The document provides a comprehensive overview of penetrant testing (PT), including procedures, techniques, advantages, limitations, and evaluation methods. It highlights the importance of pre-cleaning, penetrant application, dwell time, and removal of excess penetrant, while detailing methods such as water-washable, post-emulsifier, and solvent removable techniques. Additionally, it outlines the significance of developer application and inspection under appropriate lighting for identifying surface defects in non-porous materials.

1. PENETRANT TEST

2. Penetrant Testing
• Surface discontinuities only
• Relies on penetrant ‘bleed out’
• Magnifies discontinuity size
• Several methods

3. PT Types
• Visible dye
• Fluorescent dye
• Three removal systems:
• Solvent
• Water
• Emulsifiable

4. Clean the Surface

5. Apply Penetrant

6. Dwell Time
•Varies with the nature of the job, typically
in the range of 2 to 20 minutes, or longer in
special cases

7. Remove Excess Penetrant

8. Remove Excess Penetrant

9. Remove Excess Penetrant

10. Remove Excess Penetrant

11. Apply Developer
In this example, spray
can is too close to the
weld surface, which can
lead to excessive
developer on surface. A
distance of 10-12 inches
is better.

12. Excessive Developer
Note ‘runs’ caused by
excess developer; this
can mask
discontinuities

13. Evaluate PT
Note porosity
and crack
indications

14. Clean Part
•Post inspection removal of
developer residues may be
required, particularly if work piece
is to be weld repaired or painted.

15. PT Advantages
• Relatively simple
• All types of metals
• Quite sensitive
• Quite portable

16. PT Limitations
• Somewhat slow
• Limited to surface
• Smooth surfaces
required

17. PT Results
• Sketches
• Photographs
• Lift off tapes

18. SCOPE
• One of the NDT method (Surface
NDT Method) to detect ,defects
open to the surface only on Non-
porus materials only.

19. • PRINCIPLE : Capillary Action
• PENETRANT : Liquid
• ORIGIN OF P.T : Oil and Whiting
Method
• PENETRANT : Liquid + Dye To
Promote Color
Liquid shall have capillary action

20. Surface Tension : Max
Viscosity : Low (3 to 5 centistokes)
Contact Angle : Low (less than 5o)
Wetting Ability : Better
Capillary action can be governed by the
following PHYSICAL PROPERTIES
• Capillary action works against gravity.
• This is the advantage to carry to out penetrant test
in all positions.

21. Penetrant Test Techniques
A. Water washable technique
B. Post emulsifier technique
C. Solvent removable technique
First two techniques are Aqueous based (water based)
Last technique is Non-Aqueous (solvent based)

22. Where techniques are used?
• Technique A: Used for testing rough surface
parts, threaded parts, gear wheel parts, etc.
• Technique B: Used for testing smooth surface
parts for better sensitivity.
• Technique C: Used for testing parts at all
position (portable).

23. TECHNIQUE - A
Water Washable
TECHNIQUE - B TECHNIQUE - C
Post Emulsifier Solvent Removable
Pre cleaning Pre cleaning Pre cleaning
Penetrant Application
Water
Washable
1.Lyphophylic
2.Hydrophilic
Penetrant Application
Solvent
Removable
Dwell
time
Dwell
time
Dwell
time
Emulsifier Application
• PT TECHNIQUES
Penetrant Application
Water
Washable

24. • PT TECHNIQUES (cont.)
Excess
Penetrant
Water
Washable
Excess
Penetrant
Water
Washable
Excess Penetrant
1.Lint Free Dry Cloth
2.Slightly Moisture Dry Cloth
3.Lint Free Dry Cloth
(All in One Direction)
Light
Scanning
Light
Scanning
Light
Scanning
Developer Developer Developer
Application Application Application
Developing
Time
Developing
Time
Developing
Time

25.  PT TECHNIQUES (cont.)
Interpretation Interpretation Interpretation
Evaluating Evaluating Evaluating
Reporting Reporting Reporting
Post Cleaning Post Cleaning
Post Cleaning

26. Penetrant Test Methods
• Visible dye : Red colour
• Fluorescent dye : Yellowish Green colour
Visible dye inspection under white light or natural light
Fluorescent dye inspection under black light (UV lamp)
after darkening the area with the black cloth and
after warming up the UV lamp for minimum 5 min.

27. • Ultraviolet lamp wave length : 3650Ao
• Intensity : Min 1000mW/CM2
Max 1500mW/CM2
• Background light within : 20mW/CM2
• Eye accommodation time : Min 5 minutes
Fluorescent Dye

28. Liquid Characteristics
• Neither acid type nor alkali type but a neutral
liquid originated from petroleum derivative with a
few percentage of sulphur and chlorine (within
1% W/V)

29. Penetrant testing
Pre cleaning
Penetrant application
Dwell time
Excess penetrant removal
Thorough cleaning

30. Developer application
Developing time
Inspection
Evaluation and reporting
Post cleaning

31. P.T. Calibration Block
• An aluminum block(3" x 2" x ¼") is heated
covering 1" circle at the central region by local
heating torch
• Temperature: 500°C to 520°C
Holding time: 1minute
• Quenched in water at room temperature
• Quenched crack formed around the heat
affected zone
• Again reheated to 150°C and allowed to cool in
the atmosphere
• A pattern of quenched crack formed

32. Aluminum Block(3" X 2" X ¼")
• This can be used as a standard reference block
in penetrant testing for All methods and all
techniques
3"
2"
1/4"
1" circle
Quenched Crack
W=1.5mm

33. Advantages in P.T.
• All materials (metals and non-metals) shall be
tested for open surface defects
• P.T. can be done at all elevated positions
• Very small defects shall be easily detected

34. Limitations
• Only non-porous material shall be tested
• Nickel and nickel based alloys
Titanium and alloys
shall be tested with penetrant free from sulphur
and chlorine
• The temperature of the test part shall be
Min: 5°C Max: 52°C
Freezing point Flash point

35. • At low temperature the penetrant becomes
highly viscous (immobile)
• At high temperature the penetrant gets
evaporated
• Inter mixing of P.T. chemicals shall not be done
from different suppliers
• All P.T. chemicals shall be checked for shelf life
period
Limitations (cont.)

36. Queries?

37. Pre Cleaning (surface preparation)
• Solvent cleaning (most commonly used)
• Detergent cleaning
• Steam cleaning
• Vapor degreasing
No mechanical cleaning like filing, grinding, machining,
sand blasting, shot blasting, emerying since these may
close the defects.
For painted parts: paint shall be removed

38. Penetrant application (in excess)
• Brushing (most common type)
• Spraying
• Dipping
• Pouring

39. Dwell time (penetrate time)
• During this time the penetrant enters the defect
by capillary action and remains there.

40. Excess penetrant removal
• After dwell time all the excess penetrant
removed very carefully from the test part

41. Water washable technique
The penetrant used is self-emulsified penetrant
i.e. the penetrant is built-in with emulsifier.
First Step: Pre-cleaning of part with detergent
cleaning. After cleaning, dry the part with warm
air.
Second Step: Penetrant application in Excess
by anyone of the recommended methods.

42. Cont..
Dwell time: (Penetrate time)
Dwell time is given as recommended (say-
5min) by the manufacturer. After dwell time,
removal of excess penetrant can be done as
shown below.
Use the water from water-line with low
pressure and room temperature (neither chill
Or warm) use this water with a coarse spray
(never use fine spray).

43. Cont..
With indirect angular spray the above
indications are maintained to avoid the danger
of over washing, then dry the part for developer
application.
In water-washable technique excess penetrant
removal is done in one stage only.

44. Post-emulsifier technique
In this technique the part to be tested is
subjected to pre-cleaning by detergent cleaning.
Then the part is dried and the penetrant (oily
base) is applied on the part as recommended.
After dwell time (say 5min) emulsifier is
applied over the excess penetrant either by
spraying or dipping (but never apply emulsifier
by brushing).

45. Cont..
Give emulsification time (say 5min).
During this period, the emulsifier reacts with
the excess penetrant and the resultant mixture
becomes as a soap base which is easy for
removal with water.
After removal of excess penetrant, the part
is allowed to dry in warmer and keep it ready
for developer application.
In this technique, excess penetrant removal
is done in two stages.

46. Solvent Removable Technique
In this technique, the first step is pre-cleaning
of the part which is done by solvent cleaning.
Then the pentrant is applied on the part as
recommended.

47. Cont..
After dwell time, removal of excess penetrant is done as
shown below:
With the lint free dry cloth remove the excess penetrant
gently from the surface in one direction. By this,90%
excess penetrant removed.
With another lint free cloth slightly moistened with acetone
remove the excess penetrant gently in the same area. By
this process, 99% excess penetrant removed.
With another lint free dry cloth wipe out the same area
gently in the same direction. By this process, 100%
excess penetrant removed.
In this technique, excess penetrant removal is done in three
stages

48. Comparative study of same size
defect, same method with
different techniques
Cross sectional view of defect with visible dye
using three techniques (after removal of excess
penetrant)
A B C
Water-washable
technique
Post emulsifier
technique
Solvent
technique

49. Cont..
S.No P.T. Techniques
P.T. Methods
Visible dye Fluorescent
dye
A Water-washable Poor Very good
B Post emulsifier Good Excellent
C Solvent
Removable
Average Best

50. Thorough cleaning
After removal the test part shall be checked for
thorough cleaning.
• For visible dye scan the surface with white
light.
• For fluorescent dye scan the surface with
ultraviolet lamp (Black light).

51. Developer application
Developer very finely divided
chalk powder
Application thin and uniform
(evenly)
Dry Wet
dusting spraying

52. Developing time
Min:7min Max:30min
Before 7min some defects may
not be revealed
After 30min due to image spreading
defect interpretation may
be erroneous (wrong)

53. Inspection
After proper developing time, the test part
shall be inspected under white light for visible
dye.
Inspected under UV lamp (Black Light) for
Fluorescent Dye.

54. Observe all P.T. Indications
Relevant Indications
Linear
Relevant True
Rounded
LINEAR ROUNDED
L
W
L
W
L-Length
W-Width
L ≥ 3W L ≤ 3W

55. Non-Relevant Indications
• Thickness variation in a job
• Groove line on a job

56. • Pitting and tool marks in a job
• An extra assembly fit up in job

57. False Indications
• Penetrant on the hands of operator
• Penetrant on the work table
• A loose lint in a cloth
• While testing number of small parts
penetrant rubbing the nearby cleaned part
• Improper removal of excess penetrant

58. Evaluation and reporting
• All the true indications are evaluated as per
acceptance standard

59. Post Cleaning
• All the tested parts shall be thoroughly cleaned
off from penetrant chemicals