ASTM F29-97

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

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: 31-Dec-1990
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.03 - Metallic Materials, Wire Bonding, and Flip Chip

Relations

• Replaced By: ASTM F29-97(2002) - Standard Specification for Dumet Wire for Glass-to-Metal Seal Applications
• Effective Date: 10-Dec-1997
• Referred By: ASTM F85-76(2018) - Standard Practice for Nomenclature for Wire Leads Used as Conductors in Electron Tubes (Withdrawn 2023)
• Effective Date: 01-Jan-1991
• Referred By: ASTM E879-20 - Standard Specification for Thermistor Sensors for General Purpose and Laboratory Temperature Measurements
• Effective Date: 01-Jan-1991

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
An American National Standard
Designation: F 29 – 97
Standard Specification for
Dumet Wire for Glass-to-Metal Seal Applications
This standard is issued under the fixed designation F 29; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope designated as light, medium (regular), or dark, shall be
specified on each purchase order.
1.1 This specification covers round, copper-coated 42 %
3.3 Package sizes shall be agreed upon between the pur-
nickel-iron wire, commonly known as dumet, intended prima-
chaser and the seller.
rily for sealing to soft glass.
1.2 The values stated in inch-pound units are to be regarded
4. Chemical Composition
as the standard. The metric equivalents of inch-pound units
4.1 The copper used in the manufacture of dumet shall be
may be approximate.
99.90 % minimum copper. Silver shall be included with the
2. Referenced Documents copper. The material shall be free of reducible oxides.
4.2 The chemical composition of the nickel-iron core shall
2.1 ASTM Standards:
be as shown in Table 1.
B 170 Specification for Oxygen-Free Electrolytic Copper—
Refinery Shapes
5. Oxide Coating
D 1535 Test Method for Specifying Color by the Munsell
3 5.1 The primary standards for the entire range of colors are
System
divided into three groups covering light, medium (regular), and
D 1729 Practice for Visual Evaluation of Color Differences
3 dark as shown, with their respective limits, in Fig. 1 and Table
of Opaque Materials
4 2 (Note 1). The color range of the specimens shall be
E 3 Methods of Preparation of Metallographic Specimens
determined in accordance with 9.2.
E 29 Practice for Using Significant Digits in Test Data to
Determine Conformance with Specifications
NOTE 1—Color chip 2.5R 3.90/8.0 may be included in the dark range
E 53 Methods for Chemical Analysis of Copper merely to extend the color series for assisting the viewer in making a
better decision regarding the cut-off point between medium (regular) and
E 228 Test Methods for Linear Thermal Expansion of Solid
dark dumet.
Materials With a Vitreous Silicon Dilatometer
F 14 Practice for Making and Testing Reference Glass-
6. Thermal Expansion
Metal Bead-Seal
6.1 The nominal values for the average coefficient of linear
thermal expansion shall be as follows when determined in
3. Ordering Information
accordance with 9.1:
3.1 The wire is usually supplied with a surface coating
−7
6.1.1 Core—63 to 72 3 10 in./in.·deg °C (mm/mm·deg
consisting of a mixture of copper oxides and fused sodium
°C) over the temperature range of 30 to 400°C.
tetraborate (borax) which retards oxidation of the wire during
−7
6.1.2 Copper—177 6 3.5 3 10 in./in.·°C (mm/mm·deg
sealing in glass and further aids wetting of the wire by the
°C) over the temperature range of 30 to 300°C.
glass. The composite wire may also be purchased as bare wire
for specific applications.
3.2 The size of the wire, if applicable, the borate color range
This specification is under the jurisdiction of ASTM-Committee F-1 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.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F29
NOTE 1—Wire winding shall be in the same plane as shown and the specimen in the same plane as the color chips. The specimen shall be viewed along
direction AB at an inclined angle as illustrated.
FIG. 1 Arrangement of Color Chips for Specimen Comparison
TABLE 2 Color Ranges and Limits NOTE 2—The sheath is defined as that area exclusive of the core.
Medium (Regular)
8.3 Storage—Finished material should be stored in a con-
Dark Range Light Range
Range
tainer or room with a maximum relative humidity of 50 %.
Colors darker than chip 3.5R 3.5R 3.94/8.0 to 6.5R 7.5R 4.22/8.0 to 0.5YR
3.94/8.0 4.06/8.0, incl 4.56/8.0 incl
9. Test Methods
9.1 Thermal Expansion—Determine the thermal expansion
characteristics in accordance with Test Method E 228, except
7. Dimensional Tolerances
that the specimen shall be preheated as follows:
7.1 The specified diameters shall conform to the tolerances
9.1.1 Heat the core rod specimen in a hydrogen atmosphere
given in Table 3.
for1hat 900°C; then cool it from 900 to 200°C at a rate not
exceeding 5°C/min.
8. Workmanship and Finish
9.1.2 Determine the thermal expansion charateristics in
8.1 Internal Condition—The internal structure of the com-
accordance with Test Method E 228.
posite material, including the bond area, shall be sound and
9.2 Color of Coating— Mount the color chips on a neutral
free from pipes, porosity, or discontinuities which might
background (middle gray to white) as shown in Fig. 1. Wind
prevent the making of a satisfactory seal.
the specimen to be tested or compared on a flat surface similar
8.2 Surface Condition:
to that shown in Fig. 1. Each turn of the wire should lie parallel
8.2.1 There shall be no areas of exposed core evident on the
and as close as possible to the preceding turn without overlap-
surface of the wire.
ping. View the specimen in natural or artificial daylight in
8.2.2 The wire shall contain no longitudinal scratches, folds,
accordance with either or both Method D 1535, (Note 3) or
or lines of a depth greater than the width.
Test Method D 1729Fig. 2.
8.2.3 There shall be no oil, grease, or other surface contami-
nants on the wire.
NOTE 3—Coated wire carries a mixture of copper oxides and fused
8.2.4 The wire shall be looped or coiled over a mandrel five sodium tetraborate on the surface of the dumet, which dissolves, wholly or
in part, into the glass
...