ASTME1444-94a磁粉检测实践标准 英文版

如题

Designation: E 1444– 94a

An American National Standard

Standard Practice for

Magnetic Particle Examination1This standard is issued under the xed designation E 1444; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. This specication has been approved for use by agencies of the Department of Defense.

1. Scope 1.1 This practice establishes minimum requirements for magnetic particle examination used for the detection of surface or slightly subsurface discontinuities in ferromagnetic material. This practice is intended as a direct replacement of MIL-STD1949. Guide E 709 can be used in conjunction with this practice as a tutorial. 1.2 The magnetic particle examination method is used to detect cracks, laps, seams, inclusions, and other discontinuities on or near the surface of ferromagnetic materials. Magnetic particle examination may be applied to raw material, billets, nished and seminished materials, welds, and in-service parts. Magnetic particle examination is not applicable to nonferromagnetic metals and alloys such as austenitic stainless steels. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents 2.1 The following documents form a part of this standard practice to the extent specied herein. 2.2 ASTM Standards: A 275/A 275M Test Method for Magnetic Particle Examination of Steel Forgings2 A 456 Specication for Magnetic Particle Inspection of Large Crankshaft Forgings2 D 96 Test Methods for Water and Sediment in Crude Oil by the Centrifuge Method (Field Procedure)3 E 543 Practice for Evaluating Agencies that Perform Nondestructive Testing4 E 709 Guide for Magnetic Particle Examination4 E 1316 Terminology for Nondestructive Examinations4 2.3 ASNT Document:This practice is under the jurisdiction of ASTM Committee E-7 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.03 on Liquid Penetrant and Magnetic Particle Methods. Current edition approved Nov. 15, 1994. Published January 1995. Originally published as E 1444– 91. Last previous edition E 1444– 94. 2 Annual Book of ASTM Standards, Vol 01.05. 3 Annual Book of ASTM Standards, Vol 05.01. 4 Annual Book of ASTM Standards, Vol 03.03.1

SNT-TC-1A Recommended Practice and Supplement Magnetic Particle Inspection5 2.4 Society of Automotive Engineers (SAE)-AMS Documents:6 AMS 2300 Premium Aircraft-Quality Steel Cleanliness Magnetic Particle Inspection Procedure7 AMS 2301 Aircraft Quality Steel Cleanliness Magnetic Particle Inspection Procedure7 AMS 2303 Aircraft Qu

ality Steel Cleanliness Martensitic Corrosion Resistant Steels Magnetic Particle Inspection Procedure7 AMS 2641 Magnetic Particle Inspection Vehicle7 AMS 3040 Magnetic Particles, Nonuorescent, Dry Method7 AMS 3041 Magnetic Particles, Nonuorescent, Wet Method, Oil Vehicle, Ready-To-Use7 AMS 3042 Magnetic Particles, Nonuorescent, Wet Method, Dry Powder7 AMS 3043 Magnetic Particles, Nonuorescent, Wet Method, Oil Vehicle, Aerosol Packaged7 AMS 3044 Magnetic Particles, Fluorescent, Wet Method, Dry Powder7 AMS 3045 Magnetic Particles, Fluorescent, Wet Method, Oil Vehicle, Ready-To-Use7 AMS 3046 Magnetic Particles, Fluorescent, Wet Method, Oil Vehicle, Aerosol Packaged7 AMS 5355 Investment Castings7 2.5 Federal Standards:6 FED-STD-313 Material Safety Data Sheets, Preparation and the Submission of8 FED-STD-595 Colors8 2.6 Military Standards:6 MIL-STD-1907 Inspection, Liquid Penetrant and Magnetic Particle Soundness Requirements for Materials, Parts, and Weldments85 Available from American Society for Nondestructive Testing, 1711 Arlingate Plaza, P.O. Box 28518, Columbus, OH 43228-0518. 6 Copies of standards, specications, drawings, and publications required by manufacturers in connection with specication acquisition should be obtained from the contracting activity or as directed by the contracting officer. 7 Available from Society of Automotive Engineers, 400 Commonwealth Drive, Warrendale, PA 15096. 8 Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700 Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.

Copyright ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.

如题

MIL-STD-410NondestructiveTestingPersonnelQuali ca-

tionandCerti cation8

MIL-STD-1949MagneticParticleInspection,Methodof8

MIL-STD-2175Castings,Classi cationandInspectionof8

MIL-STD-45662CalibrationSystemsRequirements

MIL-I-83387InspectionProcess,MagneticRubber8

DoD-F-87935Fluid,MagneticParticleInspection,Suspen-

sion(Metric)8

2.7OSHADocument:9

29CFR1910.1200HazardCommunication

2.8DoDContracts—Unlessotherwisespeci ed,theedi-

tionsofthedocumentsthatareDoDadoptedarethoselistedin

theissueoftheDoDISS(DepartmentofDefenseIndexof

Speci cationsandStandards)citedinthesolicitation.

2.9OrderofPrecedence—Intheeventofcon ictbetween

thetextofthispracticeandthereferenceddocumentscited

herein,thetextofthispracticetakesprecedence.

3.Terminology

3.1De nitions—Thede nitionsrelatingtomagneticpar-

ticleexamination,whichappearinTerminologyE1316,shall

applytothetermsusedinthispractice.

3.2De nitionsofTermsSpeci ctoThisStandard:

3.2.1alternatingcurrent(ac)—anelectricalcurrentthat

reversesitsdirectionof owatregularintervals.

3.2.2ambientlight—thevisiblelightlevelmeasuredatthe

specimensurfacewiththeblacklight(s)on.

3.2.3contractingagency—aprimecontractor,subcontrac-

tor,orgovernmentagencyprocuringmagneticparticleinspec-

tionservices.

3.2.4gauss(G)—theunitof uxdensityorinductioninthe

cgselectromagneticunitsystem(1G510 4Tesla(T);inair,

1Gisequivalentto1oersted(Oe),whichequals79.58A/m).

3.2.5headshot—theproductionofcircularmagnetization

bypassingcurrentdirectlythroughthepartbeinginspected,or

centralconductor,whilebeingheldincontactwiththehead

stocksinahorizontalwetmachine.

3.2.6magnetic ux—aconceptualizationofthemagnetic

eldintensitybasedonthelinepatternproducedwheniron

lingsaresprinkledonpaperlaidoverapermanentmagnet.

Themagnetic eldliesinthedirectionofthe uxlinesandhas

anintensityproportionaltothelinedensity.

3.2.7magnetization—theprocessbywhichtheelementary

magneticdomainsofamaterialarepredominantlyalignedin

onedirection.

3.2.8retentivity—theabilityofamaterialtoretainmagne-

tismafterthemagnetizingforcehasbeenremoved.

4.Signi canceandUse

4.1Magneticparticleexaminationconsistsofmagnetizing

theareatobeinspected,applyingsuitablypreparedmagnetic

particleswhiletheareaismagnetized,andsubsequently

interpretingandevaluatinganyresultingparticleaccumula-

9AvailablefromSuperintendentofDocuments,U.S.GovernmentPrinting

Office,Washington,D.C.

20402.tions.Maximumdetectabilityoccurswhenthediscontinuityispositionedperpendiculartothemagnetic ux.Inordertodetectdiscontinuitiesinalldirections,atleasttwomagnetic elds,perpendiculartooneanotherinaplaneparalleltothesurfacebeinginspected,shallbeused,exceptwhenspeci callyexemptedbythecontractingagency.5.GeneralPractice5.1AcceptanceRequirements—Theacceptancerequire-mentsapplicabletothepartorgroupofpartsshallbeincorporatedaspartofthewrittenprocedureeitherspeci callyorbyreferencetootherapplicabledocuments,suchasMIL-STD-1907,containingthenecessaryinformation.Applicabledrawingsorotherdocumentsshallspecifytheacceptancesizeandconcentrationofdiscontinuitiesforthecomponent,withzoningofuniqueareasasrequiredbydesignrequirements.Theseacceptancerequirementsshallbeasapprovedonorasspeci edbythecontractingagency.MethodsforestablishingacceptancerequirementsforlargecrankshaftforgingsarecoveredinSpeci cationA456.MethodsforestablishingrequirementsforsteelforgingsarecoveredinTestMethodA275/A275M.MethodsforclassifyingmetalcastingsaregiveninMIL-STD-2175andAMS5355.MIL-STD-1907pro-videsaclassi cationschemeforferromagneticforgings,cast-ings,extrusions,andweldments.5.1.1Aircraft-QualitySteelCleanliness—Theexaminationofaircraft-qualitysteelforcleanlinessusingmagneticparticleexaminationshallbeasspeci edinAMS2300,2301,or2303asappropriatetothetypeofsteelbeinginspected.However,inspectionofpartsfabricatedfromthismaterialshallbeinaccordancewiththerequirementsofthispractice.5.2PersonnelQuali cation—Personnelperformingexami-nationsinaccordancewiththispracticeshallbequali edandcerti edinaccordancewithASNTPersonnelQuali cationSNT-TC-1AorMIL-STD-410formilitarypurposes,orasspeci edinthecontractorpurchaseorder.5.3AgencyQuali cation—Theagencyperformingthetest-ingorexaminationshallmeet,asaminimum,therequirementsofPracticeE543.5.4WrittenProcedure—Magneticparticleexaminationshallbeperformedinaccordancewithawrittenprocedureapplicabletothepartsorgroupofpartsundertesting.Theprocedureshallbeinaccordancewiththerequirementsandguidelinesofthispractice.Theprocedureshallbecapableofdetectingthesmallestrejectablediscontinuitiesspeci edintheacceptancerequirements.Thewrittenproceduremaybegen-eralifitclearlyappliestoallofthespeci edpartsbeingtestedandmeetstherequirementsofthispractice.Allwrittenproceduresshallbeapprovedbyanindividualquali edandcerti edatLevelIIIformagneticparticleexaminationinaccordancewith5.2.Proceduresshallbesubmittedtothecontractingagencywhenrequested.5.4.1ElementsoftheWrittenProcedure—Thewrittenpro-cedureshallincludeatleastthefollowingelements,eitherdirectlyorbyreferencetotheapplicabledocuments:5.4.1.1Procedureidenti cationnumberandthedateitwaswritten;5.4.1.2Identi cationofthepartstowhichtheprocedure

如题

applies;thisshallincludethematerialandalloyofwhichthe

partsarefabricated;

5.4.1.3Sequenceofmagneticparticleexaminationasre-

latedtomanufacturingprocessoperation,ifapplicable;

5.4.1.4Identi cationoftestpartsusedforsystemperfor-

manceveri cation(see7.1.2and7.1.3);

5.4.1.5Areasoftheparttobeexamined(includean

illustration–eithersketchorphoto);

5.4.1.6Partpreparationrequiredbeforetesting;

5.4.1.7Directionsforpositioningtheitemwithrespectto

themagnetizingequipment;

5.4.1.8Thetypeofmagnetizingcurrentandtheequipment

tobeused;

5.4.1.9Methodofestablishingthemagnetization(head,

coil,prods,yoke,cablewrap,etc.);

5.4.1.10Directionsofmagnetizationtobeused,theorderin

whichtheyareapplied,andanydemagnetizationproceduresto

beusedbetweenshots;

5.4.1.11Thecurrentlevel,orthenumberofampereturns,to

beusedandthedurationofitsapplication;

5.4.1.12Typeofmagneticparticlematerial(dryorwet,

visibleor uorescent,etc.)tobeusedandthemethodand

equipmenttobeusedforitsapplicationand,forthecaseofwet

particles,theparticleconcentrationlimits;

5.4.1.13Typeofrecordsandmethodofmarkingpartsafter

examination;

5.4.1.14Acceptancerequirements,tobeusedforevaluating

indicationsanddispositionofpartsafterevaluation;and

5.4.1.15Postinspectiondemagnetizationandcleaningre-

quirements.

5.5ExaminationSequence—Whenmagneticparticleex-

aminationisspeci ed,itshallbeperformedafterthecomple-

tionofoperationsthatcouldcausesurfaceornear-surface

defects.Theseoperationsinclude,butarenotlimitedto,

forging,heattreating,plating,passivation,coldforming,weld-

ing,grinding,straightening,machining,andproofloading.

Unlessotherwiseapprovedbythecontractingagencyoras

approvedin6.1.3,productionpartsshallbemagneticparticle

inspectedbeforetheapplicationofanycoatings.Also,parts

heattreatedtoanultimatetensilestrengthof180ksiorhigher

thatareheattreatedandsubsequentlyelectroplatedshallbe

inspectedaftertheelectroplatingoperation.

5.6RecordofExamination—Theresultsofallmagnetic

particleinspectionsshallberecorded.Allrecordedresultsshall

beidenti ed, led,andmadeavailableforreviewbythe

contractingagencyuponrequest.Recordsshallprovidefor

traceabilitytothespeci cpartorlotinspected,andtheyshall

identifytheinspectioncontractororfacilityandtheprocedures

usedintheinspection,thelotsize,andthenumberofparts

accepted.

5.7Lighting:

5.7.1VisibleLight—Visiblelightshallbeusedwhenexam-

iningwithnon uorescentparticles.Theintensityofthevisible

lightatthesurfaceofthepartundergoingexaminationshallbe

maintainedataminimumof100fc(1000lx).Theintensity

measurementshallbeconductedwithasuitableilluminance

meterwithaphotopicspectralresponse.

5.7.1.1AmbientVisibleLight—Unlessotherwisespeci ed, uorescentmagneticparticleexaminationsshallbeperformedinadarkenedareawithamaximumambientvisiblelightlevelof2fc(20lx)measuredatthepartsurface.5.7.1.2SpecialVisibleInternalLightSource—Whenexami-nationsofinternalsurfacesmustbeperformedusingspecialvisiblelightsources,theimageproducedmusthavesufficientresolutiontoeffectivelyevaluatetherequireddiscontinuities.Lightintensityshallbemeasuredattheexpectedworkingdistanceoftheequipment.5.7.2BlackLights—Allblacklightsshallbecheckedattheintervalsspeci edinTable1,andafterbulbreplacement,foroutput.Alongerperiodmaybeusedifaplanjustifyingthisextensionispreparedbythenondestructivetestingfacilityandapprovedbythecontractingagency.Theminimumacceptableintensityis1000µW/cm2atthepartbeingexamined.Blacklightre ectorsand ltersshallbecheckeddailyforcleanlinessandintegrity.Damagedordirtyre ectorsor ltersshallbereplacedorotherwisecorrectedasappropriate.5.7.3InternalPartExamination—Wherelampsarephysi-callytoolargetodirectlyilluminatetheexaminationsurface,speciallightingshallbeused.Internalfeaturessuchasbores,holes,andpassageslessthan0.5in.(12.5mm)nominaldiametershallnotrequiremagneticparticleexaminationunlessotherwisespeci edbythecontractingagency.5.8Materials:5.8.1DryParticleRequirements—DryparticlesshallmeettherequirementsofAMS3040.InapplyingAMS3040,theparticlesshallshowindicationsaslistedinTable2onthetestringspecimenofFig.1usingthefollowingprocedure:5.8.1.1Placeaconductorwithadiameterbetween1and1.25in.(25and31mm)andalengthlongerthan16in.(40cm)throughthecenterofthering.Centertheringonthelengthoftheconductor.Magnetizetheringcircularlybypassingthecurrentspeci ingasqueezebulborothersuitableapplicator,applytheparticlestothesurfaceoftheringwhilethecurrentis owing.Examinetheringwithin1minaftercurrentapplicationunderavisiblelightofnotlessthan100fc(1000lx).Thenumberofholeindicationsshallmeetorexceedthosespeci edinTable2.5.8.2WetParticleRequirements—WetparticlesshallmeettherequirementsofAMS3041,3042,3043,3044,3045,or3046,asapplicable.Inapplyingthesespeci cations,theparticlesshallshowindicationsaslistedinTable2onthetestTABLE1RequiredVeri cationIntervalsItemMaximumTimeBetweenVeri cationLighting:Blacklightintensity1dayAmbientlightintensity1dayVisiblelightintensity1daySystemPerformanceusingthetest1daypieceorringspecimenofFig.1Wetparticleconcentration8hours,oreveryshiftchangeWaterbreaktest1dayWetparticlecontamination1weekEquipmentcalibrationcheck:Gaussmeterreading(Teslameter)zeroPriortoUseGaussmeter(Teslameter)accuracy6monthsAmmeteraccuracy6monthsTimercontrol6monthsQuickbreak6monthsDeadweightcheck6

months

如题

TABLE2RequiredIndicationsWhenUsingtheRingSpecimen

ofFig.1

ParticlesUsedCentralConductorMinimumNumberof

FWDCAmperageHolesIndicated

Wetsuspension,Fluorescent,or14003

Non uorescent25005

34006

Drypowder14004

25006

3400

7

ringspecimenofFig.1usingthefollowingprocedure:

5.8.2.1Placeaconductorwithadiameterbetween1and

1.25in.(25and31mm)andalengthlongerthan16in.(40cm)

throughthecenterofthering.Centertheringonthelengthof

theconductor.Magnetizetheringcircularlybypassingthe

currentspeci edinTable2throughtheconductor.Applythe

suspensiontotheringusingthecontinuousmethod.Examine

theringwithin1minaftercurrentapplication(examinationof

non uorescentbathsshallbeconductedundervisiblelightof

notlessthan100fc(1000lx);examinationof uorescentbaths

shallbeconductedunderablacklightofnotlessthan1000

µW/cm2).Thenumberofholeindicationsshallmeetorexceed

thosespeci edinTable2.

5.8.3SuspensionVehicles—Thesuspensionvehicleforthe

wetmethodshallbealightpetroleumdistillateconformingto

AMS2641(TypeI)orDoD-F-87935,orasuitablyconditioned

waterthatconformstotherequirementsof5.8.4.When

approvedbythecontractingagency,AMS2641(TypeII)may

beused.The ashpointandviscosityshallbeinaccordance

withtherequirementsofAMS2641orDoD-F-87935.The

background uorescenceofthesuspensionvehicleshallbeless

thanthelimitspeci edinDoD-F-87935.

5.8.4ConditionedWaterVehicle—Whenwaterisusedasa

suspensionvehicleformagneticparticles,itshallbecondi-

tionedsuitablytoprovideforproperwetting,particledisper-

sion,andcorrosionprotection.Properwettingshallbedeter-

minedbyawaterbreaktest(see7.1.4.2).Smoothertest

surfacesgenerallyrequirethatagreaterpercentofwetting

agentbeaddedthanroughsurfaces.Nonionicwettingagents

arerecommended.However,wettingagentadditionsshallbe

controlledinallcasesbypHmeasurementstolimitthe

alkalinityofthesuspensiontoamaximumpHof10.0andthe

aciditytoaminimumpHof6.0.

5.8.5ParticleConcentration—Theconcentrationofpar-

ticlesinthetestbathshallbeasspeci edinthewritten

procedure.Particleconcentrationsoutsideoftherangeof0.1to

0.4mLina100-mLbathsamplefor uorescentparticlesand

1.2to2.4mLfornon uorescentparticlesshallnotbeused

unlessauthorizedbythecontractingagency.Fluorescentpar-

ticlesandnon uorescentparticlesshallnotbeusedtogether.

6.Speci cPractice

6.1PreparationofPartsforTest:

6.1.1PreinspectionDemagnetization—Thepartshallbe

demagnetizedbeforeexaminationifprioroperationshave

producedaresidualmagnetic eldthatmayinterferewiththe

examination.

6.1.2SurfaceCleanlinessandFinish—Thesurfaceofthe

parttobeinspectedshallbeessentiallysmooth,clean,dry,andfreeofoil,scale,machiningmarks,orothercontaminantsorconditionsthatmightinterferewiththeefficiencyoftheinspection.6.1.3Coatings—Magneticparticleexaminationshallnotbeperformedwithcoatingsinplacethatcouldpreventthedetectionofsurfacedefectsinferromagneticsubstrate.Suchcoatingsnormallyincludepaintorchromeplategreaterthan0.003in.(0.08mm)inthicknessandferromagneticcoatingssuchaselectroplatednickelgreaterthan0.001in.(0.03mm)inthickness.Ifcoatingsgreaterthantheselimitsarepresentduringexamination,itmustbedemonstratedthattheminimumrejectablediscontinuitiescanbedetectedthroughthemaxi-mumcoatingthicknessapplied.Whensuchcoatingsarenonconductive,theymustberemovedwhereelectricalcontactistobemade.Inhighstressapplicationswhendetectionof nedefectssuchasgrindingcracksandnonmetallicstringersisrequired,examinationwithcoatingsinplaceshallbeper-formedonlywhenithasbeenveri edthattheminimumrejectablediscontinuitiescanbedetectedinthepresenceofthecoating.6.1.4PluggingandMasking—Unlessotherwisespeci edbythecontractingagency,smallopeningsandoilholesleadingtopassagesorcavitiesthatcouldentraporremaincontami-natedwithinspectionmediashallbepluggedwithasuitablenonabrasivematerialthatcanberemovedreadilyand,inthecaseofengineparts,issolubleinoil.Effectivemaskingshallbeusedtoprotectthosecomponents,suchascertainnonme-tallics,thatmaybedamagedbycontactwiththesuspension.6.2MagnetizationMethods:6.2.1TypesofMagnetizingCurrent—Thetypesofcurrentsusedformagneticparticleexaminationarefull-waverecti edalternatingcurrent(3or1phase),half-waverecti edalternat-ingcurrent,andalternatingcurrent.Theequipmentusedshallful llthemagnetizinganddemagnetizingrequirementsad-equately,asoutlinedherein,withoutdamagetothepartundertesting,andtheyshallincludethenecessaryfeaturesrequiredforsafeoperation.6.2.2PermanentMagnets—Permanentmagnetsarenottobeusedformagneticparticleexaminationunlessspeci callyauthorizedbythecontractingagency.Whenpermanentmag-netsareused,adequatemagnetic eldstrengthshallbeestablishedinaccordancewith7.1.5.4.6.2.3Yokes—Whenusingyokes(electromagneticprobes)formagneticparticleexamination,adequatemagnetic eldstrengthshallbeestablishedinaccordancewith7.1.5.4.6.2.4MagnetizingCurrentApplication—Alternatingcur-rentistobeusedonlyforthedetectionofdefectsopentothesurface.Full-waverecti edalternatingcurrenthasthedeepestpossiblepenetrationandmustbeusedforinspectionfordefectsbelowthesurfacewhenusingthewetmagneticparticlemethod.Half-waverecti edalternatingcurrentisadvanta-geousforthedrypowdermethodbecauseitcreatesapulsatingunidirectional eldthatgivesincreasedmobilitytothepar-ticles.6.2.5MagneticFieldDirections—Discontinuitiesarediffi-culttodetectbythemagneticparticlemethodwhentheymakeananglelessthan45°tothedirectionofmagnetization.Toensurethedetectionofdiscontinuitiesinanydirection,each

如题

Notes:

NOTE1—Allholediametersare60.005in.(60.01cm).Holenumbers8thru12areoptional.

NOTE2—ToleranceontheDdistanceis60.005in.(60.01).

NOTE3—Alldimensionsare60.03in.(60.08)orasnotedinNotes1and2.

NOTE4—Alldimensionsareininches,exceptasnoted.

NOTE5—MaterialisANSI01toolsteelfromannealedroundstock.

NOTE6—Theringmaybeheattreatedasfollows:Heatto1400to1450°F(760to790°C).Holdatthistemperaturefor1h.Coolatamaximumrateof40°F/hr(22°C/hr)tobelow1000°F(540°C).Furnaceoraircooltoroomtemperature.FinishtheringtoRMS25andprotectfromcorrosion.

FIG.1ANSIKETOSToolSteel

Ring

partmustbemagnetizedinatleasttwodirectionsatright

anglestoeachother.Dependingonpartgeometry,thismay

consistofcircularmagnetizationintwoormoredirections,of

bothcircularandlongitudinalmagnetization,oroflongitudinal

magnetizationintwoormoredirections.Exceptionsnecessi-

tatedbypartgeometry,size,orotherfactorsrequirespeci c

approvalofthecontractingagency.

6.2.6MultidirectionalMagnetization—Multidirectional

magnetizationmaybeusedtoful lltherequirementfor

magnetizationintwodirectionsifitisdemonstratedthatitis

effectiveinallcriticalareas.Arti cial awsthatareetchedor

machined,asshownbyadeviceequaltoFig.2,maybeused

toestablish elddirection.Itisvitallyimportantthatthe eld

intensitybebalancedinalldirectionssothatonedirectiondoes

notoverwhelmanotherdirection.Inusingthismethod,the

particleapplicationmustbetimedsothatthemagnetization

reachesitsfullvalueinalldirectionsduringthetimeparticles

aremobileonthesurfaceundertesting(thatis,thecontinuous

method).

6.2.7DirectMagnetization—Directmagnetizationisac-

complishedbypassingcurrentdirectlythroughthepartunder

testing.Electricalcontactismadetothepartusingheadand

tailstock,prods,clamps,magneticleeches,orbyothermeans.Precautionshallbetakentoensurethattheelectricalcurrentisnot owingwhilecontactsarebeingappliedorremovedandthatexcessiveheatingdoesnotoccurinthecontactarea.Unlessotherwisespeci edbythecontractingagency,prodsshallnotbeusedfortheexaminationofaerospacecomponents( ighthardware)oron nishedsurfaces.6.2.8IndirectMagnetization—Indirectpartmagnetizationusespreformedcoils,cablewraps,yokes, eld ow xtures,oracentralconductortoproduceamagnetic eldofsuitablestrengthanddirectiontomagnetizethepartundertest.6.2.9InducedCurrentMagnetization—Inducedcurrentmagnetization(toroidalorcircumferential eld)isaccom-plishedbyinductivelycouplingaparttoanelectricalcoiltocreateasuitablecurrent owinthepartasillustratedinFig.3.Thismethodisoftenadvantageousonring-shapedpartswithacentralapertureandwithanL/Dratiolessthanthree,espe-ciallywheretheeliminationofarcingorburningisofvitalimportance.6.3MagneticFieldStrength:6.3.1MagneticFieldStrength—Theappliedmagnetic eldshallhavesufficientstrengthtoproducesatisfactoryindica-tions,butitmustnotbesostrongthatitcausesthemaskingofrelevantindicationsbynonrelevantaccumulationsof

magnetic

如题

Examplesofarti cialshimsusedinmagneticparticle

inspectionsystemveri cation.(Notdrawntoscale.)

Theshimsaremadeoflowcarbonsteel(1005steel

foil).Thearti cial awisetchedormachinedonone

sideofthefoiltoadepthof30%ofthefoilthickness.

Inuse,theshimsare rmlyattachedtothetestpart

(e.g.withtapearoundtheedges)withthe awtoward

thepart.

FIG.2Con gurationofArti cialFlawsandTheir

Designation

particles.Factorsthatdeterminetherequired eldstrength

includethesize,shape,andmaterialpermeabilityofthepart,

thetechniqueofmagnetization,themethodofparticleappli-

cation,andthetypeandlocationofthediscontinuitiessought.

Adequatemagnetic eldstrengthmaybedeterminedbyoneor

acombinationofthreemethods:

6.3.1.1Bytestingpartshavingknownorarti cialdefectsof

thetype,size,andlocationspeci edintheacceptancerequire-

ments;

6.3.1.2ByusingaHalleffectprobegaussmetercapableof

measuringthepeakvaluesofthetangent eld;and

6.3.1.3Byusingtheformulasgivenin6.3.7.1-6.3.7.4.

6.3.2WhenusingaHalleffectprobegaussmeter,tangential-

eldstrengths,measuredonthepartsurface,intherangeof30

to60G(2.4to4.8kAm 1)peakvaluesarenormallyadequate

magnetizationlevelsformagneticparticleexamination.Itis

importanttoensurethat eldstrengthsinthisrangearepresent

inallareastobeinspectedonthepart.

6.3.3MagnetizationCurrentLevels—Thecurrentvalues

givenarepeakcurrentvaluesandareapplieddirectlyto

full-waverecti edcurrent.Forothertypesofcurrent,the

operator’smanualortheequipmentmanufacturershouldbe

consultedtodeterminewhatcorrectionfactor,ifany,istobe

usedtoconvertthemeterreadingtoequivalentpeakcurrents.Theprimarycurrentsetsupanoscillating eld.Thisprimarymagnetic eldinducesacurrentintheringshapedpartundertest.FIG.3ExampleofInducedCurrent

Magnetization6.3.4ProdCurrentLevels—Whenusingprodsonmaterial3 4in.(19mm)inthicknessorless,90to115A/in.ofprodspacing(3.5to4.5A/mm)shallbeused.Formaterialgreaterthan3 4in.(19mm)inthickness,100to125A/in.ofprodspacing(4.0to5.0A/mm)shallbeused.Prodspacingshallnotbelessthan2in.(50mm)orgreaterthan8in.(200mm).Theeffectivewidthofthemagnetizing eldwhenusingprodsisonefourthoftheprodspacingoneachsideofalinethroughtheprodcenters.6.3.5DirectCircularMagnetization—Whenmagnetizingbypassingcurrentdirectlythroughthepart(thatis,usingheadshots),thecurrentshallbefrom300to800A/in.ofpartdiameter(12to32A/mm).Thediameterofthepartshallbetakenasthegreatestdistancebetweenanytwopointsontheoutsidecircumferenceofthepart.Currentswillnormallybe500A/in.(20A/mm)orlower,withthehighercurrents(upto800A/in.)beingusedtoinspectforinclusionsortoinspectlow-permeabilityalloyssuchasprecipitation-hardenedsteels.Fortestsusedtolocateinclusionsinprecipitation-hardenedsteels,evenhighercurrents,upto1000A/in.(40A/mm),maybeused.6.3.6CentralConductorCircularMagnetization—Circularmagnetizationmaybeprovidedbypassingcurrentthroughaconductorthatpassesthroughtheinsideofthepart.Inthiscase,alternatingcurrentistobeusedonlywhenthesolepurposeofthetestistoinspectforsurfacediscontinuitiesontheinsidesurfaceofthepart.Ifonlytheinsideofthepartistobeinspected,thediametershallbethegreatestdistancebetweentwopoints,180degreesapartontheinsidecircum-ference.Otherwise,thediameterisdeterminedasin6.3.5.Thefollowingtwoparagraphscovercentrallylocatedandoffsetcentralconductors:6.3.6.1CentrallyLocatedConductor—Whentheaxisofthecentralconductorislocatednearthecentralaxisofthepart,

the

如题

samecurrentlevelsasgivenin6.3.5shallapply.

6.3.6.2OffsetCentralConductor—Whentheconductor

passingthroughtheinsideofthepartisplacedagainstaninside

wallofthepart,thecurrentlevelsasgivenin6.3.5shallapply,

exceptthatthediametershallbeconsideredthesumofthe

diameterofthecentralconductorandtwicethewallthickness.

Thedistancealongthepartcircumference(interior)thatis

effectivelymagnetizedshallbetakenasfourtimesthediameter

ofthecentralconductor,asillustratedinFig.4.Theentire

circumferenceshallbeinspectedbyrotatingthepartonthe

conductor,allowingforapproximatelya10%magnetic eld

overlap.

6.3.7LongitudinalMagnetizationUsingCoils—

Longitudinalmagnetizationisoftenaccomplishedbypassing

currentthroughacoilencirclingthepart,orsectionofthepart,

tobetested(thatis,byusingacoilshot).Thisproducesa

magnetic eldparalleltotheaxisofthecoil.Forlowor

intermediate llfactorcoils,theeffective eldextendsa

distanceoneithersideofthecoilcenterapproximatelyequalto

theradiusofthecoil(seeFig.5).Forcablewraporhigh- ll

factorcoils,theeffectivedistanceofmagnetizationis9in.(230

mm)oneithersideofthecoilcenter(seeFig.6).Forparts

longerthantheseeffectivedistances,theentirelengthshallbe

inspectedbyrepositioningthepartwithinthecoil,allowingfor

approximately10%effectivemagnetic eldoverlap.

6.3.7.1LongitudinalMagnetizationwithLow-FillFactor

Coils—Whenthecross-sectionalareaofthecoilistenormore

timesthecross-sectionalareaofthepartbeinginspected,the

productofthenumberofcoilturns,N,andthecurrentin

amperesthroughthecoil,I,shallbeasfollows:

(1)Forpartspositionedtothesideofthecoil:

NI5K

~610%!(1)

where:K545000Aturns,L5lengthofthepart,andD5diameterofthepart(measuredinthesameunitsasthe

length).

(2)Forpartspositionedinthecenterofthecoil:

FIG.4TheEffectiveRegionofInspectionWhenUsinganOffset

CentralConductorisEqualtoFourTimestheDiameterofthe

Conductoras

IndicatedFIG.5EffectiveRegiononInspectionforaLowFill-Factor

CoilFIG.6EffectiveRegionofInspectionforaHigh

Fill-FactorNI5KR~610%!(2)where:R5radiusofthecoil,mm(orin.),K543000AturnsperinchifRismeasuredininches(1690Aturnspermm),L5lengthofthepart,andD5diameterofthepart(measuredinthesameunitsasthelength).Iftheparthashollowportions,replaceDwithDin6.3.7.4.TheseformulasholdonlyifL/Disgreatereffasgiventhan2andlessthan15.IfL/Dislessthan2,polepieces(piecesofferromagneticmaterialwiththesamediameterasthepartbeingtested)shallbeplacedoneachendoftheparttoeffectivelyincreasetheL/Dto2orgreater.IftheL/Disgreaterthan15,thevalueof15shallbesubstitutedforL/D.6.3.7.2LongitudinalMagnetizationwithCableWraporHigh-FillFactorCoils—Whenthecross-sectionalareaofthecoilislessthantwicethecross-sectionalarea(includinghollowportions)ofthepartundertesting,theproductofthenumberofcoilsturns,N,andthecurrentinamperesthroughthecoil,I,shallbeasfollows:NI5K/$~L/D!12%~610%!(3)where:K535000Aturns,L5lengthofthe

part,

如题

D5diameterofthepart(measuredinthesameunitsasthe

length).

Iftheparthashollowportions,replaceDwithD

6.3.7.4.TheseformulasholdonlyifL/Disgreatereffasgiven

inthan2and

lessthan15.IfL/Dislessthan2,polepieces(piecesof

ferromagneticmaterialwiththesamediameterasthepart

beingtested)shallbeplacedoneachendofthepartto

effectivelyincreasetheL/Dto2orgreater.IftheL/Disgreater

than15,thevalueof15shallbesubstitutedforL/D.

6.3.7.3LongitudinalMagnetizationforIntermediate-Fill

FactorCoils—Whenthecross-sectionalareaofthecoilis

betweentwoandtentimesthecross-sectionalareaofthepart

beinginspected,theproductofthenumberofturns,N,andthe

currentthroughthecoil,I,shallbeasfollows:

NI5~NI!h~102t!/81~NI!l~t22!/8(4)

where:(NI)l5valueofNIcalculatedforlow- llfactorcoilsusing

6.3.7.1,(NI)h5valueofNIcalculatedforhigh- llfactorcoils

t5usingratioof6.3.7.2,thecross-sectionalandareaofthecoiltothe

cross-sectionalareaofthepart(forexample,ifthe

coilis10in.indiameterandthepartisarod5in.

indiameter,t5(p352)/(p32.52)54).

6.3.7.4CalculatingtheL/DRatioforaHolloworCylindri-

calPart—WhencalculatingtheL/Dratioforahollowor

cylindricalpart,Dshallbereplacedwithaneffectivediameter,

Deff,calculatedusingthefollowing:

Deff52@~At2Ah!/p#1/2(5)

where:AAt5totalcross-sectionalofareatheofhollowthepart,portionsand

h5cross-sectionalareaofthepart.

Forcylindricalparts,thisisequaltothefollowing:

Deff5@~OD!22~ID!2#1/2(6)

where:OD5outsidediameterofthecylinder,andID5insidediameterofthecylinder.

6.4ParticleApplication:

6.4.1ContinuousMethod—Inthedrycontinuousmethod,

magneticparticlesareappliedtothepartwhilethemagnetizing

forceispresent.Inthewetcontinuousmethod,themagnetizing

current,orforce,shallbeappliedsimultaneouslywithor

immediatelyafterdivertingthesuspension.Applicationofthe

magneticparticles(see6.4.4and6.4.5)andthemagnetization

methodshallbeasprescribedintheparagraphsreferenced

herein.

6.4.2ResidualMagnetizationMethod—Intheresidualmag-

netizationmethod,themagneticparticlesareappliedtothetest

partimmediatelyafterthemagnetizingforcehasbeendiscon-

tinued.Theresidualmethodisnotassensitiveasthecontinu-

ousmethod,butitcanbeuseful,forexample,indetecting

in-serviceinducedfatiguecracksonthesurfaceofmaterial

withahighretentivity.Itisalsousefulfortheexaminationof

partsinareasinwhich,becauseofgeometricconstraints,thecontinuousmethodcannotbeused.Theresidualmethodshallbeusedonlywhenspeci callyapprovedbythecontractingagencyorwhenithasbeendocumentedthatitcandetectdefectsorarti cialdefectsintestparts.Thetestpartsshallhavethesamematerialandprocessingsteps,andsimilargeometryto,theactualpartsbeinginspected.6.4.3ProlongedMagnetization—Whenusingpolymers,slurries,orpaints,prolongedorrepeatedperiodsofmagneti-zationarenecessarybecauseoflowermagneticparticlemo-bilityinthehigh-viscosityvehicles.6.4.4DryMagneticParticleApplication—Whenusingdryparticles,the owofmagnetizingcurrentshallbeinitiatedpriortoapplicationofthemagneticparticlestothesurfaceundertestingandterminatedafterpowderapplicationhasbeencompletedandanyexcessblownoff.Thedurationofthemagnetizingcurrentshallbeatleast1 2s,andprecautionshallbetakentopreventanydamageofthepartduetooverheatingorothercauses.Drypowdershallbeappliedinamannersuchthatalight,uniform,dust-likecoatingsettlesonthesurfaceofthetestpartwhilethepartisbeingmagnetized.Speciallydesignedpowderblowersorshakersusingcompressedairorhandpowershallbeused.Theapplicatorsshallintroducetheparticlesintotheairinamannersuchthattheyreachthepartsurfaceinauniformcloudwithaminimumofforce.Afterthepowderisapplied,andbeforethemagnetizingforceisre-moved,excesspowdershallberemovedbymeansofadryaircurrentwithsufficientforcetoremovetheexcessparticles,butnotstrongenoughtodisturbparticlesheldbyaleakage eldthatisindicativeofdiscontinuities.Inordertorecognizethebroad,fuzzy,lightlyheldpowderpatternsformedbynear-surfacediscontinuities,theformationofindicationsmustbeobservedcarefullyduringbothpowderapplicationandre-movaloftheexcesspowder.Sufficienttimefortheformationandexaminationofindicationsshallbepermittedduringthetestingprocess.Thedryparticlemethodshallnotbeusedtoinspectaerospacecomponents( ighthardware)withoutspe-ci capprovalofthecontractingagency.6.4.5WetMagneticParticleApplication—Fluorescentornon uorescentparticlessuspendedinaliquidvehicleattherequiredconcentrationshallbeappliedeitherbygentlyspray-ingor owingthesuspensionovertheareatobeinspected.Propersequencingandtimingofpartmagnetizationandapplicationofparticlesuspensionarerequiredtoobtaintheproperformationandretentionofindications.Thisgenerallyrequiresthatthestreamofsuspensionbedivertedfromthepartsimultaneouslywith,orslightlybefore,energizingthemag-neticcircuit.Themagnetizingcurrentshallbeappliedforadurationofatleast1 2sforeachapplication,withaminimumoftwoshotsbeingused.Thesecondshotshouldfollowthe rstinrapidsuccession.Itshouldcomeafterthe owofsuspensionhasbeeninterruptedandbeforethepartisexaminedforindications.Underspecialcircumstances,suchastheuseofautomatedequipmentorforcriticalparts,the1 2-sdurationandthetwo-shotrequirementmaybewaivedprovideditisdemonstratedthatthetestproceduregivenin5.4candetectknowndefectsinrepresentativetestparts.Careshallbeexercisedtopreventanydamagetothepartduetooverheatingorothercauses.Weaklyheldindicationsonhighly

nished

如题

partsarereadilywashedaway,andhencecaremustbe

exercisedtopreventhigh-velocity owovercriticalsurfaces.

6.4.6MagneticSlurry/PaintApplication—Magneticpaints

orslurriesareappliedtothepartwithabrush,squeezebottle,

oraerosolcanbeforeorduringthemagnetizationoperation.

Thismethodisforspecialapplications,suchasoverheador

underwaterexamination.Thismethodshallbeusedonlywhen

speci callyapprovedbythecontractingagency.

6.4.7MagneticPolymerApplication—Polymerizablemate-

rialcontainingmagneticparticlesshallbeheldincontactwith

thetestpartduringtheperiodofitscure.Beforecuringtakes

place,andwhilethemagneticparticlesarestillmobile,thepart

shallbemagnetizedtothespeci edlevel.Thisrequires

prolongedorrepeatedperiodsofmagnetization.Thismethodis

forspecialapplications,suchasboltholes,whichcannotbe

testedreadilybythewetordrymethod,andshallbeusedonly

whenspeci callyapprovedbythecontractingagency.MIL-I-

83387establishestheinspectionprocessformagneticrubber.

6.5Evaluation—Followingmagnetizationandparticleap-

plication,thepartsshallbeexaminedforindications.All

indicationswillbeidenti edasrelevantornonrelevant.Rel-

evantindicationswillbecomparedtoaccept/rejectcriteriaand

thepartsacceptedorrejectedaccordingly.

6.6RecordingofIndications—Whenrequiredbythewritten

procedure,thelocationofallrejectableindicationsshallbe

markedonthepart,andpermanentrecordsofthelocation,

direction,andfrequencyofindicationsmaybemadebyoneor

moreofthefollowingmethods:

6.6.1WrittenDescription—Byrecordingthelocation,

length,direction,andnumberofindicationsinsketchortabular

form.

6.6.2TransparentTape—Fordryparticleindications,by

applyingtransparentadhesive-backedtapetowhichtheindi-

cationswilladhereandplacingitonanapprovedformalong

withinformationgivingitslocationonthepart.

6.6.3StrippableFilm—Bycoveringtheindicationwitha

spray-onstrippable lmthat xestheindicationsinplaceand

placingtheresultantreproductiononanapprovedformalong

withinformationgivingitslocationonthepart.

6.6.4Photography—Byphotographingorvideorecording

theindicationsthemselves,thetape,orthestrippable lm

reproductionandplacingthephotographinatabularform

alongwithinformationgivingitslocationonthepart.

6.7PostinspectionDemagnetizationandCleaning—Unless

directedotherwisebythecontractingagency,allpartsshallbe

demagnetized,cleaned,andcorrosionprotectedafterexamina-

tion.

6.7.1Demagnetization:

6.7.1.1Whenusingacdemagnetization,thepartshallbe

subjectedtoa eldwithapeakvaluegreaterthan,andinnearly

thesamedirectionas,the eldusedduringexamination.This

ac eldisthendecreasedgraduallytozero.Whenusinganac

demagnetizingcoil,holdthepartapproximately1ft(30cm)in

frontofthecoilandthenmoveitslowlyandsteadilythrough

thecoilandatleast3ft(100cm)beyondtheendofthecoil.

Repeatthisprocessasnecessary.Rotateandtumblepartsof

complexcon gurationwhilepassingthroughthe eldofthe

coil.6.7.1.2Whenusingdcdemagnetization,theinitial eldshallbehigherthan,andinnearlythesamedirectionas,the eldreachedduringexamination.The eldshallthenbereversed,decreasedinmagnitude,andtheprocessrepeated(cycled)untilanacceptablylowvalueofresidual eldisreached.6.7.1.3Wheneverpossible,partsthathavebeenmagnetizedcircularlyshallbemagnetizedinthelongitudinaldirectionbeforebeingdemagnetized.Afterdemagnetization,amagnetic eldprobeorstrengthmetershallnotdetect eldswithanabsolutevalueabove3G(240Am 1)anywhereonthepart.6.7.2PostinspectionCleaning—Cleaningshallbedonewithasuitablesolvent,airblower,orbyothermeans.Partsshallbeinspectedtoensurethatthecleaningprocedurehasremovedmagneticparticleresiduesfromcoolantholes,crev-ices,passageways,etc.,sincesuchresiduecouldhaveanadverseeffectontheintendeduseofthepart.Careshallbetakentoremoveallplugs,masking,orotherprocessingaidsthatmayaffecttheintendeduseofthepart.Partsshallbeprotectedfromanypossiblecorrosionordamageduringthecleaningprocessandshallbetreatedtopreventtheoccurrenceofcorrosionafter nalinspection.7.QualityControl7.1SystemPerformance:7.1.1SystemPerformanceVeri cation—Theoverallperfor-manceofthemagneticparticleexaminationsystem,includingtheequipment,materials,andthelightingenvironmentbeingused,shallbeveri edinitiallyandatregularintervalsthere-after.Therequiredveri cationintervalsarestatedinTable1.Recordsoftheveri cationresultsshallbemaintainedandretainedforthetimeperiodspeci edinthecontract.Frequencyofcalibrationforcurrentandvoltagemeasuringdevices,ammetershunts,timers,andgaussmetersusedintheveri ca-tionshallcomplywiththerequirementsofMIL-STD-45662orTable1,asspeci edbythecognizantLevelIII.7.1.2UseofTestPartswithDiscontinuities—Areliablemethodforinspectionsystemveri cationistheuseofrepre-sentativetestpartscontainingdefectsofthetype,location,andsizespeci edintheacceptancerequirements.Ifcorrectmag-neticparticleindicationscanbeproducedandidenti edintheserepresentativeparts,theoverallsystemandinspectionprocedureisveri ed.Partsusedforveri cationwillbedemagnetized,cleanedthoroughlyfollowingtheexamination,andcheckedunderblackorvisiblelight,asappropriatetotheexaminationprocess,toensurethatresidualindicationsdonotremain.7.1.3FabricatedTestPartswithArti cialDiscontinuities—Whenactualproductionpartswithknowndiscontinuitiesofthetype,location,andsizeneededforveri cationarenotavailableorareimpractical,fabricatedtestpartswitharti cialdisconti-nuitiesshallbeused.Arti cialdiscontinuitiesmaybefabri-catedtomeetaparticularneedormaybecommerciallyavailablemagnetic eldindicatorsorshimsasshowninFig.2andFig.7.Allapplicableconditionsfortheuseofsuchtestparts,asdescribedin7.1.2,shallapply.Whencommercialdevicesareused,theirmagneticproperties, awtypes,andsurfaceconditionshallbeasclosetotheproductionpartas

possible.

如题

FIG.7Pie- eldIndicatorforUseinMagneticParticleInspection

SystemVeri cation(AllDimensionsarein

Inches)

7.1.4SuspensionVehicleTests(Notrequiredforaerosol

cansolutions):

7.1.4.1Concentration/ContaminationTests—Particlecon-

centrationandcontaminationshallbedetermineduponstart

up,atregularintervalsthereafter,andwheneverthebathis

changedoradjusted.Therequiredtestingintervalsarestatedin

Table1.

(1)DeterminationofWetParticleConcentration—Agitate

theparticlesuspensionaminimumof30mintoensureuniform

distributionofparticlesthroughoutthebath.Placea100-mL

sampleoftheagitatedsuspensioninapear-shapedcentrifuge

tube(ofthesizeandshapespeci edinTestMethodsD96,

exceptgraduatedto1mLin0.05-mLincrements).Demagne-

tizethesampleandallowthetubetostandundisturbedforat

least60minifusingthepetroleumdistillateinAMS2641or

30minsettlingtimeforconditionedwatersuspension.Read

thevolumeofsettledparticles.Iftheconcentrationisoutofthe

tolerancestatedinthewrittenprocedure(orthatgivenin

5.8.5),addtheparticlesorsuspensionvehicle,asrequired,and

redeterminetheparticleconcentration.Ifthesettledparticles

appeartobelooseagglomeratesratherthanasolidlayer,take

asecondsample.Ifthesecondsamplealsoappearsagglomer-

ated,replacetheentiresuspension.Thirty-minutesettling

times,orotheracceleratedtests,maybeusediftheyhavebeen

veri edtogiveresultsequivalenttotheproceduredescribedin

thisparagraph.

(2)DeterminationofWetParticleContamination—Perform

thetestsspeci edin7.1.4.1(1).Inaddition,for uorescent

baths,examinetheliquidabovetheprecipitatewithblacklight.

Theliquidshallbecomparabletothe uorescenceofthe

originalsolution.Examinethegraduatedportionofthetube,

underbothblacklight(for uorescentbathsonly)andvisible

light(forboth uorescentandnon uorescentbaths),for

striationsorbands,differentincolororappearance.Bandsor

striationsmayindicatecontamination.Ifthetotalvolumeofthecontaminants,includingbandsorstriations,exceeds30%ofthevolumeofmagneticparticles,oriftheliquidisnoticeably uorescent,thebathmustbereplaced.7.1.4.2WaterBreakTest—Inthistestofwater-basedve-hicles,acleanpartwithasurface nishthesameasthepartstobetestedis oodedwiththeconditionedwater,andtheappearanceofthesurfaceisnotedafter oodingisstopped.Ifacontinuouseven lmformsovertheentirepart,sufficientwettingagentispresent.Ifthe lmofsuspensionbreaks,exposingbaresurface,insufficientwettingagentispresentortheparthasnotbeencleanedadequately.7.1.5EquipmentCalibration—MagneticparticletestingequipmentshallbecheckedforperformanceandaccuracyatthetimeofpurchaseandatintervalsthereafterasgiveninTable1,whenevermalfunctionissuspectedorwhenspeci edbythecontractingagency,andwheneverelectricalmainte-nancethatmightaffectequipmentaccuracyisperformed.7.1.5.1AmmeterAccuracy—Tochecktheequipmentam-meter,parativereadingsshallbetakenatthreeoutputlevelsencompassingtheuseablerangeoftheequip-ment.Theequipmentmeterreadingshallnotdeviatebymorethan610%offullscalefromthecurrentvalueshownbythecalibratedammeter.(Whenmeasuringhalf-wavealternatingcurrent,thecurrentvaluesshownbythecalibrateddcammeterreadingsshallbedoubled.)Thefrequencyoftheammetercheckisspeci edinTable1.7.1.5.2TimerControlCheck—Onequipmentusingatimertocontrolthecurrentduration,thetimershouldbecheckedtowithin60.1susingasuitableelectronictimer.7.1.5.3MagneticFieldQuickBreakCheck—Onequipmentthatusesaquickbreakfeature,properfunctioningofthiscircuitshallbeveri ed.Thetestmaybeperformedusingasuitableoscilloscopeorotherapplicablemethodasspeci edbytheequipmentmanufacturer.7.1.5.4DeadWeightCheck—Yokesandpermanentmagnet-ics(whenallowed)shallbedeadweighttestedatintervalsasstatedinTable1.Alternatingcurrentyokesshallhavealiftingforceofatleast10lb(45N),witha2to4-in.(50to100-mm)spacingbetweenlegs.Directcurrentyokesshallhavealiftingforceofatleast30lb(135N),witha2to4-in.(50to100-mm)spacingbetweenlegs,or50lb(225N),witha4to6-in.(100to150-mm)spacing.7.2MarkingofInspectedParts—Unlessotherwisespeci edbythecontractingagency,partsthathavebeenacceptedusingmagneticparticleexaminationshallbemarkedinaccordancewiththeapplicabledrawing,purchaseorder,contract,orasspeci edherein.Markingshallbeappliedinsuchamannerandlocationastobeharmlesstothepart.Theidenti cationshallnotbeobliteratedorsmearedbysubsequenthandlingand,whenpracticable,placedinalocationthatwillbevisibleafterassembly.Whensubsequentprocessingwouldremovetheidenti cation,theapplicablemarkingshallbeaffixedtotherecordaccompanyingthe nishedpartsorassembly.Boltsandnutsandotherfastenerproductsmaybeidenti edashavingmettherequirementsofmagneticparticleexaminationbymarkingeachpackageconspicuously.7.2.1ImpressionStamping,InkStamping,Laser

Marking,

如题

orVibroEngraving—Impressionstamping,inkstamping,laser

marking,orvibroengravingshallbeusedwhenpermittedor

requiredbytheapplicablewrittenprocedure,detailspeci ca-

tionordrawing,orwhenthenatureofthepartissuchasto

provideforimpressionstampingofpartnumbersorother

inspector’smarkings.Impressionstampingshallbelocated

onlyintheareaprovidedadjacenttothepartnumberor

inspector’sstampunlessotherwisespeci edbythecontracting

agency.

7.2.2Etching—Whenimpressionstamping,inkstamping,

lasermarking,orvibroengravingisprohibited,partsshallbe

etchedusinganetching uidorothermeansandamethodof

applicationacceptabletothecontractingagency.Theetching

processandlocationshallnotaffectthefunctioningofthepart

adversely.

7.2.3Dyeing—Whenstamping,vibroengraving,oretching

isnotpermissible,identi cationshallbeaccomplishedby

dyeing.

7.2.4OtherIdenti cation—Othermeansofidenti cation,

suchastagging,shallbeusedforpartsthathaveaconstruction

orfunctionprecludingtheuseofstamping,vibroengraving,or

etching,asinthecaseofcompletelygroundorpolishedballs,

rollers,pins,orbushings.

7.2.5IdentifyingSymbolsandColorMarkings:

7.2.5.1One-HundredPercentExamination—Whenitems

areexaminedandacceptedby100%examination,eachitem

shallbemarkedasfollows:

(1)Dyeing—Whendyeingisapplicable,adyeofacceptable

adherencewhichispredominantlyblue(perFED-STD-595)

shallbeemployed.However,ifacolorcon ictisincurredwith

anyothermethod,magneticparticleexaminationcanbe

indicatedbytwoadjacentbluedotsorothersuitablemeans.

(2)Stamping,LaserMarking,VibroEngraving,or

Etching—Whenimpressionstampingorinkstamping,laser

marking,vibroengraving,oretchingisusedtomark100%

inspectedparts,theletter“M”withacirclearounditwillbe

employed.

7.2.5.2LotInspection—Whenitemsareacceptedbymeans

ofasamplingprocedure,eachitemofanacceptedlotshallbe

markedasfollows:

(1)Dyeing—Whendyeingisapplicable,adyeofacceptable

adherencethatispredominantlyorange(perFED-STD-595)

shallbeemployed.(2)Stamping,VibroEngraving,orEtching—Whenimpres-sionstamping,vibroengravingoretchingisusedtomarklotinspectedparts,theletter“M”shallbeemployed.7.3EyeGlasses—Whenusing uorescentmaterials,inspec-torsshallnotweareyeglassesthatarephotochromicorthathavepermanentlydarkenedlenses.Thisisnotintendedtoprohibittheuseofeyeglasseswithlensestreatedtoabsorbultravioletlight.7.4Safety—Thesafehandlingofmagneticparticles(wetordry),oilvehicleswaterbaths,andwaterconditionerconcen-tratesaregovernedbythesuppliers’MaterialSafetyDataSheets(MSDS).MaterialSafetyDataSheets,conformingto29CFR1910.1200,orequivalent,mustbeprovidedbythesuppliertoanyuserandshallbepreparedinaccordancewithFED-STD-313.7.4.1Flammability—FlashpointofoilvehiclesshallbeinaccordancewithAMS2641orDoD-F-87935.Thesuppliers’MSDSshallcertifythe ashpoint.7.4.2PersonnelHazards—Precautionsagainstinhalation,skincontact,andeyeexposurearedetailedinthesuppliers’MSDS.Theseprecautionsshallbeobserved.7.4.3ElectricalHazards—Magnetizingequipmentshallbemaintainedproperlytopreventpersonnelhazardsfromelec-tricalshortcircuits.Caremustbetakentoreducearcingandthepossibleignitionofoilbaths.7.4.4BlackLight—Itisrecommendedthattheintensityofblacklightincidentonunprotectedskinoreyesnotexceed1000µW/cm2.Crackedorbrokenultraviolet ltersshallbereplacedimmediately.Brokenbulbscancontinuetoradiateultravioletenergyandmustbereplacedimmediately.Spec-taclesdesignedtoabsorbultravioletwavelengthradiationaresuggestedforclose,high,blacklightintensityexamination.7.5DarkAdaptation—Personnelmustwaitatleast1minafterenteringadarkenedareafortheireyestoadjusttothelow-levellightingbeforeperforming uorescentmagneticparticleexamination.8.Keywords8.1dye; uorescent;magneticparticle;nondestructiveevaluation;nondestructiveexamination;nondestructive

testing

如题

APPENDIX

(NonmandatoryInformation)

X1.MEASUREMENTOFTANGENTIALFIELDSTRENGTH

X1.1Caremustbeexercisedwhenmeasuringthetangen-

tialapplied eldstrengthsspeci edin6.3.2.Theactiveareaof

theHalleffectprobeshouldbenolargerthan0.2in.(5mm)by

0.2in.(5mm)andshouldhaveamaximumcenterlocation5

mmfromthepartsurface.Theplaneoftheprobemustbe

perpendiculartothesurfaceofthepartatthelocationof

measurementtowithin5degrees.Thisisdifficulttoaccom-

plishbyhandorientation,thereforetheprobeshouldbeheldin

ajigor xtureofsometype.Ifthecurrentisbeingappliedin

shots,orifalternatingcurrentorhalf-waverecti edalternatingcurrentisbeingused,thegaussmetershouldbesettoreadthepeakvalueduringtheshot.Thegaussmetershouldhaveafrequencyresponseof0to300Hzorhigher.Thedirectionandmagnitudeofthetangential eldonthepartsurfacecanbedeterminedbytwomeasurementsmadeatrightanglestoeachotheratthesamespot.Thegaussmeterprobeleadsshouldbeshieldedortwistedtopreventreadingerrorsduetovoltageinducedduringthelarge eldchangesencounteredduringmagneticparticleexamination.

ersofthisstandardareexpresslyadvisedthatdeterminationofthevalidityofanysuchpatentrights,andtheriskofinfringementofsuchrights,areentirelytheirownresponsibility.

Thisstandardissubjecttorevisionatanytimebytheresponsibletechnicalcommitteeandmustbereviewedevery veyearsandifnotrevised,eitherreapprovedorwithdrawn.YourcommentsareinvitedeitherforrevisionofthisstandardorforadditionalstandardsandshouldbeaddressedtoASTMHeadquarters.Yourcommentswillreceivecarefulconsiderationatameetingoftheresponsibletechnicalcommittee,whichyoumayattend.IfyoufeelthatyourcommentshavenotreceivedafairhearingyoushouldmakeyourviewsknowntotheASTMCommitteeonStandards,100BarrHarborDrive,WestConshohocken,PA19428.

ThisstandardiscopyrightedbyASTM,100BarrHarborDrive,WestConshohocken,PA19428-2959,UnitedStates.Individualreprints(singleormultiplecopies)ofthisstandardmaybeobtainedbycontactingASTMattheaboveaddressorat610-832-9585(phone),610-832-9555(fax),orservice@(e-mail);orthroughtheASTMwebsite

().

本文来源：https://www.bwwdw.com/article/efo1.html