INSTITUTE OF TECHNOLOGY &

MANAGEMENT

SEMINAR PRESENTATION
ON

NON DESTRUCTIVE TESTING

SESSION 2017-18

BY:AKASH TRIPATHI
MECHANICAL ENGINEERING(2014-18)
SECTION :D41(4th YEAR)
 CONTENT
 INTRODUCTION
 IMPORTANCE OF NDT
 USES OF NDT
 VISUAL TESTING
 DYE PENETRANT TESTING
 MAGNETIC PARTICLE TESTING
 ULTRASONIC TESTING
 EDDY CURRENT TESTING
 CONCLUSION
 INTRODUCTION
 Non-destructive testing (NDT) is a wide group of analysis techniques used in
science and technology industry to evaluate the properties of a material,
component or system without causing damage. Because NDT does not
permanently alter the article being inspected, it is a highly valuable technique
that can save both money and time in product evaluation, troubleshooting,
and research.
 The six most frequently used NDT methods are eddy-current, magnetic-
particle, liquid penetrant, radiographic, ultrasonic, and visual testing.
 NDT is commonly used in forensic engineering, mechanical
engineering, petroleum engineering, electrical engineering, civil
engineering, systems engineering, aeronautical engineering, medicine,
and art.
 IMPORTANCE OF NDT

 NDT increases the safety and reliability of the product during operation.
 It decreases the cost of the product by reducing scrap and conserving
materials, labor and energy.
 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.
 NDT is also used widely for routine or periodic determination of quality
of the plants and structures during service.
 This not only increases the safety of operation but also eliminates any
forced shut down of the plants.
 USES OF NDT

• Flaw Detection and Evaluation

• Leak Detection
• Location Determination
• Dimensional Measurements
• Structure and Microstructure Characterization
• Estimation of Mechanical and Physical Properties
 COMMON NDT METHOD
 VISUAL TESTING (VT)
 DYE PENETRANT TESTING (DPT)
 MAGNETIC PARTICLE TESTING (MPT)
 ULTRASONIC TESTING (UT)
 EDDY CURRENT TESTING (ECT)
 RADIOGRAPHY TESTING (RT)
 X-RAY
 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.
 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.
 Three liquids are used in this process :Cleaner,
Penetrant, Developer.
 DPT TESTING PROCESS

 At first the surface of the material that is to be

tested is cleaned by a liquid. The liquid is called
cleaner.
 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.
DPT TESTING PROCESS

 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 developer.
 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.
ADVANTAGES OF DPT

 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.
 Penetrant materials and associated equipment's are
relatively inexpensive.
LIMITATIONS OF DPT

 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.
 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.
 PRINCIPLE OF MPT

 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.
ADVANTAGES OF MPT

 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.
LIMITATION OF MPT

 Material must be ferromagnetic.

 Orientation and strength of magnetic field is critical.
 Detects surface and near-to-surface discontinuities only.
 Large currents sometimes require.
 ULTRASONIC 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.
 PRINCIPLE OF UT
 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.
ADVANTAGES OF UT

 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.
LIMITATION OF UT

 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 are difficult to test.
 EDDY CURRENT TESTING
 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.
APPLICATION OF ECT

 Crack Detection
 Corrosion Monitoring
 Material Thickness Measurements
 Coating Thickness Measurements
 Conductivity Measurements
 CRACK DETECTION IN EDDY CURRENT
 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.
ADVANTAGES OF ECT

 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
LIMITATION OF ECT

 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.
ADVANTAGES OF NDT

 The equipment's are easy to handle.

 Defects can be detected without damaging the
components.
 Methods are quick and accurate.
 Test provide safety to both tester and product.
 Test results can be easily recorded on cassettes , floppy,
etc.
DISADVANTAGE OF NDT

 It requires a higher level of training and additional

certification.
 Comparatively complicated operations
 High-value advanced instrumentation is needed.
 High capital and maintenance required
CONCLUSION

 In INDIA , 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.
 On the basis of its scope and areas we can say that many more
advancement in the field of NDT is still to come.
THANKYOU!!!
ANY QUERY!!