MPT TEST
Principle of MPT is as follows: When the workpiece to be inspected is magnetized, magnetic flux is induced. If there is a flaw on the surface, magnetic flux leaks into the air at the position of the flaw. Then magnetic particles (dyed or fluorescent encapsulated) are applied to the surface.
Magnetic Particle Testing (MPT), also referred to as Magnetic Particle Inspection, is a nondestructive examination (NDE) technique used to detect surface and slightly subsurface flaws in most ferromagnetic materials such as iron, nickel, and cobalt, and some of their alloys.