Procedure for Magnetic Particle Examination

The magnetic particle examination method may be applied to … cracks and other discontinuities on or near the surfaces of ferromagnetic materials. The sensitivity is greatest for surface discontinuities and diminishes rapidly with increasing discontinuities and diminishes rapidly with increasing depth of subsurface discontinuities below the surface.

Typical types of discontinuities than can be detected by this method are cracks, laps, seams, cold shuts and laminations. Magnetic Particle Examination shall be performed prior to post weld heat treatment unless otherwise required by the applicable code.

The surface to be examined shall be prepared following the below considerations

  • The surface to be examined and all adjacent areas within at least one (1) inch (24.54 mm) of the surface to be examined shall be dry and free of any dirt, grease, lint, scale, welding flux, spatter, oil, or other extraneous matter that would interfere with the examination.
  • Wire brushing, grinding, and filing are acceptable mechanical methods of cleaning. Grit or sandblasting may be used only to clean, but shall not be used to peen or work the surfaces to be inspected. Solvents may be employed for the removal of grease and oils.
  • Surfaces shall be smooth to the extent that there are no abrupt ridges or valleys. Tapped or other openings shall be plugged as required to prevent the entrance of magnetic particles.

Once the surface is prepare we can proceed with the examination, in the following weeks we will described these examination procedures and application methods.


  • The examination method shall be the Dry Continuous Method where the iron powder (either red, black, gray, or yellow) is applied to the surface and the magnetizing current is applied at the same time.
  • The Prod Method shall be used on castings, weldments, forgings, and fabricated parts. Where it is inconvenient to use Prods such as on machined components or small parts, the contact and/or coil method may be used.