ASTM B277-18(2024)
(Test Method)Standard Test Method for Hardness of Electrical Contact Materials
Standard Test Method for Hardness of Electrical Contact Materials
SIGNIFICANCE AND USE
3.1 The Rockwell hardness and Rockwell superficial tests are useful when the test specimens are sufficiently thick (in relation to the indentor load) to ensure that the results are not affected by the flow of metal on the surface of the anvil. On a solid piece the flow of metal on the under surface may be detected by a bulge or marking. On composite pieces where the contact materials are attached to backings of a different material, the thickness limitations imposed for a solid piece shall apply to the contact material portion of such composite pieces.
Note 1: As a matter of information, it may be stated that tests on fine silver showed that on annealed samples having a Rockwell 15T hardness of 27, the readings were not affected on thicknesses 1/16 in. (1.6 mm) or over. On thicknesses of 1/32 in. (0.8 mm) Rockwell 15T scale readings of 72 and higher were not affected.
3.2 The microindentation hardness test is of questionable significance when the metallic phases in a material are so large that the indentation does not represent an accurate average hardness. Sintered contact materials usually contain segregates differing greatly in hardness from the matrix hardness and may destroy the validity of microindentation hardness readings.
3.3 Other aspects of significance and use shall be as described in the particular ASTM test method used, as listed in Section 2.
SCOPE
1.1 This test method covers the determination of the hardness of metallic materials used for electrical contacts. Rockwell, Rockwell superficial, Brinell, and microindentation hardness tests are included, along with information on the limitations and use of these tests.
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 become familiar will 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.
1.4 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
- 31-Mar-2024
- Technical Committee
- B02 - Nonferrous Metals and Alloys
Relations
- Effective Date
- 01-Apr-2024
- Referred By
ASTM B628-98(2021) - Standard Specification for Silver-Copper Eutectic Electrical Contact Alloy - Effective Date
- 01-Apr-2024
- Referred By
ASTM B684/B684M-22 - Standard Specification for Platinum-Iridium Electrical Contact Materials - Effective Date
- 01-Apr-2024
- Effective Date
- 01-Apr-2024
Overview
ASTM B277-18(2024), Standard Test Method for Hardness of Electrical Contact Materials, defines procedures for measuring the hardness of metallic materials used in electrical contacts. Developed by ASTM International, this standard is integral for ensuring the quality and reliability of contact materials used in a range of electrical applications. The standard details the use of Rockwell, Rockwell superficial, Brinell, and microindentation hardness tests and provides guidance on when and how to apply each method based on sample characteristics.
Key Topics
- Hardness Testing Methods: The document encompasses multiple standardized test methods, including:
- Rockwell hardness test
- Rockwell superficial hardness test
- Brinell hardness test
- Microindentation hardness test
- Sample Thickness Requirements: Accurate results depend on proper specimen thickness relative to the indentor load, especially in composite or thin materials.
- Limitations: Certain methods, such as microindentation, may not yield valid results for materials with large metallic phases or significant heterogeneity, such as sintered contacts.
- Reporting Requirements: The standard specifies detailed reporting, including specimen thickness, radius of curvature for curved surfaces, and any factors affecting test results.
- Safety and Regulatory Compliance: Users are responsible for ensuring safe use, reviewing Safety Data Sheets (SDS), and following appropriate regulatory and environmental practices.
Applications
The measurement of hardness in electrical contact materials is essential in sectors where durability, consistency, and performance are critical. Key applications include:
- Manufacturing of electrical contacts: Ensures that contact points made from metals like silver or specialized alloys meet required durability and conductivity standards.
- Quality control: Reliable hardness measurements help manufacturers maintain product consistency and meet industry specifications.
- Materials selection: Engineers and designers use hardness data to select suitable metals for connectors, switches, and relays, where contact resistance and wear resistance are important.
- Composite contact evaluation: The standard covers testing both solid and composite contact materials, including those bonded to backings of different materials.
- Research and Development: Facilitates material comparison and the development of new contact materials with tailored mechanical and electrical properties.
By following ASTM B277, organizations can reduce material failure risks, improve product reliability, and maintain compliance with international quality standards for electrical components.
Related Standards
ASTM B277 references several related test methods that provide further detail and guidance for hardness testing of metallic materials:
- ASTM E10: Test Method for Brinell Hardness of Metallic Materials
- ASTM E18: Test Methods for Rockwell Hardness of Metallic Materials, including Rockwell superficial
- ASTM E384: Test Method for Microindentation Hardness of Materials
These standards are essential references for laboratories, manufacturers, and quality assurance teams performing hardness testing on electrical contact materials.
Practical Value
Implementing ASTM B277-18(2024) ensures consistent, accurate measurement of hardness in electrical contact materials, a critical property affecting contact wear and electrical performance. Adhering to this standard supports:
- Improved component reliability and safety
- Consistency in material assessment and product certification
- Efficient comparison across material types for optimal product design
For anyone involved in the production or evaluation of electrical contact materials, ASTM B277 remains an indispensable tool for quality assurance and international compliance.
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Frequently Asked Questions
ASTM B277-18(2024) is a standard published by ASTM International. Its full title is "Standard Test Method for Hardness of Electrical Contact Materials". This standard covers: SIGNIFICANCE AND USE 3.1 The Rockwell hardness and Rockwell superficial tests are useful when the test specimens are sufficiently thick (in relation to the indentor load) to ensure that the results are not affected by the flow of metal on the surface of the anvil. On a solid piece the flow of metal on the under surface may be detected by a bulge or marking. On composite pieces where the contact materials are attached to backings of a different material, the thickness limitations imposed for a solid piece shall apply to the contact material portion of such composite pieces. Note 1: As a matter of information, it may be stated that tests on fine silver showed that on annealed samples having a Rockwell 15T hardness of 27, the readings were not affected on thicknesses 1/16 in. (1.6 mm) or over. On thicknesses of 1/32 in. (0.8 mm) Rockwell 15T scale readings of 72 and higher were not affected. 3.2 The microindentation hardness test is of questionable significance when the metallic phases in a material are so large that the indentation does not represent an accurate average hardness. Sintered contact materials usually contain segregates differing greatly in hardness from the matrix hardness and may destroy the validity of microindentation hardness readings. 3.3 Other aspects of significance and use shall be as described in the particular ASTM test method used, as listed in Section 2. SCOPE 1.1 This test method covers the determination of the hardness of metallic materials used for electrical contacts. Rockwell, Rockwell superficial, Brinell, and microindentation hardness tests are included, along with information on the limitations and use of these tests. 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 become familiar will 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. 1.4 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.
SIGNIFICANCE AND USE 3.1 The Rockwell hardness and Rockwell superficial tests are useful when the test specimens are sufficiently thick (in relation to the indentor load) to ensure that the results are not affected by the flow of metal on the surface of the anvil. On a solid piece the flow of metal on the under surface may be detected by a bulge or marking. On composite pieces where the contact materials are attached to backings of a different material, the thickness limitations imposed for a solid piece shall apply to the contact material portion of such composite pieces. Note 1: As a matter of information, it may be stated that tests on fine silver showed that on annealed samples having a Rockwell 15T hardness of 27, the readings were not affected on thicknesses 1/16 in. (1.6 mm) or over. On thicknesses of 1/32 in. (0.8 mm) Rockwell 15T scale readings of 72 and higher were not affected. 3.2 The microindentation hardness test is of questionable significance when the metallic phases in a material are so large that the indentation does not represent an accurate average hardness. Sintered contact materials usually contain segregates differing greatly in hardness from the matrix hardness and may destroy the validity of microindentation hardness readings. 3.3 Other aspects of significance and use shall be as described in the particular ASTM test method used, as listed in Section 2. SCOPE 1.1 This test method covers the determination of the hardness of metallic materials used for electrical contacts. Rockwell, Rockwell superficial, Brinell, and microindentation hardness tests are included, along with information on the limitations and use of these tests. 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 become familiar will 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. 1.4 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.
ASTM B277-18(2024) is classified under the following ICS (International Classification for Standards) categories: 77.120.99 - Other non-ferrous metals and their alloys. The ICS classification helps identify the subject area and facilitates finding related standards.
ASTM B277-18(2024) has the following relationships with other standards: It is inter standard links to ASTM B277-18, ASTM B628-98(2021), ASTM B684/B684M-22, ASTM B617-98(2021). Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
ASTM B277-18(2024) is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
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: B277 − 18 (Reapproved 2024)
Standard Test Method for
Hardness of Electrical Contact Materials
This standard is issued under the fixed designation B277; 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. Significance and Use
3.1 The Rockwell hardness and Rockwell superficial tests
1.1 This test method covers the determination of the hard-
are useful when the test specimens are sufficiently thick (in
ness of metallic materials used for electrical contacts.
relation to the indentor load) to ensure that the results are not
Rockwell, Rockwell superficial, Brinell, and microindentation
affected by the flow of metal on the surface of the anvil. On a
hardness tests are included, along with information on the
solid piece the flow of metal on the under surface may be
limitations and use of these tests.
detected by a bulge or marking. On composite pieces where the
1.2 The values stated in inch-pound units are to be regarded
contact materials are attached to backings of a different
as standard. The values given in parentheses are mathematical
material, the thickness limitations imposed for a solid piece
conversions to SI units that are provided for information only
shall apply to the contact material portion of such composite
and are not considered standard.
pieces.
1.3 This standard does not purport to address all of the
NOTE 1—As a matter of information, it may be stated that tests on fine
safety concerns, if any, associated with its use. It is the
silver showed that on annealed samples having a Rockwell 15T hardness
responsibility of the user of this standard to become familiar
of 27, the readings were not affected on thicknesses ⁄16 in. (1.6 mm) or
will all hazards including those identified in the appropriate
over. On thicknesses of ⁄32 in. (0.8 mm) Rockwell 15T scale readings of
72 and higher were not affected.
Safety Data Sheet (SDS) for this product/material as provided
by the manufacturer, to establish appropriate safety, health,
3.2 The microindentation hardness test is of questionable
and environmental practices, and determine the applicability
significance when the metallic phases in a material are so large
of regulatory limitations prior to use.
that the indentation does not represent an accurate average
1.4 This international standard was developed in accor-
hardness. Sintered contact materials usually contain segregates
dance with internationally recognized principles on standard-
differing greatly in hardness from the matrix hardness and may
ization established in the Decision on Principles for the
destroy the validity of microindentation hardness readings.
Development of International Standards, Guides and Recom-
3.3 Other aspects of significance and use shall be as
mendations issued by the World Trade Organization Technical
described in the particular ASTM test method used, as listed in
Barriers to Trade (TBT) Committee.
Section 2.
2. Referenced Documents
4. Sampling
2.1 ASTM Standards:
4.1 Prepare test samples in accordance with the method
E10 Test Method for Brinell Hardness of Metallic Materials
selected from those listed in Section 2 and, where applicable,
E18 Test Methods for Rockwell Hardness of Metallic Ma-
supplemented with the requirements in 5.3.
terials
E384 Test Method for Microindentation Hardness of Mate-
5. Procedure
rials
5.1 Determine the hardness in accordance with one of the
following:
5.1.1 Test Methods E18 subject to the additional require-
This test method is under the jurisdiction of ASTM Committee B02 on
ments and precautions in 3.1, 5.2, and 5.3.
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
B02.05 on Precious Metals and Electrical Contact Materials and Test Methods.
5.1.2 Test Method E384 subject to the additional require-
Current edition approved April 1, 2024. Published May 2024. Originally
ments and precautions i
...
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