ASTM F73-96(2002)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F 73 – 96 (Reapproved 2002)
Standard Specification for
Tungsten-Rhenium Alloy Wire for Electron Devices and
Lamps
ThisstandardisissuedunderthefixeddesignationF73;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
TABLE 1 Chemical Requirements
1. Scope
Element Composition
1.1 This specification covers tungsten-rhenium alloy wire
Tungsten remainder
suitable for use in electron devices and lamps. The material is
Rhenium, % 2.5 to 3.5
known as UNS R07031.
Other elements (each), ppm, max 100
1.2 The term wire as used in this specification applies to all
Total other elements, ppm, max 500
material 0.020 in. (0.51 mm) or less in diameter that is spooled
or coiled.
5. Physical Properties
1.3 The values stated in inch-pound units are to be regarded
as the standard. The values given in parentheses are for 5.1 Tensile Strength—The tensile strength of a 10-in. (250-
information only.
mm) gage length of wire in grams-force per milligram per 200
mm shall be within the limits prescribed in Table 2, when
2. Referenced Documents
tested in accordance with 8.2.
2.1 ASTM Standards:
5.2 General Ductility Requirements—The ductility of wire
F 205 Test Method for Measuring Diameter of FineWire by
shall be sufficient to meet the following requirements:
Weighing
5.2.1 WireSizesupto75mg/200mm,incl—Six1-mlengths
F 219 Methods of Testing Fine Round and Flat Wire for
shall be tested in accordance with 8.3.1. The wire shall not
Electron Devices and Lamp
break more than two times in the six tests. Where required, a
lower limit may be negotiated between purchaser and seller.
3. Ordering Information
5.2.2 Wire Sizes over 75 mg/200 mm—Thirty successive
3.1 Orders for wire furnished to this specification shall
close-wound turns completely around mandrels shall be free
include the following information:
from splitting or cracking when tested in accordance with 8.3.2
3.1.1 Length in metres,
and examined at a magnification of 303.
3.1.2 Name of material,
5.3 Special Ductility Requirements—Wire for certain appli-
3.1.3 Straightness (see 6.2),
cations requires a special ductility as agreed upon between the
3.1.4 Finish (see 7.2),
purchaser and the seller.
3.1.5 Weight or size (see 6.1) and tolerance, and
6. Size, Straightness, and Tolerances
3.1.6 Specification number and UNS number.
6.1 Dimensional tolerances for wire for use as incandescent
NOTE 1—Atypical ordering description for straight chemically cleaned
filaments shall conform to the requirements prescribed inTable
wire is as follows: xxxx metres tungsten-rhenium alloy wire, straightened,
3.
Finish 2; 280.8 mg/200 mm (63 %), per ASTM F73 – XX (UNS
R07031).
NOTE 2—Tolerances are industry standards; closer tolerances may be
obtained in certain instances, usually at a premium.
4. Chemical Composition
6.2 Straightness—Straightness of wire 3.00 mg/200 mm
4.1 This wire shall conform to the requirements as to
and larger shall be specified as the radius of curvature or
chemical composition prescribed in Table 1.
camber of a given length of wire as agreed upon between the
purchaser and supplier. For wire under 3.00 mg/200 mm,
alternative methods may be used as agreed upon between the
This specification is under the jurisdiction of ASTM Committee F01 on
Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic
purchaser and supplier.
Materials.
Current edition approved June 10, 1996. Published August 1996. Originally
7. Workmanship, Finish, and Appearance
published as F 73 – 66 T. Last previous edition F 73 – 81 (1991).
Annual Book of ASTM Standards, Vol 10.04. 7.1 General Requirements:
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F 73 – 96 (2002)
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 60.02 mg/200 mm 0.02 mg/200 mm
Over 0.36 to 0.67, incl 60.03 mg/200 mm 0.02 mg/200 mm
Over 0.67 to 2.0, incl 63 % by weight 0.02 mg/200 mm
Over 2.0 to 760.0, incl 63 % by weight 1 %
Over 760.0 61.5 % of diameter .
7.1.1 The material shall be as smooth, as free of twists, TABLE 4 Ductility Test Conditions
bends, curls, kinks, and as free, when examined at 303, from
Forming
Mandrel Diameter,
Wire Diameter, in. (mm) Temperature
dents, swaging marks, scratches, swaging die marks, laps,
in. (mm)
of Wire, °C
seams, splits, slivers, inclusions, bumps, pits, grooves, cracks,
0.0065 to 0.010 (0.17 to 0.25), 0.025 (0.64) 400
and other physical defects as best commercial practice will
incl
permit.
Over 0.010 to 0.015 (0.25 to 0.030 (0.76) 500
0.38), incl
7.1.2 Unless black finish is specified, all types of wire shall
Over 0.015 to 0.020 (0.38 to 0.045 (1.14) 600
be free of graphite, grease, and oil.All finishes shall be as free
0.51), incl
of dirt, oxide, stains, scale, and other surface defects as best
commercial practice permits. Refer to 8.4 for inspection
methods.
7.2 Finish—The wire shall be furnished in the following
8.4 Visual Inspection—Check conformance of the wire to
finishes:
the requirements specified in 7.1.2 by visual inspection, except
7.2.1 Finish 1—Black,
that wire use
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