The magnetic field can be introduced into the test specimen by either direct or indirect magnetization. Direct magnetization occurs when the electric current is passed through the test object and a magnetic field is formed in the material. Indirect occurs when no current is passed through the test specimen, but a magnetic field is applied from the outside source. When the magnetic field is disturbed by surface or near-surface discontinuities the magnetic powder forms around an indication which can be seen quite clearly.
MT is a non-destructive method that identifies surface and near-surface flaws in ferromagnetic materials using magnetic fields and particles.
WFMT uses fluorescent magnetic particles in a liquid suspension under UV light to reveal fine or faint discontinuities, improving detection accuracy.
