The Magnetic Particles test is one of the oldest known, finding nowadays a great variety of applications in the different industries. It is applicable only for inspection of materials with ferromagnetic properties, since the magnetic flux is used inside the piece, for the detection of discontinuities.
By means of this test the detection of superficial and sub-superficial defects can be achieved, up to 3 mm below the surface of the material. The preconditioning of the surface, as in the Penetrating test, is very important, although not as demanding and rigorous.
The application of the Magnetic Particles test basically consists of magnetizing the piece to be inspected, applying the magnetic particles (fine powder of iron filings) and evaluating the indications produced by the grouping of the particles in certain points. This process varies depending on the materials used, the defects to be searched and the physical conditions of the inspection object.