标准

Designation:C978–04

StandardTestMethodfor

PhotoelasticDeterminationofResidualStressina

TransparentGlassMatrixUsingaPolarizingMicroscopeandOpticalRetardationCompensationProcedures1

Thisstandardisissuedunderthe xeddesignationC978;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.

1.Scope

1.1Thistestmethodcoversthedeterminationofresidualstressesinatransparentglassmatrixbymeansofapolarizingmicroscopeusingnullorretardationcompensationprocedures.1.2Suchresidualstressdeterminationsareofimportanceinevaluatingthenatureanddegreeofresidualstressespresentinglassmatrixesduetocord,orthedegreeof t,orsuitabilityofaparticularcombinationofglassmatrixandenamel,orappliedcolorlabel(ACL).

1.3Theretardationcompensationmethodofopticallyde-terminingandevaluatingenamelorACLresidualstresssys-temsoffersdistinctadvantagesovermethodsrequiringphysi-calpropertymeasurementsorwareperformancetestsduetoitssimplicity,reproducibility,andprecision.

1.4Limitations—Thistestmethodisbasedonthestress-opticalretardationcompensationprinciple,andisthereforeapplicableonlytotransparentglasssubstrates,andnottoopaqueglasssystems.

1.5Duetothepossibilityofadditionalresidualstressesproducedbyionexchangebetweenglassesofdifferentcom-positions,someuncertaintymaybeintroducedinthevalueofthestressopticalcoefficientinthepointofinterestduetoalackofaccurateknowledgeofchemicalcompositionintheareasofinterest.

1.6Thistestmethodisquantitativelyapplicabletoandvalidonlyforthoseapplicationswheresuchsigni cantionexchangeisnotafactor,andstressopticalcoefficientsareknownordeterminable.

1.7Theextentoftheionexchangeprocess,andhencethemagnitudesoftheresidualstressesproducedduetoionexchangewilldependontheexchangeprocessparameters.Theresidualstressdeterminationsmadeonsystemsinwhichionexchangehasoccurredshouldbeinterpretedwiththosedepen-denciesinmind.

ThistestmethodisunderthejurisdictionofASTMCommitteeC14onGlassandGlassProductsandisthedirectresponsibilityofSubcommitteeC14.10onGlassDecoration.

CurrenteditionapprovedJune1,2004.PublishedJune2004.Originallyapprovedin1987.Lastpreviouseditionapprovedin2002asC978-02.

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1.8ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.

1.9Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.

2.ReferencedDocuments2.1ASTMStandards:2

C162TerminologyofGlassandGlassProducts

C770TestMethodforMeasurementofGlassStress-OpticalCoefficient

E691PracticeforConductinganInterlaboratoryStudytoDeterminethePrecisionofaTestMethod

F218TestMethodforAnalyzingStressinGlass3.Terminology

3.1De nitions—Foradditionalde nitionsoftermsusedinthistestmethod,refertoTerminologyC162.

3.1.1cord—anattenuatedglassyinclusionpossessingopti-calandotherpropertiesdifferingfromthoseofthesurroundingglass.C1623.2De nitionsofTermsSpeci ctoThisStandard:

3.2.1analyzer—apolarizingelement,typicallypositionedbetweenthespecimenbeingevaluatedandtheviewer.

3.2.2appliedcolorlabel(ACL)—vitri ableglasscolordecorationorenamelappliedtoandfusedonaglasssurface.3.2.3polarizer—anopticalassemblythattransmitslightvibratinginasingleplanardirection,typicallypositionedbetweenalightsourceandthespecimenbeingevaluated.

ForreferencedASTMstandards,visittheASTMwebsite,www.1mpi.com’sDocumentSummarypageontheASTMwebsite.

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Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.

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