Magnetic Particle
Magnetic particle tests can only be performed on ferromagnetic materials. This method is where qualified operator places magnetic flux on the system and when applied a magnetic field and when a crack or other discontinuity is present, the magnetic flux leaks out of the system.
As it leaks, magnetic flux (magnetic field) will collect ferromagnetic particles (iron powder), making the size and shape of the discontinuity easily visible.
MT Magnetic Partial standard: AS4041 / ASME B31.3 – Pressure pipe