Detection of leakage field :
Finely divided iron particles are used for detection of leakage field. Leakage field at the surface collects and hold the iron particles together to form visible indication patterns.
- Flaws at or near the surface disturb the magnetic flux flow and produce leakage field at surface above the flaw.
- Magnetic particle build up at the leakage field produces recognizable patterns which are interpreted.
- Color of the particles must be chosen to provide adequate contrast against the part’s natural color.