ASTM B576-94(2021)

Standard Guide for Arc Erosion Testing of Electrical Contact Materials

SIGNIFICANCE AND USE
2.1 The significance of the variables set forth in this guide was proved by various laboratories using several test systems at test currents ranging from 100 to 35 000 A. These variables will be significant for any case where voltage and current are sufficient to produce arcing.
SCOPE
1.1 This guide covers the major variables which affect the rate of arc erosion of electrical contact materials and serves as a guide in developing more detailed specifications for arc-erosion tests.  
1.2 Arc erosion testing involves some vaporization of material. It is the responsibility of the user to become familiar with all hazards including those identified in the appropriate Material Safety Data Sheet for the material being tested.  
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-Oct-2021
• ICS: 29.050 - Superconductivity and conducting materials
• Technical Committee: B02 - Nonferrous Metals and Alloys
• Drafting Committee: B02.05 - Precious Metals and Electrical Contact Materials and Test Methods

Overview

ASTM B576-94(2021) - Standard Guide for Arc Erosion Testing of Electrical Contact Materials is an internationally recognized standard developed by ASTM International. This guide addresses the major variables that influence the rate of arc erosion in electrical contact materials and aids in formulating comprehensive specifications for arc-erosion testing. Arc erosion occurs in electrical contacts exposed to currents and voltages high enough to generate an arc, resulting in material vaporization and gradual degradation of contact surfaces. The standard provides a systematic approach for conducting arc erosion tests to ensure consistency, reproducibility, and safety in testing processes across laboratories and industries.

Key Topics

ASTM B576-94(2021) highlights several critical aspects influencing arc erosion of electrical contact materials. The principal topics covered include:

• Material Properties and Geometry

  • Contact area, shape (e.g., hemispherical crowns), and thickness all affect erosion rates.
  • Surface roughness and the method of mounting contacts are important test variables.

• Operational Variables

  • Contact velocity, arc length, and orientation in relation to gravity can impact erosion.
  • Temperature of the contacts before arcing and environmental conditions (such as the type, pressure, and humidity of gases or oils) influence results.

• Arcing Parameters

  • Magnitude and waveform of arc current, as well as arcing duration, must be specified to ensure relevant and consistent outcomes.
  • Total number of arcs and the duration of testing are crucial for evaluating long-term performance of contact materials.

• Mechanical Actions

  • Closing force, speed, and the presence of bounce (repeated impacting of contacts) can affect the severity of erosion.
  • Opening speed and force determine damage caused by opening arcs.

• Electrical Conditions

  • The motion of the arc, induced by external factors like magnetic fields, should be considered.
  • Polarity of the current-whether constant or alternating-can lead to different erosion behaviors.

• Health, Safety, and Environmental Considerations

  • Users must review and follow safety data sheets for tested materials.
  • The guide emphasizes the establishment of proper safety practices and adherence to legal and environmental requirements.

Applications

Arc erosion testing as outlined in ASTM B576-94(2021) is fundamental for:

• Electrical Component Development

  • Used by manufacturers of circuit breakers, relays, and switchgear to select and qualify materials for electrical contacts subject to arcing conditions.

• Material Research and Quality Assurance

  • Laboratories and research institutions rely on this standard to benchmark the arc erosion resistance of new alloys or coatings intended for electrical applications.

• Safety and Reliability Engineering

  • Power utilities and industrial facilities employ arc erosion testing to ensure equipment longevity and reduce maintenance caused by contact wear.

• Compliance and Product Certification

  • Adhering to ASTM B576-94(2021) assures that products meet international expectations for durability and performance under arc exposure.

Related Standards

For comprehensive arc erosion testing and electrical contact evaluation, the following related standards may also be relevant:

• ASTM B541 - Standard Test Method for Determining the Mechanical Properties of Electrical Contact Materials.
• ASTM B498 - Standard Specification for Electrical Contact Alloys.
• IEC 60512 - Connectors for Electronic Equipment - Tests and Measurements, including arcing and contact resistance.
• ASTM B788 - Standard Guide for Testing Thermal Stability of Electrical Contact Materials.

Keywords: ASTM B576, arc erosion, electrical contact materials, arc erosion testing, electrical contacts, erosion rate, electrical testing standards, material degradation, safety guidelines, contact materials evaluation.

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: B576 − 94 (Reapproved 2021)
Standard Guide for
Arc Erosion Testing of Electrical Contact Materials
This standard is issued under the fixed designation B576; 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.
1. Scope the manner in which the arc moves about on the surface of the
contact. A contact with a hemispherical crown presents no
1.1 This guide covers the major variables which affect the
sharp edges that would result in different amounts of erosion
rate of arc erosion of electrical contact materials and serves as
products for a given amount of arcing and aids in the control of
a guide in developing more detailed specifications for arc-
the arc when operating in air and other gases.
erosion tests.
3.1.2 The contacts may be given a type of normal shape and
1.2 Arc erosion testing involves some vaporization of ma-
surface roughness by a number of arcing operations prior to
terial. It is the responsibility of the user to become familiar
recording the contact loss. There may be a difference in the
with all hazards including those identified in the appropriate
effect of shape and diameter for different environments.
Material Safety Data Sheet for the material being tested.
3.1.3 Contact mounting, attachment, and bond integrity can
1.3 This standard does not purport to address all of the
affect the arc erosion of materials and should be specified.
safety concerns, if any, associated with its use. It is the
3.2 Contact Velocity and Maximum Arc Length—The veloc-
responsibility of the user of this standard to become familiar
ity of separation and the maximum arc length affect the erosion
with all hazards including those identified in the appropriate
rate and, therefore, should be specified in formulating a test.
Safety Data Sheet (SDS) for this product/material as provided
3.3 Contact Orientation:
by the manufacturer, to establish appropriate safety, health,
3.3.1 The orientation of the contacts with respect to the
and environmental practices, and determine the applicability
earth’s gravitational field may affect the erosion rate and,
of regulatory limitations prior to use.
therefore, should be specified. For example, the mating planes
1.4 This international standard was developed in accor-
of the contacts might be vertical or horizontal.
dance with internationally recognized principles on standard-
3.3.2 If the contact’s mating planes are horizontal and a
ization established in the Decision on Principles for the
direct test current is used, the specifications should state
Development of International Standards, Guides and Recom-
whether the anode or cathode is in the upper position.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
3.4 Environment:
3.4.1 The type, pressure, temperature, and humidity of the
2. Significance and Use
gas atmosphere or the type, pressure, and temperature of the
2.1 The significance of the variables set forth in this guide
surrounding oil, affect the erosion rate and should be specified.
was proved by various laboratories using several test systems
3.4.2 The erosion rate in air may be quite different than that
at test currents ranging from 100 to 35 000A. These variables
under oil.
will be significant for any case where voltage and current are
3.5 Arcing Current:
sufficient to produce arcing.
3.5.1 An increase in arc current will cause an increase in the
arc-erosion rate per coulomb of arcing, and thus it must be
3. Major Variables
specified.
3.1 Shape, Area, and Thickness:
3.5.2 It follows then that the wave form of the arc current is
3.1.1 The area, shape, and thickness of the contact affect the
important and source voltage and load current should be
erosion rates. As an example of shape effects, the radius of t
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