during the material casting or manufacturing processes. When penetrant is applied, it seeps into these voids, revealing their presence when viewed under ultraviolet light.

The distinctly spherical shape of the indications is a characteristic feature of porosity, as these voids often form in a bubble-like manner during the solidification of metal or other materials.

In contrast, indications linked to defects from machining, surface scratches, or tool marks would likely present differently and show unique patterns or shapes that are more linear or irregular, rather than the uniform roundness associated with porosity. This distinction makes recognizing spherical indications a valuable skill for accurately diagnosing material quality issues in engineering and manufacturing contexts.