Magnetic Particle Inspection is an extremely sensitive non-destructive testing method for use on ferrous (iron based) materials only. Magnetic particle testing can detect minute cracks open to the surface, and some slightly subsurface discontinuities. The productivity and sensitivity of this method makes magnetic particle inspection an industry inspection standard requirement. The process puts a magnetic field into the part. The presence of a surface or subsurface discontinuity in the material allows the magnetic flux to leak. Ferrous iron particles are then applied to the part. If an area of flux leakage is present, the particles will be attracted to this area. The particles will build up at the area of leakage and form what is known as an indication. The indication can then be evaluated to determine what it is, what may have caused it, and what action should be taken, if any.