ASTM E165/E165M-23

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E165/E165M − 23
Standard Practice for
Liquid Penetrant Testing for General Industry
This standard is issued under the fixed designation E165/E165M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* therefore, each system shall be used independently of the other.
Combining values from the two systems may result in non-
1.1 This practice covers procedures for penetrant examina-
conformance with the standard.
tion of materials. Penetrant testing is a nondestructive testing
1.5 This standard does not purport to address all of the
method for detecting discontinuities that are open to the surface
safety concerns, if any, associated with its use. It is the
such as cracks, seams, laps, cold shuts, shrinkage, laminations,
responsibility of the user of this standard to establish appro-
through leaks, or lack of fusion and is applicable to in-process,
priate safety, health, and environmental practices and deter-
final, and maintenance examinations. It can be effectively used
mine the applicability of regulatory limitations prior to use.
in the examination of nonporous, metallic materials, ferrous
1.6 This international standard was developed in accor-
and nonferrous metals, and of nonmetallic materials such as
dance with internationally recognized principles on standard-
nonporous glazed or fully densified ceramics, as well as certain
ization established in the Decision on Principles for the
nonporous plastics, and glass.
Development of International Standards, Guides and Recom-
1.2 This practice also provides a reference:
mendations issued by the World Trade Organization Technical
1.2.1 By which a liquid penetrant examination process
Barriers to Trade (TBT) Committee.
recommended or required by individual organizations can be
reviewed to ascertain its applicability and completeness.
2. Referenced Documents
1.2.2 For use in the preparation of process specifications and
2.1 ASTM Standards:
procedures dealing with the liquid penetrant testing of parts
D129 Test Method for Sulfur in Petroleum Products (Gen-
and materials. Agreement by the customer requesting penetrant
eral High Pressure Decomposition Device Method)
testing is strongly recommended. All areas of this practice may
D329 Specification for Acetone
be open to agreement between the cognizant engineering
D770 Specification for Isopropyl Alcohol
organization and the supplier, or specific direction from the
D1193 Specification for Reagent Water
cognizant engineering organization.
1.2.3 For use in the organization of facilities and personnel D1552 Test Method for Sulfur in Petroleum Products by
High Temperature Combustion and Infrared (IR) Detec-
concerned with liquid penetrant testing.
tion or Thermal Conductivity Detection (TCD)
1.3 This practice does not indicate or suggest criteria for
D4327 Test Method for Anions in Water by Suppressed Ion
evaluation of the indications obtained by penetrant testing. It
Chromatography
should be pointed out, however, that after indications have
D6919 Test Method for Determination of Dissolved Alkali
been found, they must be interpreted or classified and then
and Alkaline Earth Cations and Ammonium in Water and
evaluated. For this purpose there must be a separate code,
Wastewater by Ion Chromatography
standard, or a specific agreement to define the type, size,
E433 Reference Photographs for Liquid Penetrant Inspec-
location, and direction of indications considered acceptable,
tion
and those considered unacceptable.
E516 Practice for Testing Thermal Conductivity Detectors
1.4 Units—The values stated in either SI units or inch-
Used in Gas Chromatography
pound units are to be regarded separately as standard. The
E543 Specification for Agencies Performing Nondestructive
values stated in each system may not be exact equivalents;
Testing
E1208 Practice for Fluorescent Liquid Penetrant Testing
1 Using the Lipophilic Post-Emulsification Process
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
structive Testing and is the direct responsibility of Subcommittee E07.03 on Liquid
Penetrant and Magnetic Particle Methods.
Current edition approved July 1, 2023. Published August 2023. Originally
approved in 1960. Last previous edition approved in 2018 as E165/E165M – 18. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/E0165_E0165M-23. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
For ASME Boiler and Pressure Vessel Code applications see related Recom- Standards volume information, refer to the standard’s Document Summary page on
mended Test Method SE-165 in the Code. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E165/E165M − 23
E1209 Practice for Fluorescent Liquid Penetrant Testing 5. Significance and Use
Using the Water-Washable Process
5.1 Liquid penetrant testing methods indicate the presence,
E1210 Practice for Fluorescent Liquid Penetrant Testing
location, and to a limited extent, the nature and magnitude of
Using the Hydrophilic Post-Emulsification Process
the detected discontinuities. Each of the various penetrant
E1219 Practice for Fluorescent Liquid Penetrant Testing
methods has been designed for specific uses such as critical
Using the Solvent-Removable Process
service items, volume of parts, portability, or localized areas of
E1220 Practice for Visible Penetrant Testing Using Solvent-
examination. The method selected will depend accordingly on
Removable Process
the design and service requirements of the parts or materials
E1316 Terminology for Nondestructive Examinations
being tested.
E1418 Practice for Visible Penetrant Testing Using the
Water-Washable Process
6. Classification of Penetrant Materials and Methods
E2297 Guide for Use of UV-A and Visible Light Sources and
6.1 Liquid penetrant testing methods and materials are
Meters used in the Liquid Penetrant and Magnetic Particle
classified in accordance with AMS 2644 as listed in Table 1.
Methods
6.2 Fluorescent Penetrant Testing (Type I)—Fluorescent
E3022 Practice for Measurement of Emission Characteris-
penetrant testing utilizes penetrants that fluoresce brilliantly
tics and Requirements for LED UV-A Lamps Used in
when excited by UV-A radiation. The sensitivity of fluorescent
Fluorescent Penetrant and Magnetic Particle Testing
penetrants depends on their ability to be retained in the various
2.2 APHA Standard:
size discontinuities during processing, and then to bleed out
429 Method for the Examination of Water and Wastewater
into the developer coating and produce indications that will
2.3 SAE Standards:
fluoresce. Fluorescent indications are many times brighter than
AMS 2644 Inspection Material, Penetrant
their surroundings when viewed under appropriate UV-A
QPL-AMS-2644 Qualified Products of Inspection Materials,
illumination.
Penetrant
6.3 Visible Penetrant Testing (Type II)—Visible penetrant
3. Terminology
testing uses a penetrant that can be seen in visible light. The
3.1 The definitions relating to liquid penetrant testing,
penetrant is usually red, so that resultant indications produce a
which appear in Terminology E1316, shall apply to the terms
definite contrast with the white background of the developer.
used in this practice.
Visible penetrant indications must be viewed under adequate
visible light.
NOTE 1—Throughout this practice, the term blacklight has been
changed to UV-A to conform with the latest terminology in Terminology
7. Materials
E1316. Blacklight can mean a broad range of ultraviolet radiation –
fluorescent penetrant testing uses only UV-A light.
7.1 Liquid Penetrant Testing Materials consist of fluores-
cent or visible penetrants, emulsifiers (oil-base and water-
4. Summary of Practice
base), removers (water and solvent), and developers (dry
4.1 Liquid penetrant may consist of visible or fluorescent
powder, aqueous, and nonaqueous). A family of liquid pen-
material. The liquid penetrant is applied evenly over the
etrant testing materials consists of the applicable penetrant and
surface being examined and allowed to enter open discontinui-
emulsifier, as recommended by the manufacturer. Any liquid
ties. After a suitable dwell time, the excess surface penetrant is
penetrant, remover, and developer listed in QPL-AMS-2644
removed. A developer is applied to draw the entrapped pen-
can be used, regardless of the manufacturer. Penetrants and
etrant out of the discontinuity and stain the developer. The test
emulsifiers shall be from the same family; use of a penetrant
surface is then examined to determine the presence or absence
and emulsifier from different manufacturers or family groups is
of indications.
prohibited.
NOTE 2—The developer may be omitted by agreement between the
NOTE 4—Refer to 9.1 for special requirements for sulfur, halogen, and
contracting parties.
alkali metal content.
NOTE 3—Fluorescent penetrant examination shall not follow a visible
penetrant examination unless the procedure has been qualified in accor-
dance with 10.2, because visible dyes may cause deterioration or
TABLE 1 Classification of Penetrant Testing Types and Methods
quenching of fluorescent dyes.
Type I—Fluorescent Penetrant Testing
4.2 Processing parameters, such as surface precleaning,
Method A—Water-washable (see Practice E1209)
penetrant dwell time, and excess penetrant removal methods,
Method A(W)—Water Washable Penetrant (penetrant containing
are dependent on the specific materials used, the nature of the >20 % water) (see Practice E1209)
Method B—Post-emulsifiable, lipophilic (see Practice E1208)
part under examination (that is, size, shape, surface condition,
Method C—Solvent removable (see Practice E1219)
alloy), and type of discontinuities expected.
Method D—Post-emulsifiable, hydrophilic (see Practice E1210)
Type II—Visible Penetrant Testing
Method A—Water-washable (see Practice E1418)
Available from American Public Health Association, Publication Office, 1015
Method A(W)—Water Washable Penetrant (penetrant containing
Fifteenth Street, NW, Washington, DC 20005.
>20 % water) (see Practice E1418)
Available from Society of Automotive Engineers (SAE), 400 Commonwealth Method C—Solvent removable (see Practice E1220)
Dr., Warrendale, PA 15096-0001, http://www.sae.org.
E165/E165M − 23
NOTE 5—While approved penetrant materials will not adversely affect
7.4 Solvent Removers—Solvent removers function by dis-
common metallic materials, some plastics or rubbers may be swollen or
solving the penetrant, making it possible to wipe the surface
stained by certain penetrants.
clean and free of excess penetrant.
7.2 Penetrants:
7.5 Developers—Developers form a translucent or white
7.2.1 Post-Emulsifiable Penetrants are insoluble in water absorptive coating that aids in bringing the penetrant out of
and cannot be removed with water rinsing alone. They are surface discontinuities through blotting action, thus increasing
the visibility of the indications.
formulated to be selectively removed from the surface using a
7.5.1 Dry Powder Developers—Dry powder developers are
separate emulsifier. Properly applied and given a proper
used as supplied, that is, free-flowing, non-caking powder (see
emulsification time, the emulsifier combines with the excess
8.8.1). Care should be taken not to contaminate the developer
surface penetrant to form a water-washable mixture, which can
with fluorescent penetrant, as the contaminated developer
be rinsed from the surface, leaving the surface free of excessive
specks can appear as penetrant indications.
fluorescent background. Proper emulsification time must be
7.5.2 Aqueous Developers—Aqueous developers are nor-
experimentally established and maintained to ensure that
mally supplied as dry powder particles to be either suspended
over-emulsification does not result in loss of indications.
(water suspendable) or dissolved (water soluble) in water. The
7.2.2 Water-Washable Penetrants are formulated to be di-
concentration, use, and maintenance shall be in accordance
rectly water-washable from the surface of the test part, after a
with manufacturer’s recommendations. Water soluble develop-
suitable penetrant dwell time. Because the emulsifier is formu-
ers shall not be used with Type II penetrants or Type I, Method
lated into the penetrant or the penetrant is water-based (pen-
A or Method A(W) (penetrant containing >20 % water) pen-
etrant containing >20 % water), water-washable penetrants can
etrants.
be washed out of discontinuities if the rinsing step is too long
NOTE 6—Aqueous developers may cause stripping of indications if not
or too vigorous. It is therefore extremely important to exercise
properly applied and controlled. The procedure should be qualified in
proper control in the removal of excess surface penetrant to
accordance with 10.2.
ensure against overwashing. Some penetrants are less resistant
7.5.3 Nonaqueous Wet Developers—Nonaqueous wet devel-
to overwashing than others, so caution should be exercised.
opers are supplied as suspensions of developer particles in a
7.2.3 Solvent-Removable Penetrants are formulated so that
nonaqueous solvent carrier ready for use as supplied.
excess surface penetrant can be removed by wiping until most
Nonaqueous, wet developers are sprayed on to form a thin
of the penetrant has been removed. The remaining traces
coating on the surface of the part when dried. This thin coating
should be removed with the solvent remover (see 8.6.4). To
serves as the developing medium.
prevent removal of penetrant from discontinuities, care should
NOTE 7—This type of developer is intended for application by spray
be taken to avoid the use of excess solvent. Flushing the
only.
surface with solvent to remove the excess penetrant is prohib-
8. Procedure
ited as the penetrant indications could easily be washed away.
8.1 The following processing parameters apply to both
7.3 Emulsifiers:
fluorescent and visible penetrant testing methods.
7.3.1 Lipophilic Emulsifiers are oil-miscible liquids used to
8.2 Temperature Limits—The temperature of the penetrant
emulsify the post-emulsified penetrant on the surface of the
materials and the surface of the part to be processed shall be
part, rendering it water-washable. The individual characteris-
between 40 °F and 125 °F [4 °C and 52 °C] or the procedure
tics of the emulsifier and penetrant, and the geometry/surface
must be qualified at the temperature used as described in 10.2.
roughness of the part material contribute to determining the
8.3 Examination Sequence—Final penetrant examination
emulsification time.
shall be performed after the completion of all operations that
7.3.2 Hydrophilic Emulsifiers are water-miscible liquids
could cause surface-connected discontinuities or operations
used to emulsify the excess post-emulsified penetrant on the
that could expose discontinuities not previously open to the
surface of the part, rendering it water-washable. These water-
surface. Such operations include, but are not limited to,
base emulsifiers (detergent-type removers) are supplied as
grinding, welding, straightening, machining, and heat treating.
concentrates to be diluted with water and used as a dip or spray.
Satisfactory examination results can usually be obtained on
The concentration, use, and maintenance shall be in accordance
surfaces in the as-welded, as-rolled, as-cast, as-forged, or
with manufacturer’s recommendations.
ceramics in the densified condition.
7.3.2.1 Hydrophilic emulsifiers function by displacing the
8.3.1 Surface Treatment—Final penetrant testing may be
excess penetrant film from the surface of the part through
performed prior to treatments that can smear the surface but not
detergent action. The force of the water spray or air/mechanical
by themselves cause surface discontinuities. Such treatments
agitation in an open dip tank provides the scrubbing action
include, but are not limited to, vapor blasting, deburring,
while the detergent displaces the film of penetrant from the part
sanding, buffing, sand blasting, or lapping. Performance of
surface. The individual characteristics of the emulsifier and
final penetrant testing after such surface treatments necessitates
penetrant, and the geometry and surface roughness of the part
that the part(s) be etched to remove smeared metal from the
material contribute to determining the emulsification time. surface prior to testing unless otherwise agreed by the con-
Emulsification concentration shall be monitored weekly using
tracting parties. Note that final penetrant testing shall always
a suitable refractometer. precede surface peening.
E165/E165M − 23
NOTE 8—Sand or shot blasting can close discontinuities, so extreme
should be conducted prior to use. Electrostatic spray applica-
care should be taken to avoid masking discontinuities. Under certain
tion can eliminate excess liquid build-up of penetrant on the
circumstances, however, grit blasting with certain air pressures, mediums,
part, minimize overspray, and minimize the amount of pen-
or both, may be acceptable without subsequent etching when agreed by
etrant entering hollow-cored passages which might serve as
the contracting parties.
penetrant reservoirs, causing severe bleedout problems during
NOTE 9—Surface preparation of structural or electronic ceramics for
penetrant testing by grinding, sand blasting, and etching is not recom-
examination. Aerosol sprays are conveniently portable and
mended because of the potential for damage.
suitable for local application.
8.4 Precleaning—The success of any penetrant testing pro-
NOTE 11—With spray applications, it is important that there be proper
cedure is greatly dependent upon the surrounding surface and
ventilation. This is generally accomplished through the use of a properly
discontinuity being free of any contaminant (solid or liquid)
designed spray booth and exhaust system.
that might interfere with the penetrant process. All parts or
8.5.1 Penetrant Dwell Time—After application, allow ex-
areas of parts to be examined must be clean and dry before the
cess penetrant to drain from the part (care should be taken to
penetrant is applied. If only a section of a part, such as a weld,
prevent pools of penetrant from forming on the part), while
including the heat affected zone is to be examined, all
allowing for proper penetrant dwell time (see Table 2). The
contaminants shall be removed from the area being examined
length of time the penetrant must remain on the part to allow
as defined by the contracting parties. “Clean” is intended to
proper penetration should be as recommended by the penetrant
mean that the surface must be free of rust, scale, welding flux,
manufacturer. Table 2, however, provides a guide for selection
weld spatter, grease, paint, oily films, dirt, and so forth, that
of penetrant dwell times for a variety of materials, forms, and
might interfere with the penetrant process. All of these con-
types of discontinuities. The maximum dwell time shall not
taminants can prevent the penetrant from entering discontinui-
exceed that recommended by the manufacturer; if no maximum
ties (see Annex A1 on Cleaning of Parts and Materials).
is provided, the maximum dwell shall not exceed 2 h unless
8.4.1 Drying after Cleaning—It is essential that the surface
penetrant is reapplied as required.
of parts be thoroughly dry after cleaning, since any liquid
residue will hinder the entrance of the penetrant into disconti-
8.6 Penetrant Removal
nuities. Drying may be accomplished by warming the parts in
8.6.1 Water Washable (Method A and Method A(W)):
drying ovens, with infrared lamps, forced hot air, or exposure
8.6.1.1 Removal of Water Washable Penetrant—After the
to ambient temperature.
required penetrant dwell time, the excess penetrant on the
surface being examined must be removed with water. It can be
NOTE 10—Residues from cleaning processes such as strong alkalies,
pickling solutions, and chromates, in particular, may adversely react with
removed manually with a coarse spray or wiping the part
the penetrant and reduce its sensitivity and performance.
surface with a dampened rag, automatic or semi-automatic
8.5 Penetrant Application—After the part has been cleaned, water-spray equipment, or by water immersion. For immersion
rinsing, parts are completely immersed in the water bath with
dried, and is within the specified temperature range, the
penetrant is applied to the surface to be examined so that the air or mechanical agitation.
entire part or area under examination is completely covered (a) The temperature of the water shall be maintained within
with penetrant. Application methods include dipping, brushing, the range of 50 °F to 100 °F [10 °C to 38 °C].
flooding, or spraying. Small parts are quite often placed in (b) Spray-rinse water pressure shall not exceed 40 psi
[275 kPa]. When hydro-air pressure spray guns are used, the air
suitable baskets and dipped into a tank of penetrant. On larger
parts, and those with complex geometries, penetrant can be pressure should not exceed 25 psi [172 kPa].
applied effectively by brushing or spraying. Both conventional
NOTE 12—Overwashing should be avoided. Excessive washing can
and electrostatic spray guns are effective means of applying
cause penetrant to be washed out of discontinuities; spray nozzles should
liquid penetrants to the part surfaces. Not all penetrant mate-
be kept a minimum of 12 in. [30 cm] from the surface when no physical
rials are suitable for electrostatic spray applications, so tests limitations exist. With fluorescent penetrant methods perform the manual
TABLE 2 Recommended Minimum Dwell Times
A
Dwell Times (minutes)
Type of
Material Form
B C
Discontinuity
Penetrant Developer
Aluminum, magnesium, steel, castings and welds cold shuts, porosity, lack of fusion, 5 10
brass cracks (all forms)
and bronze, titanium and
high-temperature alloys
wrought materials—extrusions, laps, cracks (all forms) 10 10
forgings, plate
Carbide-tipped tools lack of fusion, porosity, cracks 5 10
Plastic all forms cracks 5 10
Glass all forms cracks 5 10
Ceramic all forms cracks, porosity 5 10
A
For temperature range from 50 °F to 125 °F [10 °C to 52 °C]. For temperatures between 40 °F and 50 °F [4.4 °C and 10 °C], recommend a minimum dwell time of 20 min.
B
Maximum penetrant dwell time in accordance with 8.5.1.
C
Development time begins as soon as wet developer coating has dried on surface of parts (recommended minimum). Maximum development time in accordance with
8.8.4.
E165/E165M − 23
rinsing operation under UV-A light so that it can be determined when the
rinsing of the part(s). The water spray pressure shall not exceed
surface penetrant has been adequately removed.
40 psi [275 kPa] when manual or hydro air spray guns are used.
8.6.2 Lipophilic Emulsification (Method B): When hydro-air pressure spray guns are used, the air pressure
shall not exceed 25 psi [172 kPa]. Water free of contaminants
8.6.2.1 Application of Lipophilic Emulsifier—After the re-
quired penetrant dwell time, the excess penetrant on the part that could clog spray nozzles or leave a residue on the part(s)
must be emulsified by immersing or flooding the parts with the
is recommended.
required emulsifier (the emulsifier combines with the excess
8.6.3.3 Application of Emulsifier—The residual surface pen-
surface penetrant and makes the mixture removable by water
etrant on part(s) must be emulsified by immersing the part(s) in
rinsing). Lipophilic emulsifier shall not be applied by spray or
an agitated hydrophilic emulsifier bath or by spraying the
brush and the part or emulsifier shall not be agitated while
part(s) with water/emulsifier solutions thereby rendering the
being immersed. After application of the emulsifier, the parts
remaining residual surface penetrant water-washable for the
shall be drained and positioned in a manner that prevents the
final rinse station. The emulsification time begins as soon as the
emulsifier from pooling on the part(s).
emulsifier is applied. The length of time that the emulsifier is
8.6.2.2 Emulsification Time—The emulsification time be-
allowed to remain on a part and in contact with the penetrant
gins as soon as the emulsifier is applied. The length of time that
is dependent on the type of emulsifier employed and the
the emulsifier is allowed to remain on a part and in contact with
surface roughness. The emulsification time should be deter-
the penetrant is dependent on the type of emulsifier employed
mined experimentally for each specific application. The sur-
and the surface roughness. Nominal emulsification time should
face finish (roughness of the part) is a significant factor in
be as recommended by the manufacturer. The actual emulsifi-
determining the emulsification time necessary for an emulsi-
cation time must be determined experimentally for each
fier. Contact emulsification time should be kept to the least
specific application. The surface finish (roughness) of the part
possible time consistent with an acceptable background and
is a significant factor in the selection of and in the emulsifica-
shall not exceed 2 min.
tion time of an emulsifier. Contact time shall be kept to the
(a) Immersion— For immersion application, parts shall be
minimum time to obtain an acceptable background and shall
completely immersed in the emulsifier bath. The hydrophilic
not exceed 3 min.
emulsifier concentration shall be as recommended by the
8.6.2.3 Post Rinsing—Effective post rinsing of the emulsi-
manufacturer and the bath or part shall be gently agitated by air
fied penetrant from the surface can be accomplished using
or mechanically throughout the cycle. The minimum time to
either manual, semi-automated, or automated water immersion
obtain an acceptable background shall be used, but the dwell
or spray equipment or combinations thereof.
time shall not be more than 2 min unless approved by the
8.6.2.4 Immersion—For immersion post rinsing, parts are
contracting parties.
completely immersed in the water bath with air or mechanical
(b) Spray Application— For spray applications, all part
agitation. The amount of time the part is in the bath should be
surfaces should be evenly and uniformly sprayed with a
the minimum required to remove the emulsified penetrant. In
water/emulsifier solution to effectively emulsify the residual
addition, the temperature range of the water should be 50 °F to
penetrant on part surfaces to render it water-washable. The
100 °F [10 °C to 38 °C]. Any necessary touch-up rinse after an
concentration of the emulsifier for spray application should be
immersion rinse shall meet the requirements of 8.6.2.5.
in accordance with the manufacturer’s recommendations, but it
8.6.2.5 Spray Post Rinsing—Effective post rinsing follow-
shall not exceed 5 %. The water spray pressure should be less
ing emulsification can also be accomplished by either manual
than 40 psi [275 kpa]. The nozzle shall produce a coarse spray
or automatic water spray rinsing. The water temperature shall
pattern similar to that used in rinsing. Contact with the
be between 50 °F and 100 °F [10 °C and 38 °C]. The water
emulsifier shall be kept to the minimum time to obtain an
spray pressure shall not exceed 40 psi [275 kPa] when manual
acceptable background and shall not exceed 2 min. The water
spray guns are used. When hydro-air pressure spray guns are
temperature shall be maintained between 50 °F and 100 °F
used, the air pressure should not exceed 25 psi [172 kPa].
[10 °C and 38 °C].
8.6.2.6 Rinse Effectiveness—If the emulsification and final
8.6.3.4 Post-Rinsing of Hydrophilic Emulsified
rinse step is not effective, as evidenced by excessive residual
surface penetrant after emulsification and rinsing; thoroughly Penetrants—Effective post-rinsing of emulsified penetrant
reclean and completely reprocess the part. from the surface can be accomplished using either manual or
automated water spray, water immersion, or combinations
8.6.3 Hydrophilic Emulsification (Method D):
thereof. The total rinse time shall not exceed 2 min regardless
8.6.3.1 Application of Hydrophilic Remover—Following the
of the number of rinse methods used.
required penetrant dwell time, the parts may be prerinsed with
(a) Immersion Post-Rinsing— If an agitated immersion
water prior to the application of hydrophilic emulsifier. This
rinse is used, the amount of time the part(s) is (are) in the bath
prerinse allows for the removal of excess surface penetrant
shall be the minimum required to remove the emulsified
from the parts prior to emulsification so as to minimize
penetrant contamination in the hydrophilic emulsifier bath, penetrant and shall not exceed 2 min. In addition, the tempera-
thereby extending its life. It is not necessary to prerinse a part ture range of the water shall be within 50 °F and 100 °F [10 °C
if a spray application of emulsifier is used.
and 38 °C]. Be aware that a touch-up rinse may be necessary
after immersion rinse, but the total wash time still shall not
8.6.3.2 Prerinsing Controls—Effective prerinsing is accom-
plished by manual, semi-automated, or automated water spray exceed 2 min.
E165/E165M − 23
(b) Spray Post-Rinsing— Effective post-rinsing following tapping the part, or by blowing with low-pressure dry, clean,
emulsification can also be accomplished by manual, semi- compressed air not exceeding 5 psi [34 kPa]. Dry developers
automatic, or automatic water spray. The water spray pressure shall not be used with Type II penetrant.
shall not exceed 40 psi [275 kPa] when manual or hydro-air 8.8.2 Aqueous Developers (Forms B and C)—Water soluble
spray guns are used. When hydro-air pressure spray guns are developers (Form B) are prohibited for use with Type II
used, the air pressure shall not exceed 25 psi [172 kPa]. The penetrants or Type I, Method A penetrants. Water suspendable
water temperature shall be between 50 °F and 100 °F [10 °C developers (Form C) can be used with both Type I and Type II
and 38 °C]. The spray rinse time shall be less than 2 min, penetrants. Aqueous developers shall be applied to the part
unless otherwise specified. immediately after the excess penetrant has been removed and
8.6.3.5 Rinse Effectiveness—If the emulsification and final prior to drying. Aqueous developers shall be prepared and
rinse steps are not effective, as evidenced by excessive residual maintained in accordance with the manufacturer’s instructions
surface penetrant after emulsification and rinsing, thoroughly and applied in such a manner as to ensure complete, even, part
reclean, and completely reprocess the part. coverage. Aqueous developers may be applied by spraying,
8.6.4 Removal of Solvent-Removable Penetrant (Method flowing, or immersing the part in a prepared developer bath.
C)—After the required penetrant dwell time, the excess pen- Immerse the parts only long enough to coat all of the part
etrant is removed by wiping with a dry, clean, lint-free surfaces with the developer since indications may leach out if
cloth/towel. Then use a clean lint-free cloth/towel lightly the parts are left in the bath too long. After the parts are
moistened with solvent to remove the remaining traces of removed from the developer bath, allow the parts to drain.
surface penetrant as determined by examination under UV-A Drain all excess developer from recesses and trapped sections
lighting for fluorescent methods and visible light for visible to eliminate pooling of developer, which can obscure discon-
methods. Perform a final wipe using a dry, clean cloth to tinuities. Dry the parts in accordance with 8.7. The dried
remove any solvent residues that might remain. Gentle wiping developer coating appears as a translucent or white coating on
must be used to avoid removing penetrant from any disconti- the part.
nuity. On smooth surfaces, an alternate method of removal can 8.8.3 Nonaqueous Wet Developers (Forms D and E)—After
be done by wiping with a clean, dry cloth. Flushing the surface the excess penetrant has been removed and the surface has
with solvent following the application of the penetrant and been dried, apply nonaqueous wet developer by spraying in
prior to developing is prohibited. such a manner as to ensure complete part coverage with a thin,
even film of developer. The developer shall be applied in a
8.7 Drying—Regardless of the type and method of penetrant
manner appropriate to the type of penetrant being used. For
used, drying the surface of the part(s) is necessary prior to
visible dye, the developer must be applied thickly enough to
applying dry or nonaqueous developers or following the
provide a contrasting background. For fluorescent dye, the
application of the aqueous developer. Drying time will vary
developer must be applied thinly to produce a translucent
with the type of drying used and the size, nature, geometry, and
covering. Dipping or flooding parts with nonaqueous develop-
number of parts being processed.
ers is prohibited, because the solvent action of these types of
8.7.1 Drying Parameters—Components shall be air dried at
developers can flush or dissolve the penetrant from within the
room temperature or in a drying oven. Room temperature
discontinuities.
drying can be aided by the use of fans. Oven temperatures shall
not exceed 160 °F [71 °C]. Drying time shall only be that NOTE 13—The vapors from the volatile solvent carrier in the developer
may be hazardous. Proper ventilation should be provided at all times, but
necessary to adequately dry the part. Components shall be
especially when the developer is applied inside a closed area.
removed from the oven after drying. Components should not
be placed in the oven with pooled water or pooled aqueous 8.8.4 Developing Time—The length of time the developer is
solutions/suspensions. to remain on the part prior to examination shall be not less than
10 min. Developing time begins immediately after the appli-
8.8 Developer Application—There are various modes of
cation of dry powder developer or as soon as the wet (aqueous
effective application of the various types of developers such as
or nonaqueous) developer coating is dry (that is, the water or
dusting, immersing, flooding, or spraying. The developer form,
solvent carrier has evaporated to dryness). The maximum
the part size, configuration, and surface roughness will influ-
permitted developing times shall be 4 h for dry powder
ence the choice of developer application.
developer (Form A), 2 h for aqueous developer (Forms B and
8.8.1 Dry Powder Developer (Form A)—Dry powder devel-
C), and 1 h for nonaqueous developer (Forms D and E).
opers shall be applied after the part is dry in such a manner as
8.9 Examination—After the applicable development time,
to ensure complete coverage of the area of interest. Parts can be
immersed in a container of dry developer or in a fluid bed of perform examination of the parts under visible light or UV-A
radiation as appropriate. It may be helpful to observe the bleed
dry developer. They can also be dusted with the powder
developer through a hand powder bulb or a conventional or out during the development time as an aid in interpreting
indications. LED UV-A sources, with the exception of Bore-
electrostatic powder gun. It is common and effective to apply
dry powder in an enclosed dust chamber, which creates an scope LED UV-A sources, shall meet the requirements of
Practice E3022.
effective and controlled dust cloud. Other means suited to the
size and geometry of the specimen may be used, provided the 8.9.1 UV-A Radiance Examination—Examine parts tested
powder is applied evenly over the entire surface being exam- with Type I fluorescent penetrant under UV-A irradiance in a
ined. Excess developer powder may be removed by shaking or darkened area. Ambient visible light shall not exceed 2 fc
E165/E165M − 23
[21.5 lx]. The ambient light measurement shall be made with a 8.10 Post Cleaning—Post cleaning is necessary when re-
suitable visible light sensor at the examination surface, with sidual penetrant or developer could interfere with subsequent
visible light sources off. processing or with service requirements. It is particularly
important where residual penetrant testing materials might
NOTE 14—Because the fluorescent constituents in the penetrant will
combine with other factors in service to produce corrosion and
eventually fade with direct exposure to UV-A sources, direct exposure of
prior to vapor degreasing or heat treating the part as these
the part under test to UV-A radiation should be minimized when not
removing excess penetrant or evaluating indications. processes can bake the developer onto the part. A suitable
technique, such as a simple water rinse, water spray, machine
8.9.1.1 UV-A Radiance Level Control—UV-A sources shall
wash, solvent soak, or ultrasonic cleaning may be employed
provide a minimum irradiance of 1000 μW/cm , at a distance
(see Annex A1 for further information on post cleaning). It is
of 15 in. [38.1 cm]. The intensity shall be checked daily to
recommended that if developer removal is necessary, it should
ensure the required output (see Guide E2297 for more infor-
be carried out as promptly as possible after examination so that
mation). Reflectors and filters shall also be checked daily for
the developer does not adhere to the part.
cleanliness and integrity. Cracked or broken ultraviolet filters
shall be replaced immediately. LED UV-A sources used to
9. Special Requirements
examine parts shall be checked daily (or before use if not used
daily) to ensure that all elements are operational. If any diode
9.1 Impurities:
element is not operational the condition shall be corrected or
9.1.1 When using penetrant materials on austenitic stainless
the unit replaced. The operational check should be performed
steels, titanium, nickel-base, or other high-temperature alloys,
by placing a white sheet of paper over the lamp and then
the need to restrict certain impurities such as sulfur, halogens,
viewing the transmitted light from each diode. LED UV-A
and alkali metals must be considered. These impurities may
sources are at full intensity at power-on, and the intensity may
cause embrittlement or corrosion, particularly at elevated
decrease as the lamp stabilizes.
temperatures. Any such evaluation shall also include consider-
ation of the form in which the impurities are present. Some
NOTE 15—Certain high-intensity UV-A sources may emit unacceptable
amounts of visible light, which can cause fluorescent indications to penetrant materials contain significant amounts of these impu-
disappear. Care should be taken to only use bulbs suitable for fluorescent
rities in the form of volatile organic solvents that normally
penetrant examination purposes.
evaporate quickly and usually do not cause problems. Other
8.9.1.2 UV-A Source Warm-Up—Unless otherwise specified materials may contain impurities, which are not volatile and
by the manufacturer, allow the UV-A source to warm up for a may react with the part, particularly in the presence of moisture
minimum of 10 min prior to use or measurement of its or elevated temperatures.
intensity. LED UV-A sources do not require warmup.
9.1.2 Because volatile solvents leave the surface quickly
8.9.1.3 Visual Adaptation—Personnel examining parts after without reaction under normal examination procedures, pen-
penetrant processing shall be in the darkened area for at least
etrant materials are normally subjected to an evaporation
1 min before examining parts. Longer times may be necessary
procedure to remove the solvents before the materials are
under some circumstances. Photochromic or tinted lenses shall
analyzed for impurities. The residue from this procedure is
not be worn during the processing and examination of parts.
then analyzed in accordance with Test Method D1552 or Test
Method D129 decomposition followed by Test Method E516,
8.9.2 Visible Light Examination—Examine parts tested with
Type II visible penetrant under either natural or artificial visible Method B (Turbidimetric Method) for sulfur. The residue may
light. Proper illumination is required to ensure adequate also be analyzed by Annex A2 on Methods for Measuring Total
sensitivity of the examination. A minimum light intensity at the Chlorine Content in Combustible Liquid Penetrant Materials
examination surface of 100 fc [1076 lx] is required (see Guide (for halogens other than fluorine) and Annex A3 on Method for
E2297 for more information). Measuring Total Fluorine Content in Combustible Liquid
Penetration Materials (for fluorine). An alternative procedure,
8.9.3 Housekeeping—Keep the examination area free of
Annex A4 on Determination of Anions by Ion
interfering debris, including fluorescent residues and objects.
Chromatography, provides a single instrumental technique for
8.9.4 Indication Verification—If allowed by the specific
rapid sequential measurement of common anions such as
procedure, indications may be evaluated by wiping the indica-
chloride, fluoride, and sulfate (see Test Method D4327). Alkali
tion with a solvent-dampened swab, brush, or lint-free cloth
metals in the residue are determined by flame photometry,
allowing the area to dry, and redeveloping the area. Redevel-
atomic absorption spectrophotometry, or ion chromatography
opment time shall be a minimum of 10 min, except nonaqueous
(see Test Method D6919).
redevelopment time should be a minimum of 3 min. If the
indication does not reappear, the original indication may be
NOTE 16—Some current standards require impurity levels of sulfur and
considered false. This procedure may be performed up to two
halogens to not exceed 1 % of any one suspect element. This level,
times for any given original indication. Unless prohibited by
however, may be unacceptable for some applications, so the actual
maximum acceptable impurity level must be decided between supplier and
the Purchaser, Specification D770 isopropyl alcohol and Speci-
user on a case by case basis.
fication D329 acetone are commonly accepted solvents.
8.9.5 Evaluation—All indications found during examination 9.2 Elevated-Temperature or Low-Temperature
shall be evaluated in accordance with acceptance criteria as Examination—Where penetrant examination is performed on
specified. Reference Photographs of indications are noted in parts that must be maintained at elevated or lowered tempera-
E433. ture during testing, special penetrant materials and processing
E165/E165M − 23
techniques may be required. Such examination requires quali- it displays the characteristics of the discontinuities encountered
fication in accordance with 10.2 and the manufacturer’s rec- in product examination.
ommendations shall be observed.
10.2.1 Requalification of the procedure to be used may be
required when a change is made to the procedure or when
10. Qualification and Requalification
material substitution is made.
10.1 Personnel Qualification—If specified in the contractual
10.3 Nondestructive Testing Agency Qualification—If a
agreement, personnel performing examinations to this practice
nondestructive testing agency as described in Practice E543 is
shall be qualified in accordance with a nationally or interna-
used to perform the examination, the agency should meet the
tionally recognized NDT personnel qualification practice or
requirements of Practice E543.
standard and certified by the employer or certifying agency, as
applicable. The practice or standard used shall be identified in 10.4 Requalification may be required when a change or
substitution is made in the type of penetrant materials or in the
the contractual agreement between the using parties.
procedure (see 10.2).
10.2 Procedure Qualification—Qualification of procedures
using times, conditions, or materials differing from those
11. Keywords
specified in this general practice or for new materials may be
performed by any of several methods and should be agreed 11.1 fluorescent liquid penetrant examination; hydrophilic
upon by the contracting parties. A test piece containing one or emulsification; lipophilic emulsification; liquid penetrant ex-
amination; nondestructive
...