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MAGNETIC PARTICLE INSPECTION (MPI) - Coggle Diagram
MAGNETIC PARTICLE
INSPECTION (MPI)
Definition
a method that can be used to detect surface and near surface defect, flaws or discontinuities in ferromagnetic material
Characteristic of ferromagnetic material
: material can be magnetized and allow the inspection to be effective
Example : iron, nickel, cobalt and alloys
Basic Step of MPI
magnetize the component which will be inspected
if there is any defect on or near the surface present, the defect will create the leakage field
after the component magnetize, iron particle dry or wet are applied to the surface of magnetized component or part
particle will be attracted and cluster at flux leakage field form a visible indication that NDT officer can detect
Ferromagnetic
(ex: iron,nickel,cobalt)
Paramagnetic
(ex: magnesium,lithium)
Diamagnetic
(ex: copper,silver,gold)
Hysteresis Loop
relationship between induced magnetic flux
density (B) and the magnetizing force (H)
Permeability
Permeability (m) is a material property that describes the ease which magnetic flux is establish in a component
main steps
Cleaning the part/component from oil, grease
Magnetization of the part to be inspected
Apply the magnetic particles such as iron(dry/wet) while the
part/component are being magnetized.
Inspect the part/component surface for any flux leakage field
Clean the part for any particle residue
Demagnetized the part/component so it will lose its
magnetism
Wet & Dry Magnetic
Particles
Advantages & Limitations