ASTM F29-97(2002)

Standard Specification for Dumet Wire for Glass-to-Metal Seal Applications

ABSTRACT
This specification covers the properties and requirements for round, copper-coated 42 % nickel-iron wire, commonly known as dumet, intended primarily for sealing to soft glass. The wires shall conform to requirements stated for chemical composition, oxide coatings, dimension, internal and surface workmanship, and storage characteristics. Materials shall also undergo tests for thermal expansion, color of coating, diameter, reducible oxides, copper analysis, and metallography.
SCOPE
1.1 This specification covers round, copper-coated 42% nickel-iron wire, commonly known as dumet, intended primarily for sealing to soft glass.  
1.2 The values stated in inch-pound units are to be regarded as the standard. The metric equivalents of inch-pound units may be approximate.

General Information

• Status: Historical
• Publication Date: 09-Dec-1997
• ICS: 31.240 - Mechanical structures for electronic equipment
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.03 - Metallic Materials, Wire Bonding, and Flip Chip

Relations

• Replaces: ASTM F29-97 - Standard Specification for Dumet Wire for Glass-to-Metal Seal Applications
• Effective Date: 10-Dec-1997
• Replaced By: ASTM F29-97(2009) - Standard Specification for Dumet Wire for Glass-to-Metal Seal Applications
• Effective Date: 01-May-2009
• Referred By: ASTM F85-76(2018) - Standard Practice for Nomenclature for Wire Leads Used as Conductors in Electron Tubes (Withdrawn 2023)
• Effective Date: 10-Dec-1997
• Referred By: ASTM E879-20 - Standard Specification for Thermistor Sensors for General Purpose and Laboratory Temperature Measurements
• Effective Date: 10-Dec-1997

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: F 29 – 97 (Reapproved 2002)
Standard Specification for
Dumet Wire for Glass-to-Metal Seal Applications
ThisstandardisissuedunderthefixeddesignationF29;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope glass. The composite wire may also be purchased as bare wire
for specific applications.
1.1 This specification covers round, copper-coated 42%
3.2 Thesizeofthewire,ifapplicable,theboratecolorrange
nickel-iron wire, commonly known as dumet, intended prima-
designated as light, medium (regular), or dark, shall be
rily for sealing to soft glass.
specified on each purchase order.
1.2 The values stated in inch-pound units are to be regarded
3.3 Package sizes shall be agreed upon between the pur-
as the standard. The metric equivalents of inch-pound units
chaser and the seller.
may be approximate.
4. Chemical Composition
2. Referenced Documents
4.1 The copper used in the manufacture of dumet shall be
2.1 ASTM Standards:
99.90% minimum copper. Silver shall be included with the
B170 SpecificationforOxygen-FreeElectrolyticCopper—
copper. The material shall be free of reducible oxides.
Refinery Shapes
4.2 The chemical composition of the nickel-iron core shall
D1535 Test Method for Specifying Color by the Munsell
be as shown in Table 1.
System
D1729 Practice for Visual Evaluation of Color Differences
5. Oxide Coating
of Opaque Materials
5.1 The primary standards for the entire range of colors are
E3 Methods of Preparation of Metallographic Specimens
dividedintothreegroupscoveringlight,medium(regular),and
E29 Practice for Using Significant Digits in Test Data to
dark as shown, with their respective limits, in Fig. 1 andTable
Determine Conformance with Specifications
6 2 (Note 1). The color range of the specimens shall be
E53 Methods for Chemical Analysis of Copper
determined in accordance with 9.2.
E228 Test Methods for LinearThermal Expansion of Solid
Materials With a Vitreous Silicon Dilatometer
NOTE 1—Color chip 2.5R 3.90/8.0 may be included in the dark range
F14 Practice for Making and Testing Reference Glass- merely to extend the color series for assisting the viewer in making a
better decision regarding the cut-off point between medium (regular) and
Metal Bead-Seal
dark dumet.
3. Ordering Information
6. Thermal Expansion
3.1 The wire is usually supplied with a surface coating
6.1 The nominal values for the average coefficient of linear
consisting of a mixture of copper oxides and fused sodium
thermal expansion shall be as follows when determined in
tetraborate (borax) which retards oxidation of the wire during
accordance with 9.1:
sealing in glass and further aids wetting of the wire by the
−7
6.1.1 Core—63to72 310 in./in.·deg °C (mm/mm·deg
°C) over the temperature range of 30 to 400°C.
This specification is under the jurisdiction of ASTM-Committee F01 on
TABLE 1 Chemical Requirements: Core Material
Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic
Element Composition, %
Materials.
Current edition approved Dec. 10, l997. Published March 1998. Originally
Nickel 41 to 43
published as F29–63 T. Last previous edition F29–78 (1991).
Manganese 0.75 to 1.25
Annual Book of ASTM Standards, Vol 02.01.
Silicon, max 0.30
Annual Book of ASTM Standards, Vol 06.01.
Carbon, max 0.10
Annual Book of ASTM Standards, Vol 03.01.
Sulfur, max 0.02
Annual Book of ASTM Standards, Vol 14.02.
Phosphorus, max 0.02
Annual Book of ASTM Standards, Vol 03.05. Iron (by difference) remainder
Annual Book of ASTM Standards, Vol 15.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F 29 – 97 (2002)
NOTE 1—Wirewindingshallbeinthesameplaneasshownandthespecimeninthesameplaneasthecolorchips.Thespecimenshallbeviewedalong
direction AB at an inclined angle as illustrated.
FIG. 1 Arrangement of Color Chips for Specimen Comparison
TABLE 2 Color Ranges and Limits
8.2.5 The nickel-iron core shall be uniformly covered with
Medium (Regular) 18% to 28% copper (by weight) and the ratio of maximum to
Dark Range Light Range
Range
minimum sheath thickness shall not exceed 2.5 to 1 on any
Colors darker than chip 3.5R 3.5R 3.94/8.0 to 6.5R 7.5R 4.22/8.0 to 0.5YR
cross section.
3.94/8.0 4.06/8.0, incl 4.56/8.0 incl
NOTE 2—The sheath is defined as that area exclusive of the core.
8.3 Storage—Finished material should be stored in a con-
−7
tainer or room with a maximum relative humidity of 50%.
6.1.2 Copper—177 6 3.5 310 in./in.·°C (mm/mm·deg
°C) over the temperature range of 30 to 300°C.
9. Test Methods
7. Dimensional Tolerances
9.1 Thermal Expansion—Determine the thermal expansion
7.1 The specified diameters shall conform to the tolerances characteristics in accordance with Test Method E228, except
given in Table 3. that the specimen shall be preheated as follows:
9.1.1 Heat the core rod specimen in a hydrogen atmosphere
8. Workmanship and Finish
for1hat 900°C; then cool it from 900 to 200°C at a rate not
exceeding 5°C/min.
8.1 Internal Condition—The internal structure of the com-
9.1.2 Determine the thermal expansion charateristics in
posite material, including the bond area, shall be sound and
accordance with Test Method E228.
free from pipes, porosity, or discontinuities which might
9.2 Color of Coating— Mount the color chips on a neutral
prevent the making of a satisfactory seal.
background (middle gray to white) as shown in Fig. 1. Wind
8.2 Surface Condition:
the specimen to be tested or compared on a flat surface similar
8.2.1 Thereshallbenoareasofexposedcoreevidentonthe
tothatshowninFig.1.Eachturnofthewireshouldlieparallel
surface of the wire.
and as close as possible to the preceding turn without overlap-
8.2.2 Thewireshallcontainnolongitudinalscratches,folds,
ping. View the specimen in natural or artificial daylight in
or lines of a depth greater than the width.
accordance with either or both Method D1535, (Note 3) or
8.2.3 Thereshallbenooil,grease,orothersurfacecontami-
Test Method D17
...