MT is especially useful for preventative maintenance of critical parts already in service and for finding defects before parts are put back in service.
BEFORE WE CAN BEGIN ANY INSPECTION, industry specifications require that the entire magnetic particle system is checked. Requirements include:
- Particle concentration
- Bath contamination
- Testing of specimens with known defects
To test with MT, the first step is to magnetize the object being tested by passing an electric current through the component. During the inspection magnetic particles are applied to the surface and any cracks will show up as a result of the particles being attracted to the "leakage field." These particles cluster wherever these cracks are, providing a visual indication for the inspector. The inspector can then assess the extent of damage and provide crucial results to engineers for disposition.