Magnetic Particle Testing

The Magnetic Particle Inspection method of Non-Destructive testing is used for locating surface and subsurface discontinuities in ferromagnetic material. Depending on its operation on the face when the material or part under test is magnetized, discontinuities that lie in a direction generally transverse to the direction of the magnetic field.

This causes a leakage field, and therefore, the presence of the discontinuity is detected by using finely divided ferromagnetic particles applied over the surface, some of these particles being gathered and held by the leakage field. This magnetically held collection of particles forms an outline of the discontinuity and indicates its location, size, shape, and extent.