Magnetic Particle Inspection

Magnetic Particle Inspection (MPI) uses magnetic fields and small magnetic particles to detect surface and sub-surface flaws in a component, thus determine a part’s serviceability or conformity to required standards. This method is used to inspect a variety of product forms including castings, forgings, and weldments.

NUSATEK is capable of carrying out magnetic particle inspection on welded items, new components, raw material and others which made up of a ferromagnetic material such as iron, nickel, cobalt, or some of their alloys. The testing include of inspection on welded pipeline, pressure vessels, completed machining items and etc.

NUSATEK offers Magnetic Particle Inspection for almost all industries that use ferromagnetic materials as their products such as structural steel, automotive, petrochemical, power generation, and aerospace industries.

The advantages of Magnetic Particle Inspection include:

  • Simple, fast, and reliable operation
  • Versatile to locate both surface and near surface defects
  • No size limitations for parts to be tested
  • Indication are directly visible on the surface

 

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    Visible Testing

    In this magnetic particle testing technique, dry particles are dusted onto the surface of the test object as the item is magnetized. Dry particle inspection is well suited for the inspections conducted on rough surfaces. When an electromagnetic yoke is used, the AC or half wave DC current creates a pulsating magnetic field that provides mobility to the powder. The primary applications for dry powders are unground welds and rough as-cast surfaces.

    Dry particle inspection is also used to detect shallow subsurface cracks. Dry particles with half wave DC is the best approach when inspecting for lack of root penetration in welds of thin materials. Half wave DC with prods and dry particles is commonly used when inspecting large castings for hot tears and cracks.

     

    Fluorescent Testing

    The indications produced using the wet magnetic particles are sharper than dry particle Indications formed on similar defects. When fluorescent particles are used, the visibility of the indications is greatly improved because the eye is drawn to the "glowing" regions in the dark setting.

      • Standard surface preparation required is maximum surface roughness depth Rt ≤10µm
      • Minimum Thickness of sample for uncouple is 25mm while couple is 3mm.

     

     

     

    Coil Testing

    Coil type Wet Magnetic Particle Testing is used to establish a longitudinal magnetic field within the part, the part is placed on the inside surface of the coil. The fluorescent liquid is then flowed over the surface of the part. A magnetizing current is applied to the part for a short duration, typically 0.5 to 1.5 seconds. (Precautions should be taken to prevent burning or overheating of the part). Leakage fields from defects attract the particles to form visible indications.