ASTM B628-98(2021)

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:B628 −98 (Reapproved 2021)
Standard Specification for
Silver-Copper Eutectic Electrical Contact Alloy
This standard is issued under the fixed designation B628; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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 3. General Requirements
3.1 SpecificationB476andTestMethodB277shallapplyto
1.1 This specification covers 72% silver-28% copper (eu-
all materials produced to this specification.
tectic) alloy rod, wire, strip, and sheet material for electrical
contacts.
4. Manufacture
1.2 Thevaluesstatedininch-poundunitsaretoberegarded
4.1 Raw materials shall be of such quality and purity that
as standard. The values given in parentheses are mathematical
thefinishedproductwillhavethepropertiesandcharacteristics
conversions to SI units that are provided for information only
prescribed in this specification.
and are not considered standard.
4.2 The material shall be finished by such operations (cold
1.3 This standard does not purport to address all of the
working, heat treating, annealing, turning, grinding, or pick-
safety concerns, if any, associated with its use. It is the
ling) as are required to produce the prescribed properties.
responsibility of the user of this standard to become familiar
5. Chemical Composition
with all hazards including those identified in the appropriate
Safety Data Sheet (SDS) for this product/material as provided 5.1 Materialproducedunderthespecificationshallconform
by the manufacturer, to establish appropriate safety, health, to the requirements as to chemical composition prescribed in
and environmental practices, and determine the applicability Table 1.
of regulatory limitations prior to use.
6. Mechanical Requirements
1.4 This international standard was developed in accor-
6.1 The material shall conform to the mechanical properties
dance with internationally recognized principles on standard-
prescribed in Table 2 or Table 3.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 6.2 All test specimens shall be full thickness or diameter
mendations issued by the World Trade Organization Technical when practical.
Barriers to Trade (TBT) Committee.
6.3 Alltestsaretobeconductedatroomtemperature,about
68°F (20°C).
2. Referenced Documents
7. Inspection and Testing
2.1 ASTM Standards:
7.1 Material furnished under this specification shall be
B277Test Method for Hardness of Electrical Contact Mate-
inspected by the manufacturer as detailed in the applicable
rials
provisions of Specification B476 and as listed below.
B476Specification for General Requirements for Wrought
7.1.1 Visual inspection at 10×.
Precious Metal Electrical Contact Materials
7.1.2 Temper test (hardness or tension, but not both). A
tensiontestisrecommendedforstripbelow0.030-in.(0.8-mm)
thickness and for wire of any diameter. A tension test is
This specification is under the jurisdiction of ASTM Committee B02 on
preferred when permitted by part size and quantity.
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
7.1.3 Dimensional tests.
B02.05 on Precious Metals and Electrical Contact Materials.
7.1.4 Spectrographic or chemical analysis when indicated
Current edition approved Nov. 1, 2021. Published December 2021. Originally
approved in 1977. Last previous edition approved in 2016 as B628–98(2016). by the purchase order.
DOI: 10.1520/B0628-98R21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 8. Keywords
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
8.1 composition; electrical contacts; impurities; precious
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. metals; silver copper alloy
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B628−98 (2021)
A
TABLE 1 Chemical Composition
Element Weight %
Silver 71.0 to 73.0
Copper balance
Total of all impurities 0.15
Zinc 0.06 max
Iron 0.05 max
Cadmium 0.05 max
Lead 0.03 max
Nickel 0.01 max
Aluminum 0.005 max
Phosphorus 0.03 max
Total others 0.06 max
A
Analysis is regularly made for the elements for which specific limits are listed. If,
however, the presence of “other” elements is suspected or indicated in the course
of routine analysis, further analysis shall be made to determine that the total of
these “other” elements and the listed impurities are not in excess o
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