1、Designation:F28896(Reapproved 2014)Standard Specification forTungsten Wire for Electron Devices and Lamps1This standard is issued under the fixed designation F288;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of last revis
2、ion.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This specification covers three types of drawn wir
3、esuitable for fabrication into parts for electron tubes,lamps,andother devices;and one type of rod for metal-to-glass sealing(grid wire is excepted):1.1.1 Type 1ACommercially pure nonsag wire(Note 2 andNote 3).1.1.2 Type 1BCommercially pure rod suitable for metal-to-glass sealing.1.1.3 Type 2AThoria
4、ted filament wire containing 1%thoria.1.1.4 Type 2BThoriated filament wire containing 2%thoria.1.2 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
5、standard.1.3 Types 1A and 1B are designated as UNS R07005.Type2A is designated as UNS R07911.Type 2B is designated asUNS R07912.1.4 The following precautionary caveat pertains only to theChemical Analysis,Section 12 of this specification:Thisstandard does not purport to address all of the safety con
6、cerns,if any,associated with its use.It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.NOTE1A dimensional measurement method for testing nonsagtungsten wire above 0.030 in.(
7、0.76 mm)in diameter is provided in TestMethod F269.NOTE2Acceptance of nonsag wire characteristics for particularapplications of size shall be by agreement between producer and consumerbased on either a flashed microstructure as shown by photomicrographs,or on dimensional measurement limits determine
8、d in accordance with TestMethod F269.2.Referenced Documents2.1 ASTM Standards:2F16 Test Methods for Measuring Diameter or Thickness ofWire and Ribbon for Electronic Devices and LampsF204 Test Method for Surface Flaws in Tungsten Seal Rodand WireF205 Test Method for Measuring Diameter of Fine Wire by
9、WeighingF219 Test Methods of Testing Fine Round and Flat Wire forElectron Devices and LampsF269 Test Method for Sag of Tungsten Wire2.2 Military Standards:MIL-STD-105 Sampling Procedures and Tables for Inspec-tion by Attributes3MIL-STD-129 Marking for Shipment and Storage33.Terminology3.1 Definition
10、 of Terms Specific to This Standard:3.1.1 wireThe term wire as used in this specificationapplies to all drawn material that is spooled or coiled,and toshort cut lengths 0.020 in.(0.51 mm)or less in diameter.3.1.2 nonsag or doped tungsten wireThis term designatesa wire which,when recrystallized,shows
11、 elongated interlock-ing grains.3.1.3 rodThe term rod as used in this specification appliesto centerless ground material 0.020 in.(0.51 mm)or larger indiameter,in short cut lengths or random cut lengths.4.Ordering Information4.1 Orders for wire and rod furnished to this specificationshall include th
12、e following information:4.1.1 Length in metres,or quantity of short cut lengths,4.1.2 Type and UNS No.(Section 1),4.1.3 Straightness(Section 10),4.1.4 Finish(Section 8),1This specification is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee
13、F01.03 on MetallicMaterials.Current edition approved June 1,2014.Published July 2014.Originally approvedin 1954.Last previous edition approved in 2009 as F288 96(2009).DOI:10.1520/F0288-96R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at servic
14、eastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk,Bldg.4 Section D,700Robbins Ave.,Philadelphia,PA 19111-5094,Attn:NPODS.Copyright ASTM International,100 Barr Harbor Drive
15、,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.1.5 Weight or size(Section 7)and tolerance,and4.1.6 Specification number.NOTE3A typical ordering description for straight chemically cleanedwire is as follows:xxxx metres,tungsten wire,Type 1A UNS R07005,straightened,Finish 2;280.8 mg/200
16、 mm(63%),to ASTM F288 XX.5.Chemical Composition5.1 The wire and rod shall conform to the chemical require-ments specified in Table 1.The sample for analysis shall berepresentative of the lot submitted.Lot size,sample size,andsampling method shall be as agreed upon by the supplier andpurchaser.6.Physical Properties6.1 Tensile StrengthThe tensile strength of a 10-in.(250-mm)gage length of wire in grams per milligram per 200 mmshall be within the limits specified in Table 2 when tested inaccordance
