1、Designation: F 288 96 (Reapproved 2002)Standard Specification forTungsten Wire for Electron Devices and Lamps1This standard is issued under the fixed designation F 288; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This specification covers three types
3、of drawn wiresuitable 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 2and Note 3).1.1.2 Type 1BCommercially pure rod suitable for metal-to-glass sealing.1.1
4、.3 Type 2AThoriated 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 the standard. The values given in parentheses are forinformation only.1.3 Types 1A and 1B are designated as UNS R07005. Type
5、2A 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 concerns,if any, associated with its use. It is the responsibi
6、lity of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.NOTE 1A dimensional measurement method for testing nonsag tung-sten wire above 0.030 in. (0.76 mm) in diameter is provided in TestMethod F 269.
7、NOTE 2Acceptance 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 determined in accordance with TestMethod F 269.2. Reference
8、d Documents2.1 ASTM Standards:F 16 Test Methods for Measuring Diameter or Thickness ofWire and Ribbon for Electronic Devices and Lamps2F 204 Test Method for Surface Flaws in Tungsten Seal Rodand Wire2F 205 Test Method for Measuring Diameter of Fine Wire byWeighing2F 219 Test Methods of Testing Fine
9、Round and Flat Wire forElectron Devices and Lamps2F 269 Test Method for Sag of Tungsten Wire22.2 Military Standards:MIL-STD-105 Sampling Procedures and Tables for Inspec-tion by Attributes3MIL-STD-129 Marking for Shipment and Storage33. Terminology3.1 Definition of Terms Specific to This Standard:3.
10、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 elongated interlock-ing grains.3
11、.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 the following information:4.1.1
12、 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),4.1.5 Weight or size (Section 7) and tolerance, and4.1.6 Specification number.1This specification is under the jurisdiction of ASTM Committee F01 onElectron
13、ics and is the direct responsibility of Subcommittee F01.03 on MetallicMaterials.Current edition approved June 10, 1996. Published August 1996. Originallypublished as B 288 54 T; redesignated F 288 in 1955. Last previous editionF 288 81 (1991).2Annual Book of ASTM Standards, Vol 10.04.3Available fro
14、m Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.NOTE 3A typical ordering description for straight chemically cleaned
15、wire is as follows: xxxx metres, tungsten wire, Type 1A UNS R07005,straightened, Finish 2; 280.8 mg/200 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 s
16、ubmitted. 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 teste
17、d inaccordance with 13.1.6.2 General Ductility RequirementsThe ductility of Types1A, 2A, and 2B wire shall be sufficient to meet the followingrequirements:6.2.1 Wire up to 75 mg/200 mm, InclusiveSix 1-m lengthsshall be tested in accordance with 13.2. The wire shall notbreak more than two times in th
18、e six tests. Where required, alower limit may be negotiated between purchaser and seller.6.2.2 Wire over 75 mg/200 mmThirty successive close-wound turns completely around mandrels shall be free ofsplitting or cracking when tested in accordance with 13.2.2 andexamined at a magnification of 303.6.2.3
19、Special Ductility RequirementsWire for certain ap-plications may require a special ductility as agreed uponbetween the purchaser and the seller.6.3 Surface DefectsType 1B rod shall not show faultswhen tested in accordance with 13.5.7. Dimensions, Weights, and Permissible Variations7.1 Dimensional to
20、lerances for Type 1A (nonsag) wire foruse as incandescent filaments shall conform to the require-ments specified in Table 3.NOTE 4Tolerances are industry standards; closer tolerances may beobtained in certain instances, usually at a premium.7.2 Out-of-roundness of wire or rod over 0.020 in. (0.51mm)
21、 in diameter shall be within 5 % of the maximum diameter,when measured by a method agreed upon by supplier andpurchaser. A referee method for this test is contained inProcedure B of Test Methods F 16.7.3 Weight/Diameter Conversion Formulas:7.3.1 The weight of Type 1A wire and Type 1B rod (density19.
22、17), is as follows:wt in mg/200 mm 5diameter in mils!23 1.943, ordiameter in mm!23 30117.3.2 The weight of Type 2A wire (density 18.80), is asfollows:wt in mg/200 mm 5diameter in mils!23 1.905, ordiameter in mm!23 29537.3.3 The weight of Type 2B wire (density 18.50), is asfollows:wt in mg/200 mm 5di
23、ameter in mils!23 1.875, ordiameter in mm!23 29068. Workmanship, Finish, and Appearance8.1 Furnish the wire in the following finishes:8.1.1 Finish 1Black, as-drawn,8.1.2 Finish 2Chemically cleaned,8.1.3 Finish 3Chemically cleaned and stress-relieved.8.1.4 Finish 4Reducing atmosphere cleaned and an-n
24、ealed,8.1.5 Finish 5Etched, and8.1.6 Finish 6Electropolished.8.2 The rod shall be furnished in the following finish:8.2.1 Finish 7Centerless ground.9. General Requirements9.1 The material shall be smooth, free of twists, bends,kinks, curls, and as free of dents, swaging marks, scratches, diemarks, l
25、aps, seams, splits, slivers, inclusions, bumps, pits,grooves, cracks, and other physical defects when examined ata magnification of 303 as best commercial practice willpermit.9.2 Unless black finish is specified, all types of wire shallhave a clean finish, free of graphite, grease, oil, and lubrican
26、ts.All finishes shall be as free of dirt, oxide, stains, scale, andother surface defects, as best commercial practice permits.Wire for hooks, supports, springs, anchors, and mesh shallhave a bright smooth surface free of cracks, holes, or craterswhen examined at a magnification of 103.9.3 Rod of Typ
27、e 1B shall have a bright smooth surface andbe capable of making acceptable metal-to-glass seals whentested in accordance with Test Method F 204.10. Straightness10.1 When ordered as straightened, straightness of wire3.00 mg/200 mm and larger shall be specified as the radius ofcurvature or camber of a
28、 given length of wire as agreed uponbetween the purchaser and supplier. For wire under 3.00mg/200 mm, alternative methods for straightness requirementsmay be used as agreed upon between the purchaser and thesupplier.11. Coiling and Spooling11.1 Spools and bands shall be clean and free of open seamso
29、r projections which might catch or tangle the wire duringwinding or unwinding.11.2 Wire shall be furnished in one continuous length andwound smoothly with no loose turns. There shall be no pilingup of turns such as to prevent free unwinding or cause kinks orbends when the wire is removed from the sp
30、ool. The outer endTABLE 1 Chemical RequirementsAType, Thoria, weight Tungsten, weightUNS number % %1A and 1B (R07005) 99.95 min2A (R07911) 0.8 min, 1.2 max balance2B (R07912) 1.7 min, 2.2 max balanceAFor all Types:Other elements (each)100 ppm max.Total other elements500 ppm max.F 2882shall be attach
31、ed firmly to the spool or band by suitable means.11.3 Spool and band dimensions are shown in Table 4.11.4 Except for Finishes 5 and 6, no spools or bands in anyone shipment shall contain less than 300 m of wire for sizes upto 35 mg/200 mm; not less than 200 m of wire between 35 and50 mg/200 mm, and
32、not less than 100 m between 50 and 100mg/200 mm. For wire sizes above 100 mg/200 mm each spoolor band shall contain no less than 50 g, minimum weight, ofwire.12. Chemical Analysis12.1 PurityDetermine purity gravimetrically or by a com-bination of spectrochemical and gravimetric analyses.12.2 Thoria
33、ContentTransfer approximately 0.5 to 1.0 gof the wire (weighed to the fourth decimal place) to a cleanporcelain boat. Place the boat in the combustion tube and bringthe temperature up to 600 to 700C. While the furnace is beingbrought to that temperature, pass a slow stream of air throughthe tube. Wh
34、en a temperature of approximately 600C has beenreached inside the tube, introduce a flow of hydrochloric acid(HCl) gas (Note 5) along with the air. Maintain a temperatureof 600 to 700C and continue the flow of HCl gas and air untilall the tungsten has been volatilized and only the white powderof tho
35、ria remains (Note 6). The thoria may be transferred to abalance pan for weighing, or weighed in the boat. If it isweighed in the boat, the weight of the boat should bedetermined both before and after the heating period, to correctfor any loss of weight by the boat during its stay in the furnace.Calc
36、ulate the thoria content as follows:Thoria, % 5mg of thoria/mg of sample!3100NOTE 5Hydrochloric acid (HCl) gas can be produced by dripping,from a separatory funnel, concentrated sulfuric acid on sodium chloride ina flask. (The optimum ratio of HCl gas to air and the optimum total gasflow through the
37、 tube have not been determined. A rate of approximatelythree bubbles of HCl gas per second has been found satisfactory.)NOTE 6In the ordinary carbon furnace two samples can be runsimultaneously. The approximate time for volatilization is 5 h.13. Test Methods13.1 Tensile StrengthDetermine the tensile
38、 strength of thewire in accordance with Test Methods F 219. Use a flat blackbackground when testing fine wire below 0.005 in. (0.13 mm)in diameter.13.2 DuctilityDetermine the ductility of the wire as fol-lows:13.2.1 Wire up to 75 mg/200 mm, InclusiveDraw the wireover a 90 steel bar edge having a rad
39、ius approximately equalto the diameter of the wire to be tested. Hold the wire againstTABLE 2 Tensile Properties of Nonsag Tungsten Wire (Type 1A)AWeight of Wire, mg/200 mmDiameter of Wire, in.(mm, Approximate)Tensile Strength, g/mg/200 mmHigh TensileWire(Finishes1 and 2)MediumTensile Wire(Finish 3)
40、Low TensileWire(Finish 4)Min Max Min Max Min MaxUp to 1.95 Up to 0.001 (0.03), incl 80 110 70 90 55 95Over 1.95 to 7.91, incl Over 0.001 to 0.002 (0.030.05, incl) 75 105 70 90 55 90Over 7.91 to 17.60, incl Over 0.002 to 0.003 (0.050.08, incl) 70 100 60 90 55 90Over 17.60 to 48.25, inclOver 48.25 to
41、198.00, inclOver 198.00 to 760.00, inclOver 0.003 to 0.005 (0.080.13), inclOver 0.005 to 0.0010 (0.130.25), inclOver 0.010 to 0.020 (0.250.51), incl65605095908060605585858050508585ATensile properties for Types 2A and 2B wire are governed by the ductility requirements specified in 6.2.TABLE 3 Permiss
42、ible Variations in Weight and Size for All Types of Wire and RodWeight of Wire, mg/200 mm Dimensional TolerancesSize Uniformity Within aSpoolUp to 0.36 60.02 mg/200 mm 0.02 mg/200 mmOver 0.36 to 0.67, incl 60.03 mg/200 mm 0.02 mg/200 mmOver 0.67 to 2.0, incl 63 weight % 0.02 mg/200 mmOver 2.0 to 760
43、.0, incl 63 weight % 1 weight %Over 760.0 61.5 % of diameter .TABLE 4 Size of Spool, Band, or CoilFlange or Head Diameter,in. (mm)Mandrel or Hub Diameter,in. (mm)Inside or Hole Diameter,in. (mm)ATraverse,in. (mm)0.715 to 0.785 0.580 to 0.605 0.437 to 0.450 0.420 to 0.435(18 to 20) (15 to 15) (11 to
44、11) (11 to 11)0.745 to 0.755 0.620 to 0.630 0.250 to 0.260 0.620 to 0.630(19 to 19) (16 to 16) (6 to 7) (16 to 16)1.88 to 2.38 1.13 to 1.63 0.340 to 0.375 0.75 to 1.0(48 to 60) (29 to 41) (8.6 to 9.5) (19 to 25)3.50 to 4.63 3.0 to 4.13 0.375 0.625(89 to 118) (76 to 105) (9.5) (16)4.0 to 4.75 3.88 to
45、 4.0 3.50 to 3.88 0.75 to 1.0(102 to 121) (98 to 102) (89 to 98) (19 to 25)AExcept on conical chamfered center mount spools.F 2883the edge of the bar with the thumb and draw the wire at anangle of 45 to the bar edge at a rate of approximately 1 m/suntil the tension on the wire is sufficient to cause
46、 a tight helicalcoil to be formed after the tension is released.13.2.2 Wire over 75 mg/200 mmWind 30 successiveclose-wound turns completely around mandrels of sizes asspecified in Table 5 at the recommended forming temperatures.13.3 Visual InspectionCheck conformance of the wire tothe requirements s
47、pecified in 9.2 by visual inspection, exceptthat wire for hooks, supports, springs, anchors, and mesh shallbe checked with a magnification of 103.NOTE 7Orders placed by agencies of the U.S. government requirespecial acceptance criteria applied to visual inspection (13.3) and dimen-sional measurement
48、 (13.4). In these instances, samples shall be selectedfor examination in accordance with MIL-STD-105 at Inspection Level I.The acceptance quality level (AQL) shall be 1.5 % defective. A unit shallbe one reel, coil, band, or spool of wire.13.4 Dimensional MeasurementsDetermine the size anduniformity
49、of wire up to 760 mg/200 mm in accordance withTest Method F 205 (Note 7).13.5 Surface Flaws, Type 1BExamination of randomlengths and cut lengths of seal rod for surface flaws shall beconducted in accordance with Test Method F 204. A fault shallconsist of a tungsten-glass seal in which a fissure, eitherdelineated by a line of bubbles, or in itself clearly discernible,is observed as prescribed in this method.14. Rejection14.1 Any spool of wire, length of rod, or individual cutpieces not conforming to the specified requirements may
