Magnetic particle testing can detect manufacturing discontinuities and damage in ferromagnetic materials. It works by magnetizing the material and applying iron-based particles that are attracted to surface or near-surface defects, revealing them. The basic procedure involves pre-cleaning, introducing a magnetic field longitudinally or circularly, applying dry or wet magnetic particles, and interpreting the indications of defects. It has advantages of detecting surface and shallow subsurface defects quickly at low cost but has limitations such as not working on non-ferrous materials and requiring cleaning.

1. MAGNETIC PARTICLE
TESTING

2. Inspeksi partikel magnetik dapat
mendeteksi diskontinuitas
produksi dan kerusakan dalam
layanan

3. PENGANTAR MAGNETISME
M a g n e t i s m e a d a l a h ke m a m p u a n m a t e r i u n t u k
m e n a r i k m a t e r i l a i n ke d i r i n y a s e n d i r i .
B e n d a ya n g m e m i l i k i s i fat ke m a g n eta n d i s e b u t
m a g n et
ku t u b m a g n et a d a l a h t i t i k d i m a n a ga r i s gaya
m a g n et ke l u a r ata u m a s u k ke s u at u b a h a n

4. FERROMAGNETIC MATERIALS
A material is considered ferromagnetic if it can be
magnetized
Ferromagnetic materials are made up of magnetic
domains
Magnetic domains point randomly in demagnetized
material, but can be aligned using electrical current
Demagnetized Magnetized

5. HOW DOES MAGNETIC PARTICLE
INSPECTION WORK?

6. HOW DOES MAGNETIC PARTICLE
INSPECTION WORK? (CONT.)

7. BASIC PROCEDURE
Basic steps involved:
1 Component pre-cleaning
2 Introduction of magnetic field
3 Application of magnetic media
4 Interpretation of magnetic particle
indications

8. PRE CLEANING
The part’s surface should be clean and dry before
inspection
Contaminants being attracted to leakage
fields, they may also interfere with interpretation of
indications.

9. INTRODUCTION OF THE MAGNETIC
FIELD
magnetic field can be introduced into a component
in a number of different ways.
A. Using a permanent magnet or an
electromagnet
B. Flowing an electrical current through the
specimen
C. Flowing an electrical current through a coil of
wire

11. DIRECTION OF THE MAGNETIC FIELD
Two general types of magnetic fields:
1) longitudinal magnetic field
2) circular magnetic field

12. IMPORTANCE OF MAGNETIC FIELD
DIRECTION
detection of defects occurs when the lines of
magnetic force are established at right angles to the
longest dimension of the defect
Flux Leakage
No Flux Leakage

13. Longitudinal (along the axis) Transverse (perpendicular the axis)
Kinds of defect

14. PRODUCING A LONGITUDINAL
MAGNETIC FIELD USING A COIL
placing the part near the
inside or a coil’s annulus.
This produces magnetic
lines of force that are
parallel to the long axis of
the test part

15. PRODUCING
A LONGITUDINAL FIELD USING PERMANE
NT OR ELECTROMAGNETIC MAGNETS

16. CIRCULAR MAGNETIC FIELDS

17. DRY MAGNETIC PARTICLES

19. WET MAGNETIC PARTICLES

20. Indications

24. DEMAGNETIZATION
Possible reasons for demagnetization
include:
May interfere with welding and/or machining
operations
Can effect gauges that are sensitive to magnetic
fields if placed in close proximity.
Abrasive particles may adhere to components
surface and cause and increase in wear to
engines components, gears, bearings etc.

25. DEMAGNETIZATION
Magnetized
Demagnetized

26. ADVANTAGES OF
MAGNETIC PARTICLE INSPECTION
Can detect both surface and near sub-surface
defects
Precleaning of components is not critical
Fast method of inspection and indications are
visible directly
low cost compared to many other NDT methods
Is a very portable inspection

27. LIMITATIONS OF
MAGNETIC PARTICLE INSPECTION
Cannot inspect non-ferrous materials
Inspection of large parts may require use of
equipment
Some parts may require removal of coating
Limited subsurface discontinuity detection
Post cleaning, and post demagnetization is often
necessary

28. TH