Designation:G28−02(Reapproved2015)StandardTestMethodsforDetectingSusceptibilitytoIntergranularCorrosioninWrought,Nickel-Rich,Chromium-BearingAlloys1ThisstandardisissuedunderthefixeddesignationG28;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thesetestmethodscovertwotestsasfollows:1.1.1MethodA,FerricSulfate-SulfuricAcidTest(Sections3–10,inclusive)—Thistestmethoddescribestheprocedureforconductingtheboilingferricsulfate—50%sulfuricacidtestwhichmeasuresthesusceptibilityofcertainnickel-rich,chromium-bearingalloystointergranularcorrosion(seeTer-minologyG15),whichmaybeencounteredincertainserviceenvironments.Theuniformcorrosionrateobtainedbythistestmethod,whichisafunctionofminorvariationsinalloycomposition,mayeasilymasktheintergranularcorrosioncomponentsoftheoverallcorrosionrateonalloysN10276,N06022,N06059,andN06455.1.1.2MethodB,MixedAcid-OxidizingSaltTest(Sections11–18,inclusive)—Thistestmethoddescribestheprocedureforconductingaboiling23%sulfuric+1.2%hydrochlo-ric+1%ferricchloride+1%cupricchloridetestwhichmeasuresthesusceptibilityofcertainnickel-rich,chromium-bearingalloystodisplayastepfunctionincreaseincorrosionratewhentherearehighlevelsofgrainboundaryprecipitation.1.2Thepurposeofthesetwotestmethodsistodetectsusceptibilitytointergranularcorrosionasinfluencedbyvaria-tionsinprocessingorcomposition,orboth.Materialsshowntobesusceptiblemayormaynotbeintergranularlycorrodedinotherenvironments.Thismustbeestablishedindependentlybyspecifictestsorbyserviceexperience.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimi...
