2023年全國碩士研究生考試考研英語一試題真題（含答案詳解+作文范文）_第1頁
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1、Designation:E1962?14StardPracticefUltrasonicSurfaceTestingUsingElectromagicAcousticTransducer(EMAT)Techniques1ThisstardisissuedunderthefixeddesignationE1962thenumberimmediatelyfollowingthedesignationindicatestheyearofigi

2、naladoptioninthecaseofrevisiontheyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperepsilon()indicatesaneditialchangesincethelastrevisionreapproval.1.Scope1.1Thispracticecoversguidelinesfutiliz

3、ingEMATtechniquesfdetectingmaterialdiscontinuitiesthatareprimarilyopentothesurface(fexamplecracksseamslapscoldshutslaminationsthroughleakslackoffusion).Thistechniquecanalsobesensitivetoflawsdiscontinuitiesthatarenotsurfa

4、cebreakingprovidedtheirproximitytothesurfaceislessthanequaltotheRayleighwavelength.1.2Thispracticecoversproceduresfthenoncontactcouplingofsurfacewavesintoamaterialviaelectromagicfields.1.3Theproceduresofthispracticeareap

5、plicabletoanymaterialinwhichacousticwavescanbeintroducedelectromagically.Thisincludesanymaterialthatiseitherelectricallyconductiveferromagicboth.1.4Thispracticeisintendedtoprovideexaminationcapabilitiesfinprocessfinalmai

6、ntenanceapplications.1.5Thispracticedoesnotprovidestardsftheevaluationofderivedindications.Interpretationclassificationultimateevaluationofindicationsalbeitnecessaryarebeyondthescopeofthispractice.Separatespecificationsa

7、greementwillbenecessarytodefinethetypesizelocationdirectionofindicationsconsideredacceptablenonacceptable.1.6Thevaluesstatedininchpoundunitsaretoberegardedasthestards.TheSIunitsgiveninparenthesesarefinfmationonly.1.7This

8、starddoesnotpurpttoaddressallofthesafetyconcernsifanyassociatedwithitsuse.Itistheresponsibilityoftheuserofthisstardtoestablishappropriatesafetyhealthpracticesdeterminetheapplicabilityofregulatylimitationspritouse.2.Refer

9、encedDocuments2.1ASTMStards:2E543SpecificationfAgenciesPerfmingNondestructiveTestingE587PracticefUltrasonicAngleBeamContactTestingE1316TerminologyfNondestructiveExaminationsE1774GuidefElectromagicAcousticTransducers(EMAT

10、s)E1816PracticefUltrasonicTestingUsingElectromagicAcousticTransducer(EMAT)Techniques2.2ANSIASNTStards:RecommendedPracticeSNTTC1APersonnelQualificationCertificationinNondestructiveTesting3ANSIASNTCP189StardfQualificationC

11、ertificationofNondestructiveTestingPersonnel32.3MilitaryStard:MILSTD410NondestructiveTestingPersonnelQualificationCertification43.Terminology3.1Definitions:3.1.1AdditionalrelatedterminologyisdefinedinTerminologyE1316.3.2

12、DefinitionsofTermsSpecifictoThisStard:3.2.1electromagicacoustictransducer(EMAT)—anelectromagicdevicefconvertingelectricalenergyintoacousticalenergyinthepresenceofamagicfield.3.2.2Lentzfces—appliedtoelectriccurrentswhenpl

13、acedinamagicfield.Lentzfcesareperpendiculartoboththedirectionofthemagicfieldthecurrentdirection.3.2.3magostrictivefces—fcesarisingfrommagicdomainwallmovementswithinamagicmaterialduring1Thispracticeisunderthejurisdictiono

14、fASTMCommitteeE07onNondestructiveTestingisthedirectresponsibilityofSubcommitteeE07.06onUltrasonicMethod.CurrenteditionapprovedOct.12014.PublishedOctober2014.iginallyapprovedin1998.Lastpreviouseditionapprovedin2009asE1962

15、09.DOI:10.1520E196214.2FreferencedASTMstardsvisittheASTMwebsitewww.astm.gcontactASTMCustomerServiceat.FAnnualBookofASTMStardsvolumeinfmationrefertothestard’sDocumentSummarypageontheASTMwebsite.3AvailablefromAmericanNatio

16、nalStardsInstitute(ANSI)25W.43rdSt.4thFloNewYkNY10036:www.ansi.g.4AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments732N.CapitolSt.NWMailStop:SDEWashingtonDC20401.ASummaryofChangessectionappearsattheendof

17、thisstardCopyright?ASTMInternational100BarrHarbDrivePOBoxC700WestConshohockenPA194282959.UnitedStates15.4ThepurposeofthispracticeistopromotetheEMATtechniqueoftheultrasonicmethodasaviablealternativetoconventionalPTMPTmeth

18、odsfdetectingthepresenceofsurfacenearsurfacematerialdiscontinuities.5.5TheuseofEMATstheionofappropriateoperatingparameterspresupposeaknowledgeofthegeometryofthecomponenttheprobablelocationsizeientationreflectivityoftheex

19、pectedflawstheallowablerangeofEMATliftoffthelawsofphysicsgoverningthepropagationofultrasonicwaves.ThisprocedurepertainstoaspecificEMATsurfaceinspectionapplication.6.BasisofApplication6.1Thefollowingitemsaresubjecttocontr

20、actualagreementbetweenthepartiesusingreferencingthestard:6.1.1PersonnelQualification6.1.1.1Ifspecifiedinthecontractualagreementpersonnelperfmingexaminationtothispracticeshallbequalifiedinaccdancewithanationallyinternatio

21、nallyrecognizedNDTpersonnelqualificationpracticestardsuchasANSIASNTCP189SNTTC1AMILSTD410asimilardocumentcertifiedbytheemployercertifyingagencyasapplicable.Thepracticestarduseditsapplicablerevisionshallbeidentifiedintheco

22、ntractualagreementbetweentheusingparties.6.1.2QualificationofNondestructiveAgencies—IfspecifiedinthecontractualagreementNDTagenciesshallbequalifiedevaluatedasdescribedinPracticeE543.TheapplicableeditionofPracticeE543shal

23、lbespecifiedinthecontractualagreement.6.1.3ProceduresTechniques—Theprocedurestechniquestobeutilizedshallbeasspecifiedinthecontractualagreement.6.1.4SurfacePreparation—Thepreexaminationsurfacepreparationcriteriashallbeina

24、ccdancewith10.2.2unlessotherwisespecified.6.1.5TimingExtentofExamination—Shallbespecifiedinthecontractualagreement6.1.6ReptingCriteriaAcceptanceCriteria—ReptingcriteriaftheexaminationresultsshallbeinaccdancewithSection12

25、unlessotherwisespecified.Acceptancecriteriashallbespecifiedinthecontractualagreement.6.1.7ReexaminationofRepairedReWkedItems—Reexaminationofrepairedrewkeditemsisnotaddressedinthispracticeifrequiredshallbespecifiedintheco

26、ntractualagreement.7.Techniques7.1ThispracticedescribesthreeseparatetechniquesfEMATsurfacewaveexamination.Thefirstinvolvespulseechopitchcatchtechniquesfthedetectionofreflectedsurfacewaves.Thesecondtechniqueinvolvesapitch

27、catchmethodsensitivetotheattenuationofsurfacewaves.Thethirdtechniqueinvolvessurfacewavediffractionwithfocusedmeercoils.7.2PulseEchoPitchCatchReflectedSurfaceWaveTechnique—Thesetechniquesareanalogoustoconventionalultrason

28、ictechniques.Thetechniquesuseeitherone(pulseecho)two(pitchcatch)EMATsenssrelyuponthereceptionofreflectedsurfacewavesfromtheflaw.Theadvantageofthesetechniquesissimplicity.Onedisadvantageisthedifficultyindetectingallflawie

29、ntationswithoutelabatescanningroutines.Alsowhenthesetechniquesareusedfweldapplicationsaproblemarisesinthattherootcrownoftheweldcanproducereflectionsthatareprominentenoughtointerferewithevenobscureflawsignals.Whensuchinte

30、rferencesareapparentitisrecommendedthatoneoftheothertwotechniquesdescribedhereinbeutilizedtoavoidtheseproblems.7.3PitchCatchAttenuationTechnique—Theattenuationtechniqueismosteffectivelyappliedusingthearrangementofsenssil

31、lustratedinFig.3.ThetechniqueindicatesthepresenceofaflawbynotingattenuationoftheUTsignal.Thesenssusesmallpermanentmagstogeneratenarrowsurfacewavebeamsthatcrossatrightangles.ThepreferredtechniquerequirestwochannelsofEMATi

32、nstrumentationalthoughitmaybemodifiedfonechanneloperation.Toimplementonechanneloperationthedistancebetweenonetransmitterreceiverpairisincreasedslightlytodisplacethetworeceivedsignalsintime.Thetransmittercoilsarethenwired

33、inseriesthereceivercoilsarewiredinseries.ThisarrangementallowsbothpairsofEMATcoilstobeusedwithonechannelofEMATinstrumentation.Oneadvantagetotheattenuationtechniqueissensitivitytoallflawientations.Anotheradvantagetousingt

34、heattenuationtechniqueistheabilitytoscanbothsidesofaweldsimultaneously.Italsoscanslargeareasofthematerialinonescan.Adisadvantagerelatestothebeamwidthwhichmustbenarrowfocusedindertoachieveaminimumof6dBofattenuation.7.4Dif

35、fractionTechnique—ThebasisofthediffractiontechniqueisillustratedinFig.4.TwocollinearfocusedEMATs(transmitterreceiver)onepulseechoEMATarepositionedatanangle(thediffractionangle)withrespecttothenmaltotheweldcenterline.Thew

36、eldrootcrownactasaspecularreflectwhosesignalsarereflectedawayfromtheEMATreceiver.Theflawishoweverdetectedoverawideangularrangebymeansofdiffraction.Dependinguponthesizeoftheflawrelativetotheultrasonicwavelengthitactsaseit

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