1. NON DESTRUCTIVE TESTING
A PRESENTATION OVER
NON DESTRUCTIVE TESTING
Prepared by :-
ANUJ SHARMA
4th year
Mechanical engg.

2. Non Destructive Testing
Nondestructive testing (NDT) has been defined as
comprising those test methods used to examine an
object, material or system without impairing its
future usefulness.
Used for 100% checking of material in a production
quality control system.

3. Characteristics of NDT
Applied directly to the product
Tested parts are not damaged
Various tests can be performed on the same product
Specimen preparation not required
Can be performed on parts that are in service
Low time consumption
Low labour cost

4. NDT Methods Visual Inspection Liquid penetrant method
Ultrasonic Inspection
Radiography methods
Eddy current testing
Magnetic particle testing

5. 1 Visual Inspection Most basic and common inspection method.
Tools include fiberscope, borescopes, magnifying glasses and mirrors.
Portable video inspection unit with zoom allows inspection of large tanks and vessels, railroad tank cars, sewer lines.
Robotic crawlers permit observation in hazardous or tight areas, such as air ducts, reactors, pipelines.

6. 2. Liquid Penetrant Method
This method is frequently used for the detection of surface breaking flaws in non- ferromagnetic materials.
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.

7. Liquid Penetrant Method

8. 3. Ultrasonic Flaw Detection
This technique is used for the detection of internal and surface defects in sound conducting materials.
High frequency sound waves are introduced into a material and they are reflected back from surfaces or flaws.
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.

9. Principle & Block Diagram of UT

10. 4. X-Ray Radiography
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.

11. Inspection through Radiography
X-ray film

12. 5. Eddy Current & Electro-Magnetic Methods
Eddy current technique are for the detection of surface or subsurface flaws, conductivity measurement and coating thickness measurement.
In Eddy current testing, a coil carrying AC current is placed closed to the component surface.
When the eddy current flows through the metal the crack is detected as the change in Impedance.

13. Inspection through Eddy Current

14. 6. Magnetic Particle Crack Detection
This method is suitable for the detection of surface and near surface discontinuities in magnetic material, mainly ferritie steel and iron.
The part is magnetized.
Finely milled iron particles coated with a dye pigment are then applied to the specimen.
This indication can be visually detected under proper lighting conditions.

15. Inspection through Magnetic Particle Crack Detection

16. Uses of NDT To detect internal or surface flaws
To measure the dimensions of materials
To determine the materials’ structure
To evaluate the physical and mechanical properties of materials
To avoid failures, prevent accidents and save human life;
To make a profit for the user
To ensure customer satisfaction and maintain the manufacturer's reputation
To aid in better product design
To control manufacturing processes
To lower manufacturing costs
To maintain uniform quality level

17. Area of Application Mechanical Engineering Aerospace Engineering
Civil Engineering
Electrical Engineering
Industrial & Manufacturing Engineering
Systems Engineering
Medicine
Forensics
Art

18. Thank You