Introduction of NDT

1. 1
A
PRESENTATION
ON
NON DISTRUCTIVE
TESTING
ASHISH KR. SINGH
ROLL NO -1509040044
MECHNICAL ENGG.
IEC-CET GR . NOIDA

2. CONTENT
• Introduction
• What is NDT
• Application of NDT
• Types
• visual inspection
• liquid penetrant method
• ultrasonic inspection
• Radiography
• Application
• conclusion

3. • Non-destructive testing (NDT) is a wide group of analysis
techniques used in science and industry to evaluate the
properties of a material, component or system without
causing damage.
• The terms Nondestructive examination (NDE),
Nondestructive inspection (NDI), and Nondestructive
evaluation (NDE) are also commonly used to describe
this technology.

4. Definition of NDT
•NDT stands for non-destructive testing.
•In other words it is a way of testing
without destroying.
•This means that the component- the
casting, weld or forging, can continue to
be used and that the non destructive
testing method has done no harm.

5. Common Application of NDT
• Inspection of Raw Products
• Inspection Following Secondary
Processing
• In-Services Damage Inspection

6. Four Most Common NDT
Methods
• Visual
• Liquid Penetrant
• Ultrasonic
• Radiography

7. VISUAL INSPECTION
•A non destructive method used to evaluate an item
observation.
•Usually the first method employed for locating suspected
defects.
•Also the oldest and most commonly used NDT method.
•Visual Inspection, or Visual Testing (VT), is the oldest and
most basic method of inspection.

8. Most basic and common
inspection method.
Tools include
fiberscopes,
borescopes, magnifying
glasses and mirrors.
Robotic crawlers permit
observation in hazardous or
tight areas, such as air
ducts, reactors, pipelines.
Portable video inspection
unit with zoom allows
inspection of large tanks
and vessels, railroad tank
cars, sewer lines.

9. • A liquid with high surface wetting characteristics is
applied to the surface of the part and allowed time
to seep into surface breaking defects.
• The excess liquid is removed from the surface of
the part.
• A developer (powder) is applied to pull the trapped
penetrant out the defect and spread it on the
surface where it can be seen.
• Visual inspection is the final step in the process.
The penetrant used is often loaded with a
fluorescent dye and the inspection is done under
UV light to increase test sensitivity.
Liquid Penetrant Inspection

10. • Principle
A liquid penetrant is applied
at the surface of the
specimen. The penetrant is
drawn by the surface flaws
due to capillary action and
this is subsequently revealed
by a developer, in addition
with visual inspection.
• Procedure
– Cleaning the surface
– Application of the penetrant
– Removal of excess penetrant
– Developing
– Inspection

11. ULTRASONIC INSPECTION
• ultrasonic testing is a family of non-destructive
testing techniques based on the propagation of
ultrasonic waves in the object.
• A transducer applies ultrasonic pulse waves in the
frequency range of 0.5 to 10MHz in the material.
• Ultrasonic testing is very sensitive test method for detection
of embedded linear discontinuities
• Ultrasonic testing is faster and economical as compared to
radiographic examination.

12. •High frequency sound waves are introduced into a
material and they are reflected back from surfaces or
flaws.
Reflected sound energy is displayed versus time, and
inspector can visualize a cross section of the specimen
showing the depth of features that reflect sound.
f
plate
crack
0 2 4 6 8 10
initial
pulse
crack
echo
back surface
echo
Oscilloscope, or flaw
detector screen
Ultrasonic Inspection (Pulse-Echo)

13. • Radiographic Testing is a non-destructive testing (NDT)
method that examines the volume of a specimen.
• Radiography uses X-rays and gamma-rays to produce a
radiograph of a specimen.
• Radiography is an imaging technique using X-rays, gamma
rays or similar radiation to view the internal form of an
object.
• The formation of an image of the test piece either on a
photographic film.

14. Radiography
The radiation used in radiography
testing is a higher energy (shorter
wavelength) version of the
electromagnetic waves that we
see as visible light. The radiation can
come from an X-ray generator or a
radioactive source.
High Electrical Potential
Electrons
-+
X-ray Generator
or Radioactive
Source Creates
Radiation
Exposure Recording Device
Radiation
Penetrate
the Sample

15. • Quality control & material inspection
• Detection of failure of rail rolling stock axes, pressure
columns, earthmoving equipments, mill rolls, mixing
equipments, etc.
• Measurement of metal section thickness
• Thickness measurements – refinery & chemical
processing equipments, submarine hulls, aircraft
sections, pressure vessels, etc.
• Inspect pipe & plate welds
• Inspect pins, bolts & shafts for cracks
• Detect internal corrosion

16. Advantages
• Sensitive to surface & subsurface discontinuities.
• Superior accuracy – position, size & shape of defect.
• Minimum depth of penetration for flaw detection.
• High art preparation.
Limitations
• Surface accessibility for ultrasonic transmission.
• Highly skilled & trained manpower.
• Coupling medium required.

17. • NDT can save and/or avoid costs in millions of dollars
for facilities that use its methods.
• There are proven NDT technologies to do this, from
conventional to more advanced ones that are
essentially based on the conventional ones.
• Their required training requirements and proper
application are paramount for realizing ever-
increasing benefits.