In the field or on the manufacturing floor, Magnetic Particle Testing (MT) inspection is one of the fastest, most cost-efficient ways to identify miniscule cracks or discontinuities in components before they go into service. This method provides real-time results, and equipment portability makes it ideal for field inspections.
Any ferrous metal object that is magnetized becomes surrounded by an invisible magnetic field. If there is a crack or hole in the object, that magnetic field is disrupted. During magnetic particle testing, metal shavings are applied to the object, and they are attracted to these disruptions.
The 4 Steps of Magnetic Particle Inspection
Magnetic Particle Inspection is performed in four steps:
- Induce a magnetic field in the test area
- Apply magnetic particles to the specimen's surface
- View the surface, looking for cluster or “flux leakage field” around defects
- Demagnetize and clean the test area
MT is performed two ways: wet and dry. Wet MT allows the metal shavings to move more freely over surfaces. Dry MT is especially practical when testing pipes where high temperatures prevent the use of liquid.
MT provides real-time results. The equipment is easily transported for field inspections. That’s why a wide spectrum of industries including petrochemical, structural steel, power-generation, automotive and aerospace companies rely on MT to find potential failure points. MT is also used to inspect the integrity of fasteners, automotive parts, castings, weldments and forgings, among other components.