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DYE PENETRANT
EXAMINATION
PROCEDURE
Doc. TNS/PT/01/Rev-1
PROCEDURE DYE PENETRANT EXAMINATION.
TNS/PT/04(Q. C. Documents)
1. SCOPE:
This work instruction covers Dye Penetrant Examination activities as per the ASME
Section V Article 6. The liquid penetrant examination method is an effective means for
detecting discontinuities, which are open to the surface of nonporous metals and other
materials. Typical discontinuities detectable by this method are cracks, seams, laps,
cold shuts, laminations, and porosity. In principle, a liquid penetrant is applied to the
surface to be examined and allowed to enter discontinuities. All excess penetrant is
then removed, the part is dried, and a developer is applied. The developer functions
both as a blotter to absorb penetrant that has been trapped in discontinuities, and as a
contrasting background to enhance the visibility of penetrant indications.
The following SE Standard provide details, which may be considered in the specific
procedure used:
(a) SE-165, Standard Practice for Liquid Penetrant Inspection Method
2. Operators Examination:
The operators are qualified as per SNT –TC-1A or equivalent standard, the examiner
should be qualified from PAEC or ASNT by CUSTOMER based on the technical
knowledge and experience of NDT operations.
3.Surface preparation:
In general, satisfactory results may be obtained when the surface of the part is in the
as-welded, as-rolled, as-cast, or as-forged condition. Surface preparation by grinding,
machining, or other methods may be necessary where surface irregularities could mask
indications of unacceptable discontinuities.
CAUTION: Conditioning of surfaces prior to examination can affect the results.
Prior to each liquid penetrant examination the surface to be examined and all adjacent
areas within at least in. shall be dry and free of all dirt, grease, lint, scale, welding flux,
weld spatter, paint, oil, and other extraneous matter that could obscure surface
openings or otherwise interfere with the examination.
-4 Drying after Preparation
After cleaning, drying of the surfaces to be examined shall be accomplished by normal
evaporation or with forced hot or cold air. A minimum period of time shall be established
to ensure that the cleaning solution has evaporated prior to application of the penetrant.
The surface to be tested, shall be clean dry and free from grease or any other to the
correct removal of the excess Penetrant or the right interpretation of the indications.
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DYE PENETRANT
EXAMINATION
PROCEDURE
Doc. TNS/PT/01/Rev-1
5. Test Medium System:
Standard Practice for Liquid Penetrant Inspection Method
Test Medium System
Manufacturer
Magna Flux
Dye Penetrant
SKL-SP1
Developer
SKD-S2
Cleaner/water wash
SKC-S
It is not permissible to interchange the test medium system on the same test item. Other
test media require prior consent of customer.
6. Execution Methodology:
7.Application of the Dye Penetrant:
An adequate quantity of the Dye Penetrant is to be applied to the surface, to be tested
by spraying or coating, the surface must be completely wet, during the penetration
process the Dye Penetrant should not be allowed to dry on the any part of the surface to
be tested.
The penetrant may be applied by spraying by using compressed-air-type appara-tus.
Processing details for applying the penetrant, the length of time that the penetrant will
remain on the surface (dwell time), and the temperature of the surface and penetrant
during the examination if outside 60°F to 125°F range. Processing details for removing
excess penetrant from the surface, and for drying the surface before applying the
developer;
7.1 Penetration Time
Penetration time is critical. The minimum penetration time shall be as required in Table
Material
form
Type of discontinuity
Penetrant Developer
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DYE PENETRANT
EXAMINATION
PROCEDURE
Doc. TNS/PT/01/Rev-1
Steel
Casting/Weld
Cold shuts, Porosity
5 minutes
Lake of fusion, Cracks all forms
7minutes
7.2 Excess Penetrant Removal.
After the specified penetration time has elapsed, any penetrant remaining on the
surface shall be removed, taking care to minimize removal of penetrant from
discontinuities.
7.3 Water Washable Penetrants. Excess water washable penetrant shall be removed
with a water spray. The water pressure shall not exceed 50psi (345kPa), and the water
temperature shall not exceed 110°F (43°C).
8.Developing
The developer shall be applied as soon as possible after penetrant removal; the time
interval shall not exceed that established in the procedure. Insufficient coating thickness
may not draw the penetrant out of discontinuities; conversely, excessive coating
thickness may mask indications. With color contrast penetrants, only a wet developer
shall be used.
8.1 Wet Developer Application
Prior to applying suspension type wet developer to the surface, the developer must be
thoroughly agitated to ensure adequate dispersion of suspended particles.
Aqueous Developer Application: Aqueous developer may be applied either a wet or dry
surface. It shall be applied by brushing, spraying, or other means, provided a thin
coating is obtained over the entire surface being examined.
8.2 Developing time for final interpretation be-gins immediately after the application of a
wet developer coating is dry. The minimum developing time shall be as required in the
above mentioned Table.
11.Evaluation Time:
When the developer has dried
After 25 Minutes
Also depend upon manufacturer’s instruction in MSDS.
12.Re-Examination:
It is not possible to make a clear evaluation of the indications then the Entire
examination process must be repeated starting with the initial Cleaning and repeat
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DYE PENETRANT
EXAMINATION
PROCEDURE
Doc. TNS/PT/01/Rev-1
examination is to be carried out using the same Test medium system as for the initial
test.
13.Evaluation Standards:
Cracks and clustered porosity are inadmissible.
Linear indications are extending greater than 3 mm are not admissible.
In case of chain porosity and linear indications less than/ equal to 3 mm
In the heat-effected zones of branches of header/tube, the zone should
Be milled and re-examined.
If elongated indication occur, the inspector is to be informed and this is
Also applies in the case of indications that occur systematically.
14. Examination after Repair:
A re-examination of the entire seam is to be carried out if a Cast/weld is
Repaired or replaced.
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