1. Penetrant Testing

2. Penetrant Properties Surface Tension and Wetting ability
P = 2S Cos  W
A good penetrant should have high surface tension and a small contact angle

3. Affects the rate at which penetrant enters a defect
Viscosity
Affects the rate at which penetrant enters a defect
The more viscous the penetrant the slower it enter openings
OIL
GREASE

4. PENSKE MARTEN CLOSED CUP TEST
Flash Point
Temperature recorded
Flash point
The minimum temperature at which liquid will gives off enough vapour which will flash with an application of small flame
sparkplug
thermometer
vapour
Closed container
Liquid under test
water
PENSKE MARTEN CLOSED CUP TEST
Heat

5. Typical Penetrant Tank
Penetrant Properties
Specific Gravity
Penetrant has Lower SG than water : 0.9
Reason: If penetrant used in tank water will be on the bottom
Typical Penetrant Tank
Water
Penetrant
Wire mesh
Contaminants
Drainage

6. Specific Gravity Checked using a HYDROMETER Water Penetrant Scales
Balast / weight
Water
Penetrant

7. Penetrant Line

8. Penetrant Properties Volatility
High volatility = High rate of evaporation
A good penetrant has low volatility

9. Penetrant Properties Chemical inertness
Maximum levels for sulphur, halogens and sodium are specified
Sulphur and halogens may cause stress corrosion or intergranullar corrosion
Halogens:
Very reactive elements. Examples:
Chlorine
Iodine
Bromine
Fluorine

10. Penetrant Properties Solubility
Penetrant must hold sufficient dye in solution at ambient or high temperatures
Solvent Ability
Must be able to remove penetrant from specimen

11. Penetrant Properties Tolerance to Contaminants Health Hazard Toxicity
Odour
Skin contact
Availability and Cost

12. System classification
PENETRANT
Colour contrast
Fluorescent
Dual
REMOVAL
Water washable
Solvent
Post emulsifiable

13. Penetrant Systems PENETRANT Colour contrast Fluorescent Dual REMOVAL
Solvent
Water washable
Post emulsifiable
DEVELOPERS
Dry powder
Aqueous
Non-Aqueous

14. Control Checks
Overall system performance

15. Overall System Performance
Quench cracked aluminium alloy block
Chromium plated cracked test panel
Cracked test piece

16. ARB BLOCK- Aeronautical Registration Board Block
COMPARATOR BLOCK
ARB BLOCK- Aeronautical Registration Board Block
Two sided aluminum block which been quenched – to produce thermal cracks
May be used to check/compare performance of penetrant chemicals (penetrant, emulsifier, developer)

17. Two different penetrant applied on each section of block
How to use the ARB block
Two different penetrant applied on each section of block
NEW
OLD
The excess penetrant is removed and developer applied
Indication are observed
Now process is repeat with the penetrant applied to different section
OLD
NEW
OLD PENETRANT IS WEAK
OLD PENETRANT IS OK

18. TAM panel or SHERWIN panel
CHROMIUM PLATED BLOCK
TAM panel or SHERWIN panel
Section for checking effectiveness of cleaning
Section for checking sensitivity
Cleaning not effective
Less sensitive

19. Control Checks Overall system performance
Water wash temperature and pressure
Colour intensity
Penetrant remover
Developer
UV lamp output
UV monitor
Water tolerance

20. Control Checks - Frequency
Daily
Weekly
Monthly
Annual
Overall system performance
Water wash temperature and pressure
Colour intensity
Penetrant remover
Developer
UV lamp output
UV monitor
Water tolerance

21. Maintenance Checks Tank levels Equipment cleanliness
Airline cleanliness
Processing units
UV lamp maintenance
Clean tanks

22. Penetrant Systems PENETRANT Colour contrast Fluorescent Dual REMOVAL
Solvent
Water washable
Post emulsifiable
DEVELOPERS
Dry powder
Aqueous
Non-Aqueous

23. BS EN 571 Removal Penetrant Type I Fluorescent Method A Water
Type II Colour contrast
Type III Dual
Method A Water
Method B Lipophilic Emulsifier
Method C Solvent
Method D Hydrophilic
Method E Water and solvent

24. BS EN 571 Removal Developer Form a Dry Method A Water
Form b Water soluble
Form c Water suspendable
Form d Solvent based
Form e Peelable
Method A Water
Method B Lipophilic Emulsifier
Method C Solvent
Method D Hydrophilic
Method E Water and solvent

25. BS EN 571 Fluorescent Solvent removable Solvent based developer Type I
Method C
Form d

26. Mil-L-25135 Group I Solvent removed,Visible
Group II Post emulsified,Visible
Group III Water washable,Visible
Group IV Water washable,Fluorescent(L)
Group V Post emulsified,Fluorescent(M)
Group VI Post emulsified,Fluorescent(H)
Group VII Solvent removed,Fluorescent

27. Mil-L-6866 Type I Fluorescent Type II Visible Method A Water
Method B Post emulsifiable
Method C Solvent
Type II Visible
Method A Water
Method B Post emulsifiable
Method C Solvent

28. Selection of System Nature of discontinuities (size and type)
Geometry and intricacy
Surface condition
Component material
Size and position
Equipment and expertise available
Cost
Number of components to be tested

29. Selection of System
Inspection of a large number of threaded components
What method will you select and why ?
Fluorescent water washable with dry powder developer
Fluorescent for mass inspections
Water washable more suited than solvents to batch inspections
Post emulsifiable difficult to remove from threads

30. Selection of System Inspection of turbine blades for fatigue cracks
What method will you select and why ?
Fluorescent post emulsifiable with non-aqueous developer
Fluorescent more sensitive than colour contrast
Post emulsifiable more sensitive than water washable
Non-aqueous developer most sensitive