ASTM F288-96(2009)

Standard Specification for Tungsten Wire for Electron Devices and Lamps

ABSTRACT
This specification covers three types of drawn pure and thoriated tungsten wire suitable for fabrication into parts for electron tubes, lamps, and other electron devices, and one type of rod for metal-to-glass sealing (grid wire is excepted): Type 1A, Type 1B, Type 2A, and Type 2B. Types 1A and 1B are designated as UNS R07005; Type 2A is designated as UNS R07911; and Type 2B is designated as UNS R07912. The wire and rod shall conform to the prescribed chemical requirements for thoria and tungsten and to the specified physical properties such as tensile strength, ductility, and surface defects. The weight/diameter conversion formulas are given. Wires shall be furnished in the following specified finishes: Finish 1, Finish 2, Finish 3, Finish 4, Finish 5, Finish 6, and Finish 7. The material shall be smooth, free of twists, bends, kinks, curls, and as free of dents, swaging marks, scratches, die marks, laps, seams, splits, slivers, inclusions, bumps, pits, grooves, cracks, and other physical defects Unless black finish is specified, all types of wire shall have a clean finish, free of graphite, grease, oil, and lubricants. Wire for hooks, supports, springs, anchors, and mesh shall have a bright smooth surface free of cracks holes, or craters. The requirements for straightness, and coiling and spooling are detailed as well. The following analysis and tests shall be performed: chemical analysis, tensile test, ductility test, visual inspection, dimensional measurements, and examination for surface flaws.
SCOPE
1.1 This specification covers three types of drawn wire suitable for fabrication into parts for electron tubes, lamps, and other devices; and one type of rod for metal-to-glass sealing (grid wire is excepted):
1.1.1 Type 1A—Commercially pure nonsag wire (Note 2 and Note 3).
1.1.2 Type 1B—Commercially pure rod suitable for metal-to-glass sealing.
1.1.3 Type 2A—Thoriated filament wire containing 1 % thoria.
1.1.4 Type 2B—Thoriated filament wire containing 2 % thoria.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.3 Types 1A and 1B are designated as UNS R07005. Type 2A is designated as UNS R07911. Type 2B is designated as UNS R07912.
1.4 The following precautionary caveat pertains only to the Chemical Analysis, Section 12 of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.  
Note 1—A dimensional measurement method for testing nonsag tungsten wire above 0.030 in. (0.76 mm) in diameter is provided in Test Method F 269.
Note 2—Acceptance of nonsag wire characteristics for particular applications of size shall be by agreement between producer and consumer based on either a flashed microstructure as shown by photomicrographs, or on dimensional measurement limits determined in accordance with Test Method F 269.

General Information

• Status: Historical
• Publication Date: 30-Apr-2009
• ICS: 29.060.10 - Wires
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.03 - Metallic Materials, Wire Bonding, and Flip Chip

Relations

• Replaces: ASTM F288-96(2002) - Standard Specification for Tungsten Wire for Electron Devices and Lamps
• Effective Date: 01-May-2009
• Replaced By: ASTM F288-96(2014) - Standard Specification for Tungsten Wire for Electron Devices and Lamps
• Effective Date: 01-Jun-2014
• Referred By: ASTM F290-94(2020) - Standard Specification for Round Wire for Winding Electron Tube Grid Laterals
• Effective Date: 01-May-2009

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:F288 −96(Reapproved 2009)
Standard Specification for
Tungsten Wire for Electron Devices and Lamps
ThisstandardisissuedunderthefixeddesignationF288;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) 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. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This specification covers three types of drawn wire
suitableforfabricationintopartsforelectrontubes,lamps,and F16Test Methods for Measuring Diameter or Thickness of
Wire and Ribbon for Electronic Devices and Lamps
other devices; and one type of rod for metal-to-glass sealing
(grid wire is excepted): F204Test Method for Surface Flaws in Tungsten Seal Rod
and Wire
1.1.1 Type 1A—Commerciallypurenonsagwire(Note2and
Note 3). F205Test Method for Measuring Diameter of Fine Wire by
Weighing
1.1.2 Type 1B—Commercially pure rod suitable for metal-
to-glass sealing. F219Test Methods ofTesting Fine Round and FlatWire for
Electron Devices and Lamps
1.1.3 Type 2A—Thoriated filament wire containing 1%
thoria. F269Test Method for Sag of Tungsten Wire
1.1.4 Type 2B—Thoriated filament wire containing 2%
2.2 Military Standards:
thoria.
MIL-STD-105Sampling Procedures and Tables for Inspec-
tion by Attributes
1.2 Thevaluesstatedininch-poundunitsaretoberegarded
MIL-STD-129Marking for Shipment and Storage
as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only
3. Terminology
and are not considered standard.
3.1 Definition of Terms Specific to This Standard:
1.3 Types 1Aand 1B are designated as UNS R07005. Type
3.1.1 wire—The term wire as used in this specification
2A is designated as UNS R07911. Type 2B is designated as
applies to all drawn material that is spooled or coiled, and to
UNS R07912.
short cut lengths 0.020 in. (0.51 mm) or less in diameter.
1.4 The following precautionary caveat pertains only to the
3.1.2 nonsag or doped tungsten wire—This term designates
Chemical Analysis, Section 12 of this specification: This
a wire which, when recrystallized, shows elongated interlock-
standard does not purport to address all of the safety concerns,
ing grains.
if any, associated with its use. It is the responsibility of the user
3.1.3 rod—Thetermrodasusedinthisspecificationapplies
of this standard to establish appropriate safety and health
to centerless ground material 0.020 in. (0.51 mm) or larger in
practices and determine the applicability of regulatory limita-
diameter, in short cut lengths or random cut lengths.
tions prior to use.
NOTE 1—A dimensional measurement method for testing nonsag
4. Ordering Information
tungsten wire above 0.030 in. (0.76 mm) in diameter is provided in Test
4.1 Orders for wire and rod furnished to this specification
Method F269.
shall include the following information:
NOTE 2—Acceptance of nonsag wire characteristics for particular
applicationsofsizeshallbebyagreementbetweenproducerandconsumer
4.1.1 Length in metres, or quantity of short cut lengths,
based on either a flashed microstructure as shown by photomicrographs,
4.1.2 Type and UNS No. (Section 1),
orondimensionalmeasurementlimitsdeterminedinaccordancewithTest
4.1.3 Straightness (Section 10),
Method F269.
4.1.4 Finish (Section 8),
1 2
This specification is under the jurisdiction of ASTM Committee F01 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Materials. Standards volume information, refer to the standard’s Document Summary page on
CurrenteditionapprovedMay1,2009.PublishedJuly2009.Originallyapproved the ASTM website.
in 1954. Last previous edition approved in 2002 as F288 – 96 (2002). DOI: AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
10.1520/F0288-96R09. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F288−96 (2009)
4.1.5 Weight or size (Section 7) and tolerance, and 7.3.1 TheweightofType1AwireandType1Brod(density
4.1.6 Specification number. 19.17), is as follows:
wt inmg/200mm5 diameterinmils 31.943, or
NOTE 3—Atypical ordering description for straight chemically cleaned ~ !
wire is as follows: xxxx metres, tungsten wire, Type 1A UNS R07005, ~diameterinmm! 33011
straightened, Finish 2; 280.8 mg/200 mm (63%), toASTM F288–XX.
7.3.2 The weight of Type 2A wire (density 18.80), is as
5. Chemical Composition
follows:
5.1 Thewireandrodshallconformtothechemicalrequire-
wtinmg/200mm5 diameterinmils 31.905, or
ments specified in Table 1. The sample for analysis shall be ~ !
~diameterinmm! 32953
representative of the lot submitted. Lot size, sample size, and
sampling method shall be as agreed upon by the supplier and
purchaser.
7.3.3 The weight of Type 2B wire (density 18.50), is as
follows:
6. Physical Properties
wtinmg/200mm5 diameterinmils 31.875, or
~ !
6.1 Tensile Strength—The tensile strength of a 10-in. (250-
diameterinmm 32906
~ !
mm) gage length of wire in grams per milligram per 200 mm
shall be within the limits specified in Table 2 when tested in
accordance with 13.1.
8. Workmanship, Finish, and Appearance
6.2 General Ductility Requirements —The ductility of
8.1 Furnish the wire in the following finishes:
Types 1A, 2A, and 2B wire shall be sufficient to meet the
8.1.1 Finish 1—Black, as-drawn,
following requirements:
8.1.2 Finish 2—Chemically cleaned,
6.2.1 Wire up to 75 mg/200 mm, Inclusive —Six1-mlengths
shall be tested in accordance with 13.2. The wire shall not 8.1.3 Finish 3—Chemically cleaned and stress-relieved.
break more than two times in the six tests. Where required, a
8.1.4 Finish 4—Reducing atmosphere cleaned and an-
lower limit may be negotiated between purchaser and seller.
nealed,
6.2.2 Wire over 75 mg/200 mm—Thirty successive close-
8.1.5 Finish 5—Etched, and
wound turns completely around mandrels shall be free of
8.1.6 Finish 6—Electropolished.
splittingorcrackingwhentestedinaccordancewith13.2.2and
8.2 The rod shall be furnished in the following finish:
examined at a magnification of 30×.
6.2.3 Special Ductility Requirements —Wire for certain
8.2.1 Finish 7—Centerless ground.
applications may require a special ductility as agreed upon
between the purchaser and the seller.
9. General Requirements
6.3 Surface Defects— Type 1B rod shall not show faults
9.1 The material shall be smooth, free of twists, bends,
when tested in accordance with 13.5.
kinks,curls,andasfreeofdents,swagingmarks,scratches,die
marks, laps, seams, splits, slivers, inclusions, bumps, pits,
7. Dimensions, Weights, and Permissible Variations
grooves, cracks, and other physical defects when examined at
7.1 Dimensional tolerances for Type 1A (nonsag) wire for
amagnificationof30×asbestcommercialpracticewillpermit.
use as incandescent filaments shall conform to the require-
9.2 Unless black finish is specified, all types of wire shall
ments specified in Table 3.
have a clean finish, free of graphite, grease, oil, and lubricants.
NOTE 4—Tolerances are industry standards; closer tolerances may be
All finishes shall be as free of dirt, oxide, stains, scale, and
obtained in certain instances, usually at a premium.
other surface defects, as best commercial practice permits.
7.2 Out-of-roundness of wire or rod over 0.020 in. (0.51
Wire for hooks, supports, springs, anchors, and mesh shall
mm)indiametershallbewithin5%ofthemaximumdiameter,
have a bright smooth surface free of cracks, holes, or craters
when measured by a method agreed upon by supplier and
when examined at a magnification of 10×.
purchaser. A referee method for this test is contained in
9.3 Rod of Type 1B shall have a bright smooth surface and
Procedure B of Test Methods F16.
be capable of making acceptable metal-to-glass seals when
7.3 Weight/Diameter Conversion Formulas:
tested in accordance with Test Method F204.
A
10. Straightness
TABLE 1 Chemical Requirements
Type, Thoria, weight Tungsten, weight
10.1 When ordered as straightened, straightness of wire
UNS number % %
3.00 mg/200 mm and larger shall be specified as the radius of
1A and 1B (R07005) . 99.95 min
2A (R07911) 0.8 min, 1.2 max balance
curvature or camber of a given length of wire as agreed upon
2B (R07912) 1.7 min, 2.2 max balance
between the purchaser and supplier. For wire under 3.00
A
For all Types:
mg/200 mm, alternative methods for straightness requirements
Other elements (each)—100 ppm max.
may be used as agreed upon between the purchaser and the
Total other elements—500 ppm max.
supplier.
F288−96 (2009)
A
TABLE 2 Tensile Properties of Nonsag Tungsten Wire (Type 1A)
Tensile Strength, g/mg/200 mm
High Tensile
Medium Low Tensile
Diameter of Wire, in. Wire
Weight of Wire, mg/200 mm Tensile Wire Wire
(mm, Approximate) (Finishes
(Finish 3) (Finish 4)
1 and 2)
Min Max Min Max Min Max
Up to 1.95 Up to 0.001 (0.03), incl 80 110 70 90 55 95
Over 1.95 to 7.91, incl Over 0.001 to 0.002 (0.03–0.05, incl) 75 105 70 90 55 90
Over 7.91 to 17.60, incl Over 0.0
...