ASTM B780-16(2021)

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, 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-2021
• 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 B476-01(2012) - Standard Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials
• Effective Date: 01-May-2012
• Refers: ASTM B476-01(2006) - Standard Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials
• Effective Date: 01-Jun-2006
• Refers: ASTM B476-01 - Standard Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials
• Effective Date: 10-May-2001

Overview

ASTM B780-16(2021) specifies the requirements for an electrical contact alloy composed of 75% silver, 24.5% copper, and 0.5% nickel. This standard covers the manufacture and quality of rods, wires, strips, and sheets used for electrical contacts. Developed by ASTM International, it ensures consistent chemical composition, mechanical properties, and product performance for critical applications where electrical conductivity and durability are essential.

This document is widely recognized and used by manufacturers and engineers to guarantee that silver-copper-nickel alloy electrical contact materials meet international quality and safety standards.

Key Topics

• Material Composition:

  • Silver: 74.0–76.0%
  • Copper: 23.5% minimum (balance by difference)
  • Nickel: 0.35–0.65%
  • Strict limits on impurities: zinc, iron, cadmium, and lead
  • Total impurities not to exceed specified levels

• Product Forms:

  • Rods
  • Wires
  • Strips
  • Sheets

• Manufacturing Processes:

  • Cold working
  • Heat treating
  • Annealing
  • Turning, grinding, or pickling as needed to achieve required properties

• Mechanical Properties:

  • Mechanical tests at room temperature (68°F / 20°C)
  • Evaluation includes tensile strength, elongation, hardness, and reduction in area or thickness
  • Requirements tailored for various product forms and tempers

• Quality Assurance:

  • Regular chemical analysis for major and minor elements
  • Additional impurity analysis as needed
  • Compliance with referenced general requirements in ASTM B476
  • Mandatory inspection and certification

• Safety and Compliance:

  • Users must address all safety, health, and regulatory considerations, consulting manufacturer-provided Safety Data Sheets (SDS)
  • Aligns with internationally recognized standardization principles (WTO TBT Committee)

Applications

ASTM B780-16(2021) silver-copper-nickel alloy is crucial in fields requiring highly conductive and corrosion-resistant electrical contact materials. Common areas of application include:

• Electrical Switchgear:
  Used in arcing contacts and various switching components where high durability and consistent conductivity are vital.

• Relays and Connectors:
  Ensures reliable electrical performance and longevity in industrial, automotive, and telecommunication systems.

• Semiconductor and Circuit Breaker Contacts:
  Provides the necessary mechanical strength and electrical properties for precision electronic components.

• High-Reliability Assemblies:
  Employed in aerospace, defense, and critical control systems, where adherence to stringent material standards is mandatory.

By complying with ASTM B780, manufacturers and engineers can assure optimal electrical conductivity, wear resistance, and long service life in demanding electrical applications.

Related Standards

• ASTM B476: Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials. Provides the baseline requirements referenced within ASTM B780 for material inspection, testing, and supply.

• Other Relevant ASTM Standards:

  • Standards related to electrical contact materials
  • Specifications on testing methods for mechanical properties and composition analysis

• International Harmonization:
  ASTM B780 is developed in accordance with the WTO Technical Barriers to Trade (TBT) Committee’s principles, facilitating international trade and regulatory compliance.

For producers and users of electrical contact materials, familiarity with ASTM B780 and related standards ensures product quality, safety, and worldwide market acceptance.

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:B780 −16 (Reapproved 2021)
Standard Specification for
75% Silver, 24.5% Copper, 0.5% Nickel Electrical Contact
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. Materials and Manufacture
1.1 This specification covers an electrical contact material 4.1 Raw materials shall be of such quality and purity that
with the nominal composition of 75% silver, 24.5% copper, thefinishedproductwillhavethepropertiesandcharacteristics
and 0.5% nickel in the form of rod, wire, strip, and sheet. prescribed in this specification.
1.2 Thevaluesstatedininch-poundunitsaretoberegarded 4.2 The material shall be finished by such operations (cold
as standard. The values given in parentheses are mathematical working, heat-treating, annealing, turning, grinding, or pick-
conversions to SI units that are provided for information only ling) as are required to produce the prescribed properties.
and are not considered standard.
5. Chemical Composition
1.3 This standard does not purport to address all of the
5.1 Materialproducedunderthisspecificationshallconform
safety concerns, if any, associated with its use. It is the
to the chemical composition limits prescribed in Table 1.
responsibility of the user of this standard to become familiar
with all hazards including those identified in the appropriate
5.2 These specification limits do not preclude the possible
Safety Data Sheet (SDS) for this product/material as provided
presence of other unnamed elements, impurities, or additives.
by the manufacturer, to establish appropriate safety, health,
Analysis shall be regularly made only for the minor elements
and environmental practices, and determine the applicability listed in the table. However, if a user knows of elements that
of regulatory limitations prior to use.
might be detrimental to their application or has other reasons
1.4 This international standard was developed in accor- for requiring analysis for specific elements, then agreement
dance with internationally recognized principles on standard-
between manufacturer and purchaser for both limits and
ization established in the Decision on Principles for the
methods of analysis should be required for elements not
Development of International Standards, Guides and Recom-
specified.
mendations issued by the World Trade Organization Technical
6. Mechanical Properties
Barriers to Trade (TBT) Committee.
6.1 Thematerialshallconformtotheapplicablemechanical
2. Referenced Documents
properties prescribed in Table 2 or Table 3.
2.1 ASTM Standards:
6.2 Alltestspecimensshallbethefullthicknessordiameter
B476Specification for General Requirements for Wrought
as the size supplied when practical. The test procedures shall
Precious Metal Electrical Contact Materials
follow the ASTM specifications referred to in Specification
B476.
3. Ordering Information
6.3 Alltestsaretobeconductedatroomtemperature,about
3.1 Refer to Specification B476.
68°F (20°C).
7. Inspection, Rejection and Rehearing, Certification,
This specification is under the jurisdiction of ASTM Committee B02 on
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee Product Marking, and Supplementary Requirements
B02.05 on Precious Metals and Electrical Contact Materials.
7.1 Material furnished to this specification shall meet the
Current edition approved April 1, 2021. Published April 2021. Originally
approved in 1987. Last previous edition approved in 2016 as B780–16. DOI: requirements listed in Sp
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