Magnetic Particle Inspection
What is Magnetic Particle Inspection (MPI)?
Magnetic Particle Testing (MT)/Magnetic Particle Inspection (MPI) is a non-destructive testing method for detecting discontinuities that are primarily linear and located at or near the surface of ferromagnetic components and structures. Ferromagnetic materials – such as iron, nickel and cobalt – are strongly attracted to a magnet and can easily be magnetised.
This testing method is based on the principle that magnetic flux in a magnetised object is locally distorted by the presence of a discontinuity. This distortion causes some of the magnetic field to exit and re-enter the test object at the discontinuity. This phenomenon is called magnetic flux leakage. The flux leakage field attracts the added magnetic particles and they will produce a visible indication of the discontinuity.
Magnaflux magnetic particle products will help you to tell a harmless scratch from a dangerous crack. The magnetic particle method is used to find defects that are in or just under the surface of ferromagnetic materials. The magnetic particles will gather around the defect, making it easy to locate and repair.
Magnetic particle inspection can be carried out using:
- Coloured (typically black) or fluorescent magnetic particles.
- Dry or wet magnetic particles.
- A residual or continuous test method.
- Different ways to magnetise the component.
For more information on the MPI process, read our Frequently Asked Questions.
- High sensitivity method for ferromagnetic materials.
- Easy detection of cracks, surface breaking flaws and near surface flaws.
- Simple and easy to perform, even in remote locations.
- Reliable, fast and economic.