ASTM B662-94(2012)
(Specification)Standard Specification for Silver-Molybdenum Electrical Contact Material
Standard Specification for Silver-Molybdenum Electrical Contact Material
ABSTRACT
This specification covers electrical contact components made from silver-molybdenum by powder metallurgical procedures. Chemical analysis of the samples shall be done to determine their chemical composition. The material shall be finished by different methods like braze alloy backing, tumbling to polish surfaces, special surface finish, and cleaning.
SIGNIFICANCE AND USE
Proprietary methods for the manufacture of these materials vary significantly among suppliers, and these methods influence such properties as arc erosion, contact resistance, and the tendency to weld in service. Since the performance of contacts in a device depends on numerous factors outside the contact itself (opening speed, closing speed, contact pressure, contact bounce, environmental variations, assembly technique and variations, etc.), this specification cannot ensure performance control in the application. As part of the qualification on initial samples, it is recommended that the user functionally and electrically test the materials for all devices applicable to the material's use. This specification will provide a means for the contact manufacturer and contact user to reach agreement on the details of the material to be supplied for a specific use, and reasonable assurance that future lots will be similar in properties and microstructure to the initial test or sample contacts supplied.
SCOPE
1.1 This specification covers electrical contact components made from silver-molybdenum by powder metallurgical procedures.
1.2 This specification covers compositions within the silver-molybdenum 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 Material Safety Data Sheet (MSDS) for this product/material as provided by the manufacturer, to establish appropriate safety and health practices, and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: B662 −94 (Reapproved 2012)
Standard Specification for
Silver-Molybdenum Electrical Contact Material
This standard is issued under the fixed designation B662; 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 3.1.4 Certification (see Section 13), and
3.1.5 Other features as agreed upon between the manufac-
1.1 This specification covers electrical contact components
turer and purchaser.
made from silver-molybdenum by powder metallurgical pro-
cedures.
4. Chemical Composition
1.2 Thisspecificationcoverscompositionswithinthesilver-
4.1 The material shall conform to composition limits as
molybdenum system normally specified by users of contacts.
agreed upon between the manufacturer and the purchaser.
1.3 The values stated in inch-pound units are to be regarded
as standard. No other units of measurement are included in this 4.2 The chemical analysis shall be made in accordance with
standard. the methods prescribed in the newest edition of Volume 01.02
of the Annual Book of ASTM Standards or by any other
1.4 This standard does not purport to address all of the
approved method agreed upon between the manufacturer and
safety concerns, if any, associated with its use. It is the
the purchaser.
responsibility of the user of this standard to become familiar
with all hazards including those identified in the appropriate
5. Physical Properties
Material Safety Data Sheet (MSDS) for this product/material
as provided by the manufacturer, to establish appropriate
5.1 The manufacturer and the purchaser shall agree on
safety and health practices, and determine the applicability of
qualification tests for determination of physical properties.
regulatory limitations prior to use.
5.2 The tests shall be performed on production parts,
wherever practical or applicable. (Small size contacts do not
2. Referenced Documents
2 lend themselves to accurate conductivity measurement.)
2.1 ASTM Standards:
B328 Test Method for Density, Oil Content, and Intercon-
5.3 The tests shall be determined after consideration of the
nected Porosity of Sintered Metal Structural Parts and
function of the part.
Oil-Impregnated Bearings (Withdrawn 2009)
5.4 The typical properties of two most common types of
silver-molybdenum contacts are given in the appendix.
3. Ordering Information
3.1 Orders for this material under this specification shall
6. Finishing of Contacts
include the following information:
6.1 The material shall be finished by such operations as
3.1.1 Dimensions (see Section 10),
3.1.2 Chemical composition (see tables in the appendix as a necessary to meet requirements agreed upon between the
manufacturer and the purchaser of the contacts (braze alloy
guideline),
3.1.3 Physical properties (see Section 5 and the appendix as backing, tumbling to polish surfaces, special surface finish,
silver-rich surface layer, cleaning, etc.).
a guideline),
7. Dimensions, Mass, and Permissible Variations
This specification is under the jurisdiction of ASTM Committee B02 on
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
7.1 Permissible variations in dimensions shall be within the
B02.05 on Precious Metals and Electrical Contact Materials.
limits specified on drawings describing the contacts and
Current edition approved May 1, 2012. Published May 2012. Originally
approved in 1979. Last previous edition approved in 2006 as B662 – 94 (2006). accompanying the order; or shall be within the limits specified
DOI: 10.1520/B0662-94R12.
in the purchase order.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
8. Workmanship, Finish, and Appearance
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 8.1 The parts shall be free of defects in material or process-
The last approved version of this historical standard is referenced on
www.astm.org. ing that would seriously affect their performance.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B662 − 94 (2012)
9. Significance and Use additives. Analysis shall be regularly made only for the minor
elements listed in the table. However, if a user knows of
9.1 Proprietary methods for the manufacture of these mate-
elements that might be detrimental to their application or has
rials vary significantly among suppliers, and these methods
other reasons for requiring analysis for specific elements, then
influence such properties as arc erosion, contact resistance, and
agreement between manufacturer and purchaser for both limits
the tendency to weld in service. Since the performance of
and methods of analysis should be required for elements not
contacts in a device depends on numerous factors outside the
specified.
contact itself (opening speed, closing speed, contact pressure,
contact bounce, environmental variations, assembly technique
10.3 Physical Tests—The manufacturer and the purchaser
and variations, etc.), this specification cannot ensure perfor- shall agree on a representative number of specimens for
mance control in the application.As part of the qualification on
physical tests including microstructure.
initial samples, it is recommended that the user functionally
and electrically test the materials for all devices applicable to 11. Inspection
the material’s use. This specification will provide a means for
11.1 Unlessotherwisespecified,inspectionofpartssupplied
the contact manufacturer and contact user to reach agreement
on contract shall be made by the purchaser.
on the details of the material to be supplied for a specific use,
and reasonable assurance that future lots will be similar in
12. Rejection
properties and microstructure to the initial test or sample
12.1 Unless otherwise specified, rejections based on tests
contacts supplied.
made in accordance with the
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