ASTM B702-93(2019)
(Specification)Standard Specification for Copper-Tungsten Electrical Contact Material
Standard Specification for Copper-Tungsten Electrical Contact Material
ABSTRACT
This specification covers electrical contact components made from copper tungsten by powder metallurgical procedures. The material shall conform to the chemical composition limits as agreed upon between the manufacturer and the user using the newest edition of Annual Book of ASTM standards, or any other approved method agreed upon. Qualification tests for determination of physical properties shall be performed on production parts, wherever practical or applicable. The tests shall be determined after consideration of the function of the part.
SCOPE
1.1 This specification covers electrical contact components made from copper tungsten by powder metallurgical procedures.
1.2 This specification covers compositions within the copper tungsten system normally specified by users of contacts.
1.3 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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 become familiar with all hazards including those identified in the appropriate Data Safety Sheet (SDS) for this product/material as provided by the manufacturer, to establish appropriate safety, health, and environmental practices, and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B702 −93 (Reapproved 2019)
Standard Specification for
Copper-Tungsten Electrical Contact Material
This standard is issued under the fixed designation B702; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope such properties as arc erosion, contact resistance, and tendency
to weld in service. Since the performance of contacts in a
1.1 This specification covers electrical contact components
device depends on numerous factors outside the contact itself
made from copper tungsten by powder metallurgical proce-
(opening speed, closing speed, contact pressure, contact
dures.
bounce, environmental variations, assembly technique and
1.2 This specification covers compositions within the cop-
variations, etc.) this specification cannot ensure performance
per tungsten system normally specified by users of contacts.
control in the application.As part of the qualification on initial
1.3 The values stated in inch-pound units are to be regarded
samples it is recommended that the user functionally electri-
as standard. No other units of measurement are included in this
cally test the materials for all devices applicable to the
standard.
material’s use. This specification will provide a means for the
contact manufacturer and contact user to reach agreement on
1.4 This standard does not purport to address all of the
the details of material to be supplied for a specified use and
safety concerns, if any, associated with its use. It is the
reasonable assurance that future lots will be similar in proper-
responsibility of the user of this standard to become familiar
ties and microstructure to the initial test or sample contacts
with all hazards including those identified in the appropriate
supplied.
Data Safety Sheet (SDS) for this product/material as provided
by the manufacturer, to establish appropriate safety, health,
4. Ordering Information
and environmental practices, and determine the applicability
of regulatory limitations prior to use.
4.1 Orders for this material under this specification shall
1.5 This international standard was developed in accor-
include the following information:
dance with internationally recognized principles on standard-
4.1.1 Dimensions (see Section 8),
ization established in the Decision on Principles for the
4.1.2 Chemical composition (see reference tables in Related
Development of International Standards, Guides and Recom-
Material as possible guideline),
mendations issued by the World Trade Organization Technical
4.1.3 Physical properties (see Section 6 and reference tables
Barriers to Trade (TBT) Committee.
as guideline),
4.1.4 Certification (see Section 11), and
2. Referenced Documents
4.1.5 Other features as agreed upon between the vendor and
2.1 ASTM Standards:
the user.
B328 Test Method for Density, Oil Content, and Intercon-
nected Porosity of Sintered Metal Structural Parts and
5. Chemical Requirements
Oil-Impregnated Bearings (Withdrawn 2009)
5.1 The material shall conform to composition limits as
3. Significance and Use
agreed upon between the manufacturer and the user.
3.1 Proprietary methods for manufacture of these materials
5.2 The chemical analysis shall be made in accordance with
varysignificantlyamongsuppliersandthesemethodsinfluence
the methods prescribed in the newest edition of Annual Book of
1 ASTM Standards, or by any other approved method agreed
This specification is under the jurisdiction of ASTM Committee B02 on
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee upon between the manufacturer and the purchaser.
B02.05 on Precious Metals and Electrical Contact Materials.
Current edition approved Nov. 1, 2019. Published November 2019. Originally
6. Other Properties
approved in 1982. Last previous edition approved in 2015 as B702 – 93 (2015).
DOI: 10.1520/B0702-93R19.
6.1 The manufacturer and the purchaser shall agree on
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
qualification tests for determination of physical properties.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
6.2 The tests shall be performed on production parts,
the ASTM website.
wherever practical or applicable. (Small size contacts do not
The last approved version of this historical standard is referenced on
www.astm.org. lend themselves to accurate conductivity measurement.)
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B702 − 93 (2019)
6.3 The tests shall be determined after consideration of the 9.2.1 These specification limits do not preclude the possible
function of the part. presence of other unnamed elements, impurities or additives.
Analysis shall be regularly made only for the minor elements
6.4 The typical properties of five most common types of
listed in the table. However, if a user knows of elements that
copper-tungsten contacts are given in Appendix X1.
might be detrimental to their application or has other reasons
for requiring analysis for specific elements, then agreement
7. Dimensions and Permissible Variations
between manufacturer and purchaser for both limits and
7.1 Permissible variations in dimensions shall be within the
methods of analysis should be required for elements not
limits specified on drawings describing the contacts and
specified.
accompanying the order, or shall be within the limits specified
9.3 Physical Tests—The manufacturer and the purchaser
in t
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