ASTM F29-97(2012)

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 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 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.

General Information

• Status: Historical
• Publication Date: 30-Jun-2012
• 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(2009) - Standard Specification for Dumet Wire for Glass-to-Metal Seal Applications
• Effective Date: 01-Jul-2012
• Referred By: ASTM F85-76(2018) - Standard Practice for Nomenclature for Wire Leads Used as Conductors in Electron Tubes (Withdrawn 2023)
• Effective Date: 01-Jul-2012
• Referred By: ASTM E879-20 - Standard Specification for Thermistor Sensors for General Purpose and Laboratory Temperature Measurements
• Effective Date: 01-Jul-2012

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:F29 −97 (Reapproved 2012)
Standard Specification for
Dumet Wire for Glass-to-Metal Seal Applications
ThisstandardisissuedunderthefixeddesignationF29;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope tetraborate (borax) which retards oxidation of the wire during
sealing in glass and further aids wetting of the wire by the
1.1 This specification covers round, copper-coated 42%
glass. The composite wire may also be purchased as bare wire
nickel-ironwire,commonlyknownasdumet,intendedprimar-
for specific applications.
ily for sealing to soft glass.
3.2 Thesizeofthewire,ifapplicable,theboratecolorrange
1.2 The values stated in inch-pound units are to be regarded
designated as light, medium (regular), or dark, shall be
as standard. The values given in parentheses are mathematical
specified on each purchase order.
conversions to SI units that are provided for information only
and are not considered standard. 3.3 Package sizes shall be agreed upon between the pur-
chaser and the seller.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Chemical Composition
responsibility of the user of this standard to establish appro-
4.1 The copper used in the manufacture of dumet shall be
priate safety and health practices and determine the applica-
99.90% minimum copper. Silver shall be included with the
bility of regulatory limitations prior to use.
copper. The material shall be free of reducible oxides.
2. Referenced Documents
4.2 The chemical composition of the nickel-iron core shall
2.1 ASTM Standards: be as shown in Table 1.
B170Specification for Oxygen-Free Electrolytic Copper—
5. Oxide Coating
Refinery Shapes
5.1 The primary standards for the entire range of colors are
D1535Practice for Specifying Color by the Munsell System
dividedintothreegroupscoveringlight,medium(regular),and
D1729Practice for Visual Appraisal of Colors and Color
dark as shown, with their respective limits, in Fig. 1 and Table
Differences of Diffusely-Illuminated Opaque Materials
2 (Note 1). The color range of the specimens shall be
E3Guide for Preparation of Metallographic Specimens
determined in accordance with 9.2.
E29Practice 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
E53Test Method for Determination of Copper in Unalloyed
merely to extend the color series for assisting the viewer in making a
Copper by Gravimetry better decision regarding the cut-off point between medium (regular) and
dark dumet.
E228Test Method for Linear Thermal Expansion of Solid
Materials With a Push-Rod Dilatometer
6. Thermal Expansion
F14Practice for Making andTesting Reference Glass-Metal
6.1 The nominal values for the average coefficient of linear
Bead-Seal
thermal expansion shall be as follows when determined in
accordance with 9.1:
3. Ordering Information
−7
6.1.1 Core—63 to 72×10 in./in.·deg °C (mm/mm·deg
3.1 The wire is usually supplied with a surface coating
°C) over the temperature range of 30 to 400°C.
consisting of a mixture of copper oxides and fused sodium
−7
6.1.2 Copper—177 6 3.5×10 in./in.·°C (mm/mm·deg
°C) over the temperature range of 30 to 300°C.
This specification is under the jurisdiction of ASTM-Committee F01 on
Electronics and is the direct responsibility of Subcommittee F01.03 on Metallic
7. Dimensional Tolerances
Materials.
7.1 The specified diameters shall conform to the tolerances
Current edition approved July 1, 2012. Published August 2012. Originally
approved in 1963. Last previous edition approved in 2009 as F29–97(2009). DOI:
given in Table 3.
10.1520/F0029-97R12.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 8. Workmanship and Finish
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
8.1 Internal Condition—The internal structure of the com-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. posite material, including the bond area, shall be sound and
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F29−97 (2012)
TABLE 1 Chemical Requirements: Core Material
9.2 Color of Coating— Mount the color chips on a neutral
Element Composition, % background (middle gray to white) as shown in Fig. 1. Wind
Nickel 41 to 43 the specimen to be tested or compared on a flat surface similar
Manganese 0.75 to 1.25
tothatshowninFig.1.Eachturnofthewireshouldlieparallel
Silicon, max 0.30
and as close as possible to the preceding turn without overlap-
Carbon, max 0.10
Sulfur, max 0.02 ping. View the specimen in natural or artificial daylight in
Phosphorus, max 0.02
accordancewitheitherorbothMethodD1535,(Note3)orTest
Iron (by difference) remainder
Method D1729, Fig. 2.
NOTE 3—Coated wire carries a mixture of copper oxides and fused
TABLE 2 Color Ranges and Limits sodiumtetraborateonthesurfaceofthedumet,whichdissolves,whollyor
in part, into the glass during the sealing operation. The sealing technique
Medium (Regular)
Dark Range Light Range
is influenced by the amount of coating, and color has been established as
Range
a means of estimating the thickness of this mixture.The color varies from
Colors darker than chip 3.5R 3.5R 3.94/8.0 to 6.5R 7.5R 4.22/8.0 to 0.5YR
a dark red-purple to a light yellow-red as the thickness decreases. The
3.94/8.0 4.06/8.0, incl 4.56/8.0 incl
method,describedinTestMethodD1535,isbasedonthecolor-perception
attributes of hue, lightness, and saturation and is used as the means for
specifying color.This method employs the Munsell color-notation system
TABLE 3 Dimensional Tolerances
in which visual scales are assigned to each of the color-perception
attributes. In this system, the attributes are called hue, H, value, V, and
Diameter, in. (mm) Tolerance, in.
chroma,C,writtenintheformHV/C.Byusingacombinationofnumbers
(mm)
andletters,apparentcolormaybeexactlyspecified.Thedimensionsofthe
0.007 to 0.013 (0.18 to 0.33) ±0.0003 (±0.008)
surface-color-perception solid are illustrated in Fig. 2.
Over 0.013 to 0.018 (0.33 to 0.46) ±0.0004 (±0.010)
Over 0.018 (0.46) ±0.0005 (±0.013)
9.3 Diameter—The diameter
...