• The magnetic field must intersect the main plane of the discontinuity, ideally at right angles.

• Special care is needed to avoid local heating and arc burns at points of electrical contact with the surface.

• It can only be applied to ferromagnetic materials.

• Only surface and near-surface flaws can be detected.

• Reliable results cannot be obtained on very rough surfaces. The ability of magnetic particles to reveal discontinuities is reduced by non-ferromagnetic layers on the surface (paint, coatings, etc.).