Magnetic Particle Inspection

Magnetic Particle Inspection is used for detecting surface breaking and slightly subsurface defects in ferromagnetic materials. The process puts a magnetic field into the part, either directly or indirectly and the presence of a surface or subsurface break will allow the magnetic flux to leak.

Uses for Magnetic Particle Inspection

This a great technique for use on welds and other areas where cracking may be present.

Typically we use the technique on carbon steel assets. Stainless steels and other non-ferromagnetic materials would be better suited to dye penetrant inspection.

Surface Finish & Preparation

MPI requires a clean bare metal finish for correct inspection. We recommend the cleaning of welds to SA 2 ½ to a near white metal finish.  This is defined as:

  • Removal of nearly all mill scale, rust, rust scale, paint, or foreign matter by the use of abrasives propelled through nozzles or by centrifugal wheels, to the degree hereafter specified.
  • A Near-White Blast Cleaned Surface Finish is defined as one from which all oil, grease, dirt, mill scale, rust, corrosion products, oxides, paint or other foreign matter have been completely removed from the surface except for very light shadows, very slight streaks or slight discolorations caused by rust stain, mill scale oxides, or light, tight residues of paint or coating that may remain.
  • At least 95 percent of each square inch of surface area shall be free of all visible residues, and the remainder shall be limited to the light discoloration mentioned above.

Comprehensive Reporting

You will receive a comprehensive inspectors report detailing results and the findings of the inspection. The standard of our reports is just one of the things that makes us stand out in the industry.

If you would like to discuss your NDT inspection project, would like to see a sample report, or to arrange an initial no-obligation meeting, call us on 01469 541 586 or complete our contact form below: