Designation:F288−96(Reapproved2019)StandardSpecificationforTungstenWireforElectronDevicesandLamps1ThisstandardisissuedunderthefixeddesignationF288;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thisspecificationcoversthreetypesofdrawnwiresuitableforfabricationintopartsforelectrontubes,lamps,andotherdevices;andonetypeofrodformetal-to-glasssealing(gridwireisexcepted):1.1.1Type1A—Commerciallypurenonsagwire(Note2andNote3).1.1.2Type1B—Commerciallypurerodsuitableformetal-to-glasssealing.1.1.3Type2A—Thoriatedfilamentwirecontaining1%thoria.1.1.4Type2B—Thoriatedfilamentwirecontaining2%thoria.1.2Thevaluesstatedininch-poundunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesaremathematicalconversionstoSIunitsthatareprovidedforinformationonlyandarenotconsideredstandard.1.3Types1Aand1BaredesignatedasUNSR07005.Type2AisdesignatedasUNSR07911.Type2BisdesignatedasUNSR07912.1.4ThefollowingprecautionarycaveatpertainsonlytotheChemicalAnalysis,Section12ofthisspecification:Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafety,health,andenvironmentalpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.NOTE1—Adimensionalmeasurementmethodfortestingnonsagtungstenwireabove0.030in.(0.76mm)indiameterisprovidedinTestMethodF269.NOTE2—Acceptanceofnonsagwirecharacteristicsforparticularapplicationsofsizeshallbebyagreementbetweenproducerandconsumerbasedoneitheraflashedmicrostructureasshownbyphotomicrographs,orondimensionalmeasurementlimitsdeterminedinaccordancewithTestMethodF269.1.5Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard...
