Magnetic particle testing:Magnetic Particle TestingIt is called MT for short. Its basic principle utilizes the interaction between magnetic leakage field and magnetic powder at the defect of workpiece. It takes advantage of the difference between the magnetic permeability of iron and steel products and that of iron and steel products at the surface and near surface defects (such as cracks, slag inclusions, hairlines, etc.), after magnetization, the magnetic field at the discontinuity of these materials will be distorted, forming the magnetic leakage field on the workpiece surface at the leakage of some magnetic flux, so as to attract magnetic powder The magnetic particle accumulation & mdash; & mdash; marks at the defects appear the defect position and shape under the appropriate light conditions. The magnetic particle detection is realized by observing and explaining the accumulation of these magnetic particles. In industry, magnetic particle testing can be used as the final inspection of finished products to ensure that the workpiece will not produce harmful defects on the surface after various processing procedures (such as welding, metal heat treatment, grinding). It can also be used for the inspection of semi-finished products and raw materials such as bars, billets, forgings, castings, etc. to find the existing surface defects. For transportation departments such as railway, aviation, smelting, chemical industry, power and various machinery manufacturers, magnetic particle inspection is often used for important steel parts during regular maintenance of equipment to detect fatigue cracks and other defects in use and prevent catastrophic accidents during continuous use of equipment.