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Designation:A341/A341M–00StandardTestMethodforDirectCurrentMagneticPropertiesofMaterialsUsingD-CPermeametersandtheBallisticTestMethods1ThisstandardisissuedunderthefixeddesignationA341/A341M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodprovidesdcpermeametertestsforthebasicmagneticpropertiesofmaterialsintheformofbars,rods,wire,orstripspecimenswhichmaybecut,machined,orgroundfromcast,compacted,sintered,forged,extruded,rolled,orotherfabricatedmaterials.Itincludestestsfordeterminationofthenormalinductionundersymmetricallycyclicallymagnetized(SCM)conditionsandthehysteresisloop(B-Hloop)takenunderconditionsofrapidlychangingorsteepwavefrontreversalsofthedirectcurrentmagneticfieldstrength.1.2ThistestmethodshallbeusedinconjunctionwithPracticeA34/A34M.1.3Thistestmethodcoversarangeofmagneticfieldstrengthinthespecimenfromabout0.05Oe[4A/m]uptoabove5000Oe[400kA/M]throughtheuseofseveralpermeameters.Theseparatepermeameterscoverthistestregioninseveraloverlappingranges.1.4Normalinductionandhysteresispropertiesmaybedeterminedoverthefluxdensityrangefromessentiallyzerotointrinsicsaturationformostmaterials.1.5RecommendationsoftheusefulmagneticfieldstrengthrangeforeachofthepermeametersareshowninTable12.Also,seeSections3and4forgenerallimitationsrelativetotheuseofpermeameters.1.6ThesymbolsandabbreviateddefinitionsusedinthistestmethodappearwithFig.1andinappropriatesectionsofthisdocument.Fortheofficialdefinitions,seeTerminologyA340.Notethatthetermfluxdensityusedinthisdocumentissynonymouswiththetermmagneticinduction.1.7Thevaluesandequationsstatedincustomarycgs-emuandinch-poundorSIunitsaretoberegardedseparatelyasstandard.Withinthisstandard,SIunitsareshowninbracketsexceptforthesectionsconcerningcalculationswherethereareseparatesectionsfortherespectiveunitsystems.Thevaluesstatedineachsystemmaynotbeexactequivalents;therefore,eachsystemshallbeusedindependentlyoftheother.Combin-ingvaluesfromthetwosystemsmayresultinnonconformancewiththisstandard.1.8Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:A34/A34MPracticeforSamplingandProcurementTest-ingofMagneticMaterials3A340TerminologyofSymbolsandDefinitionsRelatingtoMagneticTesting3A596/A596MTestMethodforDirect-CurrentMagneticPropertiesofMaterialsUsingtheBallisticMethodandRingSpecimens32.2IECStandard:Publication60404-4,Ed.2.0MagneticMaterials–Part4:MethodsofMeasurementofD.C.MagneticPropertiesofIronandSteel,IEC,199542.3OtherDocuments:NISTCircularNo.74,pg.2695NISTScientificPaper117,SPBTA53.SignificanceandUse3.1Permeametersrequiretheuseofyokestocompletethemagneticcircuitandarethereforeinherentlylessaccuratethanringtestmethods.RefertoTestMethodA596/A596Mforfurtherdetailsonringtestmethods.However,whentestingcertainshapesasbarsorwhenmagneticfieldstrengthinexcessof200Oe[15.9ormorekA/m]arerequired,permeametersaretheonlypracticalmeansofmeasuringmagneticproperties.3.2Thistestmethodissuitableforspecificationacceptance,serviceevaluation,researchanddevelopmentanddesign.1ThistestmethodisunderthejurisdictionofASTMCommitteeA06onMagneticPropertiesandisthedirectresponsibilityofSubcommitteeA06.01onTestMethods.CurrenteditionapprovedOct.10,2000.PublishedDecember2000.OriginallypublishedasA341–69.LastpreviouseditionA341/A341M–95.2Theboldfacenumbersinparenthesesrefertoalistofreferencesattheendofthisstandard.3AnnualBookofASTMStandards,Vol03.04.4AvailablefromAmericanNationalStandardsInstitute,11W.42ndSt.,13thFloor,NewYork,NY10036.5AvailablefromNationalInstituteofStandardsandTechnology,(NIST),Gaithersburg,MD20899.1Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.3.3Whenthetestspecimenisfabricatedfromalargersampleandisinthesameconditionasthelargersample,itmaynotexhibitmagneticpropertiesrepresentativeoftheoriginalsample.Insuchinstancesthetestresults,whenviewedincontextofpastperformancehistory,willbeusefulforjudgingthesuitabilityofthematerialfortheintendedapplication.4.Interferences4.1Ingeneral,permeametersdonotmaintainauniformmagneticfieldineithertheaxialorradialdirectionsaroundthetestspecimen.Thefieldgradientsinbothofthesedirectionswilldifferinthevariouspermeameters.AlsotheH-sensingandB-sensingcoilsofthedifferentpermeametersarenotidenticalinarea,inturns,orinlengthoridenticallylocated.Althoughtestspecimensarepreparedtohaveuniformphysicalcrosssection,theymayhaveundetectednonuniformmagneticprop-ertiesradiallyoraxiallyalongthespecimenlengthadjacenttotheHorBcoils.Somepermeametersmayalsointroduceclampingstrainsintothetestspecimen.Fortheabovereasonstestresultsobtainedonatestspecimenwithonetypeper-meametermaynotagreecloselywiththoseobtainedonthe