Dye penetrant testing is a non-destructive testing method used to detect surface-breaking defects in materials. It involves applying a penetrant that seeps into defects, removing excess penetrant, and applying a developer that draws the penetrant out of defects to the surface where it is visible. The document discusses the dye penetrant testing process, materials used including penetrants, developers and their classifications, as well as the principles, equipment, advantages, limitations and safety precautions of the method.

1. UNIT-II
Die penetrate test /liquid
penetrate inspection
PRESENTED BY-
SHIVAM SHARMA

2. INTRODUCTION:- Dye Penetrant Testing
• This method is commonly used for detect the surface cracks
or defects.
• Dye penetrant Testing (DPT) is one of the most widely used
nondestructive Testing (NDT) methods.
• DPT can be used to inspect almost any material provided that
its surface is not extremely rough.

3. Dye Penetrant Testing Proces
Three liquids are
used in this method.
1. Cleaner
2. Penetrant
3. Developer

4. Dye Penetrant Testing of a Boiler
At first the surface of the material that is to be tested is
cleaned by a liquid. The liquid is called cleaner.

5. Dye Penetrant Testing of a Boiler
Then a liquid with high surface wetting characteristics is applied to
the surface of the part and allowed time to seep into surface
breaking defects. This liquid is called penetrant. After five or ten
minutes the excess penetrant is removed from the surface.

6. Dye Penetrant Testing of a Boiler
Then another liquid is applied to pull the trapped penetrant out
the defect and spread it on the surface where it can be seen. This
liquid is called deveoper.

7. Findings
After Dye Penetrant Testing
there are two surface cracks are
Detected.

8. PRINCIPLE
• The basic principle upon which penetrant testing is based is that
of capillary “attraction” or “action.”
• Capillary action is a surface tension phenomenon that permits
liquids to be drawn into tight openings as a result of the energies
that are present at the surfaces of the openings.
• In most high school physics classes, the principle of capillary
action is demon-strated by placing a glass straw into a beaker
filled with colored water.
• The surface tension associated with the opening of the glass
straw, or capillary, causes the liquid level to move to a higher
level inside that capillary than the level of the liquid in the
beaker.
FIGURE- Demonstration of capillary
action. (a) Glass panels clamped
together. (b) Visible color contrast
penetrant applied to edge of panels

9. SCOPE OF PENETRANT TESTING
This procedure covers the liquid penetrant examination by solvent removable penetrant
process using color contrast technique for detecting surface discontinuities of base metal &
weldment required by the applicable code & specifications.
This test method covers procedures for penetrant examination of butt and fillet weld with
the associated heat effected zone (haz) on the parent metal and components. They are non-
destructive testing methods for detecting discontinuities that are open to the surface such as
cracks, porosity and lack of fusion by liquid penetrant testing conducted in accordance with
the requirements of the referenced codes and standards.
• Setup and calibrate equipment
• Interpret and evaluate results with respect to applicable codes, standards and
specifications
• Familiar with the scope and limitations of the methods
• Write test reports

10. ADVANTAGES OF DYE PENETRANT TESTING
This method has high sensitivity to small surface discontinuities.
Large areas and large volumes of parts/materials can be inspected
rapidly and at low cost.
Indications are produced directly on the surface of the part and
constitute a visual representation of the flaw.
Aerosol spray can make penetrant materials very portable.
Penetrant materials and associated equipments are relatively
inexpensive.

11. LIMITATIONS OF DYE PENETRANT TESTING
Only surface breaking defects can be detected.
Precleaning is critical since contaminants can mask defects.
The inspector must have direct access to the surface being
inspected.
Surface finish and roughness can affect inspection sensitivity.
Post cleaning of acceptable parts or materials is required.
Chemical handling and proper disposal is required.

12. Dye Penetrant Test (PT)
For ferrous and
non-ferrous
material.
Used on most
welded joints.
Followed by
radiographic
test if required.

13. WORKING PRINCIPLE OF PENETRANT TEST
• SURFACE PREPARATION- It is one of the
most critical step involved in penetrant test
i.e., surface must be free from dust, rust,
water, oil, grease or other foreign particles
besides this, if metal is machined, forged or
casted. Because all the above processes
prevents the penetrant from entering.
• APPLICATION OF PENETRANT- After
cleaning the surface from any type of
foreign contaminants, penetrants are applied
may be by immersing the job into penetrant
dilution or by brushing or by spraying.
• DWELL- It is a certain period of time for
which penetrant is left to be in contact with
surface of job till it dries. This dwell period
varies according to type of penetrant used.
• REMOVAL OF EXCESS PENETRANT-
This is a very complicated step, where
precise level of its is required to remove the
excess penetrant from the surface while
leaving penetrants for defects also. It may be
done by direct ringing with water, by
cleansing with a solvent.

14. Conti…
• APPLICATION OF DEVELOPER- For
clear visualisation of defect, a thin layer of
developer is applied on the surface of job,
which draws out the penetrant trapped in
flaws back to the upper surface. Developer
may be used in dry or wet form.
• DEVELOPMENT OF INDICATION-
After application of developer’s it is left
over the surface of job for minimum 10
minutes or more than 10 minutes for tight
cracks only. This standing time will lead
extraction of trapped penetrant from the
core of flaw.
• INSPECTION- Here comes the turn of
visual inspection which is processed under
the effect of light. This light helps in
detecting indications coming from flaw.
• CLEAN SURFACE- At last, cleaning of
developer’s from the surface of job is
done.

15. Equipment & techniques
• Penetrant systems range from simple portable kits to large, complex in-line
test systems.
• The kits contain-
• pressurized cans of the penetrant,
• cleaner/remover,
• solvent,
• Developer
• brushes,
• swabs, and
• cloths.
• A larger fluorescent penetrant kit will include a black light.
• These kits are used when examinations are to be conducted in remote areas,
in the field, or for a small area of a test surface.
• In contrast to these portable penetrant kits, there are a number of diverse
stationary-type systems.
• These range from a manually operated penetrant line with a number of
tanks, to very expensive automated lines, in which most steps in the process
are performed automatically.

16. Conti…
• In this particular system, there is a tank for the penetrant, a tank for the water rinse, a
drying oven, and a developer station. The final station is the examination area, which
includes a black light.
• This manually operated system is a typical small water-removable penetrant line. The
steps in the testing process would be: cleaning of the parts, application
• Of the penetrant, removal of the penetrant with a water spray, drying, application of the
developer, and finally, inspection. This entire process is covered in much greater detail in
section V, techniques.

17. Penetrant testing materials
A penetrant must possess a number of important characteristics. A
penetrant must-
• Spread easily over the surface of the material being inspected to
provide complete and even coverage.
• be drawn into surface breaking defects by capillary action.
• remain in the defect but remove easily from the surface of the
part.
• remain fluid so it can be drawn back to the surface of the part
through the drying and developing steps.
• be highly visible or fluoresce brightly to produce easy to see
indications.
• must not be harmful to the material being tested or the inspector.

18. Further classification
According to the method used to
remove the excess penetrant from the
part, the penetrants can be classified
into:
•Method A - water washable
•Method B - post emulsifiable,
lipophilic
•Method C - solvent removable
•Method D- post emulsifiable,
hydrophilic
Based on the strength or
detectability of the indication that
is produced for a number of very
small and tight fatigue cracks,
penetrants can be classified into
five sensitivity levels are shown
below:
•Level ½ - ultra low sensitivity
•Level 1 - low sensitivity
•Level 2 - medium sensitivity
•Level 3 - high sensitivity
•Level 4 - ultra-high sensitivity

19. Why Liquid Penetrant Inspection?
• To improves the detectability of flaws
There are basically two ways that a
penetrant inspection process
makes flaws more easily seen.
(1) LPI produces a flaw indication
that is much larger and easier for
the eye to detect than the flaw
itself.
(2) LPI produces a flaw indication
with a high level of contrast
between the indication and the
background.
The advantage that a liquid
penetrant inspection (LPI) offers
over an unaided visual inspection is
that it makes defects easier to see
for the inspector.

20. Penetrant Types
DYE PENETRANTS
• The liquids are colored so that
they provide good contrast
against the developer
• Usually red liquid against white
developer
• Observation performed in
ordinary daylight or good
indoor illumination
Fluorescent penetrants
• Liquid contain additives to give
fluorescence under UV
• Object should be shielded from
visible light during inspection
• Fluorescent indications are easy to
see in the dark
Standard: Aerospace Material Specification
(AMS) 2644.

21. Emulsifiers
• When removal of the penetrant from the defect due to over-washing of the part is
a concern, a post emulsifiable penetrant system can be used. Post emulsifiable
penetrants require a separate emulsifier to break the penetrant down and make it
water washable.
• Method B - Lipophilic Emulsifier,
• Method D - Hydrophilic Emulsifier
• Lipophilic emulsification systems are oil-based materials that are supplied in
ready-to-use form.
• Hydrophilic systems are water-based and supplied as a concentrate that must be
diluted with water prior to use .

22. Developer
• The role of the developer is to pull the trapped penetrant material out of
defects and to spread the developer out on the surface of the part so it can be
seen by an inspector.
• The fine developer particles both reflect and refract the incident ultraviolet
light, allowing more of it to interact with the penetrant, causing more
efficient fluorescence.
• The developer also allows more light to be emitted through the same
mechanism.
• This is why indications are brighter than the penetrant itself under UV light.
• Another function that some developers performs is to create a white
background so there is a greater degree of contrast between the indication
and the surrounding background.

23. Developer’s Types
Using dye and developer from different
manufacturers should be avoided.
Form a - Dry Powder
Form b - Water Soluble
Form c - Water Suspendable
Form d - Nonaqueous Type 1: Fluorescent (Solvent Based)
Form e - Nonaqueous Type 2: Visible Dye (Solvent Based)
Form f - Special Applications

24. ZYGLO TEST -INTRODUCTION
 It is simple, reliable and economical testing method of NDT , that
helps to locate and identify surface defects
 It is used for inspecting defects in materials like alumininum,
copper, plastics, stainless steel, titanium or ferrous materials etc.
 Defects which is to be inspected may be seams, forging laps,
Porosity, cold shuts, fatigue crack, heat treat cracks etc.
 It is a quick and accurate process for locating surface flaws

25. STEPS INVOLVED IN ZYGLO FLUORESCENT
PENETRANT TEST
There are six steps involved in this testing method
Part preparation or pre cleaning
Application of penetrant
Removal of penetrant
Part drying
Application of developers
Inspection

26. 1.PART PREPARATION
• Pre-cleaning is done before application of penetrant and used for
effective inspection
• It is used to remove rust, greese, oil, wax, paint etc. From the surface
of material
• Thin cleaners like caustic and acid are used to remove paints
• Aqueous cleaners are used to remove oil
• Clean and completely dry part is to be inspected before applying
penetrant

27. 2.Application Of Penetrant
• After cleaning of part, zyglo penetrant is applied by spraying,
brushing or immersing
• After application a waiting time is required, for the penetrant action
takes place
• This waiting time is called as dwell time
• Dwell time is depends on the material being inspected and the type of
defect

28. 3.Removal Of Penetrant
Zyglo testing involves four method for removing penetrants-
A) lipophilic method (post emulsifier):
• In this method emulsifiers are usually applied on it by dipping it in a
tank followed by draining for 2-4 minutes
• Then it is washed off with water
B) hydrophilic method (post remover):
• The PR method prevents excessive penetrant removal because it only
provides limited solvent action
• A water spray pre-rinse removes excessive penetrant, when part is
immersed in a tank for 20 sec. To 5 minutes
• After immersion post-rins removes any remaining penetrant by water
spraying

30. Removal of penetrant cont……
C) water washable:
• In this method, spray washing is done with water at temp. Of 50-100
0F
• Black light is used to determine the removal of penetrants
• Over washing of penetrant is to be avoided in this method
D) solvent removal method:
• This method is used when use of water as penetrant remover is
Ineffective

31. 4.PART DRYING
It involves the drying of part with hot air dryer at temp. Below 160 F
Over drying is avoided as over drying can reduce effectiveness of
inspection

32. 5.Application of developers
Developers draws penetrants out of the cracks making defects
indication much more prominent
Zyglo method involves use of three types of developers:
A) dry powder developer
B) aqueous developer
C) non-aqueous developer

34. 6.INSPECTION
After the application of developer, a 10 min. Dwell time for
developer is required
Then part placed in a dark area for inspection
For zyglo fluorescent penetrant test MAGNAFLUX ZB-100F black
light is used

35. POST CLEANING
After the inspection is complete, post cleaning is a good idea
This step usually a water spray, removes most inspection materials
Brushing is normally required to remove non aqueous developers

36. ADVANTAGES
High sensitive to small surface discontinuities
Large areas and large volumes of parts/material scan
Be inspected rapidly and at low cost
Parts with complex geometry shapes are routinely Inspected

37. DISADVANTAGES
Penetrant stains clothes and skin and must be treated with
Care
The method is limited to surface defects
Training is required for the inspector
Post cleaning of acceptable parts or materials is required

38. SAFETY PRECAUTION
Wear protective gloves to avoid skin irritation
Do not smoke or eat while using NDT materials
Wash hands thoroughly after using NDT materials
Avoid clothing contact with NDT materials
Avoid breathing spray mists, air borne powders and solvent vapors
Store all NDT materials in closed containers well apart from
Open flames or other heat sources