ASTM B780-16

Standard Specification for 75 % Silver, 24.5 % Copper, 0.5 % Nickel Electrical Contact Alloy

ABSTRACT
This specification covers electrical contact alloys with the nominal composition of 75% silver, 24.5% copper, and 0.5% nickel in the form of rods, wires, strips, and sheets. Raw materials shall be of such quality and purity that the products, which shall be finished by such operations as cold working, heat treatment, annealing, turning, grinding, or pickling, shall adhere to the chemical composition and mechanical property requirements prescribed here. Besides analysis for the elements silver, copper, and nickel, further analysis is to be made for suspected or indicated impurities, such as zinc, iron, cadmium, and lead, to make sure that their total does not exceed specified limits. Mechanical tests, which are to be conducted at room temperature, shall evaluate the materials' tensile strength, elongation, Rockwell hardness, and area and thickness reduction.
SCOPE
1.1 This specification covers an electrical contact material with the nominal composition of 75 % silver, 24.5 % copper, and 0.5 % nickel in the form of rod, wire, strip, and sheet.  
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 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 and health practices, and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Apr-2016
• 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

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:B780 −16
Standard Specification for
75% Silver, 24.5% Copper, 0.5% Nickel Electrical Contact
1
Alloy
This standard is issued under the fixed designation B780; 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 4.2 The material shall be finished by such operations (cold
working, heat-treating, annealing, turning, grinding, or pick-
1.1 This specification covers an electrical contact material
ling) as are required to produce the prescribed properties.
with the nominal composition of 75% silver, 24.5% copper,
and 0.5% nickel in the form of rod, wire, strip, and sheet.
5. Chemical Composition
1.2 Thevaluesstatedininch-poundunitsaretoberegarded
5.1 Materialproducedunderthisspecificationshallconform
as standard. The values given in parentheses are mathematical
to the chemical composition limits prescribed in Table 1.
conversions to SI units that are provided for information only
and are not considered standard.
5.2 These specification limits do not preclude the possible
1.3 This standard does not purport to address all of the
presence of other unnamed elements, impurities, or additives.
safety concerns, if any, associated with its use. It is the
Analysis shall be regularly made only for the minor elements
responsibility of the user of this standard to become familiar
listed in the table. However, if a user knows of elements that
with all hazards including those identified in the appropriate
might be detrimental to their application or has other reasons
Safety Data Sheet (SDS) for this product/material as provided
for requiring analysis for specific elements, then agreement
by the manufacturer, to establish appropriate safety and health
between manufacturer and purchaser for both limits and
practices, and determine the applicability of regulatory limi-
methods of analysis should be required for elements not
tations prior to use.
specified.
2. Referenced Documents
6. Mechanical Properties
2
2.1 ASTM Standards:
6.1 Thematerialshallconformtotheapplicablemechanical
B476Specification for General Requirements for Wrought
properties prescribed in Table 2 or Table 3.
Precious Metal Electrical Contact Materials
6.2 Alltestspecimensshallbethefullthicknessordiameter
3. Ordering Information
as the size supplied when practical. The test procedures shall
3.1 Refer to Specification B476.
follow the ASTM specifications referred to in Specification
4. Materials and Manufacture B476.
4.1 Raw materials shall be of such quality and purity that
6.3 Alltestsaretobeconductedatroomtemperature,about
thefinishedproductwillhavethepropertiesandcharacteristics
68°F (20°C).
prescribed in this specification.
7. Inspection, Rejection and Rehearing, Certification,
1
This specification is under the jurisdiction of ASTM Committee B02 on
Product Marking, and Supplementary Requirements
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
B02.05 on Precious Metals and Electrical Contact Materials.
7.1 Material furnished to this specification shall meet the
Current edition approved May 1, 2016. Published May 2016. Originally
requirements listed in Specification B476.
approved in 1987. Last previous edition approved in 2010 as B780–98(2010).
DOI: 10.1520/B0780-16.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 8. Keywords
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
8.1 arcing contacts; contacts; conductivity; electrical con-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. tacts; precious metals; silver alloy; silver-copper alloy; wire
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
B780−16
TABLE 1 Chemical Composition
NOTE1—Analysisisregularlymadefortheelementsforwhichspecific
limitsarelisted.Ifhowever,thepresenceof“other”elementsissuspected
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 is not in excess of the total impurities limit.
NOTE 2—Refer to 5.2.
Element Weight,%
Silver 74.0–76.0
Copper (23.5 min) report by difference
Nickel 0.35–0.65
Impurities
Zinc 0.06 max
Iron 0.05 max
Cadmium 0.01 max
Lead 0.03 max
Total of all impurities 0.15 max
TABLE 2 Mechanical Properties of Wire and Rod
%
Tensile Strength
Area Elonga-
Temper B and
Reduction, tion in
Designation S No.
ksi MPa
% 2 in. (51
mm), min
...

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: B780 − 98 (Reapproved 2010) B780 − 16
Standard Specification for
75 % Silver, 24.5 % Copper, 0.5 % Nickel Electrical Contact
1
Alloy
This standard is issued under the fixed designation B780; 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 an electrical contact material with the nominal composition of 75 % silver, 24.5 % copper, and
0.5 % nickel in the form of rod, wire, strip, and sheet.
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 with all hazards including those identified in the appropriate Material Safety Data
Sheet (MSDS)(SDS) 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.
2. Referenced Documents
2
2.1 ASTM Standards:
B476 Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials
3. Ordering Information
3.1 Refer to Specification B476.
4. Materials and Manufacture
4.1 Raw materials shall be of such quality and purity that the finished product will have the properties and characteristics
prescribed in this specification.
4.2 The material shall be finished by such operations (cold working, heat-treating, annealing, turning, grinding, or pickling) as
are required to produce the prescribed properties.
5. Chemical Composition
5.1 Material produced under this specification shall conform to the chemical composition limits prescribed in Table 1.
5.2 These specification limits do not preclude the possible presence of other unnamed elements, impurities, or additives.
Analysis shall be regularly made only for the minor elements listed in the table. However, if a user knows of elements that might
be detrimental to their application or has other reasons for requiring analysis for specific elements, then agreement between
manufacturer and purchaser for both limits and methods of analysis should be required for elements not specified.
6. Mechanical Properties
6.1 The material shall conform to the applicable mechanical properties prescribed in Table 2 or Table 3.
6.2 All test specimens shall be the full thickness or diameter as the size supplied when practical. The test procedures shall follow
the ASTM specifications referred to in Specification B476.
1
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 Oct. 1, 2010May 1, 2016. Published October 2010May 2016. Originally approved in 1987. Last previous edition approved in 20042010 as
B780 – 98 (2004).(2010). DOI: 10.1520/B0780-98R10.10.1520/B0780-16.
2
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’sstandard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
B780 − 16
TABLE 1 Chemical Composition
NOTE 1—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 is not in excess of the total impurities limit.
NOTE 2—Refer to 5.2.
Element Weight,%
Silver 74.0–76.0
Copper (23.5 min) report by difference
Nickel 0.35–0.65
Impurities
Zinc 0.06 max
Iron 0.05 max
Cadmium 0.05 max
Cadmium 0.01 max
Lead 0.03 max
Total of all impurities 0.15 max
TABLE 2 Mechanical Properties of Wire and Rod
%
Tensile Strength
Area Elonga-
Temper
...