UNIT I NDT NON- DESTRUCTIVE TESTING

1 NON- DESTRUCTIVE TESTINGDEPARTMENT OF MECHANICALENGINEERINGINSTITUTE OF AERONAUTICALENGINEERING(Autonomous)DUNDI GAL, HYDERABAD -500043B. Tech VI semester (IARER16)BYMr. A. VENUPRASAD, AssociateProfessorMr. A. ANUDEEP KUMAR, AssistantProfessor1 UNIT INDTNON- DESTRUCTIVE TESTING2 Other terms used in NDTNon- DESTRUCTIVE examination (NDE)Non- DESTRUCTIVE inspection (NDI)Non- DESTRUCTIVE evaluation (NDE)3 OBJECTIVE OF NDT Material sorting Material characterization Property monitoring (for process control) Thickness measurement Defect Detection/ Location and Defect characterization.

2 ,grindingcracks,voids(pores),andfatiguec racks(Generatedduringservice).4 NDT(Non- DESTRUCTIVE TESTING )?Non-destructivetesting(NDT)istheproces sofinspecting, TESTING ,orevaluatingmateri als,componentsorassembliesfordiscontinui ties, , TESTING NDTisanexaminationthatisperformedonanobj ectofanytype,size,shapeormaterialtodeter minethepresenceorabsenceofdiscontinuitie s,ortoevaluateothermaterialcharacteristi cs 67 Types of NDT8 Visual Inspection Visualinspectionisthesimplest,fastestand mostwidelyusedNDTmethod. Visualinspectioniscommonlydefinedas theexaminationofamaterialcomponent,orpro ductforconditionsofnonconformanceusingli ghtandeyes,aloneorinconjunctionwithvario usaids.

3 Visualinspectionoftenalsoinvolvesshaking ,listening,feeling,andsometimesevensmell ingthecomponentbeinginspected. Visualinspectioniscommonlyemployedtosupp ort/complimentotherNDTmethods. Detected(Applicility)This visual inspection is commonly detect surface characteristics such as finish, Scratches, cracks or check stain in transparent inspect Seeingisbelievingandtheartofseeingisthev isualinspectiontechnique. Visualtestingrequiresadequateilluminatio nofthetestsurfaceandpropereye-sightofthe tester. ,theopticalaidssuchasmirrors,magnifyingg lasses,microscopes, of VT Simple and easy to use.

4 Relatively inexpensive. TESTING speed is high. TESTING can be performed on components which are in service. Permanent record are available when latest equipment is used. 12 Limitation The test result depend on skill and knowledge of tester. Limited to detection of surface flaws. Eye resolution is weak. Eye Checking of the surface condition of the component. Checking of alignment of surfaces. Checking of shape of the component. Checking for evidence of leaking. Checking for internal side of visual testingUnaided or direct visual TESTING , and Aided visual or direct visual TESTING Asthenamesuggest,theunaidedvisualtesting iscarriedoutwithnakedeye(andwithoutusing anyopticalaids) PARTICL TESTING (MT) MAGNETICPARTICLTESTING(MT) LINES OF FLUX: It is the number of magnetic field lines passing through a surface (such as a loop of wire).

5 The magnetic flux through a closed surface is always zero.. The SI unit of magnetic flux is the Weber (Wb) The magnetic lines of forces existing in a magnetic field is called magnetic flux. The lines of flux ran through the magnets from south to north, exiting the north pole and re entering the south pole. The lines of flux formed closed loops that never With direct magnetization, current is passed directly through thecomponent. The flow of current causes a circular magnetic field to form in and around theconductor. When using the direct magnetization method, care must be taken to ensure that good electrical contact is established and maintained between the test equipment and the test component to avoid damage of the component (due to arcing or overheating at high resistancepoints).

6 2122 Clamping The Component Between Two ElectricalContacts One way involves clamping the component betweentwo electrical contacts in a special piece ofequipment. Current is passed through the component and a circular magnetic field is established in and around ORPRODS A second technique involves using clamps or prods, which are attached or placed in contact with the component. Electrical current flows through the component from contact tocontact. The current sets up a c path of ,thereareseveralwaysthatindirectmagnetiz ationcanbeaccomplished.

7 :- Theuseofpermanentmagnetsisalowcostmethod ofestablishingamagneticfield. However,theiruseislimitedduetolackofcont rolofthefieldstrengthandthedifficultyofp lacingandremovingstrongpermanentmagnetsf romthe26 PERMANENT MAGNETELECTROMAGNET27 ELECTROMAGNET Electromagnetsintheformofanadjustablehor seshoemagnet(calledayoke)eliminatethepro blemsassociatedwithpermanentmagnetsandar eusedextensivelyinindustry. Electromagnetsonlyexhibitamagneticfluxwh enelectriccurrentisflowingaroundthesofti roncore. Whenthemagnetisplacedonthecomponent, TESTING29 INTRODUCTION Ultrasonictesting(UT)istheoneofthepopula rflawdetectionnon-destructivetestingmeth ods.

8 Inultrasonictestinghighfrequencysoundene rgyisusedtoidentifysurfaceansub-surfaced iscontinuities. Becauseofitshighpenetrationcapacity, of Propagation Longitudinal waves Shear waves Surface waves (Rayleigh), and Lamb waves (plate)32longitudinal waves In a longitudinal waves, Particle motion in the medium is parallel to the direction of the wave front33 Transverse wave34 Transverse wave Atransversewaveisamovingwavethatconsists ofoscillationsoccurringperpendicular(rig htangled)tothedirectionofenergytransfer( orthepropagationofthewave).35 Surface waves Surfacewavesrepresentanoscillatingmotion thattravelsalongthesurfaceofatestpieceto adepthofonewavelength.

9 Used in UT3738 FREQUENCY Generallythechoiceoftestfrequencydepends upontwofactors:theminimumsizeofdefect, Penetration Depth:Penetration depth is the maximum depth in a material, the flaws can be located by the ultrasonic waves in TESTING . Scattering:Scattering is the reflection of sound beam its original direction of propagation. Absorption:Absorption is conversion of sound energy from one form to some another IIIRADIOGRAPHY TESTING46 RADIOGRAPHY TESTING Theradiationusedinradiographytestingisah igherenergy(shorterwavelength) Electrical PotentialElectrons-+X-ray Generator or Radioactive Source Creates RadiationExposure Recording DeviceRadiation Penetrate the Sample48 Introduction ThismodulepresentsinformationontheNDTmet hodofradiographicinspectionorradiography .

10 Radiographyusespenetratingradiationthati sdirectedtowardsacomponent. Thesedifferencesin absorption canberecordedonfilm, Electromagnetic Radiation General Principles of Radiography Sources of Radiation Gamma Radiography X-ray Radiography Imaging Modalities Film Radiography Computed Radiography Real-Time Radiography Direct Digital Radiography Computed Radiography Radiation Safety Advantages and Limitations Glossary of Terms50 Electromagnetic Radiation TheradiationusedinRadiographytestingisah igherenergy(shorterwavelength) Principles of Radiography Thefilmdarkness(density)