Pengenalan NDT.pptx

INTRODUCTION TO
NON DESTRUCTIVE TESTING (NDT)
Eka Prasetya Siregar
ASNT NDE (RT,UT, MT, PT, VT) Level III
ASNT ID : 190523

Curriculum Vitae
Nama : Eka Prasetya Siregar
Tempat/Tanggal Lahir : Medan, 20 – 09 – 1982
Adress : Perumahan Pemedas
Permai Blok E No. 27 Kel. Teluk Pemedas, Kec

What is NonDestructive Testing ?
A general definition of NonDestructive Testing (NDT) is an examination,
test, or evaluation performed on any type of test object without changing or
altering that object in any way, in order to determine the absence or
presence of conditions or discontinuities that may have an effect on the
usefulness or serviceability of that object

Nondestructive tests may also be conducted to measure other test object
characteristics, such as size; dimension; configuration; or structure,
including alloy content, hardness, grain size, etc.
The simplest of all definitions is basically an examination that is
performed on an object of any type, size, shape or material to determine
the presence or absence of discontinuities

Nondestructive testing (NDT) is a profession that blends quality assurance
and materials science.
NDT is used to inspect and evaluate materials, components, or assemblies
without destroying their serviceability.
Through a set of test methods, technicians identify cracks, voids,
inclusions, and weld discontinuities, as well as identify misassembled
subcomponents.

NDT is used to ensure product integrity and reliability, control
manufacturing processes, lower production costs, and maintain a uniform
quality level. Without it, the safety and reliability of components can be
seriously jeopardized. This makes NDT crucial to help prevent catastrophic
failures such as airplane and locomotive crashes, pipeline leaks and
explosions, nuclear reactor failures, and ships sinking.

Industries that utilize NDT include:
 Aerospace
 Manufacturing
 Energy (oil and gas, nuclear)
 Chemical
 Infrastructure (Bridges, Highways, Buildings)
 Transportation (Automotive, Railways)
 Maritime
 Construction

NDT Method :
1. Acoustic Emission Testing (AE)
2. Electromagnetic Testing (ET)
3. Ground Penetrating Radar (GPR)
4. Guided Wave (GW)
5. Thermal/Infrared Testing (IR)
6. Laser Testing (LM)
7. Leak Testing (LT)
8. Magnetic Flux Leakage (MFL)
9. Magnetic Particle Testing (MT)
10. Microwave Testing (MW)
11. Neutron Radiographic Testing (NR)
12. Liquid Penetrant Testing (PT)
13. Radiographic Testing (RT)
14. Ultrasonic Testing (UT)
15. Vibration Analysis (VA)
16. Visual Testing (VT)

Nondestructive evaluation can be conveniently divided into seven distinct
areas:
1. Flaw detection and evaluation
2. Leak detection and evaluation
3. Metrology (measurement of dimension) and evaluation
4. Location determination and evaluation
5. Structure or microstructure characterization
6. Estimation of mechanical and physical properties
7. Stress (strain) and dynamic response determination

Flaw Detection and Evaluation
Flaw detection is usually considered the most important aspect of NDT.
There are many conceivable approaches to selecting NDT methods. One
approach is to consider that there are only six primary factors involved in
selecting an NDT
method(s):
1. The reason(s) for performing the NDT
2. The type(s) of flaws of interest in the object
3. The size and orientation of flaw that is rejectable
4. The anticipated location of the flaws of interest in the object
5. The size and shape of the object
6. The characteristics of the material to be evaluated

Flaw Detection and Evaluation
The most important question to be answered before an NDE method can
be selected is,
What is the reason(s) for choosing an NDE procedure?
There are a number of possible reasons, such as:
1. Determining whether an object is acceptable after each fabrication
step; this can be called in-process NDE or in-process inspection
2. Determining whether an object is acceptable for final use; this can be
called final NDE or final inspection
3. Determining whether an existing object already in use is acceptable
for continued use; this can be called in-service NDE or in-service
inspection

CONCERNS REGARDING NDT
There are certain misconceptions and misunderstandings that should be
addressed regarding nondestructive testing.
1. One widespread misconception is that the use of nondestructive
testing will ensure, to a degree, that a part will not fail or
malfunction. This is not necessarily true
2. Another misconception involves the nature and characteristics of the
part or object being examined.
3. At times, the erroneous assumption is made that if a part has been
examined using an NDT method or technique, there is some magical
transformation that guarantees that the part is sound.
4. Another widespread misunderstanding is related to the personnel
performing these examinations. Since NDT is a “hands-on”
technology, the qualifications of the examination personnel become a
very significant factor

CONDITIONS FOR EFFECTIVE NONDESTRUCTIVE TESTING
There are many variables associated with nondestructive testing that
must be controlled and optimized. The following are major factors that
must be considered in order for a nondestructive test to be effective.
1. The product must be “Testable” and “Accessible”
2. Approved procedures must be followed
3. Equipment is operating properly
4. Documentation is complete
5. Personnel are qualified

Radiographic testing (RT), involves exposing a test object to penetrating
radiation so that the radiation passes through the object being inspected and
a recording medium placed against the opposite side of that object

Radiography Testing is the general term given to material inspection methods
that are based on the differential absorption of penetrating radiation--either
electromagnetic radiation of very short wavelength or particulate radiation--
by the part or test piece (object) being inspected. Because of differences in
density and variations in thickness of the part or differences in absorption
characteristics caused by variations in composition, different portions of a test
piece absorb different amounts of penetrating radiation. These variations in
the absorption of the penetrating radiation can be monitored by detecting the
unabsorbed radiation that passes through the test piece

Radiographic testing usually requires EXPOSING FILM to X or gamma rays that
have penetrated a specimen, PROCESSING the exposed film, and
INTERPRETING the resultant radiograph.
ADVANTAGES OF RADIOGRAPHY (RT)
1. Can be used with most materials.
2. Provides a permanent visual image.
3. Reveals the internal nature of material.
4. Discloses fabrication errors.
5. Reveals structural discontinuities.
LIMITATIONS OF RT
1. Impracticable to use on specimens of complex geometry.
2. The specimen must lend itself to two-side accessibility.
3. Laminar type discontinuities are often undetected by RT.
4. Safety considerations imposed by X and gamma rays must be considered.
5. It is a relatively expensive means of nondestructive testing.

PRINCIPLES OF RADIOGRAPHY
Three basic elements of radiography
include
1. a radiation source,
2. the testpiece or object being
evaluated, and
3. a sensing material

RADIATION SOURCES
Two types of electromagnetic radiation are used in radiographic inspection :
x-rays and -rays, because of their relatively short wavelengths (high
energies), have the capability of penetrating opaque materials to reveal
internal flaws
X-rays and -rays are physically indistinguishable; they differ only in the
manner in which they are produced. X-rays result from the interaction
between a rapidly moving stream of electrons and atoms in a solid target
material, while -rays are emitted during the radioactive decay of unstable
atomic nuclei.

RADIATION SOURCES
-rays
X-rays

INTERACTION OF RADIATION WITH
MATERIAL
Gamma ray ENERGIES are determined by the TYPE OF SOURCE.
Gamma ray INTENSITY (number of rays) is determined by the ACTIVITY, or
curie strength of the isotope.
X-ray ENERGIES are determined by the VOLTAGE applied to the X-ray tube.
X-ray INTENSITY is determined by the CURRENT (Milliampere) applied to the
X-ray tube filament.
X-rays and gamma rays include a wide range of energies; therefore, they vary
in their penetrating abilities.
LOW ENERGY, or “SOFT”, X-rays CANNOT PENETRATE AS DEEPLY AS HIGH
ENERGY “HARD” X-rays.

MATERIAL
X-rays and gamma rays include a wide range of energies; therefore, they vary
in their penetrating abilities.
LOW ENERGY, or “SOFT”, X-rays CANNOT PENETRATE AS DEEPLY AS HIGH
ENERGY “HARD” X-rays.

MATERIAL
Radiation is Absorbed and Scattered by Material
There are three common absorption processes that influence the amount
of radiation that passes through a part.
The three absorption processes are:
1. PHOTOELECTRIC EFFECT occurs primarily with low-energy X-ray
photons (up to 0.3 MeV). In the photoelectric effect, the electron
ABSORBS ALL OF THE PHOTON’S ENERGY.
2. COMPTON EFFECT occurs with medium-energy X-ray photon (about 0.3
to 3.0 MeV) interact with high atomic number materials. The PHOTON
IS WEAKENED in this process as SOME OF ITS ENERGY IS ABSORBED in
removing an electron, and a LOWER-ENERGY SCATTERED PHOTON is
resulted.
3. PAIR PRODUCTION occurs only with high-energy photons of 3.0 MeV or
more.

MATERIAL

FILM RADIOGRAPHY
The emulsion coatings are covered by
two separate anti stress layers (3 + 4). To
achieve a rugged surface, the top layer
has received the matting agent.
THERE IS NO PARTIAL EXPOSURE OF A
SILVER GRAIN.
Areas on the film of light and dark simply
represents the number of grains exposed
in that area.
a transparent polyester or cellulose acetate is used as the base of radiographic film.
most radiographic film has a sensitive emulsion on both sides of the acetate base.
the outer layer of the film is a layer of gelatin which protects the emulsion layer from
scratches.
the soft emulsion layer (image layer) has suspended in it microscopic grains of silver
bromide.
these silver bromide grains when exposed to light or radiation would become visible
and turn the film black.

FILM RADIOGRAPHY
The emulsion coatings are covered by
two separate anti stress layers (3 + 4). To
achieve a rugged surface, the top layer
has received the matting agent.
THERE IS NO PARTIAL EXPOSURE OF A
SILVER GRAIN.
Areas on the film of light and dark simply
represents the number of grains exposed
in that area.
However, the IMAGE IS “LATENT” and no visible change in film would be noticeable
UNTIL AFTER DEVELOPMENT.
A LATENT IMAGE IS FORMED on the film WHEN some of the SILVER BROMIDE GRAINS
ARE IONIZED by the X-ray, gamma ray, or light.
The LATENT IMAGE IS MADE VISIBLE by developing the film where the ionized SILVER
BROMIDE GRAINS are REDUCED TO BLACK METALLIC SILVER.
Each Individual grain that has been exposed then helps form the image on the film.

FILM RADIOGRAPHY
MORE EXPOSED GRAINS gives a DARKER IMAGE.
The DIFFERENCE in radiographic films is mainly DUE TO the various in GRAIN SIZES.
(even the largest of which are microscopic) Because “GRAININESS” (visible clumps of
grains) is present in all film, THE LARGER THE GRAIN THE LESS SHARP THE IMAGE.
The LARGER GRAINED FILMS expose more silver to the rays per grain, therefore, the
IMAGE IS EXPOSED MORE QUICKLY. The fine DETAIL however is LACKING with coarse–
grained film.

PROCESS RT
1. RADIATION SOURCE
2. MATERIAL
3. FILM RT
4. INTERPRETATION

FILM PROCESSING
Developing
Stopping (rinsing)
Fixing
Washing

DUTIES OF A RADIOGRAPHIC
INTERPRETER
1. Mask off any unwanted light on the viewer
2. View radiographs under subdued background light
3. Ensure, as far as reasonably practicable, each radiograph is correctly identified to
the weld it represents
4. Ensure that the weld locations are identified, e.g. has the correct number tape
been used
5. Assess the quality of the radiograph
a) Measure radiographic density
b) Calculate IQI Sensitivity – also ensure the
IQI’s are of the correct type and correctly
positioned.
c) Assess radiographic Contrast
d) Assess definition/graininess
e) Do artifacts interfere with interpretation

DUTIES OF A RADIOGRAPHIC
INTERPRETER
6. Check the radiograph to determine if any obstruction between the source of
radiation and the film interferes with interpretation, e.g. lead numbers
7. Identify the type of weld if possible – normally already known
8. Check the parent material on the radiography for arch strikes, hard stamping, etc,
when applicable
9. Check the weld on the radiograph for defects, stating type and region
10. State action to be taken, e.g. accept the
radiograph and weld, reshoot, repair, remove the
entire weld, visual check, grind and investigate.

RADIOGRAPHIC QUALITY VARIABLES

• Sensitivity: the smallest discernible detail and/or contrast change (e.g., IQI hole
or wire) in a radiographic image.
• Contrast : The comparison between film densities for different areas of the
radiograph
• Definition : The line of demarcation between areas of different densities
If the image is clear and sharp the radiograph is said to have GOOD
Definition
Contrast

2 3 2 5
Subject Contrast
DIFFERENT
TRANSMITTED RADIATION INTENSITY

Source Size
A B

Source to Object Distance (SOD)

Object to Film Distance (OFD)

Screen to Film Contact
-
Poor Definition
-
Screen
Film

IMAGE QUALITY INDICATOR
SET A SET B SET C SET D
0,0032 0,010 0,032 0,1
0,004 0,013 0,04 0,126
0,005 0,016 0,05 0,16
0,0063 0,020 0,063 0,2
0,008 0,025 0,08 0,25
0,010 0,032 0,1 0,32

IMAGE QUALITY INDICATOR
Group Material
03 Magnesium
02 Aluminium
01 Titanium
1 Carbon steel
2 Aluminium bronze
3 Inconel
4 Monel
5 Tin bronze

Radiographic Techniques
 Single Wall Single Image (SWSI)
• film inside, source outside
 Single Wall Single Image (SWSI) panoramic
• film outside, source inside (internal exposure)
 Double Wall Single Image (DWSI)
• film outside, source outside (external exposure)
 Double Wall Double Image (DWDI)
• film outside, source outside (elliptical exposure)

Single Wall Single Image

Double Wall Single Image

Double Wall Double Image

INTRODUCTION TO THE BASIC CONCEPT
The most common technique used in ultrasonic testing is the pulse echo
technique.
This makes use the phenomenon the sound waves travel in straight lines and
are reflected by an obstacle placed in their path.
We can pass sound wave through solid materials and receive echoes from
the back wall of the material. If a defect is present in the material then the
sound energy would be reflected back from it and give an echo earlier that
that from the back wall because the sound has not travelled as far.
The strength or amplitude of this echo will be an indication of the size of the
defect and the distance travelled by the sound will tell us its depth.

Sound energy is transmitted from the probe into the test specimen at
surface “A” producing an echo at A1. some of the sound is reflected by the
defect at “B” and the resulting echo appears at B1. the remainder of the
sound continues through the specimen to be reflected by the back wall “C”,
the echo from the back wall appearing at C1
If the screen is calibrated from a test block of known thickness then the
depth of the defect from the specimen surface (A to B) can be read off the

The nature of sound
Sound is caused by mechanical vibrations
In order for sound to pass there must be a medium that will support
mechanical vibrations therefore SOUND CANNOT TRAVEL IN A VACUM.
The particle (molecules) within the medium vibrate passing on energy from
one to another giving the effect of sound movement through the material.

The nature of sound
The ability to support sound depends on the elasticity and density of the
medium.
Since these properties will vary, from one material to another, some material
will pass sound more easily than others.

The nature of sound
Sound follows a waveform:

THE PROPAGATION OF SOUND
The Ultrasonic Beam
The Dead Zone
Seen on the CRT as an extension of the initial pulse, the dead zone is the ringing time of
the crystal and is minimized by the damping medium behind the crystal.
The dead zone can be seen at the start of the trace on a CRT displaying A-scan, but only
with single crystal probes.
The dead zone increases when the probe frequency decreases

The Ultrasonic Beam
The near or Fresnel zone
In this region of the beam, the sound intensity is variable owing to wave interference.
Therefor, reflectors or flaws lying in this zone may appear smaller or larger than their
actual size. The signal heights displayed on the CRT are unpredictable so it is desirable
to keep the near zone length to minimum.
Near Zone Length (mm) =
It can be seen from the formula that the near zone can be decreased by decreasing
the crystal diameter or decreasing the probe frequency.
The far or Fraunhoffer zone
In the far zone the beam diverges resulting in a decay in sound intensity as the
distance from the crystal is increased, just as a beam of light from a torch gets
weaker the further it travels.
K factor, 0% intensity, edge = 1,22; 50% edge = 0,56, 10% edge = 1,08

From the beam spread formula, that the beam divergence can be decreased by
increasing the crystal diameter or by increasing the probe frequency.
Unfortunately this will extend the length of the near zone. So in probe design there is
a compromise to obtain a minimal beam spread and a short near zone

In the far zone the amplitudes of reflected sound from large and small reflectors
follow different laws
LARGER REFLECTORS (larger than the width of the ultrasonic beam) follow the
INVERSE LAW – the amplitude is inversely proportional to the distance,
SMALL REFLECTORS (Smaller than the width of the beam) follow the INVERSE SQUARE
LAW – The amplitude is inversely proportional to the square of the distance.

A2=
𝐷1
𝐷2
𝑥 𝐴1 A2=
(𝐷1)2
(𝐷2)2 𝑥 𝐴1

MODE OF PROPAGATION
Longitudinal or Compression Waves

MODE OF PROPAGATION
Shear or Transverse Waves

MODE OF PROPAGATION
Surface or Rayleigh Waves
Plate or Lamb Waves

ACOUSTIC IMPEDANCE
Acoustic Impedance (Z) is the resistance of a material to the passage of ultrasound.
It is the product of the material density () and sound velocity (c).
Z =  c
The amount of ultrasound passing from one material to another depends on this
difference between the two materials. This difference is expressed as the acoustic
impedance ratio.
The amount of energy reflected at an interface can be calculated with the following
formula

ACOUSTIC IMPEDANCE
Acoustic Impedance (Z) is the resistance of a material to the passage of ultrasound.
It is the product of the material density () and sound velocity (c).
Z =  c
The amount of ultrasound passing from one material to another depends on this
difference between the two materials. This difference is expressed as the acoustic
impedance ratio.
The amount of energy reflected at an interface can be calculated with the following
formula
It can be seen from the formula that:
HIGH ACOUSTIC IMPEDANCE RATIO (e.g. 20 : 1) = More Reflected Energy
LOW ACOUSTIC IMPEDANCE RATIO (e.g. 1:1) = More Transmitted Energy

COUPLANT
Because of the very high acoustic impedance ration of air to a solid material almost
100% of the energy is reflected at an interface between them.
Common Couplants are : Water, Oil, Grease dan glycerine
NB.
1. Viscosity of the couplant may be a consideration, ideally rough surface require a
more viscous couplant to effectively fill the air gaps more uniformly
2. Whatever couplatn is used for calibration/setting the search sensitivity, this must
be used throughout the subsequent inspection

ATTENUATION
Attenuation is defined as the loss in intensity of the ultrasonic beam as it passes
through a material and is dependent upon the physical properties of the material.
Scatter
This is the major cause of attenuation and is the redirection of the sound waves
reflecting off grain boundaries, porosity and non metallic inclusions, etc., and
becomes more apparent on the inspection when the size of grains become ≥ 1/10 of
the wavelength of the search unit being employed.
Absorption
As the sound travels through a material a small amount of the energy is used up by
the interaction of the particles, as the vibrate, causing friction which is dissipated as
heat

SOUND GENERATION
The Piezo electric effect
This is defined as the property of certain crystals to convert electrical energy into
mechanical energy and vice versa. These crystals maybe naturally occurring
artificially manufactured or grown in solution

SOUND GENERATION
Piezo Electric Crystals
These crystals may be X-cut or Y-cut depending on which orientation they are sliced
from the crystal material.
The crystal used in ultrasonic testing are X-cut due to the mode of vibration they
produce compressional. This means that crystal is sliced with its major plane (the
crystal face) perpendicular to the X axis of the crystal material.

SOUND GENERATION
Reflection
Angle of Incidence = Angle of Reflection
Refraction
This describe what happens to an ultrasonic beam when it passes from one medium to
another where the two media have different acoustical velocities, e.g. from Perspex to
steel. The beam changes direction or angle in the vertical plane

MODE CONVERSION
A change in wave form from one to another, together with the accompanying
change in velocity, due to reflection or refraction at an interface

MODE CONVERSION
Critical Angles

EQUIPMENT
The Ultrasonic Flaw Detector (Flow Diagram of a Typical A Scan Flaw Detector

EQUIPMENT
Transducer Selection

TESTING TECHNIQUES
Ultrasonic testing is a very versatile inspection method, and inspections can be
accomplished in a number of different ways.
Ultrasonic inspection techniques are commonly divided into three primary
classifications.
1. Pulse-echo and Through Transmission (Relates to -whether reflected or
transmitted energy is used)
2. Normal Beam and Angle Beam(Based on the angle, the sound energy
enters the test article)
3. Contact and Immersion(Based on the method of coupling of transducer to
test article)

TESTING TECHNIQUES
PULSE ECHO
 It consists of pulser/receiver transducer, and display device.
 In this technique, a transducer sends the pulse of energy, in the material,
And reflected energy (echo) is received by the same transducer.
 Reflection occurs from back surface and the discontinuity.
 The amount of reflected sound energy is displayed on the screen on Y-axis
and time on X-axis, which provides the inspector information about the size
and the location--of features that reflect the sound.

TESTING TECHNIQUES
Digital display showing signal generated
from sound reflecting off back surface.
Digital display showing the presence of a
reflector midway through material, with
lower amplitude back surface reflector
The pulse-echo technique allows testing when access to only one side of
the material is possible, and it determines the location of reflectors
precisely.
PULSE ECHO

TESTING TECHNIQUES
THROUGH – TRANSMISSION TECHNIQUE
Two transducers--located on opposing sides of the
test specimen are used. One transducer acts as a
transmitter, the other as a receiver.
•Discontinuities in the sound path will result in a
partial or total loss of sound being transmitted
and be indicated by a decrease in the received
signal amplitude.
Advantage
Through transmission is useful in detecting
discontinuities that are not good reflectors. -
Limitation
•It does not provide depth information.

TESTING TECHNIQUES
THROUGH – TRANSMISSION TECHNIQUE
Digital display showing
received sound through
material thickness.
Digital display showing loss of
received signal due to
presence of a discontinuity in
the sound field.

TESTING TECHNIQUES
NORMAL AND ANGLE BEAM
In normal beam technique, the sound beam is
introduced into the test article at 90 degree to the
surface. -
•In angle beam testing, the sound beam is
introduced into the test article at some angle other
than 90 deg.-
•The choice between normal and angle beam
inspection usually depends on two considerations:
 The orientation of the feature of interest: the
sound should be directed to produce the largest
reflection from the feature.

TESTING TECHNIQUES

TESTING TECHNIQUES
 To get useful levels of sound energy into a material, the air between the
transducer and the test article must be removed. This is referred to as
coupling.
 In contact testing, a couplant is used-such as water, oil or a gel is applied
between the transducer and the part.
 In immersion testing, the part and the transducer are place in a water
bath. This arrangement allows better movement of the transducer while
maintaining consistent coupling.
 With immersion testing, an echo from the front surface of the part is
seen in the signal but otherwise signal interpretation is same for the two
techniques.
 Adv. Useful for rough surfaces.

DISPLAYING ULTRASONIC
INDICATIONS

INDICATIONS
A – SCAN
B – SCAN

INDICATIONS
C – SCAN
S – SCAN

INDICATIONS
DISPLAY PAUT EQUIPMENT

APPLICATION
A – SCAN
the screen is calibrated to display 8 inches full screen width (FSW). The
test object is 6 inches thick.
How far is the discontinuity from the sound entry surface?

APPLICATION
Ultrasonic thickness gauging is done periodically in the petrochemical and
utility industries to determine loss of thickness due to corrosion/erosion.
Applications are piping systems, storage and containment facilities, pressure
vessels.

APPLICATION
One of the most widely used methods of inspecting weldments is ultrasonic
inspection.
Full penetration groove welds lend themselves readily to angle beam shear
wave examination.

Advantage of Ultrasonic Testing
• Sensitive to small discontinuities both surface and subsurface.
• Only one-sided access is needed when pulse-echo technique is used.
• High accuracy in determines discontinuity location as well as size.
• Minimum part preparation required.
• Electronic equipment provides instantaneous results.
• Detailed images can be produced with automated systems.
Limitations of Ultrasonic Testing
• Surface must be accessible to transmit ultrasound.
• Skill and training required is more than with some other methods.
• Normally requires a coupling medium to promote transfer of sound energy
into test specimen.
• Materials that are rough, irregular in shape & very thin are difficult to
inspect.
• Cast iron and other coarse grained materials are difficult to inspect due to
low sound transmission and high signal noise. -
• Linear defects oriented parallel to the sound beam may go undetected.
• Reference standards are required

INTRODUCTION
Liquid penetrant testing is a nondestructive means of locating surface
discontinuities based on capillarity or capillary action. Capillary action is
responsible for both penetrant entry and exit from discontinuities.
In the liquid penetrant method, the liquid is applied to the surface of the
specimen and sufficient time is allowed for penetration of surface
discontinuities. If the discontinuity is small or narrow as in a crack or
pinhole, capillary assist the penetration.
After sufficient time has passed for the penetrant to enter the
discontinuity, the surface of the part is cleaned. Capillary action is again
employed to act as blotter to draw penetrant from the discontinuity.

INTRODUCTION
Capillary Action
Defect at open to Surface
DI BAWAH
PERMUKAAN
DI BAGIAN
DALAM
Tdk dapat dideteksi oleh uji
penetran
Dapat dideteksi oleh uji penetran

PENETRANT TEST
The selection of the best process depends upon:
1. Sensitivity required.
2. Number of articles to be tested.
3. Surface condition of part being inspected.
4. Configuration of test specimen.
5. Availability of water, electricity, compressed air, suitable testing area, etc.
List below indicates the penetrant systems, ranging from the most sensitive
and expensive to the least one.
1. Post-emulsified – fluorescent.
2. Solvent-removable – fluorescent.
3. Water-washable – fluorescent.
4. Post-emulsified – visible.
5. Solvent-removable – visible.
6. Water-washable – visible.

STEP 1
The following are typical cleaning
methods:
1. Detergent cleaning
2. Vapor degreasing
3. Steam cleaning
4. Solvent cleaning
5. Rust and surface scale remover
6. Paint removal
7. Etching
8. Ultrasonic cleaning
9. Mechanical cleaning

Pengenalan NDT.pptx

Recommended

Recommended

More Related Content

Similar to Pengenalan NDT.pptx

Similar to Pengenalan NDT.pptx (20)

Recently uploaded

Recently uploaded (20)

Pengenalan NDT.pptx

Editor's Notes