Designation:A1084−15aStandardTestMethodforDetectingDetrimentalPhasesinLeanDuplexAustenitic/FerriticStainlessSteels1ThisstandardisissuedunderthefixeddesignationA1084;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thepurposeofthistestmethodistoallowdetectionofthepresenceofdetrimentalchromium-containingphasesinselectedleanduplexstainlesssteelstotheextentthattoughnessorcorrosionresistanceisaffectedsignificantly.Suchphasescanformduringmanufactureandfabricationofleanduplexproducts.Thistestmethoddoesnotnecessarilydetectlossesoftoughnessnorcorrosionresistanceattributabletoothercauses,norwillitidentifytheexacttypeofdetrimentalphasesthatcausedanylossoftoughnessorcorrosionresistance.Thetestresultisasimplepass/failstatement.1.2Leanduplex(austenitic-ferritic)stainlesssteelsaretypi-callyduplexstainlesssteelscomposedof30to70%ferritecontentwithatypicalalloycompositionhavingCr>17%andMo<1%andwithadditionsofNickel,Manganese,Nitrogenandcontrolledlowcarboncontentaswellasotheralloyingelements.ThisstandardtestmethodappliesonlytothosealloyslistedinTable1.SimilartestmethodsforsomehigheralloyedduplexstainlesssteelsaredescribedinTestMethodsA923,buttheproceduresdescribedinthisstandarddiffersignificantlyforallthreemethodsfromtheonesdescribedinTestMethodsA923.1.3Leanduplexstainlesssteelsaresusceptibletotheformationofdetrimentalchromium-containingcompoundssuchasnitridesandcarbidesandotherundesirablephases.Typicallythisoccursduringexposuresinthetemperaturerangefromapproximately300to955°C(570to1750ºF)withamaximumsusceptibilityinthetemperaturerangearound650to750°C(1200to1385ºF).Thespeedoftheseprecipitationreactionsisafunctionofcompositionandthethermalorthermo-mechanicalhistoryofeachindividualpiece.Thepres-enceofanamountofthesephasescanbedetrimentaltotoughnessandcorrosionresi...
