Magnetic Particle Testing (MT)
Magnetic Particle Testing (MT) is used to detect discontinuities in ferromagnetic material such as iron, nickel, cobalt and the alloys. Magnetic particles are applied to the test piece and a discontinuity that causes a disruption in the induced magnetic field attracts the applied particles, then producing an indication.
Important is a highly effective inspection tool that is sensitive to the presence of cracks, laps, seams and similar types of surface and near-surface discontinuities.
Depending on the type and orientation of discontinuities, test parts should be examined in two orthogonal (perpendicular) directions because discontinuities must have a major dimensions perpendicular to the magnetic field lines of force in order to be detected.