MPT-Test Presentation
MPT-Test Presentation
MPT-Test Presentation
PARTICLE TESTING
INTRODUCTION
• Surface and Sub Surface Defects
MAGNETIC FLUX
UNMAGNETIZED STATE
MAGNETIZED STATE
Magnetic Domains
PRINCIPLE
FLUX LEAKAGE
MPT PROCESS
MAGNETIC FIELD CHARACTERISTICS
• Permanent Magnets
• Horse Shoe Magnets – U shaped
ELECTRO MAGNETS
• Electron Flow
• Fleming Right Hand Rule
MAGNETIC MATERIALS
• Diamagnetic Materials
- Permeability less than that of vacuum
• Paramagnetic Materials
- Permeability >= 1 or that of air
• Ferro magnetic Materials
- Permeability >>> that of air
• MAGNETIC FLUX ( Ø )
Field.
UNITS : Webers
• FLUX DENSITY ( B) - flux per unit area
UNITS : Gauss
B=Ø/A
1 Wb = 10^8 lines of flux
1 Wb / m^2 = 1 Tesla
1 Gauss = 10^-4 Wb / m^2
• PERMEABILITY
♦ COERCIVE FORCES
- The magnetic force required for
removal of your residual magnetism .
MAGNETIC HYSTERESIS LOOP
VAPOUR DEGREASING
MAGNETISATION - Fleming’s Right Hand Rule
CIRCULAR
LONGITUDINAL
MAGNETISING METHODS
CIRCULAR LONGITUDINAL
MAGNETISATION MAGNETISATION
LARGE CASTINGS HOLLOW SECTIONS
MAGNETIC YOKE
LONGITUDINAL MAGNETIZATION
• YOKE
• COIL
CIRCULAR MAGNETIZATION
• PRODS
• CENTRAL CONDUCTOR
• HEAD SHOT MACHINE
• AC
110 to 440 VOLTS
• HALF WAVE DIRECT CURRENT
• FULL WAVE DIRECT CURRENT
inch
- 100 to 300 Amps/ Inch on part dia upto 15
inch
LONGITUDINAL MAGNETIZATION
MAGNETIC FIELD STRENGTH
NI = 45000 / ( L / D )
TOL : + OR – 10 %
DRY APPLICATION
Good sub surface sensitivity
Less sensitive for surface
Good defect indication
WET APPLICATION OF POWDER
Easy to apply
Employed in stationary equipment
Very high sensitivities- fluorescent
powder
- wet flourescent
-- WET CONTINUOUS
-- DRY CONTINUOUS
RECORDING
--- TAPE TRANSFER
--- PHOTOGRAPHY
POST CLEANING
APPLICATIONS
TRANSPORTATION INDUSTRY
FORGINGS
TURBINES
GAUSS METER
SETTLING TEST
VISIBLE POWDER CONCENTRATION
1.2 TO 2.4 ml PER 100 ml Bath Sample
FLOUROSCENT POWDER
CONCENTRATION
SUSPENSION LIQUID
-- KEROSENE
-- PERTROLEUM HYDRO CARBON LIQUIDS
ADVANTAGES
CHEAPER EQUIPMENT
GOOD INDICATIONS & SENSITIVITY
SUPERIOR TO OTHER SOPHISTICATED
TECHNIQUES
LIMITATIONS
ONLY FOR FERRO MAGNETIC MATERIALS
DEMAGNETISING IS REQUIRED
SURFACE BURNING AT ELECTRICAL
CONTACT
NEAR SURFACE DEFECTS CAN ONLY BE
FOUND