ASTM B476-21 - 1.11.2021
 
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.

Property

Unit

Rounded Unit
for Observed or
Calculated Value

Chemical composition

percent

?

Hardness
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

Resistivity

???cm

?

Tensile strength

psi (MPa)

nearest 1000 psi (nearest 10
MPa)

Yield Strength

psi (MPa)

nearest 1000 psi (nearest
10 MPa)

Elongation

?

?

Below 5 %

percent

nearest multiple of 0.5 %

5 % and over

percent

nearest 1 %

Grain size

?

?

Up to 0.055 mm incl.

mm

nearest multiple of 0.005
mm

Over 0.055 to 0.160, mm, incl.

mm

nearest 0.01 mm

 
1. Scope

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, health, and environmental 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.

 
2. Referenced Documents

B772-97

Standard Guide for Specifying the Chemical Compositions for Electrical Contact Materials (Arcing and Nonarcing)

E3-11(2017)

Standard Guide for Preparation of Metallographic Specimens

E8-04

Standard Test Methods for Tension Testing of Metallic Materials

B63-07(2018)

Standard Test Method for Resistivity of Metallically Conducting Resistance and Contact Materials

E29-22

Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications

E55-23

Standard Practice for Sampling Wrought Nonferrous Metals and Alloys for Determination of Chemical Composition

E112-13(2021)

Standard Test Methods for Determining Average Grain Size

E384-22

Standard Test Method for Microindentation Hardness of Materials