1. NON-DESTRUCTIVE TESTINGby
GROUP-E
MEMBERS
1 JUDE RINALDO
2 JUDE PRADEEP
3 AARYL D’SA
4 SWAROOP SUNDER

2. Describe the five types of non-destructive test used in ship construction

3. NON-DESTRUCTIVE TESTING
In this process the material is tested for any flaws without applying any kind of stress
The test piece is not destroyed or deformed
Non-destructive tests are desirable for materials that are costly or difficult to fabricate or that have been formed into finished or semi finished products.
At the end of these tests there are no damage to the components
Non-destructive testing is required to enable the soundness of ship welds to be assessed

4. NON-DESTRUCTIVE TESTING
There are five of non destructive tests:
Visual examination
Dye penetrant test
Magnetic particle inspection
Radiographic inspection
Ultra sonic inspection

5. VISUAL EXAMINATION
Any surface defects are noticed by the experienced and responsible personnel
Some of the defects are:
Incorrect bead shape
High spatters
Under cutting
Bad stop and start points
Incorrect alignment
Surface cracks

6. VISUAL EXAMINATION
Visual inspection can be simply visual i.e. with the naked eye or at magnifications up to 40 times.
This test can be done in conjunction with NDT or as stand alone.
When this test is done as stand alone then it is used for identifying macro manufacturing defects.

7. VISUAL EXAMINATION
When used in conjunction with NDT it is essentially applied at every stage involving human eye e.g. reading measuring instrument screens.
This forms the simplest form of investigation used as there are no sophisticated and costly instruments used.

8. VISUAL EXAMINATION Advantages It is a routine procedure
The cost of visual inspection is low
It can be very effective where examination is made before,during, and after welding

9. DYE PENETRANT TEST Process
Liquid ( containing either dye or ultra violet-sensitive substances) is sprayed onto specimen
The liquid is drawn into the crack by capillary action, then by highlighting its presence after application of a developing agent
It will show up a surface flaw
To aid the detection of a surface crack, the dye is often luminous and is revealed under an ultra violet light

10. DYE PENETRANT TEST
The dye penetrant test consists of the following steps:
The surface of the metal to be inspected is cleaned first and a low viscosity penetrant is sprayed on.
After a set time the surface is cleaned again.
Then a developer is coated on the surface the dye seeps out if there is any crack and stains the developer red

11. DYE PENETRANT TEST Disadvantages Advantages
A simple way to detect surface opening cracks and porosities in non porous and clean specimen
Low-cost
It can detect small defect on smooth and clean surfaces
Disadvantages
Cannot be used for rough and dirty surfaces

12. MAGNETIC PARTICLE INSPECTION
Process
It is carried out by locally magnetizing the specimen by a yoke or a coil
Then by spreading a fluid of magnetic particles e.g. iron fillings suspended in paraffin on its surface
Any discontinuity such as a surface crack will show up as the particles will concentrate at the point where there is an alteration in the magnetic field

13. MAGNETIC PARTICLE INSPECTION
A component is place between two poles of a magnet The lines of magnetism concentrate around flaws.
Magnetic particles are then applied, in a light oil or dry sprayed, onto the surface where they indicate the lines of magnetism and any anomalies

14. MAGNETIC PARTICLE INSPECTION

15. MAGNETIC PARTICLE INSPECTION
Advantages
Portable
Fast and rapid
Low cost
Defects like cracks, slag inclusions and gas porosities can be detected
Disadvantages
Can be used only in Ferro-magnetic material only

16. RADIOGRAPHIC INSPECTION
Process
A material is subjected to radiation from one side, and record the radiation emitted from the opposite side
Either x ray or gamma ray devices may be used to provide the source of radiation
Ant obstacle in the path of the radiation will affect the radiation density emitted and may be recorded
As radiation will expose photo graphic plates, they are used to record the emitted rays
The photographic plates records changes in radiation density emitted
Thus any defects in welding can be found out by this method

17. RADIOGRAPHIC INSPECTION
Equipment used

18. RADIOGRAPHIC INSPECTION
Advantages
It can give a permanent record of the test for future evidence
It is a quick process
Accurate results
Disadvantages
Cannot use for thick sections
Cannot use in places of difficult access
The process fails without electricity
To interpret the weld radiograph a large amount of experience is required
gamma rays is an alternative to x rays because of this disadvantages

19. ULTRASONIC INSPECTION
Process
The principle of ultrasonic inspection depends on the fact that pulses of ultrasonic energy are reflected from any surface which they encounter
Virtually total reflection occurs at an air-metal interface, and therefore to get the ultrasonic wave into the metal a liquid (usually grease) is placed between the source and metal
Pulsed beams of ultrasonic waves pass through the object

20. ULTRASONIC INSPECTION
Waves traveling through a plate may be reflected from the surface of the metal and also from the surfaces of any flaws in the metal
A receiver detects the reflected waves signal, which is displayed after signal amplification and analysis by the instrument
The pattern of reflection is revealed on either Cathode ray tube or liquid crystal display
From that we will be able to recognize type and location of flaws

21. ULTRASONIC INSPECTION
Advantages
Low cost
Equipments used are easy to handle
No health hazards
The technique is used for locating fine cracks, which are missed by radiography
They can also be used for assessing the thickness of structural members