Magnetic Particle Testing
MT is a nondestructive testing method utilized for detecting surface and very near-surface discontinuities in ferromagnetic materials.
Parts that are being examined can either have the magnetic field induced by direct or indirect magnetization.
Bench directly or indirectly induces magnetic fields.
Coils, Yokes, and wrapped cable indirectly induce magnetic fields
Dry Mag Particle
Wet Particle (Bath)
Current used in MT testing can be either AC or DC
AC is best for tight surface discontinuities due to "skin effect
Advantages of MT
Quick & Uncomplicated
Immediate indication of discontinuities
Most reliable for surface discontinuities
Disadvantages of MT
restricted to ferromagnetic materials
Power supply needed for most techniques
Cannot be used on thick painted materials
Surface condition can effect results
Paints and particle can be hazardous