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NEST Institute of Non Destructive Testing

Nest (National Employment Service and Training) is a leadingtraining institute for ASNT level II. We are the only training centregiving 100% placement assistance to the candidates till candidates

get placed. Our trainers are having more than ten years of fieldexperience in industries like petroleum refineries and power plant(nuclear, thermal). The candidates will get both theoretical andpractical during the training session. We are moulding our candidateswith advance training medium like visual and audio to enrich theirknowledge. Our candidates will get a globally authenticationcertificates from ASNT America Society for Non Destructive Testinglevel II as per SNT-TC-1A standard on successful completion of training and practical exams.

Our candidates will get onsite training in the particularindustries like refineries and power plant to get a real timeexperience. Nest takes whole responsibilities of our candidatesdeveloping in their career. Other than NDT training, we are providingMotivation class, personality development session to get through intheir interviews with fear.

Nest Institute of NDT posse’s high quality international standardtraining for NDT in accordance with quality management system andpursuing placement for candidates to improve their career.

To give quality training and education along with placement forthe youngsters to enrich their career (or) to make their life delightful.

CoursesVISUAL TESTING, LIQUID PENETRANT TESTING, MAGNETIC

PARTICLE TESTING, RADIOGRAPHY TESTING, ULTRASONIC TESTING.

VISUAL TESTING, LIQUID PENETRANT TESTING,

The earliest and most useful method of NDT is visual examination.Important details can be collected during VT which would be usefulfor future analysis and also to decide on the types of NDT to be usedfor as further analysis. Also, VT should be carried out as acomplementary method to all other NDT methods. VT should proceedand succeed all other examinations. Inaccessible areas can beinspected by means of boroscope and fibre-optic techniques.Depending upon the severity of the surface defect and thecomponent in use, decision will be taken for salvaging the component

or not. If the product is found unacceptable during visual examination

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itself, further NDT need not be carried out, thus saving time and costof inspection.

VT is selected for detecting the following discontinuities:

1. Surface deposits2. Scaling3. Corrosion4. Discoloration5. Oxidation bulging6. Missing parts7. Mechanical damage8. Dimensional conformance9. Gross effects visible on the surface10. Distortion of components during fabrication and in

services11. General corrosion on the surface of a component

LIQUID PENETRANT TESTING

Liquid penetrant testing (LPT) is another means of

enhancing the capability of visual examination. It is suitable for useon smooth surfaces of all materials, magnetic as well as non-magnetic. It is limited to surface defects. Its inability to indicate thedepth or breadth of flaw should be kept in mind while selecting thismethod for particular application.

Use of LPT for porous materials is ruled out since the absorptioninto the pores would mask the presence of defects. A clean surface isa pre-resist as penetrant cannot enter in to the cracks that are filledwith dirt, oil, or other matter.

Size, shape, weight and number of work pieces to be inspected

often influence the selection of a penetrant system. The desireddegree of sensitivity and the cost are the most important factors inselecting a system.

LPT can also be used for leak testing. In this case, thecomponent casting is filled with penetrant and developer is appliedoutside the surface.

LPT is selected for detecting the following types of discontinuities on the surface of a component.

1. Cracks of any orientation

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5. Voids6. Forging laps7. Grinding cracks8. Corrosion cracks9. Fatigue cracks

Discontinuities just below the surface (within around 6mm depth fromthe surface sensitivity goes down as a defect is deeper):

1. Larger size cracks in various orientations2. Pores3. Slag inclusions

RADIOGRAPHY TESTING

The other NDT methods are used for detection of defects whichare open to the surface nearer to the surface. To detect more deeplyseated discontinuities, NDT methods with test medium capable of deeper penetration and system that senses even minute changes inthe characteristics, behaviour of the test medium is required.Radiographic inspection is one of the most widely used methods of NDT as this is applied to all metals and alloys, both ferrous andnonferrous, for detection of volumetric type of defects. The range of capabilities offered by the variety of sources and equipments hasbrought radiography to the forefront of NDT techniques.

Testing of multilayer vessels and welds is generally a difficulttask due to in accessible inner layers. RT is the only NDT method toevaluate multilayered vessels during manufacturing stages and in-service.Development of micro focal X-ray units has made it possible toextend radiographic practice to meet the requirements of morestringent quality levels demanded for critical applications, besides ahost of new applications. It is know that the sensitivity in radiographydepends to a large extend on the focal spot size. In micro focalradiography, the focal spot size is less than 100microns and typically15-50 micron as compared to a few mm or ½ a mm in conventional

radiography. Using micro focal RT, intricate geometrical componentssuch as tube to tube sheet. Welds can be tested with a sensitivity of even 1% of wall thickness 0-3mm. micro focal RT can be used fordetection of micro cracks of around 25micron in size. Anotherapplication of micro focal RT is to check the integrity of micro-weldsused electronic integrated circuits.

One of the advantages of RT is that no prior preparation of thesurface of the component is necessary. The main disadvantage of theRT is the possible hazards due to exposure to radiation if proper care

is not taken.

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RT is selected to detect and size the following types of discontinuities

1. Cracks (parallel to the radiation beam)2. Volumetric defects such as slag inclusions, voids etc:3. Porosity

4. Blockages or deposits inside the pipe lines are pressurevessels

5. Material thickness6. To detect hidden foreign material inside a component

ULTRASONIC TESTING

Ultrasonic testing involves use of high frequency sound wavescoupled to the components to be inspected and studying thereflection pattern of these waves. UT is finding increased applicationsin various industries. Several wave modes such as longitudinal, shearand surface waves can be used depending on the orientation andlocation of the discontinuities. Different techniques such as pulse-echo, through transmission, and pitch-catch or employed. Theadvantages of UT are real time availability of results, higherpenetrating power of these waves, higher sensitivity for plannerdefects, independence sensitivity over depths, low cost forinspection, higher portability to the equipment and compatibility forautomation. But the subjectivity of the results on the operators

training and skill is stumbling block for its wider acceptance. With theadvent of microprocessors and automation, operator dependability isbeing eliminated to a larger extent and UT finding increasedapplications in industries such as power, railways, chemical,aerospace etc:

UT of cast metals and alloys is rendered difficult due to theinfluence of casting intricacy, micro structural variations and surfaceroughness. Defects occurring in the cast structure have irregularsurfaces which scatter the acoustic waves and makes UT moredifficult. Hence successful use of UT for inspection of castings

depends greatly upon the skill and expertise of the operator.

UT is the most suitable method of NDT for in-service inspection(ISI) of components in power plants, chemical process industries, etc:.Many times, RT cannot be applied for ISI due to the requirements of two side accessibility. UT is more sensitive flaw growth monitoringhas compared with RT in view of all these advantages; the first choiceof ISI is UT for volumetric defects in components except for heatexchangers and condensers where ECT is preferred.

UT is selected to detect the size the following type of discontinuities

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1. Surface breaking and hidden cracks in any orientation2. Inter granular cracks3. Laps4. Laminations

5. Volumetric defects such slag inclusions, voids, ect6. Porosity7. Wall thickness measurements8. Creep9. Hydrogen encriptment10. Liquid level measurement11. To detect blockages, deposits, etc. in the pipe lines

and pressure vessels

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