SEMINAR
ON
NON-DESTRUCTIVE
TESTING
Department Of Automobile
Engineering
Submitted by: Ajith K
CONTENT
1. Introduction
2. What is NDT
3. Applications
4. Objectives
5. Types of NDT
6. Liquid penetrant method
1. Application
2. Advantages & Limitations
7. Ultrasonic flaw detection
1. Application
2. Advantages & Limitations
8. Radiography
1. X-ray radiography & fluoroscopy
1. Merits & Demerits
2. Difference b/n Radiography & fluoroscopy
9. Importance of NDT
10. Conclusion
Introduction
1. 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.
2. The term Nondestructive examination (NDE),
Nondestructive inspection (NDI),and Nondestructive
evaluation (NDE) are also commonly used to
describe this technology
What is NDT?
1. NDT stands for non-destructive testing
2. In other words it is a way of testing without destroying.
3. 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
Common Application of NDT
1. Inspection of raw products
2. Inspection of following secondary processing
3. In-service damage inspection
Objectives
1. To avoid failures, prevent accidents and save human life
2. To make a profit for the user
3. To ensure customer satisfaction and maintain the
manufacturer’s reputation
4. To aid in better product design
5. To control manufacturing processes
6. To lower manufacturing costs
Types of NDT
1. Visual inspection
2. Liquid penetrant method
3. Ultrasonic inspection
4. Radiography methods
1. X-ray Radiography & Fluoroscopy
2. Y-ray Radiography
5. Eddy current Testing
6. Magnetic particle Testing
7. Thermography
Liquid penetrant method
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
1. Cleaning the surface
2. Application of the penetrant
3. Applying Developer
4. Inspecting after a few minutes
Application
1. Turbines rotor, discs & blades
2. Aircraft wheels, casting, forged components, welded
assemblies
3. Automotive parts-pistons, cylinders, etc.
4. Bogie frames of railway locomotives &rolling stack
5. Electrical ceramic parts – spark plugs and insulators
6. Moulded plastic parts
Advantages & Limitations
ADVANTAGES
1. Simple and expensive
2. Versatile and portable
3. Applicable to ferrous,non-ferrous, non-magnetic and complex
shaped material which are non-porous and of any dimension
4. Detects cracks, seams, lack of bonding, etc.
LIMITATION
1. Detects surface flaws only
2. Surface cleaning before and after inspection
3. Deformed surfaces and surface coating prevent detection
Ultrasonic Inspection
Whenever there is a change in the medium, the ultrasonic waves are
reflected. Thus, from the intensity of the reflected echoes, the flaws are
detected without destroying the material
Application
1. Detection of failure if rail rolling stock axles, pressure column,
earthmoving equipments, Mill rolls , mixing equipments, etc.
2. Measurement of metal section thickness
3. Thickness measurements – refinery & chemical processing
equipments, submarine hulls, aircraft sections, pressure
vessels, etc.
4. Inspect pipe & plate welds
5. Inspect pins, bolts & shafts for cracks
6. Detect internal corrosion
Advantages & Limitation
ADVANTAGES
1. Sensitive to surface & subsurface discontinuities
2. Superior depth of penetration for flaw detection
3. High accuracy – position, size & shape of defect
4. Instantaneous result
5. Automated detailed images
LIMITATION
1. Surface accessibility for ultrasonic transmission
2. Highly skilled & trained manpower
3. Irregular, rough, coarse grained or non homogenous parts,
linear defects oriente parallell to the beam cannot be
inspected – low transmission & high noise
4. Coupling medium required
Radiography
The formation of an image of the test piece either on a
photographic film or on a fluorescent screen due to x-rays
or y-rays passing through the test piece
1. X-ray Radiography
2. X-ray Fluoroscopy
X-ray Radiography
PRINCIPLE
X-rays are passed through the specimen under inspection and it is differentially
absorbed by the specimen. The transmitted x-rays are received by the
photographic film and the film is developed. The dark and light shadows reveal
the defects present in the specimen and hence the defects are defected.
X-ray Fluoroscopy
Principle
X-rays are passed through the specimen and is made to fall on a fluorescent
screen. With respect to the defects in the specimen, there will be a variation
in intensity
Merits & Demerits
MERITS DEMERITS
1. Low cost 1. Poor resolution
2. Image viewed immediately on 2. Low image contrast
screen
3. Electronic image intensifier
3. Time consumption is less required for increasing the
contrast
Difference between Radiography &
Fluoroscopy
RADIOGRAPHY FLUOROSCOPY
1. Image developed on photographic 1. Image is developed on fluorescent
film screen.
2. High resolution & contrast 2. Fair resolution and low contrast.
3. Immediate image cannot be 3. Immediate image can be viewed
obtained. through the monitor.
4. X-ray energy is converted into 4. X-ray energy is converted into
chemical energy. visible light.
5. Expensive 5. Inexpensive.
6. Time consumption is high. 6. Time consumption is low
Importance of NDT
1. Applied directly to the product
2. Tested parts are not damaged
3. Various tests can be performed on the same product
4. Low of time consumption
5. Low labour cost
What are the common defects?
1. Thickness variation
2. Cracks
3. Poor penetration
4. Porosity
Conclusion
NDT can save 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 benefit.
References
1. www.google.com
2. www.wikipedia.com
THANKS
