1、BRITISH STANDARD BS EN 820-1:2002 Advanced technical ceramics Methods of testing monolithic ceramics Thermomechanical properties Part 1: Determination of flexural strength at elevated temperatures The European Standard EN 820-1:2002 has the status of a British Standard ICS 81.060.30 BS EN 820-1:2002
2、 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 6 March 2003 BSI 6 March 2003 ISBN 0 580 41375 6 National foreword This British Standard is the official English language version of EN 820-1:2002. It supersedes DD ENV 820-1:1994 which is with
3、drawn. The UK participation in its preparation was entrusted to Technical Committee RPI/13, Advanced technical ceramics, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which im
4、plement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication
5、does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/Euro
6、pean committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pa
7、ges 2 to 10, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN8201 October2002 ICS81.060.30 SupersedesENV820
8、1:1993 Englishversion AdvancedtechnicalceramicsMethodsoftestingmonolithic ceramicsThermomechanicalpropertiesPart1:Determination offlexuralstrengthatelevatedtemperatures CramiquestechniquesavancesMthodedessaides cramiquesmonolithiquesPropritsthermodynamiques Dterminationdelarsistancelaflexiontempratu
9、res leves HochleistungskeramikMonolithischeKeramik ThermomechanischeEigenschaftenTeil1:Bestimmung derBiegefestigkeitbeierhhtenTemperaturen ThisEuropeanStandardwasapprovedbyCENon8August2002. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope
10、an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagema
11、debytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheManagementCentrehasthesamestatusasthe official versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Iceland,Ireland,Italy,Luxembourg,Malta,Netherlan
12、ds,Norway,Portugal,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2002CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No
13、.EN8201:2002EEN8201:2002(E) 2 Contents page Foreword3 1 Scope 4 2 Normativereferences 4 3 Termsanddefinitions. .4 4 Apparatus .5 4.1 General5 4.2 Testjig .5 4.3 Heatingdevice 6 4.4 Testmachine 6 4.5 Linearmeasuringdevices .6 4.6 Dryingoven . .7 5 Testpieces. .7 6 Testtemperaturesandnumberoftests . .
14、7 7 Testprocedure .7 8 Calculations8 9 Accuracyandreferences . .9 10 Testreport 10EN8201:2002(E) 3 Foreword ThisdocumentEN8201:2002hasbeenpreparedbyTechnicalCommitteeCEN/TC184“Advancedtechnical ceramics“,thesecretariatofwhichisheldbyBSI. ThisEuropeanStandardshallbegiventhestatusofanationalstandard,e
15、itherbypublicationofanidenticaltextor byendorsement,atthelatestbyApril2003,andconflictingnationalstandardsshallbewithdrawnatthelatestby April2003. ThisdocumentsupersedesENV8201:1993. ThisdocumenthasbeenpreparedunderamandategiventoCENbytheEuropeanCommissionandtheEuropean FreeTradeAssociation. EN820 A
16、dvancedtechnicalceramicsMethodsoftestingmonolithicceramicsThermomechanicalproperties consistsofthreeParts: Part1:Determinationofflexuralstrengthatelevatedtemperatures Part2:Determinationofselfloadeddeformation Part3:Determinationresistancetothermalshockbywaterquenching AccordingtotheCEN/CENELECInter
17、nalRegulations,thenationalstandardsorganizationsofthefollowing countriesareboundtoimplementthisEuropeanStandard:Austria,Belgium,CzechRepublic,Denmark,Finland, France,Germany,Greece,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,Spain, Sweden,SwitzerlandandtheUnitedKingdom.EN8201:
18、2002(E) 4 1Scope ThisPartofthisEuropeanStandardspecifiesamethodofdeterminingthethreepointorfourpointflexuralstrengthof advancedmonolithictechnicalceramicsatelevatedtemperaturesasagreedbetweenpartiestothetest.Thetestcan beperformedinanyappropriateatmosphere. 2 Normativereferences ThisEuropeanStandard
19、incorporatesbydatedorundatedreference,provisionsfromotherpublications.These normativereferencesarecitedattheappropriateplacesinthetext,andinthepublicationslistedhereafter.Fordated references,subsequentamendmentstoorrevisionsofanyofthesepublicationsapplytothisEuropeanStandardonly whenincorporatedinit
20、byamendmentorrevision.Forundatedreferencesthelatesteditionofthepublicationreferred toapplies(includingamendments). EN8431, AdvancedtechnicalceramicsMonolithicceramicsMechanicaltestsatroomtemperaturePart1: Determinationofflexuralstrength. ENV8435, AdvancedtechnicalceramicsMonolithicceramicsMechanical
21、testsatroomtemperaturePart5: Statisticalanalysisoffracturedata. EN100022, MetallicmaterialsTensiletestingPart2:Verificationoftheforcemeasuringsystemofthetensile testingmachine. ENISO17025, Generalrequirementsforthecompetenceoftestingandcalibrationlaboratories. IEC60584, ThermocouplesPart1:Referencet
22、ables. IEC60584, ThermocouplesPart2:Tolerances. ISO3611, Micrometercallipersforexternalmeasurement. 3 Termsanddefinitions ForthepurposesofthisEuropeanStandard,thefollowingtermsanddefinitionsapply. 3.1 nominalflexuralstrength maximumnominalstressattheinstantoffailuresupportedbythematerialwhenloadedin
23、elasticbending NOTE Itisrecognisedthatflexuralstrengthtestsonceramicsatelevatedtemperaturemayrevealinelasticbehaviourin thematerial.Undersuchconditions,thenominalflexuralstrengthcalculatedinaccordancewiththisstandardisnotstrictly a validresult,sinceittendstooverestimatethetruesurfacestressinthetestp
24、iece.Thismethodrequiresthatthe load/displacementrelationshipforeachtestpieceateachtemperatureisinspected,andthevalidityoftheresultdetermined. 3.2 threepointflexure meansofbendingabeamtestpiecewherebythetestpieceissupportedonbearingsnearitsends,andacentralload isappliedEN8201:2002(E) 5 3.3 fourpointf
25、lexure meansofbendingabeamtestpiecewherebythetestpieceissupportedonbearingsnearitsends,andisloaded equallyattwopointssymmetricallydisposedaboutthecentreofthesupportedspan 3.4 inelasticdeformation forthepurposesofthetest,thedeformationofatestspecimenunderloadwhichisnotentirelyelasticandreversibleon r
26、emovaloftheload 3.5 subcriticalcrackgrowth extensionofexistingcracksorflawsunderastresswhichdoesnotproduceinstantfailure NOTE Thiseffectcanbeduetotheintrinsiccrackpropagationofthematerial,additionallyinfluencedbytheenvironment. 4Apparatus 4.1General Thetestiscarriedoutinasimilarmannertothatprescribe
27、dinEN8431fortestingatroomtemperature,withthe exceptionsthatthetestjigshallbeconstructedfrommaterialswhicharecapableofremaininglinearlyelasticatthe temperatureoftesting,andthatameansofheatingthetestjigandtestpiecetothetesttemperatureisrequired. 4.2 Testjig Thetestjigshallbeofadesignthatallowsfullarti
28、culationforalignmentofthesupportandloadingrollersonthe surfacesofthetestpiece,andinwhichtherollersarecapableofrollingtominimisefrictionbetweentherollersandthe testpiece. NOTE1 Itisrecognisedthatpracticallimitationscanrestrictthedesignofthetestjig,andoxidationeffectscanrestrict its function.Insuchcas
29、es,alternativesmaybeemployed,butdeviationsfromthefunctionspecifiedaboveshouldbereportedin thereport(seeclause10,d). Theouterspanofthetestjigshallbeeither20,0mm0,5mm(spanA)or40,0mm0,5mm(spanB).Forthreepoint flexuretheloadingrollershallbecentralisedrelativetothespantowithin0,2mm.Forfourpointflexure,th
30、einnerspan shallbe10,00,2mm(spanA)or20,0mm0,2mm(spanB).Theinnerrollersshallbesymmetricallypositioned relativetotheouterrollerstobetterthan0,2mm. NOTE2 Thisrepresentsarelaxationofcentralisationrequirementscomparedwithroomtemperaturetesting(requirement 0,1mm,seeEN8431)becauseitcanbecomerelativelymored
31、ifficulttosetuptestjigsinsidefurnaces. Measurementsofthepositionsoftherollersshallbemadewithatravellingmicroscope(4.5.2). Therollersshallbemadefromamaterialwhichiscapableofremaininglinearlyelasticuptothemaximumtemperature oftheseriesoftests.Forteststo400C,hardenedsteelrollersasinEN8431shallsuffice.F
32、orhighertemperaturesit isrecommendedthatthetestjigisconstructedfromfinegrainedstrongrefractoryceramicmaterials. NOTE3 Fortemperaturesupto1400C,highpurityhighaluminaceramicmaterialscanbeused.Fortemperaturesupto1 500Cinairorupto1700 Cinneutralatmospheres,sinteredsiliconcarbideisrecommended. Considerat
33、ionshouldbegiventoanypotentialreactionbetweenthetestmaterialandtherollersatthemaximumtest temperature,andthechoiceofrollermaterialshallbemadesuchthatreactionsareminimised.Inparticular,nonoxide ceramicmaterialsmaytendtooxidise,andtheoxidethenmayreactwiththeloadingrollers.Rollersshallbe maintainedwith
34、acleansmoothburrfreesurfaceforalltests.Theyshallbeinspectedbeforeanytesttoensurethey areundamaged,andarecapableofrollingfreelyinthejigatthestartofthetest.Ifnecessary,rollersshouldbe replacedtomaintaincorrectjigfunction.Similarly,reactionsbetweenthemainceramiccomponentsofthetestjigshall beminimizedby
35、appropriatechoiceofmaterial.EN8201:2002(E) 6 NOTE4 Atveryhightemperatures,theprogressiveoxidationofnonoxidejigcomponentscanleadtothedevelopmentof frictionaleffectsduetoinabilityoftherollerstorollfreely.Sucheffectscanleadtouncertaintiesinnominalflexurals trengthof upto5%.Itisnotpossibletoquantifythis
36、effect,whichislikelytobetime,temperatureandmaterialdependent.Jigcompo nents canbefoundtohaveweldedtogetheroncoolingtoroomtemperature.Theyshouldbegentlyseparatedandcleanedbeforere use. Theloadshallbeappliedtothetestjigthroughsolidorhollowcolumnswhichareloadedbythetestmachine.These columnsshallbeofama
37、terialwhichremainslinearlyelastictothemaximumtestingtemperature. NOTE5 Toascertainthis,thecolumnsofthetestjigcanbebroughtintocontactattheappropriatetesttemperaturewithor withoutthejiginplace.Aloadequivalenttothatestimatedtobeneededtofracturetestpiecesisapplied,andtheapparent load displacementrelatio
38、nshipisexaminedforevidenceofnonlinearitywithincreasingload(seeclause8). 4.3 Heatingdevice Thetestjigshallbecontainedwithinafurnaceorsuitableheatingdeviceofdesignappropriatetothemaximum temperatureforthetests,andcapableofreachingthemaximumtestingtemperaturewithin3h. NOTE1 Theuseofveryfastheatingrates
39、isnotrecommendedbecauseofriskoffractureofceramiccomponentsinthetest jigorcolumns. Thetemperaturecontrolsystemusedwiththefurnaceshallbecapableofcontrollingtowithin5Cusingasuitable thermocouple.Thetemperatureofthetestpieceshallberecordedusingasecondthermocouplemanufacturedin accordancewiththemanufactu
40、ringtolerancesstatedinIEC605842,allowingtheuseofreferencetablesinIEC 605841or,alternatively,calibratedinamannertraceabletotheInternationaltemperaturescaleITS90.Thetipofthe thermocoupleshallbeclosetobutnottouchingthetestpiece.Itshallpreviouslyhavebeendeterminedthatthe temperatureofthetestpieceshallno
41、tvarybymorethan5Coveritslengthaftera15minuteholdtimeatthe requiredtestingtemperature. NOTE2 Foruseinanairatmosphere,thefurnacecanmostconvenientlybeofasplitdesignallowingaccesstothetestjig inthepositionfortesting.Foracontrolledatmosphere,asimilararrangementmaybeusedwiththetestjigsurroundedbya gastigh
42、tworktube,oralternatively,asealedatmospherefurnacemaybeemployed.Theflowconditionsforgasshouldalsobe considered.Itshouldpreferablybestaticoroflimitedflowratetominimiseproblemsofinhomogeneoustestpiecetemperature . Inallcasesitisdesirabletohavereadyaccesstothetestjigduringsetup.Amultipletestjigorhotspe
43、cimeninsertion system canhavesomeadvantagesintermsoftotaltimerequiredfortesting,butcareshouldbetakenthatthejigandtestpiece alignmentrequirementsaremaintainedforalljigsand/ortestpieces,andthe15mintemperatureequilibrationtimeisusedfo r eachtestpiece. NOTE3 Itisadvisabletoemploywatercoolingforpartsofthefurnaceandloadingcolumnsystemtominimisethe temperaturevariationsofth
