ASTM F73-96(2017)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:F73 −96 (Reapproved 2017)
Standard Specification for
Tungsten-Rhenium Alloy Wire for Electron Devices and
Lamps
ThisstandardisissuedunderthefixeddesignationF73;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 Length in metres,
3.1.2 Name of material,
1.1 This specification covers tungsten-rhenium alloy wire
3.1.3 Straightness (see 6.2),
suitable for use in electron devices and lamps. The material is
3.1.4 Finish (see 7.2),
known as UNS R07031.
3.1.5 Weight or size (see 6.1) and tolerance, and
1.2 The term wire as used in this specification applies to all
3.1.6 Specification number and UNS number.
material0.020in.(0.51mm)orlessindiameterthatisspooled
NOTE 1—Atypical ordering description for straight chemically cleaned
or coiled.
wireisasfollows:xxxxmetrestungsten-rheniumalloywire,straightened,
1.3 Thevaluesstatedininch-poundunitsaretoberegarded
Finish 2; 280.8 mg/200 mm (63%), per ASTM F73–XX (UNS
R07031).
as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only
4. Chemical Composition
and are not considered standard.
4.1 This wire shall conform to the requirements as to
1.4 This standard does not purport to address all of the
chemical composition prescribed in Table 1.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Physical Properties
priate safety and health practices and determine the applica-
5.1 Tensile Strength—The tensile strength of a 10-in. (250-
bility of regulatory limitations prior to use.
mm) gage length of wire in grams-force per milligram per 200
1.5 This international standard was developed in accor-
mm shall be within the limits prescribed in Table 2, when
dance with internationally recognized principles on standard-
tested in accordance with 8.2.
ization established in the Decision on Principles for the
5.2 General Ductility Requirements—The ductility of wire
Development of International Standards, Guides and Recom-
shall be sufficient to meet the following requirements:
mendations issued by the World Trade Organization Technical
5.2.1 WireSizesupto75mg/200mm,incl—Six1-mlengths
Barriers to Trade (TBT) Committee.
shall be tested in accordance with 8.3.1. The wire shall not
2. Referenced Documents
break more than two times in the six tests. Where required, a
2.1 ASTM Standards: lower limit may be negotiated between purchaser and seller.
F205Test Method for Measuring Diameter of Fine Wire by
5.2.2 Wire Sizes over 75 mg/200 mm—Thirty successive
Weighing
close-wound turns completely around mandrels shall be free
F219Test Methods ofTesting Fine Round and FlatWire for
fromsplittingorcrackingwhentestedinaccordancewith8.3.2
Electron Devices and Lamps
and examined at a magnification of 30×.
5.3 Special Ductility Requirements—Wire for certain appli-
3. Ordering Information
cations requires a special ductility as agreed upon between the
3.1 Orders for wire furnished to this specification shall
purchaser and the seller.
include the following information:
6. Size, Straightness, and Tolerances
This specification is under the jurisdiction of ASTM Committee F01 on
6.1 Dimensional tolerances for wire for use as incandescent
Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic
Materials, Wire Bonding, and Flip Chip. filamentsshallconformtotherequirementsprescribedinTable
Current edition approved June 1, 2017. Published June 2017. Originally
3.
approvedin1966.Lastpreviouseditionapprovedin2013asF73–96(2013).DOI:
10.1520/F0073-96R17.
NOTE 2—Tolerances are industry standards; closer tolerances may be
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
obtained in certain instances, usually at a premium.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.2 Straightness—Straightnessofwire3.00mg/200mmand
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. largershallbespecifiedastheradiusofcurvatureorcamberof
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F73−96 (2017)
TABLE 1 Chemical Requirements
Element Composition
Tungsten remainder
Rhenium, % 2.5 to 3.5
Other elements (each), ppm, max 100
Total other elements, ppm, max 500
TABLE 2 Tensile Properties for UNS R07031
Tensile Strength, gf/(mg/200 mm)
Weight of Wire, mg/200 mm High-Tensile Wire (Finishes 1 and 2) Medium-Tensile Wire (Finish 3)
Min Max Min Max
0.70 to 2.00, incl 85 120 75 105
Over 2.00 to 3.00, incl 75 110 70 100
Over 3.00 to 5.80, incl 65 105 60 100
Over 5.80 to 10.50, incl 75 110 70 100
Over 10.50 to 15.50, incl 70 105 65 95
Over 15.50 65 100 60 90
TABLE 3 Permissible Variations in Weight and Size for All Types of Wire
Weight of Wire, mg/200 mm Dimensional Tolerances Size Uniformity End-to-End (Within a Spool)
Up to 0.36 ±0.02 mg/200 mm 0.02 mg/200 mm
Over 0.36 to 0.67, incl ±0.03 mg/200 mm 0.02 mg/200 mm
Over 0.67 to 2.0, incl ±3 % by weight 0.02 mg/200 mm
Over 2.0 to 760.0, incl ±3 % by weight 1 %
Over 760.0 ±1.5 % of diameter .
a given length of wire as agreed upon between the purchaser 8.2 Tensile Strength—Determine the tensile strength of the
and supplier. For wire under 3.00 mg/200 mm, alternative wire in accordance with Section 8 of Method F219. Use a flat
methods may be used as agreed upon between the purchaser black background when testing fine wire below 0.005 in. (0.13
and supplier. mm) in diameter.
8.3 Ductility—Determine the ductility of the wire as fol-
7. Workmanship, Finish, and Appearance
lows:
7.1 General Requirements: 8.3.1 Wire up to 75 mg/200 mm, incl—Drawthewireovera
7.1.1 The material shall be as smooth, as free of twists, 90° steel bar edge having a radius approximately equal to the
bends, curls, kinks, and as free, when examined at 30×, from diameter of the wire to be tested. Hold the wire against the
dents, swaging marks, scratches, swaging die marks,
...