ASTM B663/B663M-20

Standard Specification for Silver-Tungsten Carbide Electrical Contact Material

ABSTRACT
This specification covers electrical contact components made from silver-tungsten carbide by powder metallurgical procedures. This specification covers compositions within the silver-tungsten carbide system. The material shall conform to composition limits. Chemical analysis shall be performed to deteremine material conformance to specified composition requirements. The contact components shall agree on qualification tests for determination of physical properties. The tests shall be performed on production parts wherever practical or applicable. The test shall be determined after consideration of the function of the part.
SCOPE
1.1 This specification covers electrical contact components made from silver-tungsten carbide materials by powder metallurgical processes.  
1.2 This specification covers compositions within the silver-tungsten carbide system normally specified by users of contacts.
Note 1: Table X1.1 and Table X1.2 in Appendix X1 provide a list of typical compositions used for various applications.  
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
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 Safety Data 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

• Status: Published
• Publication Date: 30-Sep-2020
• ICS: 77.120.99 - Other non-ferrous metals and their alloys
• Technical Committee: B02 - Nonferrous Metals and Alloys
• Drafting Committee: B02.05 - Precious Metals and Electrical Contact Materials and Test Methods

Relations

• Refers: ASTM B328-96(2003)e1 - Standard Test Method for Density, Oil Content, and Interconnected Porosity of Sintered Metal Structural Parts and Oil-Impregnated Bearings (Withdrawn 2009)
• Effective Date: 10-Apr-2003
• Refers: ASTM B328-96(2003) - Standard Test Method for Density, Oil Content, and Interconnected Porosity of Sintered Metal Structural Parts and Oil-Impregnated Bearings
• Effective Date: 10-Apr-2003
• Refers: ASTM B328-96 - Standard Test Method for Density, Oil Content, and Interconnected Porosity of Sintered Metal Structural Parts and Oil-Impregnated Bearings
• Effective Date: 10-Sep-1996

Overview

ASTM B663/B663M-20: Standard Specification for Silver-Tungsten Carbide Electrical Contact Material sets out requirements for electrical contact components manufactured using silver-tungsten carbide by powder metallurgical processes. This standard defines acceptable compositions within the silver-tungsten carbide system, inspection, testing, and certification practices to ensure compliance and suitability for use in demanding electrical applications. The specification is recognized by ASTM International and is utilized in applications requiring robust, conductive, and durable electrical contacts.

Key Topics

• Material Scope: The standard covers all electrical contact components made from silver-tungsten carbide materials produced via powder metallurgy, including composition ranges and the necessity for conformance testing.
• Composition Limits: Typical allowable composition ranges for silver and tungsten carbide are provided, with limits for impurities such as copper, nickel, and cobalt. These limits help set minimum standards for reliable electrical and mechanical performance.
• Testing and Qualification: The standard emphasizes agreement between manufacturer and purchaser on specific qualification tests. Both chemical and physical properties must be verified, often requiring analysis of production components.
• Dimensional and Appearance Requirements: Components must meet specified dimensions, mass, and permissible variation requirements. The finish and appearance must be free of material or processing defects that could compromise performance.
• Certification and Inspection: Testing, certification, and lot sampling are outlined, with specified actions in case of nonconformance. Certification of compliance and test reports must be provided when requested by the purchaser.
• International Standardization: The document is developed in alignment with World Trade Organization (WTO) principles for international standards, supporting global applicability, trade, and consistency.

Applications

Silver-tungsten carbide electrical contact materials manufactured to ASTM B663/B663M-20 are used where a combination of high conductivity, wear resistance, and arc erosion resistance is critical. Typical application areas include:

• Switchgear: Electrical switches and circuit breakers that must withstand frequent switching and high currents benefit from these robust contact materials.
• Relays and Contactors: Industrial relays, contactors, and similar apparatus use silver-tungsten carbide contacts for reliable operation in high-load conditions.
• Power Distribution Components: The specification is applicable in busbars, connectors, and related components exposed to heavy electrical loads and environments where reliability is critical.
• Electromechanical Devices: Components requiring repeated actuation or operation in harsh environments, where contact welding and loss of conductivity are concerns.

Materials compliant with this standard are particularly valued for their balance of electrical and mechanical properties, including hardness, conductivity, and resistance to arc erosion and welding.

Related Standards

For organizations specifying, manufacturing, or procuring silver-tungsten carbide electrical contacts, the following related standards may be relevant:

• ASTM B328: Test Method for Density, Oil Content, and Interconnected Porosity of Sintered Metal Structural Parts and Oil-Impregnated Bearings (historical reference for analysis procedures).
• ASTM B700: Standard Specification for Electrodeposited Coatings of Silver for Engineering Use, important for applications requiring additional silver layers.
• ASTM B844: Standard Guide for Metallic Wear and Erosion Test Methods (relevant to performance assessment).
• IEC 60439: International standards for low-voltage switchgear and controlgear assemblies, often referencing material compatibility.
• ISO 9001: Quality management systems, ensuring process reliability in the manufacture of contact materials.

By adhering to ASTM B663/B663M-20, manufacturers and end-users can assure consistency, safety, and performance of electrical contact materials in critical power, industrial, and commercial applications. The standard supports global sourcing, trade, and integration into systems requiring proven, reliable electrical contact solutions.

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: B663/B663M −20
Standard Specification for
Silver-Tungsten Carbide Electrical Contact Material
This standard is issued under the fixed designation B663/B663M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope B328 Test Method for Density, Oil Content, and Intercon-
nected Porosity of Sintered Metal Structural Parts and
1.1 This specification covers electrical contact components
Oil-Impregnated Bearings (Withdrawn 2009)
made from silver-tungsten carbide materials by powder metal-
lurgical processes.
3. Significance and Use
1.2 Thisspecificationcoverscompositionswithinthesilver-
3.1 This specification provides a means for the contact
tungsten carbide system normally specified by users of con-
manufacturer and contact user to establish agreement on the
tacts.
material to be supplied for a specific application including
NOTE 1—Table X1.1 and Table X1.2 in Appendix X1 provide a list of
microstructure and other properties.
typical compositions used for various applications.
3.2 As part of the qualification, it is recommended that the
1.3 The values stated in either SI units or inch-pound units
user functionally and electrically test the materials for all
are to be regarded separately as standard. The values stated in
devices applicable to the material’s use.
each system are not necessarily exact equivalents; therefore, to
ensure conformance with the standard, each system shall be
NOTE2—Theperformanceofcontactsinadevicedependsonnumerous
used independently of the other, and values from the two
factors outside the contact itself (opening speed, closing speed, contact
pressure, contact bounce, environmental variations, assembly technique
systems shall not be combined.
and variations, etc.). Proprietary methods for the manufacture of these
1.4 This standard does not purport to address all of the
materials vary significantly among suppliers, and these methods influence
safety concerns, if any, associated with its use. It is the
suchpropertiesasarcerosion,contactresistance,andthetendencytoweld
in service.
responsibility of the user of this standard to become familiar
with all hazards including those identified in the appropriate
4. Ordering Information
Safety Data Sheet (SDS) for this product/material as provided
by the manufacturer, to establish appropriate safety, health,
4.1 Orders for this material under this specification shall
and environmental practices, and determine the applicability include the following information:
of regulatory limitations prior to use.
4.1.1 Dimensions (see Section 9),
1.5 This international standard was developed in accor- 4.1.2 Chemicalcomposition(seeTableX1.1andTableX1.2
dance with internationally recognized principles on standard-
in Appendix X1 as a guideline),
ization established in the Decision on Principles for the 4.1.3 Physicalproperties(seeSection6andAppendixX1as
Development of International Standards, Guides and Recom-
a guideline),
mendations issued by the World Trade Organization Technical 4.1.4 Certification (see Section 12), and
Barriers to Trade (TBT) Committee.
4.1.5 Other features as agreed upon between the manufac-
turer and purchaser.
2. Referenced Documents
2 5. Chemical Composition
2.1 ASTM Standards:
5.1 The material shall conform to composition limits as
agreed upon between the manufacturer and the purchaser.
This specification is under the jurisdiction of ASTM Committee B02 on
Typical chemical ranges are listed in Table X1.1 and Table
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
X1.2 of Appendix X1.
B02.05 on Precious Metals and Electrical Contact Materials.
Current edition approved Oct. 1, 2020. Published October 2020. Originally
5.2 The chemical analysis shall be made in accordance with
approved in 1979. Last previous edition approved in 2016 as B663/B663M – 16.
the methods prescribed inVolume 01.02 of the Annual Book of
DOI: 10.1520/B0663_B0663M-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B663/B663M − 20
ASTM Standards or by any other approved method agreed for requiring analysis for specific elements, then agreement
upon between the manufacturer and the purchaser. between manufacturer and purchaser for both limits and
methods of analysis should be required for elements not
6. Physical Properties
specified.
6.1 The manufacturer and the purchaser shall agree on
9.3 Physical Tests—The manufacturer and the purchaser
qualification tests for determination of physical properties.
shall agree on a representative number of specimens for
physical tests including microstructure.
6.2 The tests shall be performed on production parts,
wherever practical or applicable. (Small size contacts do not
10. Inspection
lend themselves to accurate conductivity measurement.)
10.1 Unless otherwise specified, inspection of parts sup-
6.3 The tests shall be determined after consideration of the
plied on contract shall be made by the purchaser.
function of the part.
11. Rejection and Rehearing
6.4 The typical properties of three most common types of
11.1 Rejection:
silver-tungsten carbide contacts are given in Appendix X1.
11.1.1 Product that fails to conform to the specification
7. Dimensions, Mass, and Permissible Variations
requirementswhentestedbythepurchaserorpurchaser’sagent
shall be subject to rejection.
7.1 Permissible variations in dimensions shall be within the
11.1.2 Rejection shall be reported to the manufacturer or
limits specified on drawings describing the contacts and
supplier promptly. In addition, a written notification of rejec-
accompanying the order, or shall be within the limits specified
tion shall follow.
in the purchase order.
11.1.3 In case of dissatisfaction with results of the test upon
8. Workmanship, Finish, and Appearance
which rejection is based, the manufacturer, or supplier, shall
have the option to make claim for a rehearing.
8.1 The parts shall be free of defects, in material or
processing, that would seriously affect their performance.
11.2 Rehearing:
11.2.1 As a result of product rejection, the manufacturer, or
8.2 Finishing of Contacts—Thematerialshallbefinishedby
supplier, shall have the option to make claim for a retest to be
suchoperationsasnecessarytomeetrequirementsagreedupon
conducted by the manufacturer, or supplier, and the purchaser.
between the
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B663/B663M − 16 B663/B663M − 20
Standard Specification for
Silver-Tungsten Carbide Electrical Contact Material
This standard is issued under the fixed designation B663/B663M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This specification covers electrical contact components made from silver-tungsten carbide materials by powder metallurgical
processes.
1.2 This specification covers compositions within the silver-tungsten carbide system normally specified by users of contacts.
NOTE 1—Table X1.1 and Table X1.2 in Appendix X1 provide a list of typical compositions used for various applications.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined.
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 Safety Data Sheet
(SDS) for this product/material as provided by the manufacturer, to establish appropriate safety safety, health, and healthenvi-
ronmental 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.
2. Referenced Documents
2.1 ASTM Standards:
B328 Test Method for Density, Oil Content, and Interconnected Porosity of Sintered Metal Structural Parts and Oil-Impregnated
Bearings (Withdrawn 2009)
3. Significance and Use
3.1 This specification provides a means for the contact manufacturer and contact user to establish agreement on the material to
be supplied for a specific application including microstructure and other properties.
This specification is under the jurisdiction of ASTM Committee B02 on Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee B02.05 on
Precious Metals and Electrical Contact Materials.
Current edition approved May 1, 2016Oct. 1, 2020. Published May 2016October 2020. Originally approved in 1979. Last previous edition approved in 20122016 as
B663 – 94 (2012).B663/B663M – 16. DOI: 10.1520/B0663/B0663M-16.10.1520/B0663_B0663M-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B663/B663M − 20
3.2 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, qualification, 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.material’s
use.
NOTE 2—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.). 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.
4. Ordering Information
4.1 Orders for this material under this specification shall include the following information:
4.1.1 Dimensions (see Section 109),
4.1.2 Chemical composition (see Table X1.1 and Table X1.2 in Appendix X1 as a guideline),
4.1.3 Physical properties (see Section 6 and Appendix X1 as a guideline),
4.1.4 Certification (see Section 1312), and
4.1.5 Other features as agreed upon between the manufacturer and purchaser.
5. Chemical Composition
5.1 The material shall conform to composition limits as agreed upon between the manufacturer and the purchaser. Typical
chemical ranges are listed in Table X1.1 and Table X1.2 of Appendix X1.
5.2 The chemical analysis shall be made in accordance with the methods prescribed in the newest edition of Volume 01.02 of the
Annual Book of ASTM Standards or by any other approved method agreed upon between the manufacturer and the purchaser.
6. Physical Properties
6.1 The manufacturer and the purchaser shall agree on qualification tests for determination of physical properties.
6.2 The tests shall be performed on production parts, wherever practical or applicable. (Small size contacts do not lend themselves
to accurate conductivity measurement.)
6.3 The tests shall be determined after consideration of the function of the part.
6.4 The typical properties of three most common types of silver-tungsten carbide contacts are given in Appendix X1.
7. Dimensions, Mass, and Permissible Variations
7.1 Permissible variations in dimensions shall be within the limits specified on drawings describing the contacts and
accompanying the order, or shall be within the limits specified in the purchase order.
8. Finishing of Contacts Workmanship, Finish, and Appearance
8.1 The parts shall be free of defects, in material or processing, that would seriously affect their performance.
B663/B663M − 20
8.2 Finishing of Contacts—The material shall be finished by such operations as necessary to meet requirements agreed upon
between the manufacturer and the purchaser of the contacts (braze alloy backing, tumbling to polish surfaces, special surface finish,
silver-rich surface layer, cleaning, etc.).
9. Workmanship, Finish, and Appearance
9.1 The parts shall be free of defects in material or processing, that would seriously affect their performance.
9. Sampling
9.1 Lot—Unless otherwise specified, a lot shall consist of parts of the same form and dimensions, made of powders of the same
particle size range and composition, processed under the same conditions, and submitted for inspection at the same time.
9.2 Chemical Analysis
9.2.1 At least one sample for chemical analysis shall be taken from each lot. A representative sample of chips may be obtained
by milling, drilling, or crushing at least two pieces with dry tools, without lubrication. In order to obtain oil free chips, the parts
selected for test s
...