514.464.8237       info@uberspec.com         

MAGNETIC PARTICLE INSPECTION

Magnetic Particle Inspection (MPI)

Basic Principles:

Magnetic particle Inspection (MPI) is a non-destructive testing (NDT) process for detecting surface and slightly subsurface discontinuities in ferromagnetic materials. A magnetic field is set up in the part being tested by either passing electric current directly through it (direct magnetization), inducing a magnetic field in it (indirect magnetization), or a combination of both methods.

If there is a surface or subsurface flaw in the material, the magnetic lines of force will be deviated to the surface outside the part. By applying ultra-fine magnetic particles on the surface, they will be attracted to this leakage field and form a visible indication. The particles can either be fluorescent or non-fluorescent, depending on the sensitivity of the inspection.

Advantages:

  • Large surface areas of complex parts can be inspected rapidly.
  • Surface and subsurface flaws can be detected.
  • Surface preparation is less critical than it is in penetrant inspection.
  • Magnetic particle indications are produced directly on the surface of the part where the flaw is located.

Disadvantages:

  • Only ferromagnetic materials can be inspected with this method.
  • Alignment of the magnetic field and defect is critical.
  • Large currents may be needed for very large parts.
  • Surfaces should be relatively smooth.
  • Parts must be demagnetized and cleaned after inspection.

Magnetic Particle inspection for these sectors

aviation safety inspection

Aerospace

During the fabrication of aircraft assemblies, critical components need to be inspected by…

vehicle safety inspection

Automotive

The high production rate in the automotive industry leaves no room for defective components to…

industrial ndt

Industrial

Any part or component used in industrial systems (ex: pumps, valves, gears, industrial…