Standard Historical Last Updated: Dec 02, 2021
ASTM B476-01(2017)

Standard Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials

Significance and Use

11.1 For purpose of determining compliance with the specified limits for requirements of the properties listed in the following table, an observed value or a calculated value shall be rounded as indicated in accordance with Practice E29.



Rounded Unit
for Observed or
Calculated Value

Chemical composition



Knoop (100-g load unless other-
  wise specified)
Vicker (specify load)
Rockwell (all scales, specify which)
Rockwell superficial (all scales,
  specify which)


nearest unit on the last right
 hand place of figure of
 specified limit




 Tensile strength

 psi (MPa)

nearest 1000 psi (nearest 10

 Yield Strength

 psi (MPa)

nearest 1000 psi (nearest
 10 MPa)




 Below 5 %


nearest multiple of 0.5 %

 5 % and over


nearest 1 %

Grain size



 Up to 0.055 mm  incl.


nearest multiple of  0.005

 Over 0.055 to 0.160, mm, incl.


nearest 0.01 mm


This specification covers general requirements common to wrought precious metal electrical contact alloy products in the form of sheet, strip, wire, and rod. The raw material shall be of such quality and purity that the finished product shall have the properties and characteristics prescribed in the applicable product specification. The product shall be produced by a combination of hot or cold working operations, it shall be finished, unless otherwise specified, by cold working, annealing, or heat treatment as may be necessary to meet the specified properties. Surfaces of all material furnished to this specification shall be smooth, clean, and free from scratches, stains, rough spots, slivers, laps, scale, pits, and any other injurious defects. Test methods such as chemical analysis and physical tests shall be performed accordingly.


1.1 This specification covers general requirements common to wrought precious metal electrical contact alloy products in the form of sheet, strip, wire, and rod. Unless otherwise specified in the purchase order or in an individual specification, these general requirements shall apply to wrought electrical contact materials where indicated in the applicable product specifications issued by ASTM.

1.2 In case of conflict, the requirements on the purchase order, the individual specification, and this general specification shall prevail in the sequence named.

1.3 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.

1.4 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 and health 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.

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Book of Standards Volume: 02.04
Developed by Subcommittee: B02.05
Pages: 4
DOI: 10.1520/B0476-01R17
ICS Code: 77.120.99