ASTM D395-03

StandardTestMethodsfor

RubberProperty—CompressionSet1ThisstandardisissuedunderthefixeddesignationD395;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheDepartmentofDefense.

1.Scope

1.1Thesetestmethodscoverthetestingofrubberintendedforuseinapplicationsinwhichtherubberwillbesubjectedtocompressivestressesinairorliquidmedia.Theyareapplicableparticularlytotherubberusedinmachinerymountings,vibra-tiondampers,andseals.Twotestmethodsarecoveredasfollows:

TestMethod

A—CompressionSetUnderConstantForceinAirB—CompressionSetUnderConstantDeflectioninAir

Section7–1011–14

E145SpecificationforGravity-ConvectionandForced-VentilationOvens33.SummaryofTestMethods

3.1Atestspecimeniscompressedtoeitheradeflectionorbyaspecifiedforceandmaintainedunderthisconditionforaspecifiedtimeandataspecifiedtemperature.

3.2Theresidualdeformationofatestspecimenismeasured30minafterremovalfromasuitablecompressiondeviceinwhichthespecimenhadbeensubjectedforadefinitetimetocompressivedeformationunderspecifiedconditions.

3.3Afterthemeasurementoftheresidualdeformation,thecompressionset,asspecifiedintheappropriatetestmethod,iscalculatedaccordingtoEq1andEq2.

4.SignificanceandUse

4.1Compressionsettestsareintendedtomeasuretheabilityofrubbercompoundstoretainelasticpropertiesafterpro-longedactionofcompressivestresses.Theactualstressingservicemayinvolvethemaintenanceofadefinitedeflection,theconstantapplicationofaknownforce,ortherapidlyrepeateddeformationandrecoveryresultingfromintermittentcompressiveforces.Thoughthelatterdynamicstressing,liketheothers,producescompressionset,itseffectsasawholearesimulatedmorecloselybycompressionflexingorhysteresistests.Therefore,compressionsettestsareconsideredtobemainlyapplicabletoserviceconditionsinvolvingstaticstresses.Testsarefrequentlyconductedatelevatedtempera-tures.

5.TestSpecimens

5.1Specimensfromeachsamplemaybetestedinduplicate(Option1)ortriplicate(Option2).ThecompressionsetofthesampleinOption1shallbetheaverageofthetwospecimensexpressedasapercentage.ThecompressionsetofthesampleinOption2shallbethemedian(middlemostvalue)ofthethreespecimensexpressedasapercentage.

5.2Thestandardtestspecimenshallbeacylindricaldiskcutfromalaboratorypreparedslab.

5.2.1Thedimensionsofthestandardspecimensshallbe:

1.2Thechoiceoftestmethodisoptional,butconsiderationshouldbegiventothenatureoftheserviceforwhichcorrelationoftestresultsmaybesought.Unlessotherwisestatedinadetailedspecification,TestMethodBshallbeused.1.3TestMethodBisnotsuitableforvulcanizatesharderthan90IRHD.

1.4ThevaluesstatedinSIunitsaretoberegardedasthestandard.

1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.

2.ReferencedDocuments2.1ASTMStandards:

D1349PracticeforRubber—StandardTemperaturesforTesting2D3182PracticeforRubber—Materials,Equipment,andProceduresforMixingStandardCompoundsandPrepar-ingStandardVulcanizedSheets2D3183PracticeforRubber—PreparationofPiecesforTestPurposesfromProducts2D3767PracticeforRubber—MeasurementofDimensions2D4483PracticeforDeterminingPrecisionforTestMeth-odsStandardsintheRubberandCarbonBlackIndustries2ThesetestmethodsareunderthejurisdictionofASTMCommitteeD11onRubberandarethedirectresponsibilityofSubcommitteeD11.10onPhysicalTesting.

CurrenteditionapprovedAug.10,2003.PublishedSeptember2003.Originallyapprovedin1934.Lastpreviouseditionapprovedin2002asD395–02.2AnnualBookofASTMStandards,Vol09.01.

13AnnualBookofASTMStandards,Vol14.04.

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1

D395–03

Type

Thickness,mm(in.)Diameter,mm(in.)

AB1A12.560.5(0.4960.02)29.060.5(1.1460.02)

2B6.060.2(0.2460.01)13.060.2(0.5160.01)

TABLE1Type1PrecisionResults,%CompressionSet—Test

MethodA

Material12

AMeanLevel1.73(%)26.1

WithinLaboratoryASr0.0500.898

r0.1422.54

(r)8.29.7

BetweenLaboratoryASR0.1902.37

R0.546.71

(R)31.125.7

Type1specimenisusedinTestMethodsAandB.Type2specimenisusedinTestMethodB.

5.2.2Whencuttingthestandardspecimen,thecirculardiehavingtherequiredinsidedimensionsspecifiedin5.2.1shallberotatedinadrillpressorsimilardeviceandlubricatedbymeansofasoapsolution.Aminimumdistanceof13mm(0.51in.)shallbemaintainedbetweenthecuttingedgeofthedieandtheedgeoftheslab.Thecuttingpressureshallbeaslightaspossibletominimizecuppingofthecutedges.Thediesshallbemaintainedcarefullysothatthecuttingedgesaresharpandfreeofnicks.

5.3Anoptionalmethodofpreparingthestandardspecimenmaybethedirectmoldingofacirculardiskhavingthedimensionsrequiredforthetestmethodusedandspecifiedin5.2.1.

NOTE1—Itshouldberecognizedthatanequaltimeandtemperature,ifusedforboththeslabandmoldedspecimen,willnotproduceanequivalentstateofcureinthetwotypesofspecimen.Ahigherdegreeofcurewillbeobtainedinthemoldedspecimen.Adjustments,preferablyinthetimeofcure,mustbetakenintoconsiderationifcomparisonsbetweenthespecimenspreparedbydifferentmethodsaretobeconsideredvalid.NOTE2—Itissuggested,forthepurposeofuniformityandclosertolerancesinthemoldedspecimen,thatthedimensionsofthemoldbespecifiedandshrinkagecompensatedfortherein.Atwo-platemoldwithacavity13.060.1mm(0.51060.004in.)inthicknessand29.2060.05mm(1.14860.002in.)indiameter,withoverflowgrooves,willprovideType1specimensforTestMethodAandTestMethodB.Asimilarmoldbuthavingacavityof6.360.3mm(0.2560.012in.)inthicknessand13.260.1mm(0.5260.004in.)indiameterwillprovideType2specimensforTestMethodB.

Sr=withinlaboratorystandarddeviation.r=repeatability(inmeasurementunits).(r)=repeatability(inpercent).

SR=betweenlaboratorystandarddeviation.R=reproducibility(inmeasurementunits).(R)=reproducibility(inpercent).

5.5.4Theresultsobtainedonthespecimenspreparedbyoneofthemethodsmaybecomparedonlytothosepreparedbythesamemethod.

5.6Forroutineorproductspecificationtesting,itissome-timesmoreconvenienttopreparespecimensofadifferentsizeorshape,orboth.Whensuchspecimensareused,theresultsshouldbecomparedonlywiththoseobtainedfromspecimensofsimilarsizeandshapeandnotwiththoseobtainedwithstandardspecimen.Forsuchcases,theproductspecificationshoulddefinethespecimenastothesizeandshape.Ifsuitablespecimenscannotbepreparedfromtheproduct,thetestmethodandallowablelimitsmustbeagreeduponbetweentheproducerandthepurchaser.

6.Conditioning

6.1Storeallvulcanizedtestspecimensorproductsamplestobetestedatleast24hbutnotmorethan60days.Whenthedateofvulcanizationisnotknown,maketestswithin60daysafterdeliverybytheproducerofthearticlerepresentedbythespecimen.

6.2Allowbuffedspecimenstorestatleast30minbeforespecimensarecutfortesting.

6.3Conditionallspecimensbeforetestingforaminimumof3hat2362°C(73.463.6°F).Specimenswhosecompressionsetpropertiesareaffectedbyatmosphericmoistureshallbeconditionedforaminimumof24hinanatmospherecontrolledto5065%relativehumidity.

7.PrecisionandBias47.1Theseprecisionstatementshavebeenpreparedinac-cordancewithPracticeD4483.PleaserefertoPracticeD4483forterminologyandothertestingandstatisticalconcepts.7.2PreparedtestspecimensoftworubbersforTestMethodsAandBweresuppliedtofivelaboratories.Theseweretestedinduplicateeachdayontwoseparatetestingdays.Atestresult,therefore,istheaverageoftwotestspecimens,forbothTestMethodsAandB.

7.3OnelaboratorydidnotruntheTestMethodAtesting;therefore,theprecisionforTestMethodAisderivedfromfourlaboratories.

7.4TheType1precisionresultsaregiveninTable1andTable2.

5.4Whenthestandardtestspecimenistobereplacedbyaspecimentakenfromavulcanizedrubberpartofgreaterthicknessthantheoneindicatedin5.2.1,thesamplethicknessshallbereducedfirstbycuttingtransverselywithasharpknifeandthenfollowedbybuffingtotherequiredthicknessinaccordancewithPracticeD3183.

5.5AnalternativemethodofpreparingspecimensisbyplyingupcylindricaldiskscutfromastandardsheetpreparedinaccordancewithPracticeD3182usingthespecimensizesspecifiedin5.2.1andcuttingasdescribedin5.2.2,orwhereadrillpressisnotavailablecuttingthespecimenswithasinglestrokefromacuttingdie.

5.5.1Thedisksshallbeplied,withoutcementing,tothethicknessrequired.Suchpliesshallbesmooth,flat,ofuniformthickness,andshallnotexceedseveninnumberforType1specimensandfourinnumberforType2specimens.

5.5.2Careshallbetakenduringhandlingandplacingofthepliedtestspecimeninthetestfixturebykeepingthecircularfacesparallelandatrightanglestotheaxisofthecylinder.5.5.3Theresultsobtainedonpliedspecimensmaybedifferentfromthoseobtainedusingsolidspecimensandtheresultsmaybevariable,particularlyifairistrappedbetweendisks.

2

SupportingdatahavebeenfiledatASTMInternationalHeadquartersandmaybeobtainedbyrequestingResearchReportRR:D11–1138.

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D395–03

TABLE2Type1PrecisionResults,%CompressionSet—Test

MethodB

Material12

AMeanLevel13.7(%)52.8WithinLaboratoryASrr(r)0.5911.6712.20.5671.603.0BetweenLaboratoryASRR(R)1.544.3631.85.9216.831.7

Sr=withinlaboratorystandarddeviation.

r=repeatability(inmeasurementunits).(r)=repeatability(inpercent).

SR=betweenlaboratorystandarddeviation.R=reproducibility(inmeasurementunits).(R)=reproducibility(inpercent).

7.5Bias—Intestmethodstatisticalterminology,biasisthedifferencebetweenanaveragetestvalueandthereferenceortruetestpropertyvalue.Referencevaluesdonotexistforthesetestmethodssincethevalueorlevelofthetestpropertyisexclusivelydefinedbythetestmethod.Bias,therefore,cannotbedetermined.

TESTMETHODA—COMPRESSIONSETUNDER

CONSTANTFORCEINAIR8.Apparatus

8.1DialMicrometer—Adialmicrometer,formeasuringspecimenthickness,inaccordancewithPractice3767,MethodA1.

8.2CompressionDevice,consistingofaforceapplicationspringandtwoparallelcompressionplatesassembledbymeansofaframeorthreadedboltinsuchamannerthatthedeviceshallbeportableandself-containedaftertheforcehasbeenappliedandthattheparallelismoftheplatesshallbemaintained.Theforcemaybeappliedinaccordancewitheither8.2.1or8.2.2.

8.2.1CalibratedSpringForceApplication—Therequiredforceshallbeappliedbyascrewmechanismforcompressingacalibratedspringtheproperamount.Thespringshallbeofproperlyheat-treatedspringsteelwithendsgroundandper-pendiculartothelongitudinalaxisofthespring.AsuitablecompressiondeviceisshowninFig.1.Thespringshallconformtothefollowingrequirements:

8.2.1.1Thespringshallbecalibratedatroomtemperature2365°C(73.469°F)byapplyingsuccessiveincrementsofforcenotexceeding250N(50lbf)andmeasuringthecorrespondingdeflectiontothenearest0.2mm(0.01in.).Thecurveobtainedbyplottingtheforcesagainstthecorrespondingdeflectionsshallhaveaslopeof7063.5kN/m(400620lbf/in.)at1.8kN(400lbf).Theslopeisobtainedbydividingthetwoforcesaboveandbelow1.8kNbythedifferencebetweenthecorrespondingdeflections.

8.2.1.2Theoriginaldimensionsofthespringshallnotchangeduetofatiguebymorethan0.3mm(0.01in.)afterithasbeenmountedinthecompressiondevice,compressedunderaforceof1.8kN(400lbf),andheatedintheovenforoneweekat70°C62°C(15863.6°F).Inordinaryuse,aweeklycheckofthedimensionsshallshownogreaterchangethanthisoveraperiodof1year.

8.2.1.3Theminimumforcerequiredtoclosethespring(solid)shallbe2.4kN(530lbf).

3

FIG.1DeviceforCompressionSetTest,UsingCalibratedSpring

Loading,TestMethodA

8.2.2ExternalForceApplication—Therequiredforceshallbeappliedtothecompressionplatesandspringbyexternalmeansafterthetestspecimenismountedintheapparatus.Eitheracalibratedcompressionmachineorknownmassesmaybeusedforforceapplication.Provisionshallbemadebytheuseofboltsandnutsorotherdevicestopreventthespecimenandspringfromlosingtheirinitialdeflectionswhentheexternalforceisremoved.Thespringshallhaveessentiallythesamecharacteristicsasdescribedin8.2.1,butcalibrationisnotrequired.AsuitablecompressiondeviceisshowninFig.2.8.3Plates—Theplatesbetweenwhichthetestspecimeniscompressedshallbemadeofsteelofsufficientthicknesstowithstandthecompressivestresseswithoutbending.

8.3.1Thesurfacesagainstwhichthespecimenisheldshallhaveachromiumplatedfinishandshallbecleanedthoroughlyandwipeddrybeforeeachtest.

8.3.2Thesteelsurfacescontactingtherubberspecimensshallbegroundtoamaximumroughnessof250µm(10µin.)andthenchromiumplatedandpolished.

8.3.3Thechromiumplatingandsubsequentpolishingshallnotaffectthefinalfinishbeyondthetolerancestatedin8.3.2.

NOTE3—Thespecificationsregardingthesurfaceroughness(smooth-ness)ofthecontactsurfacesoftheplatesistobeconsideredonlyatthetimeofmanufactureorrefurbishingasitisnotapropertythatiseasilydeterminedinthecourseofroutineuse.Thesuitabilityfortheuseofthedeviceistobedeterminedbytheuser.

8.4Oven,conformingtothespecificationforaTypeIIBlaboratoryovengiveninSpecificationE145.

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D395–03

8.4.8.3Thethermostaticcontroldeviceshallbesolocatedastogiveaccuratetemperaturecontroloftheheatingmedium.Thepreferredlocationisadjacenttothetemperaturemeasuringdevicelistedinsection8.4.6.

8.4.8.4Anactualcheckshallbemadebymeansofmaxi-mumreadingthermometersplacedinvariouspartsoftheoventoverifytheuniformityoftheheating.9.Procedure

9.1OriginalThicknessMeasurement—Measuretheoriginalthicknessofthespecimentothenearest0.02mm(0.001in.).Placethespecimenontheanvilofthedialmicrometersothatthepresserfootwillindicatethethicknessatthecentralportionofthetopandbottomfaces.

9.2ApplicationofCompressiveForce—Assemblethespecimensinthecompressiondevice,usingextremecaretoplacethemexactlyinthecenterbetweentheplatestoavoidtilting.Ifthecalibratedspringdevice(seeFig.1)isused,applythecompressiveforcebytighteningthescrewuntilthedeflectionasreadfromthescaleisequivalenttothatshownonthecalibrationcurveforthespringcorrespondingtoaforceof1.8kN(400lbf).Withtheexternalloadingdevice(seeFig.2),applythisforcetotheassemblyinthecompressionmachineorbyaddingrequiredmasses,butinthelattercase,takecaretoaddthemassgraduallywithoutshock.Tightenthenutsandboltsjustsufficientlytoholdtheinitialdeflectionsofthespecimenandspring.Itisimperativethatnoadditionalforcebeappliedintighteningthebolts.

9.3TestTimeandTestTemperature—Chooseasuitabletemperatureandtimeforthecompressionset,dependingupontheconditionsoftheexpectedservice.Incomparativetests,useidenticaltemperatureandheatingperiods.ItissuggestedthatthetesttemperaturebechosenfromthoselistedinPracticeD1349.Suggestedtestperiodsare22hand70h.Thespecimenshallbeatroomtemperaturewheninsertedinthecompressiondevice.Placetheassembledcompressiondeviceintheovenwithin2haftercompletionoftheassemblyandallowittoremaintherefortherequiredtestperiodindryairatthetesttemperatureselected.Attheendofthetestperiod,takethedevicefromtheovenandremovethespecimensimmedi-atelyandallowittocool.

9.4CoolingPeriod—Whilecooling,allowthespecimenstorestonapoorthermallyconductingsurface,suchaswood,for30minbeforemakingthemeasurementofthefinalthickness.Conductthecoolingperiodatastandardlaboratorytempera-tureof2362°C(73.463.6°F).Specimenswhosecompres-sionsetpropertyisaffectedbyatmosphericmoistureshallbecooledinanatmospherecontrolledto5065%relativehumidity.

9.5FinalThicknessMeasurement—Aftertherestperiod,measurethefinalthicknessatthecenterofthespecimeninaccordancewith9.1.10.Calculation

10.1Calculatethecompressionsetasapercentageoftheoriginalthicknessasfollows:

CA5[~to2ti!/to#3100

(1)

FIG.2DeviceforCompressionSetTest,UsingExternalLoading,

TestMethodA

8.4.1TypeIIBovensspecifiedinTestMethodE145aresatisfactoryforusethrough70°C.ForhigherTemperaturesTypeIIAovensarenecessary.

8.4.2Theinteriorsizeshallbeasfollowsorofanequivalentvolume:

Interiorsizeofairoven:

min.

max.

300bt300mmby300mm(12by12by12in.)

900by900by1200mm(36by36by48in.)

8.4.3Provisionshallbemadeforplacingtestspecimensintheovenwithouttouchingeachotherorthesidesoftheagingchamber.

8.4.4Theheatingmediumfortheagingchambershallbeaircirculatedwithinitatatmosphericpressure.

8.4.5Thesourceofheatisoptionalbutshallbelocatedintheairsupplyoutsideoftheagingchamber.

8.4.6Asuitabletemperaturemeasurementdevicelocatedintheuppercentralportionofthechambernearthetestspeci-mensshallbeprovidedtorecordtheactualagingtemperature.8.4.7Automatictemperaturecontrolbymeansofthermo-staticregulationshallbeused.

8.4.8Thefollowingspecialprecautionsshallbetakeninorderthataccurate,uniformheatingisobtainedinallpartsoftheagingchamber.

8.4.8.1Theheatedairshallbethoroughlycirculatedintheovenbymeansofmechanicalagitation.Whenamotordrivenfanisused,theairmustnotcomeincontactwiththefanmotorbrushdischargebecauseofdangerofozoneformation.

8.4.8.2Bafflesshallbeusedasrequiredtopreventlocaloverheatinganddeadspots.

4

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D395–03

where:

CA=Compressionset(TestMethodA)asapercentageof

theoriginalthickness,

to=originalthickness(see9.1),and

=finalthickness(see9.5).ti11.Report

11.1Reportthefollowinginformation:

11.1.1Originaldimensionsofthetestspecimen,includingtheoriginalthickness,to,

11.1.2Actualcompressiveforceonthespecimenasdeter-minedfromthecalibrationcurveofthespringandspringdeflectionreading(see8.2.1)orasappliedbyanexternalforce(see8.2.2),

11.1.3Thicknessofthetestspecimen30minafterremovalfromtheclamp,ti,

11.1.4Typeoftestspecimenused,togetherwiththetimeandtemperatureoftest,

11.1.5Compressionset,expressedasapercentageoftheoriginalthickness,

11.1.6Testmethodused(TestMethodA),and11.1.7Numberofspecimenstested.

TESTMETHODB—COMPRESSIONSETUNDER

CONSTANTDEFLECTIONINAIR12.Apparatus

12.1DialMicrometer—Adialmicrometer,formeasuringthespecimenthickness,inaccordancewithPracticeD3767,MethodA1.

NOTE4—Forvulcanizateshavingahardnessbelow35IRHD,theforceonthepresserfootshouldbereducedto0.260.05N(0.0460.01lbf).

12.5Plates—Theplatesbetweenwhichthetestspecimeniscompressedshallbemadeofsteelofsufficientthicknesstowithstandthecompressivestresseswithoutbending.

12.5.1Thesurfacesagainstwhichthespecimenisheldshallhaveachromium-platedfinishandshallbecleanedthoroughlyandwipeddrybeforeeachtest.

12.5.2Thesteelsurfacescontactingtherubberspecimensshallbegroundtoamaximumroughnessof250µm(10µin.)andthenchromiumplatedandpolished.

12.5.3Thechromiumplatingandsubsequentpolishingshallnotaffectthefinalfinishbeyondthetolerancestatedin12.5.2.13.Procedure

13.1OriginalThicknessMeasurement—Measuretheorigi-nalthicknessofthespecimentothenearest0.02mm(0.001in.).Placethespecimenontheanvilofthedialmicrometersothatthepresserfootwillindicatethethicknessatthecentralportionofthetopandbottomfaces.

13.2ApplicationofCompressiveForce—Placethetestspecimenbetweentheplatesofthecompressiondevicewiththespacersoneachside,allowingsufficientclearanceforthebulgingoftherubberwhencompressed(seeFig.3).Wherealubricantisapplied,itshallconsistofathincoatingofalubricanthavingsubstantiallynoactionontherubber.Formostpurposes,asiliconorfluorosiliconfluidissuitable.Tightentheboltssothattheplatesaredrawntogetheruniformlyuntiltheyareincontactwiththespacers.Theamountofcompressionemployedshallbeapproximately25%.Asuitablemechanicalorhydraulicdevicemaybeusedtofacilitateassemblinganddisassemblingthetestfixture.

13.3TestTimeandTemperature—Chooseasuitabletem-peratureandtimeforthecompressionset,dependingupontheconditionsoftheexpectedservice.Incomparativetests,useidenticaltemperatureandtestperiods.ItissuggestedthatthetesttemperaturebechosenfromthoselistedinPracticeD1349.Suggestedtestperiodsare22hand70h.Thetestspecimenshallbeatroomtemperaturewheninsertedinthecompressiondevice.Placetheassembledcompressiondeviceintheovenwithin2haftercompletionoftheassemblyandallowittoremaintherefortherequiredtestperiodindryairatthetesttemperatureselected.Attheendofthetestperiod,takethedevicefromtheovenandremovethetestspecimenimmediatelyandallowthemtocool.

13.4CoolingPeriod—Whilecooling,allowthetestspeci-mentorestonapoorthermallyconductingsurface,suchaswood,for30minbeforemakingthemeasurementofthefinalthickness.Maintaintheconditionsduringthecoolingperiodinaccordancewith9.4.

13.5FinalThicknessMeasurement—Aftertherestperiod,measurethefinalthicknessatthecenterofthetestspecimeninaccordancewith13.1.14.Calculation

12.2SpacerBars,tomaintaintheconstantdeflectionre-quiredunderTestMethodB.

12.2.1SpacerbarsforType1samplesshallhaveathicknessof9.560.02mm(0.37560.001in.).

12.2.2SpacerbarsforType2samplesshallhaveathicknessof4.5060.01mm(0.177060.0005in.).

12.3CompressionDevice,consistingoftwoormoreflatsteelplatesbetweentheparallelfacesofwhichthespecimensmaybecompressedasshowninFig.3.Steelspacersfortherequiredpercentageofcompressiongivenin13.2shallbeplacedoneachsideoftherubberspecimenstocontroltheirthicknesswhilecompressed.thesteelsurfacescontactingtherubberspecimensshallbegroundtoamaximumroughnessof250µm(10µin.)andthenchromiumplatedandpolished(seeNote3).

12.4Oven,see8.4.

FIG.3DeviceforCompressionSetTestUnderConstant

Deflection,TestMethodB

14.1Calculatethecompressionsetexpressedasapercent-ageoftheoriginaldeflectionasfollows:

CB5[~to2ti!/~to2tn!#3100

(2)

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5

D395–03

where:

CB=compressionset(TestMethodB)expressedas

percentageoftheoriginaldeflection,t0=originalthicknessofspecimen(13.1),ti=finalthicknessofspecimen(13.5),andtn=thicknessofthespacerbarused.

NOTE5—Lubricationoftheoperatingsurfacesofthecompressiondeviceisoptionalwhilegivingmorereproducibleresults;lubricationmaysomewhatalterthecompressionsetvalues.

15.Report

15.1Reportthefollowinginformation:

15.1.1Originaldimensionsofthetestspecimenincludingtheoriginalthickness,to,

15.1.2Percentagecompressionofthespecimenactuallyemployed,

15.1.3Thicknessofthetestspecimen30minafterremovalfromtheclamp,ti,

15.1.4Typeoftestspecimenused,togetherwiththetimeandtemperatureoftest,

15.1.5Whetherornotthesurfacesofthecompressiondevicearelubricated.Iftheyare,whattypelubricationwasused,

15.1.6Compressionset,expressedasapercentageoftheoriginaldeflection,

15.1.7Testmethodused(TestMethodB),and15.1.8Numberofspecimenstested.

16.Keywords

16.1compressionset;compressionsetunderconstantde-flection;compressionsetunderconstantforce;deflection;deformation;elasticproperty;hysteresis;recovery

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6