Magnetic Particle Testing (MT) is a non-destructive testing (NDT) technique that is used to detect surface and near-surface discontinuities in ferromagnetic materials.
This method involves magnetizing the material being tested and applying a magnetic field to the surface. Ferromagnetic particles, either dry or suspended in a liquid, are then applied to the surface of the material. These particles are attracted to any areas where there is a magnetic flux leakage, indicating the presence of a defect. The particles are applied in such a way that they form a visible indication of the defect, which can be observed under white light or black light, depending on the type of particles used.
MT is a widely used method for detecting surface cracks, seams, laps, and other defects in materials such as steel, iron, nickel, and cobalt and is commonly used in industries such as automotive, manufacturing, and construction. It is a relatively simple and quick test that can be performed on site, which makes it an attractive option for inspecting large structures or components.