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Designation:B193–02StandardTestMethodforResistivityofElectricalConductorMaterials1ThisstandardisissuedunderthefixeddesignationB193;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheDepartmentofDefense.1.Scope1.1Thistestmethodcoversthedeterminationoftheelec-tricalresistivityofmetallicelectricalconductormaterial.Itprovidesforanaccuracyof60.30%ontestspecimenshavingaresistanceof0.00001V(10μV)ormore.Weightresistivityaccuracymaybeadverselyaffectedbypossibleinaccuraciesintheassumeddensityoftheconductor.1.2Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:A111SpecificationforZinc-Coated(Galvanized)“Iron”TelephoneandTelegraphLineWire2A326SpecificationforZinc-Coated(Galvanized)HighTensileSteelTelephoneandTelegraphLineWire3B9SpecificationforBronzeTrolleyWire4B105SpecificationforHard-DrawnCopperAlloyWiresforElectricConductors4B298SpecificationforSilver-CoatedSoftorAnnealedCopperWire4B355SpecificationforNickel-CoatedSoftorAnnealedCopperWire4B415SpecificationforHard-DrawnAluminum-CladSteelWire4B566SpecificationforCopper-CladAluminumWire4B800Specificationfor8000SeriesAluminumAlloyWireforElectricalPurposes—AnnealedandIntermediateTem-pers42.2NISTDocument:NBSHandbook100—CopperWireTables53.Resistivity3.1Resistivity(ExplanatoryNote1)istheelectricalresis-tanceofabodyofunitlength,andunitcross-sectionalareaorunitweight.3.2VolumeResistivityiscommonlyexpressedinohmsforatheoreticalconductorofunitlengthandcross-sectionalarea;ininch-poundunitsinV·cmil/ftandinacceptablemetricunitsinV·mm2/m.Itmaybecalculatedbythefollowingequation:rv5~A/L!Rwhere:rv=volumeresistivity,V·cmil/ftorV·mm2/m,A=cross-sectionalarea,cmilormm2,L=gagelength,usedtodetermineR,ftorm,andR=measuredresistance,V.3.3WeightResistivityiscommonlyexpressedinohmsforatheoreticalconductorofunitlengthandweight.Themethodforcalculatingweightresistivity,basedonresistance,length,andweightmeasurements,ofatestspecimenisgiveninExplanatoryNote2.4.Apparatus4.1Resistanceshallbemeasuredwithacircuitconfigura-tionandinstrumentationthathasaresistancemeasurementcapabilityof60.15%accuracy.5.TestSpecimen5.1Thetestspecimenmaybeintheformofawire,strip,rod,bar,tube,orshape.Itshallbeofuniformcrosssectionthroughoutitslengthwithin60.75%ofthecross-sectionalarea.Whereverpossibleitshallbethefullcrosssectionofthematerialitrepresents,ifthefullcrosssectionissuchthattheuniformityofthecross-sectionalareacanbeaccuratelydeter-mined.5.2Thetestspecimenshallhavethefollowingcharacteris-tics:1ThistestmethodisunderthejurisdictionofASTMCommitteeB01onElectricalConductorsandisthedirectresponsibilityofSubcommitteeB01.02onMethodsofTestandSamplingProcedure.CurrenteditionapprovedApr.10,2002.PublishedApril2002.OriginallypublishedasB193–44T.LastpreviouseditionB193–01.2AnnualBookofASTMStandards,Vol01.06.3Discontinued;see1989AnnualBookofASTMStandards,Vol01.06.4AnnualBookofASTMStandards,Vol02.03.5AvailablefromtheNationalInstituteofStandardsandTechnology(NIST),Gaithersburg,MD20899.1Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.5.2.1Aresistanceofatleast0.00001V(10μV)inthetestlengthbetweenpotentialcontacts,5.2.2Atestlengthofatleast1ftor300mm,5.2.3Adiameter,thickness,width,orotherdimensionsuitabletothelimitationsoftheresistancemeasuringinstru-ment,5.2.4Nosurfacecracksordefectsvisibletotheunaidednormaleye,andsubstantiallyfreefromsurfaceoxide,dirt,andgrease,and5.2.5Nojointsorsplices.6.Procedure6.1Makealldeterminationsofthedimensionsandweightofthetestspecimenusinginstrumentsaccurateto60.05%.Inordertoassurethisaccuracyinmeasuringthelengthbetweenpotentialcontacts,thesurfaceincontactwiththetestspecimenshallbeasubstantiallysharpknife-edgewhenusingaKelvin-typebridgeorapotentiometer.6.2Thecross-sectionaldimensionsofthespecimenmaybedeterminedbymicrometermeasurements,andasufficientnumberofmeasurementsshallbemadetoobtainthemeancrosssectiontowithin60.10%.Incaseanydimensionofthespecimenislessthan0.100in.andcannotbemeasuredtotherequiredaccuracy,determinethecross-sectionfromtheweight,density,andlengthofthespecimen.6.3Whenthedensityisunknown,determinethedensitybyweighingaspecimenfirstinairandtheninaliquidofknowndensityatthetesttemperature,whichshallberoomtempera-turetoavoiderrorsduetoconvectioncurrents.Exercisecareinremovingallairbubblesfromthespecimenwhenweighingitintheliquid.Calculatethedensityfromthefollowingequa-tion:d5~Wa3d!/~Wa2Wl!where:d=densityofthespecimen,g/cm3;Wa=weightofthespecimeninair,g;Wl=weightofthespecimenintheliquid,g;andd=densityoftheliquidatthetesttemperature,g/cm3.6.4Whenpotentialleadsareused,makesurethedistancebetweene
本文标题:ASTM B193-02导电材料电阻率的测试方法
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