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NON-DESTRUCTIVE TESTING by GROUP-E MEMBERS 1 JUDE RINALDO 2 JUDE PRADEEP 3 AARYL DSA 4 SWAROOP SUNDER.

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Presentation on theme: "NON-DESTRUCTIVE TESTING by GROUP-E MEMBERS 1 JUDE RINALDO 2 JUDE PRADEEP 3 AARYL DSA 4 SWAROOP SUNDER."— Presentation transcript:

1 NON-DESTRUCTIVE TESTING by GROUP-E MEMBERS 1 JUDE RINALDO 2 JUDE PRADEEP 3 AARYL DSA 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 There are five of non destructive tests: Visual examination Dye penetrant test Magnetic particle inspection Radiographic inspection Ultra sonic inspection NON-DESTRUCTIVE TESTING

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 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. VISUAL EXAMINATION

7 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. VISUAL EXAMINATION

8 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 VISUAL EXAMINATION

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 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 DYE PENETRANT TEST

11 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 DYE PENETRANT TEST

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 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 MAGNETIC PARTICLE INSPECTION

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 Equipment used RADIOGRAPHIC INSPECTION

18 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 RADIOGRAPHIC INSPECTION

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 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 ULTRASONIC INSPECTION

21 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 ULTRASONIC INSPECTION


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