ASTM_F_73_-_96_2013.pdf

Designation:F7396(Reapproved 2013)Standard Specification forTungsten-Rhenium Alloy Wire for Electron Devices andLamps1This standard is issued under the fixed designation F73;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This specification covers tungsten-rhenium alloy wiresuitable for use in electron devices and lamps.The material isknown as UNS R07031.1.2 The term wire as used in this specification applies to allmaterial 0.020 in.(0.51 mm)or less in diameter that is spooledor coiled.1.3 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2F205 Test Method for Measuring Diameter of Fine Wire byWeighingF219 Test Methods of Testing Fine Round and Flat Wire forElectron Devices and Lamps3.Ordering Information3.1 Orders for wire furnished to this specification shallinclude the following information:3.1.1 Length in metres,3.1.2 Name of material,3.1.3 Straightness(see 6.2),3.1.4 Finish(see 7.2),3.1.5 Weight or size(see 6.1)and tolerance,and3.1.6 Specification number and UNS number.NOTE1A typical ordering description for straight chemically cleanedwire is as follows:xxxx metres tungsten-rhenium alloy wire,straightened,Finish 2;280.8 mg/200 mm(63%),per ASTM F73 XX(UNSR07031).4.Chemical Composition4.1 This wire shall conform to the requirements as tochemical composition prescribed in Table 1.5.Physical Properties5.1 Tensile StrengthThe tensile strength of a 10-in.(250-mm)gage length of wire in grams-force per milligram per 200mm shall be within the limits prescribed in Table 2,whentested in accordance with 8.2.5.2 General Ductility RequirementsThe ductility of wireshall be sufficient to meet the following requirements:5.2.1 Wire Sizes up to 75 mg/200 mm,inclSix 1-m lengthsshall be tested in accordance with 8.3.1.The wire shall notbreak more than two times in the six tests.Where required,alower limit may be negotiated between purchaser and seller.5.2.2 Wire Sizes over 75 mg/200 mmThirty successiveclose-wound turns completely around mandrels shall be freefrom splitting or cracking when tested in accordance with 8.3.2and examined at a magnification of 30.5.3 Special Ductility RequirementsWire for certain appli-cations requires a special ductility as agreed upon between thepurchaser and the seller.6.Size,Straightness,and Tolerances6.1 Dimensional tolerances for wire for use as incandescentfilaments shall conform to the requirements prescribed in Table3.NOTE2Tolerances are industry standards;closer tolerances may beobtained in certain instances,usually at a premium.6.2 StraightnessStraightness of wire 3.00 mg/200 mm andlarger shall be specified as the radius of curvature or camber ofa given length of wire as agreed upon between the purchaserand supplier.For wire under 3.00 mg/200 mm,alternativemethods may be used as agreed upon between the purchaserand supplier.1This specification is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.03 on MetallicMaterials.Current edition approved May 1,2013.Published May 2013.Originallyapproved in 1966.Last previous edition approved in 2009 as F73 96(2009).DOI:10.1520/F0073-96R13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.Workmanship,Finish,and Appearance7.1 General Requirements:7.1.1 The material shall be as smooth,as free of twists,bends,curls,kinks,and as free,when examined at 30,fromdents,swaging marks,scratches,swaging die marks,laps,seams,splits,slivers,inclusions,bumps,pits,grooves,cracks,and other physical defects as best commercial practice willpermit.7.1.2 Unless black finish is specified,all types of wire shallbe free of graphite,grease,and oil.All finishes shall be as freeof dirt,oxide,stains,scale,and other surface defects as bestcommercial practice permits.Refer to 8.4 for inspectionmethods.7.2 FinishThe wire shall be furnished in the followingfinishes:7.2.1 Finish 1Black,7.2.2 Finish 2Chemically cleaned,7.2.3 Finish 3Chemically cleaned and stress relieved,7.2.4 Finish4Reducingatmospherecleane