ASTM G60-01

Designation:G60–01AnAmericanNationalStandardStandardPracticeforConductingCyclicHumidityExposures1ThisstandardisissuedunderthefixeddesignationG60;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoversproceduresforconductingcyclichumidityexposureswithacorrosivedip.2Itsetsforththeconditionsrequiredincyclichumiditytesting.1.2Thispracticedoesnotprescribethetypeofexposurespecimenorexposureperiodsnortheinterpretationtobegiventotheresults.1.3ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoconsultandestablishappropriatesafetyandhealthpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:D1193SpecificationforReagentWater3G1PracticeforPreparing,Cleaning,andEvaluatingCor-rosionTestSpecimens43.SignificanceandUse3.1Theproceduredescribedisusedtoobservethebehaviorofsteelsunderexposureconditionsthatretardtheformationofaprotectivetypeofrust.Itisalsousedtoevaluatesealcoatoninsulation.3.2Thispracticeshouldnotbeusedtoranksteelsthatformaprotectivetypeofrustunderatmosphericexposurecondi-tions.4.Apparatus4.1Theapparatusrequiredforcyclichumidityexposuresconsistsofatestchamber,provisionsforheatingthechamber,ahumidifyingtower,adryingtrain,adipmechanism,provi-sionsforintroducinganddrainingthesolution,asupplyofcompressedair,specimensupports,andnecessarymeansofcontrol.4.2Thesizeanddetailedconstructionoftheapparatusareoptional,providedtheconditionsobtainedmeettherequire-mentsofthispractice.4.3AschematicdiagramoftheapparatusisshowninFig.1.4.4Theapparatusshouldbecapableofprovidingan8-hhumiditycyclethreetimesperday,asshowninFig.2,andadipcycleonceaday.4.4.1Thecyclicvariationofhumiditycanbeobtainedbyvariationofthetemperatureofthewaterinthehumidifyingtower.Thetemperatureofthewateriscycledthermostaticallysuchthattherelativehumidityofairbubblingthroughthewaterataminimumrateof1L/min(.04ft3/min)willvarybetween100and50%whenthetemperatureoftheairinthetestchamberisbroughtto5261°C(12562°F).4.4.2Therangeofrelativehumiditycanbeextendedbyaddingadryingperiodtothehumiditycycledescribedabove.Theminimumrelativehumidityshallbe#20%andthemaximumrelativehumidityshallbe$95%foreachcycle.4.4.3Dropsofsolutionwhichaccumulateontheceilingorcoverofthechambershallnotbepermittedtofallonthespecimensbeingexposed.NOTE1—Instrumentstocontinuouslyrecordtemperatureandhumidityarenotmandatory,buttheseprovidethemostreliableandeconomicalwayofrecordingsuchinformation.Intheabsenceofsuchinstrumenta-tion,temperatureandhumiditymeasurementshallbemade,atleasttwiceaday,atthemaximumandminimumhumidityinacycle.4.5MaterialsofConstruction:4.5.1Thetestchambershouldbemadeofinertmaterialssuchasplastics,glass,ormetalslinedwithimperviousplastics,rubberorepoxy-typematerials,ormaterialsexhibitingequiva-lentcorrosionresistance.Materialofconstructionshallbesuchthatitwillnotaffectthecorrosivenessoftheexposureatmosphere.4.5.2Thedipsolutioncontainershouldnotbeaffectedbyorcausecontaminationofthedipsolution.4.6SpecimenSupports:4.6.1Thespecimen-supportingdeviceshouldnotbeaf-fectedbyorcausecontaminationofthedipsolution.SeeNote2.4.6.2Themethodofsupportingspecimenswillvarywiththeapparatususedforconductingthetests,butshouldbedesignedtoinsulatethespecimensfromeachotherphysically1ThispracticeisunderthejurisdictionofASTMCommitteeG01onCorrosionofMetalsandisthedirectresponsibilityofSubcommitteeG01.05onLaboratoryCorrosionTests.CurrenteditionapprovedJune10,2001.PublishedJuly2001.OriginallypublishedasG60–79.LastpreviouseditionG60–95.2Opinsky,A.J.,Thomson,R.F.,andBoegehold,A.L.,“ACyclicHumidityAcceleratedCorrosionTestforSheetSteel”,ASTMBulletin,January1953.3AnnualBookofASTMStandards,Vol11.01.4AnnualBookofASTMStandards,Vol03.02.1Copyright©ASTM,100BarrHarborDrive,WestConshohocken,PA19428-2959,UnitedStates.andelectricallyandtoinsulatethespecimensfromanymetalliccontainerorsupportingdeviceusedwithintheapparatus.Thespecimensshallnotcontactanymaterialcapableofactingasawick.NOTE2—Suitablematerialsfortheconstructionorcoatingofracksandsupportsareglass,rubber,plastic,orsuitablycoatedwood.Baremetalshallnotbeused.Specimensshallpreferablybesupportedfromthebottomortheside.Slottedwoodenstripsaresuitableforthesupportofflatpanels.Suspensionfromglasshooksorwaxedstringmaybeusedaslongasthespecifiedpositionofthespecimensisobtained,ifnecessary,bymeansofsecondarysupportatthebottomofthespecimens.4.6.3Shapeandformofthespecimensupportshouldassurefreecontactofthespecimenwiththecorrosivesolution,theliquidline,orthevaporphase.Inastackedrack,thefirstandlastspecimensshouldbedummyspecimenssothattheoutermostexposurespecimensareshieldedbytheirneighborsinthesamemannerasspecimensinthemiddleofthestack