Dye Penetrant Inspection Procedure
This article provides you with a example dye penetrant inspection procedure. This
procedure contains water washable process with fluorescent systems and dry
developer
1.0
SCOPE
1.1
This procedure establishes the general requirements of Penetrant Testing of ferrous
and non-ferrous components (essentially non-porous) and welds by Water Washable
Process, Visible and Fluorescent Penetrant Systems and are to be followed by NDT
personnel Third Party.
2.0
PURPOSE:
2.1
The requirements are intended to detect discontinuities that are open to test-surface
and free from contaminants by interpreting the surface indications and evaluating them in
accordance with the applicable referenced codes, standards or specifications by certified NDT
personnel qualified in PT to Level II.
2.2
Customers approved specific Inspection/Evaluation manuals have also to be followed
strictly, if available and applicable.
2.3
Any conflicts between any points of this procedure and the referenced documents or
job specifications of customer shall be resolved (if given in writing) by the appointed ASNT
NDT Level III or the Divisional Manager (NDT) or his authorised representative.
2.4
Where special circumstances require unique techniques of Penetrant Testing by Water
Washable Process, specific technique sheets shall be attached as Annex: IV etc., with the
written approval of NDT Level III.
3.0
REFERENCES:
4.0
SUMMARY OF TEST METHOD & WATER WASHABLE PENETRANTS
4.1
A liquid penetrant which may be a visible or a fluorescent material is applied evenly
over the surface being examined and allowed to enter open discontinuities. After a suitable
dwell time, the excess surface penetrant is removed. A developer is applied to draw the
entrapped penetrant out of the discontinuity and stain the developer. The test surface is then
examined to determine the presence or absence of indications.
Note: Caution - Fluorescent penetrant examination shall not follow a visible penetrant
examination because visible dyes may cause deterioration or quenching of fluorescent dyes.
4.2
Processing parameters, such as surface precleaning, penetration time and excess
penetrant removal methods, are determined by the specific materials used, the nature of the
part under examination, (that is, size, shape, surface condition, alloy) and type of
discontinuities expected.
4.3
Liquid penetrant examination methods indicate the presence, location and, to a limited
extent, the nature and magnitude of the detected discontinuities. Each of the various
methods has been designed for specific uses such as critical service items, volume of parts,
portability or localised areas of examination. The method selected will depend accordingly on
the service requirements.
4.4
Water-Washable Penetrants are designed to be directly water-washable from the
surface of the test part, after a suitable penetrant dwell time. Because the emulsifier is builtin to the water-washable penetrant, it is extremely important to exercise proper process
control in removal of excess surface penetrant to ensure against overwashing. Waterwashable penetrants can be washed out of discontinuities if the rinsing step is too long or too
vigorous. Some penetrants are less resistant to overwashing than others.
4.5
Post-Emulsifiable penetrants with lipophilic and hydrophilic emulsifiers are not
included in this procedure.
5.0
EQUIPMENT AND MATERIALS:
5.1 This procedure is intended for use with the following consumables or their equivalent. It
has to be ensured that the consumables are selected in such a way that they are compatible
to the test surface and object and as per test requirements.
Dye Penetrant Inspection - Water Washable, Fluorescent Penetrant System
Manufacturer
PENETRANT
REMOVER
DEVELOPER
Sherwin
HM-440, HM-430
Water
D-100, D-100NF
Ardrox
P133D, P134D, P135D
Water
9D1B
Magnaflux
ZL-60C
Water
SKD-LT or ZP-9F
5.2
Intermixing
of
penetrant
materials
from
different
families
(manufacturers) is not permitted by this procedure.
Manufacturers recommendation for compatible penetrant systems must be
adhered with.
5.3
Dye Penetrant Inspection - Control of Contaminants
When testing nickel based alloys, austenitic stainless steels and titanium,
contaminant content of penetrant materials shall be controlled. Control shall be
based on the manufacturers batch certification which shall include, as a
minimum, the manufacturers name, batch number and chemical contaminant
content as determined in accordance with---------------------.
Only dye penetrant inspection materials having a batch number printed on the
container and traceable to a valid manufacturers batch certification on file shall
be used.
6.0
This
PARTS TO BE EXAMINED:
procedure
shall
be
used
---------------------------------------------------------------
for
in
parts
accordance
with
applicable code or specifications for parts or welds.
When welds are tested, at least one inch of the base material on both sides of the
weld is to be covered.
7.0
7.1
SURFACE PREPARATION:
Prior to the test, the area to be inspected and
If mechanical methods of cleaning like grinding, machining or sanding is
necessary, the surface area shall be etched to remove smeared metal.
After etching, suitable neutralising solutions shall be used and test surface be
washed with water.
7.3
Unless otherwise recommended by the manufacturer, welded components
or parts cleaned by Vapour degreasing, organic solvents or detergents, and
properly protected from contamination, need not be re-cleaned with penetrant
cleaner (remover) prior to application of the penetrant.
On occasion, a wire brush may be helpful in removing rust, surface scale, but it is
used only when no other means of removal will surface. It shall be followed by
cleaning with penetrant cleaner if compatible.
7.4
Dye Penetrant Inspection - Drying:
Evaporation time, following precleaning, shall be 5 minutes minimum. Where
indications of retained moisture exist, the evaporation time shall be increased till
no evidence of moisture in the area of test can be detected.
8.0
EXAMINATION:
8.1
Dye Penetrant Inspection - Temperature Limitations:
The temperature of the penetrant materials and the surface of the part should be
between ----- and ----- for fluorescent water washable penetrants and
8.2
Dye Penetrant Inspection - Penetrant Application:
a) Either immersion (dipping), flow-on, spray, or brushing technique is used to
apply the penetrant to the precleaned dry specimen.
b) The penetrant is applied evenly over the entire area.
c) Fillers shall be used on the upstream side of the air inlet when using
compressed air to apply penetrant.
8.3
Dye Penetrant Inspection - Dwell times:
a) Penetrant dwell times are critical and should be adjusted depending on
temperature and other conditions and may require qualification by demonstration
for specific applications.
b) Typical minimum penetration times are given in the Table-1.
c) Penetrant shall remain on the test surface for the entire dwell time period.
d) Care shall be taken to prevent drying out of the applied penetrant and
additional penetrant must be applied to re-wet the surface.
Dye Penetrant Inspection - Typical Minimum Penetration Times (30
minutes)
8.4
Dye Penetrant Inspection - Excess Penetrant Removal:
After the elapse of penetrant dwell time, the excess penetrant is removed by
water spray. Water at --- to --- and a pressure not exceeding ---- is applied with
droplet type sprayer specifically designed for penetrant removal. The nozzle of
sprayer is held so that water strikes the surface of the specimen at an angle of
approximately ---- degrees. Care is to be taken to avoid over-washing, which
causes washout of penetrant from discontinuities. Other methods of referenced codes or
specifications could also be used if applicable for the test surface conditions.
8.5
Dye Penetrant Inspection - Drying:
The test surface must be dry prior to the application of non-aqueous or dry
developers
Excessive heat or too long a drying time tends to bake the penetrant
out of discontinuities.
8.6
Dye Penetrant Inspection - Developer Application:
When the drying process is complete, the specimen is ready for the application
Dry developer is applied to the
An even thin coat/film of developer is preferred.
Applied developer shall not be removed from test surface.
8.7
8.7.1
Dye Penetrant Inspection:
The area under inspection shall be observed during application of
developer and at intervals during development time.
8.7.2
The recommended development time is between 7 and 30 minutes.
Development time begins directly after application of dry developer
8.7.3
Indications getting formed and formed at the test surface (by the blotting
action of developer) be noticed, analysed (relevant indications be noted) under
adequate lighting conditions.
8.7.4
Lighting Conditions:
b) Examine fluorescent penetrant indications under black light in a darkened
area.
Visible ambient light should not exceed 2 ft candles (20 Lx).
The
measurement should be made with a suitable photographic-type visible light
meter on the surface being examined.
Black Light Level Control - Black light intensity, minimum of 1000 W/cm2,
should be measured on the surface being examined, with a suitable black light
meter. The black light wavelength shall be in the range of 320 to 380 nm.
The intensity shall be checked at least once every 8 hours, or whenever the work
station is changed. Cracked or broken ultraviolet (UV) filters should be replaced
immediately. Defective bulbs, which radiate UV energy, must be replaced before
further use. Since a drop in line voltage can cause decreased black light output
with consequent inconsistent performance, a constant-voltage transformer should
be used when there is evidence of voltage fluctuation.
Caution: Certain high-intensity black light may emit unacceptable amounts of
visible light, which will cause fluorescent indications to disappear. Care should be
taken to use only bulbs certified by the supplier to be suitable for
such
examination purposes.
Note: The recommended minimum light intensity is intended for general usage.
For critical examination, higher intensity levels may be required.
Black Light Warm Up - Allow the black light to warm up for a minimum of 10 min
prior to its use or measurement of the intensity of the ultraviolet light emitted.
Visual Adaptation - The examiner should be in the darkened area for at least 5
min before examining parts to allow the eyes to adapt to the dark viewing.
Caution - Photochromic lenses shall not be worn during examination.
9.0
INTERPRETATIONS AND EVALUATIONS OF INDICATIONS:
9.1
All
indications
shall
be
evaluated
in
accordance
of
the
----------------------------------9.2
Acceptance
Criteria
are
listed
for
----------------------------------------------------------------------------------nt.
Any
conflicts
and
between
these
documents
--------------------------------------------------------------------------------------------------------------------------------------------------------- shall be resolved by the
NDT Level III or Divisional Manager (NDT) .
9.3 Mechanical discontinuities at the surface can result in false or irrelevant
indications.
Any indications which is believed to be non relevant shall be
regarded as a discontinuity and shall be re-examined to verify whether or not
actual defects are present.
9.4 Non relevant indications and broad areas of pigmentation which would mask
indications of defects are unacceptable and require corrective action by cleaning
or other suitable means of surface preparation as described herein and retest.
9.5 Make sure that surface indications are not false indications i.e. machining
marks, mechanical conditions or other surface conditions which cause or produce
false indications.
9.6
Interpretation of indications found and determined to be rejectable shall be
based on the size of the indication. Linear indications are those having a length
greater than three times the width.
Rounded indications are those that are
circular or elliptical shape with the length equal to or less than three time the
width.
9.7 All examination shall be reported on the penetrant testing report form.
10.
10.1
SAFETY:
The certified Inspector shall be responsible for compliance with applicable
safety rules in the use of liquid penetrant materials.
10.2
Liquid penetrant should not be heated or exposed to open flames.
10.3
Penetrant materials may be highly volatile, relatively toxic and the liquid
may cause skin irritation. Adequate ventilation at all times shall be used.
10.5
Avoid looking directly into black light source, since the eyeball contains a
fluid that fluoresces if black light shines directly into the eye.
11.
POST CLEANING:
11.1
Post cleaning is required to remove any excess residues from the
penetrant process.
11.2
A suitable cleaning technique such as water wash, vapours degreasing,
solvent soak
11.3
may be employed.
Caution should be exercised to remove all developer prior to vapour
degreasing as vapour degreasing can bake the developer on parts.
11.4
Post cleaning of water washable fluorescent penetrant tests could be done
by flushing surface with forced water spray or by. Clean cloth and or absorbent
paper towel and or dry air jet could also be used.
12.
PERSONNEL QUALIFICATION AND CERTIFICATION
12.1
.
PENETRANT TESTING ACCEPTANCE CRITERIA
The acceptance criteria given hereunder for relevant indications for various
------------------------ shall be used in general throughout of Third Party. The
inspector using this is cautioned that Code requirements do change, and that in the case
of conflict it shall be referred (in writing) to the appointed NDT Level III or the Divisional
Manager (NDT) .
B2 control tests attached woth table B.1
Refrence Test block type 2 attached with figure 2 iso 3452-3
