ASTM B702-93 (2024) PDF

Full title and description

ASTM B702-93 (reapproved 2024) — Standard Specification for Copper‑Tungsten Electrical Contact Material. This concise specification defines requirements for copper‑tungsten (W‑Cu) electrical contact components produced by powder‑metallurgical procedures, including composition ranges, physical properties, and manufacturing/finish considerations appropriate for electrical switching and contact applications.

Abstract

Short specification covering electrical contact components made from copper‑tungsten produced by powder metallurgy. The standard describes the system compositions normally specified by users, notes that values are stated in inch‑pound units, and reminds users to consider safety data sheets and applicable regulatory limits when using the material. Qualification testing of production parts is recommended where practical.

General information

• Status: Active / reapproved (reapproval cycle shown as 2024).
• Publication date: Original designation 1993; reapproved/reaffirmed 2024 (designation shown as B702‑93(2024)).
• Publisher: ASTM International.
• ICS / categories: 77.150.30 (Copper products / nonferrous metal contact materials).
• Edition / version: ASTM B702: 93(2024) — original 1993 edition with periodic reapproval entries (referenced as current/active).
• Number of pages: Short specification — typically 3 pages.

Scope

This specification covers electrical contact components made from copper‑tungsten produced by powder‑metallurgical procedures and compositions within the copper‑tungsten system normally specified by contact users. The standard states that values are given in inch‑pound units and emphasizes the user's responsibility to follow safety data sheets and regulatory requirements; qualification testing on production parts is recommended where applicable.

Key topics and requirements

• Material system: copper‑tungsten (WCu) contact materials manufactured via powder metallurgy (sintering, infiltration or related processes).
• Composition classes and typical grades (e.g., WCu variants such as 50/50, 60/40 and other user‑specified ratios); compositions are agreed between manufacturer and user.
• Physical properties and acceptance testing: density, conductivity, hardness and other production qualification tests to be agreed or performed on production parts as appropriate.
• Units and presentation: inch‑pound units are the standard for the document; metric conversions are not included in the specification text.
• Finish and fabrication notes: typical finishing, brazing/backing or surface treatment considerations when preparing contacts for end use.
• Safety and regulatory reminder: the standard does not exhaustively address safety hazards—users must consult SDS/MSDS and applicable regulations before use.

Typical use and users

Primary users are contact manufacturers, switch and relay OEMs, electrical engineers and procurement/specification teams who design or produce separable and fixed electrical contacts for power switching, circuit‑breaking, grounding switches, relays and other devices requiring arc‑resistant contact materials. Typical applications include high‑current switching, power distribution equipment, and specialized electrodes where a balance of conductivity and arc‑resistance is required.

Related standards

Standards on related contact materials and test methods developed by the same ASTM subcommittee include (selection): ASTM B631 (Silver‑Tungsten electrical contact materials), ASTM B663 (Silver‑Tungsten Carbide contact materials), and other contact/material specifications and test methods published under Subcommittee B02.05. Users frequently cross‑reference these and other ASTM contact‑material standards and relevant test methods when specifying or testing contact parts.

Keywords

copper‑tungsten; WCu; electrical contact material; powder metallurgy; contact contacts; arc erosion; conductivity; density; WCu50/50; contact alloys; ASTM B702.

FAQ

Q: What is this standard?

A: ASTM B702-93(2024) is a short ASTM specification that defines requirements for copper‑tungsten electrical contact materials produced by powder‑metallurgical methods. It provides composition, testing and user/producer agreement guidance for contact components.

Q: What does it cover?

A: It covers copper‑tungsten contact components (composition ranges in the W‑Cu system), recommended qualification/testing practices for production parts where practical, units (inch‑pound), and safety/regulatory reminders; specific mechanical/property limits and finishing requirements are agreed between manufacturer and user per the specification.

Q: Who typically uses it?

A: Contact manufacturers, power‑switch and relay OEMs, electrical designers, procurement/specification engineers, and test laboratories involved in production or qualification of electrical contacts.

Q: Is it current or superseded?

A: The document is shown as the 1993 original edition with periodic reapproval and is listed as reapproved/active in 2024 (designation shown as B702‑93(2024)). Users should confirm the current status and any available editorial reapprovals or revisions with ASTM International prior to purchase or citation.

Q: Is it part of a series?

A: It is part of the ASTM volume covering nonferrous metals and electrical contact materials maintained by subcommittee B02.05; related contact‑material specifications (silver‑tungsten, silver‑tungsten carbide, graphite sliding contacts, etc.) are published under the same committee and commonly cross‑referenced.

Q: What are the key keywords?

A: copper‑tungsten, WCu, electrical contact, powder metallurgy, contact material, arc erosion, conductivity, ASTM B702.