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2. Presentation on
Non-Destructive Testing (NDT)
Presented By
Engr. Shahin Manjurul Alam
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3. Automobile & Heavy
Duty Filter
Different types of
Scientific
Equipments
Non Destructive
Testing (NDT)
Products
Lubricants/Engine
Oil/ Motor oil
Condition
Monitoring
Products
NDT Services
VT, PT, MT, UT, ET &
RT
MRO & Packaging
Products
Cold Welding
Materials & Services

4. Contents
 Organization
Non-Destructive Testing (NDT)
 Six most common NDT methods
 Process of each NDT Method
 Advantages and limitations of NDT methods
Conclusion
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5. Company Profile www.sajetc.com
Saj Engineering & Trading Company is established in 1998 to provide the Non-
Destructive Testing (NDT) and Condition Monitoring (CM) solution in Bangladesh industrial
Market. Since then we are providing the NDT and CM solution in different types of
industries like power generation, fertilizer, chemical, aviation shipbuilding, gas production
and distribution, cement, welding, paper, sugar, pharmaceuticals, research and
educational institutions. For the automobile and industrial market we are supplying
lubricants, filter, radiator and spark plug. For our products we represent the most
renowned manufacturers in the world.
As we have all sorts of latest NDT and CM products we have developed an industrial
inspection service provider under the name of Saj Industrial & Inspection Company.
And till now we have completed 35 Projects successfully and some projects is in our hand.
Products:
1.Non-Destructive Testing Products
2.Condition Monitoring Products
3.Sakura Automobile and Generator Filter
4.Air Conditioner Energy Saver
5.Maintenance Repair & Overhauling (MRO)
Products
6.PertaminaLubricants
7.Scientific/Laboratory Equipments
Our Services:
1. Remote Visual Inspection/Endoscope
2. Ultrasonic Testing
3. Magnetic Particle Testing
4. Radiography Testing
5. PenetrantTesting
6. Vibration Analysis
7. Dynamic Balancing
8. Transformer Leakage Repair
9. Thermography Service
10. Hardness Testing

6. Non-Destructive testing is the
use of noninvasive techniques to
determine the integrity of a
material, component or structure
or quantitatively measure some
characteristics of an object. It is
the testing of materials, for
surface or internal flaws or
metallurgical condition, without
interfering in any way with the
integrity of the material or its
suitability for service.
Non-Destructive Testing
(NDT)
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i.e. Inspect or measure without doing harm.
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1. NDT increases the safety and reliability of the product
during operation.
2. It decreases the cost of the product by reducing scrap and
conserving materials, labor and energy.
3. It enhances the reputation of the manufacturer as a
producer of quality goods. All of the above factors boost
the sales of the product which bring more economical
benefits for the manufacturer.
4. NDT is also used widely for routine or periodic
determination of quality of the plants and structures during
service.
5. This not only increases the safety of operation but also
eliminates any forced shut down of the plants.
Importance of NDT
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Methods of NDT
Visual
Liquid Penetrant
Magnetic Particle
Eddy Current
Ultrasonic
X-ray
Microwave
Acoustic Emission
Thermography
Laser Interferometry
Replication
Flux Leakage
Acoustic Microscopy
Magnetic Measurements
Tap Testing
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Six Most Common NDT
Methods
1. Visual Testing (VT)
2. Dye Penetrant Testing (DPT)
3. Magnetic Particle Testing (MPT)
4. Ultrasonic Testing (UT)
5. Eddy Current Testing (ECT)
6. Radiography Testing (RT)

10. Visual Testing
Visual testing is the most basic and common inspection method
involves in using of human eyes to look for defects. But now it
is done by the use special tools such as video scopes,
magnifying glasses, mirrors, or borescopes to gain access and
more closely inspect the subject area.
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Visual Testing Equipments:
•Mirrors (especially small, angled mirrors),
•Magnifying glasses,
•Microscopes (optical and electron),
•Borescopes and fiber optic borescopes,
•Closed circuit television (CCTV) systems,
•Videoscope.

11. Visual Testing Equipments
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Fig: Advanced VideoscopeFig: Videoscope
Fig: Magnifying glass
Fig: Borescopes
Fig. Microscope

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Dye Penetrant Testing
This method is commonly used for detect the surface cracks or
defects. Dye penetrant Testing (DPT) is one of the most widely
used nondestructive Testing (NDT) methods. DPT can be used
to inspect almost any material provided that its surface is not
extremely rough.
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www.sajetc.comDye Penetrant Testing Process
Three liquids are
used in this method.
1. Cleaner
2. Penetrant
3. Developer

14. Dye Penetrant Testing of a Boiler
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At first the surface of the material that is to be tested is cleaned
by a liquid. The liquid is called cleaner.
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15. Dye Penetrant Testing of a Boiler
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Then a liquid with high surface wetting characteristics is applied
to the surface of the part and allowed time to seep into surface
breaking defects. This liquid is called penetrant. After five or ten
minutes the excess penetrant is removed from the surface.
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16. Then another liquid is applied to pull the trapped penetrant out
the defect and spread it on the surface where it can be seen. This
liquid is called deveoper. 16
www.sajetc.comDye Penetrant Testing of a Boiler

17. Findings
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After Dye Penetrant Testing
there are two surface cracks are
Detected.
Two surface cracks
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Advantages of Dye Penetrant
Testing
 This method has high sensitivity to small surface
discontinuities.
 Large areas and large volumes of parts/materials can be
inspected rapidly and at low cost.
 Indications are produced directly on the surface of the part
and constitute a visual representation of the flaw.
 Aerosol spray can make penetrant materials very portable.
 Penetrant materials and associated equipments are relatively
inexpensive.
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19. Limitations of Dye Penetrant
Testing
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 Only surface breaking defects can be detected.
 Precleaning is critical since contaminants can mask defects.
 The inspector must have direct access to the surface being
inspected.
 Surface finish and roughness can affect inspection sensitivity.
 Post cleaning of acceptable parts or materials is required.
 Chemical handling and proper disposal is required.

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Magnetic Particle Testing
This method is suitable for the detection
of surface and near surface
discontinuities in magnetic material,
mainly ferrite steel and iron. Magnetic
particle Testing (MPT) is a
nondestructive testing method used for
defect detection. MPT is fast and
relatively easy to apply, and material
surface preparation is not as critical as it
is for some other NDT methods.
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In the first figure the magnetized metal has no crack and there only two
poles that is north pole and south pole. And in second figure the
magnetized metal has a crack and at the crack point there creates
another north and south pole for the magnetic flux leakage.
SN
S N
N S
Magnetic Flux Line
Fig.1: Magnetized Metal with no crack Fig.2: Magnetized Metal with crack
CrackMagnetic Flux Leakage
Basic Principle of MPT

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Magnetic Particle Testing
Process
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The first step in a magnetic
particle testing is to magnetize the
test component by a MPT
equipment. If there any defects on
the surface or near to the surface
are present, the defects will create
a leakage field.
Then finely milled iron particles coated with a dye pigment are
applied to the specimen. These particles are attracted to magnetic
flux leakage fields and will cluster to form an indication directly
over the defects. This indication can be visually detected under
proper lighting conditions.

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Magnetic Particle Testing in Superheater
Pipe Welding
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First the welding joint is magnetized by MPT equipment. Then finely
milled iron particles are applied to the magnetized weld joint.

24. Magnetic Particle Testing in Gas
Pipe Welding
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Iron particles make a
cluster at the welding
joint for magnetic
flux leakage because
of welding defects.
Cluster

25.  It does not need very stringent pre-cleaning operation.
 It is the best method for the detection of surface and near to
the surface cracks in ferromagnetic materials.
 Fast and relatively simple NDT method.
 Generally inexpensive.
 Will work through thin coating.
 Highly portable NDT method.
 It is quicker.
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Advantages Magnetic Particle
Testing
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26. Limitations of Magnetic Particle
Testing
 Material must be ferromagnetic.
 Orientation and strength of magnetic field is critical.
 Detects surface and near-to-surface discontinuities only.
 Large currents sometimes require.
.
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27. www.sajetc.comUltrasonic Testing
This technique is used for the detection
of internal surface (particularly distant
surface) defects in sound conducting
materials. In this method high
frequency sound waves are introduced
into a material and they are reflected
back from surface and flaws. Reflected
sound energy is displayed versus time,
and inspector can visualize a cross
section of the specimen showing the
depth of features.
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A typical UT system consists of several functional units, such as
the pulser/receiver, piezoelectric transducer, and display devices. A
pulser/receiver is an electronic device that can produce high
voltage electrical pulses. Driven by the pulser, the transducer
generates high frequency ultrasonic energy. The sound energy is
introduced and propagates through the materials in the form of
waves. When there is a discontinuity (such as a crack) in the wave
path, part of the energy will be reflected back from the flaw
surface. The reflected wave signal is transformed into an electrical
signal by the piezoelectrical transducer and is displayed on a
screen.
Basic Principle of Ultrasonic
Testing
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29. Basic Principle of Ultrasonic
Testing
In the figure below, the reflected signal strength is displayed
versus the time from signal generation, when a echo was
received. Signal travel time can be directly related to the
distance. From the signal, information about the reflector
location, size, orientation and other features can sometimes
be gained.
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0 2 4 6 8 10
crack
echo
back surface
echo
initial
pulse
Oscilloscope, or flaw
detector screen
plate
crack
Piezoelectric
Transducer

30. Piezoelectric Transducer
A transducer is a device that converts energy from one form to
another. Presently, piezoelectric material is commonly used as a
basic component of transducers. A piezoelectric element is a
crystal which delivers a voltage when mechanical force is
applied between its faces, and it deforms mechanically when
voltage is applied between its faces. Because of these
characteristics piezoelectric element is capable of acting as both
a sensing and a transmitting element. Piezoelectric transducers
have been conventionally used to convert electric signals into
sound wave, or to convert sound wave into electric signals.
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31. Piezoelectric Transducer
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Signal wire
Piezoelectric element
case

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Test Techniques:
Normal and Angle Beam
• In normal beam testing, 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
angles other than 90.
• 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.
- Obstructions on the surface of the
part that must be worked around.

33. Couplant
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A couplant is a material (usually liquid)
that facilitates the transmission of ultrasonic
energy from the transducer into the test
specimen. Couplant is generally necessary
because the acoustic impedance mismatch
between air and solids (i.e. such as the test
specimen) is large. The couplant displaces
the air and makes it possible to get more
sound energy into the test specimen so that
a usable ultrasonic signal can be obtained.
In contact ultrasonic testing a thin film of
oil, glycerin or water is generally used
between the transducer and the test surface
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34. Calibration Standards
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Calibration is a operation of configuring the ultrasonic test
equipment to known values. This provides the inspector with
a means of comparing test signals to known measurements.
Calibration standards come in a wide variety of material
types, and configurations due to the diversity of inspection
applications.
The following slides provide examples of specific types of
standards.

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www.sajetc.comCalibration Standards
Thickness calibration standards
may be flat or curved for pipe and
tubing applications, consisting of
simple variations in material
thickness.
Distance/Area Amplitude standards
utilize flat bottom holes or side
drilled holes to establish known
reflector size with changes in
sound path form the entry surface.
ASTM Distance/Area Amplitude
IIW
This calibration standards for use
in angle beam inspections when
flaws are not parallel to entry
surface.

36. Advantages of Ultrasonic Testing
 Thickness and lengths up to 30 ft can be tested.
 Position, size and type of defect can be determined.
 Instant test results.
 Portable.
 Capable of being fully automated.
 Access to only one side necessary.
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37. Limitations of Ultrasonic Testing
 The operator can decide whether the test piece is defective or
not while the test is in progress.
 Considerable degree of skill necessary to obtain the fullest
information from the test.
 Very thin sections can prove difficult.
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38. Eddy Current Testing
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This method is widely used to detect
surface flaws, to measure thin walls from
one surface only, to measure thin coatings
and in some applications to measure
depth. This method is applicable to
electrically conductive materials only. In
this method eddy currents are produced in
the product by bringing it close to an
alternating current carrying coil. The main
applications of the eddy current technique
are for the detection of surface or
subsurface flaws, conductivity
measurement and coating thickness
measurement.

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www.sajetc.comApplication of ECT
Crack Detection
Corrosion Monitoring
Material Thickness Measurements
Coating Thickness Measurements
Conductivity Measurements

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Electromagnetic Induction
•Eddy currents are created through a process called
electromagnetic induction.
•When alternating current is applied to the conductor, such as
copper wire, a magnetic field develops in and around the
conductor.
•This magnetic field expands as the alternating current rises to
maximum and collapses as the current is reduced to zero.

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Current Flow
Electromagnetic Induction
If another electrical conductor is brought into the proximity of
this changing magnetic field, the reverse effect will occur.
Magnetic field cutting through the second conductor will cause
an “induced” current to flow in this second conductor. Eddy
currents are a form of induced currents!
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Crack Detection
Crack detection is one of the primary uses of eddy current
inspection. Cracks cause a disruption in the circular flow patterns
of the eddy currents and weaken their strength. This change in
strength at the crack location can be detected.
Magnetic Field
From Test Coil
Magnetic Field
From
Eddy Currents
Eddy Currents
Crack

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Eddy Current Testing
Equipments

44. Probes - Mode of Operation
Eddy current probes are available in a large variety of shapes
and sizes. In fact, one of the major advantages of eddy current
inspection is that probes can be custom designed for a wide
variety of applications. Eddy current probes are classified by the
configuration and mode of operation of the test coils.
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www.sajetc.comDifferent Types of Probes
Absolute Probes Surface Probes Bobbin Probes

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Advantages of Eddy Current
Testing
Sensitive to small cracks and other defects
Detect surface and near surface defects
Inspection gives immediate results
Equipment is very portable
Method can be used for much more than flaw detection
Inspects complex shapes and sizes of conductive materials

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www.sajetc.comLimitations of Eddy Current
Testing
Only conductive materials can be inspected.
Surface must be accessible to the probe.
Skill and training required is more extensive than other
techniques.
Surface finish and roughness may interfere.
Depth of penetration is limited.

48. Radiography Testing
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Radiography Testing (RT), or industrial
radiography is a nondestructive testing (NDT)
method of inspecting materials for hidden flaws
by using the ability of short wavelength
electromagnetic radiation (high energy photons)
to penetrate various materials.
Radiographic Testing Method is nothing but to
take the shadow picture of an object onto a film
by the passage of X-ray or Gamma ray through
it. It is the same as the medical radiography (X-
ray). Only difference in their wave length.

49. Radiography Testing Process
The principles are the same for both X and Gamma radiography.
In X-radiography the penetrating power is determined by the
number of volts applied to the X-Ray tube - in steel
approximately 1000 volts per inch thickness is necessary. To
produce an X or Gamma radiograph, the film package is placed
close to the surface of the subject. The source of radiation is
positioned on the other side of the subject some distance away,
so that the radiation passes through the subject and on to the
film.
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50. Radiography Testing Process
After the exposure period the film is removed, processed, dried,
and then viewed by transmitted light on a special viewer.
Various radiographic and photographic accessories are
necessary, including such items as radiation monitors, film
markers, image quality indicators, darkroom equipment, etc.
Where the last is concerned there are many degrees of
sophistication, including fully automatic processing units.
These accessories are the same for both X and Gamma
radiography systems. Also required are such consumable items
as radiographic film and processing chemicals
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X-ray film
Top view of developed film
Electrons
-+
Radiation
Penetrate
the Sample
Radiography Testing Process
X-ray Generator or
Radioactive Source
Creates Radiation
Radioactive Source

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Essential Elements for Radiography
Testing
1. A source of penetrating radiation, such as an X-ray machine.
2. The object to be radiographed, such as a weldment.
3. A recording or viewing device, usually photographic (X-ray)
film enclosed in a light tight holder.
4. A qualified radiographer trained to produce a satisfactory
exposure.
5. A person skilled in the interpretation of radiographs.

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Radiographic Image
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Radiographic image
Normal image

54. Radiation Safety
Ionizing radiation is an extremely important NDT tool but it
can pose a hazard to human health. For this reason, special
precautions must be observed when using and working around
ionizing radiation. Complicating matters further is the fact that
Gamma and X-ray radiation are not detectable by the human
body. However, the risks can be minimized when the radiation
is handled and managed properly.
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55. Information is presented pictorially.
 A permanent record is provided which may be viewed at a
time and place distant from the test.
Useful for thin sections.
Sensitivity declared on each film suitable for any material.
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Advantages of Radiography
Testing

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Possible health hazard.
 Need to direct the beam accurately for two-dimensional
defects.
 Film processing and viewing facilities are necessary
 Not suitable for automation.
 Not suitable for surface defects.
Limitations of Radiography
Testing

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In Bangladesh NDT is a new technology and system for
industrial inspection and testing. Many developed countries are
used this technology because of its huge benefits.
Modern NDT methods will become just as an important tool for
risk based inspection approaches and maintenance planning. For
this purpose every industry should have a NDT division with
NDT personnel.
Conclusion

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