Magnetic Particle (MT) is induced in the object. Iron fillings are then dusted onto the surface of the object being tested. If there is a defect, the fillings will cluster along the edges of the flaw. Variations include wet suspension and dry particle.


  • The training is less demanding that UT, RT or ET training.
  • MT is quick and cost effective.
  • The results are instant and easy to interpret.
  • Positive and reliable method of testing.
  • Surface preparation not as critical.


  • Only effective in ferromagnetic materials.
  • Discontinuity detection is limited to at or near surface.
  • Parts need to be de-greased and de-magnetized before and after inspection.
  • Magnetic flux must be normal to the plant of the defect to show indications.