Magnetic Flux Leakage (MFL) is a method of non-destructive testing used to detect corrosion and pitting in steel structures. It uses a powerful magnet to magnetize the steel. At areas where there is corrosion or missing metal, the magnetic field “leaks” from the steel. We are able to chart the recording of the leakage field which is then used to interpret and identify damaged areas and to estimate the depth of metal loss.


  • Sensitive to pits in carbon steel.
  • Can be used on fine tubes.
  • Relatively high speed inspection.
  • Very good sensitivity for pitting.


  • Sizing of defects is very limited.
  • Very poo for detecting axial cracks.
  • Signal sensitivity depends on pull speeds and isolated pin hole type flaws cannot be detected.