ASTM F73-96 (2025) PDF

Full title and description

ASTM F73-96 — Standard Specification for Tungsten‑Rhenium Alloy Wire for Electron Devices and Lamps. This designation covers UNS R07031 tungsten‑rhenium alloy wire intended for use in electron tubes, lamp filaments, and related electronic components; it specifies chemical composition, finishes, mechanical properties and test methods for wire 0.020 in. (0.51 mm) diameter or smaller.

Abstract

This specification defines the required chemical composition (tungsten with approximately 2.5–3.5 % rhenium, limits on other impurities), allowable finishes, tensile and ductility requirements, dimensional tolerances for wire ≤0.020 in. (0.51 mm) diameter, and the test methods used to verify conformance (chemical analysis, tensile testing, ductility, visual inspection and dimensional measurement). The wire is identified by UNS R07031.

General information

• Status: Active / maintained by ASTM F01 (listed as F73‑96(2025) on the ASTM committee reapproval schedule — reapproval activity noted).
• Publication date: Original approval June 10, 1996 (designation F73‑96). Reapproval activity recorded in subsequent years (R2013, R2017) and shown on committee listings for 2025.
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: 29.060.10 — Wires / Electronics materials.
• Edition / version: Designation F73‑96 (with recorded reapprovals such as R2013 and R2017, and committee listing referencing (2025)).
• Number of pages: Short specification — typically published as a 3‑page ASTM specification.

Scope

The standard applies to tungsten‑rhenium alloy wire (UNS R07031) intended for use in electron devices and lamps where small‑diameter spooled or coiled wire (0.020 in. / 0.51 mm diameter or less) is required. It prescribes chemical composition limits, permitted finishes, mechanical property ranges (tensile strength and ductility), and required tests to demonstrate conformity. The standard clarifies units (inch‑pound as primary) and notes safety/user responsibility for application‑specific concerns.

Key topics and requirements

• Chemical composition: tungsten remainder with rhenium typically about 2.5–3.5 %; strict ppm limits on other elements and total impurities.
• Identification: material identified as UNS R07031 (tungsten‑rhenium alloy).
• Size and form: applies to wire ≤0.020 in. (0.51 mm) diameter presented spooled or coiled.
• Mechanical properties: tensile strength and ductility requirements given by weight/length tables (see tensile property tables for specific limits by wire weight).
• Finishes: multiple finishes defined (Finish 1 through Finish 5) with corresponding application/handling guidance.
• Required tests: chemical analysis, tensile testing, ductility measurements, visual surface inspection and dimensional checks.
• Surface quality: specifies acceptable surface condition (free of twists, bumps, pits, cracks, laps and similar defects as commercial practice allows).

Typical use and users

Manufacturers and suppliers of electron tubes, specialty lamps and filaments, vacuum tube OEMs, materials engineers and metallurgists specifying small‑diameter high‑temperature alloy wire, and quality/control laboratories performing acceptance testing all commonly use this specification. It is referenced by procurement, inspection, and product engineering teams when tungsten‑rhenium wire is required.

Related standards

Standards for related materials and test methods under the same ASTM committee include other tungsten and molybdenum wire/rod specifications and test methods (for example: ASTM F288 for tungsten wire for electron devices and lamps, ASTM F289 for molybdenum wire, and related sag and surface‑flaw test methods). Committee F01 listings show coordinated reapprovals and related documents.

Keywords

tungsten‑rhenium, WRe, UNS R07031, filament wire, electron devices, lamp wire, alloy wire, wire finishes, tensile strength, ductility, small‑diameter wire.

FAQ

Q: What is this standard?

A: ASTM F73‑96 is the ASTM specification that defines chemical, mechanical and quality requirements for tungsten‑rhenium alloy wire (UNS R07031) used in electron devices and lamps.

Q: What does it cover?

A: It covers wire 0.020 in. (0.51 mm) diameter or less, specifying composition (notably ~2.5–3.5 % Re), finishes, tensile and ductility limits, and required tests such as chemical analysis, tensile testing, ductility, visual inspection and dimensional checks.

Q: Who typically uses it?

A: OEMs of electron tubes and specialty lamps, materials suppliers, procurement and inspection teams, and metallurgical laboratories use this specification for purchase, qualification and acceptance of tungsten‑rhenium wire.

Q: Is it current or superseded?

A: The original designation is F73‑96 (issued 1996). The specification has been subject to reapproval cycles (records show reapprovals such as R2013 and R2017) and appears on committee listings with a (2025) entry indicating reapproval/maintenance activity; always check ASTM International for the official latest status and edition.

Q: Is it part of a series?

A: Yes — it sits within ASTM Committee F01 (Electronics) material specifications and is related to other wire and wire‑test standards (for tungsten and molybdenum) that cover similar applications and test methods.

Q: What are the key keywords?

A: Tungsten‑rhenium, UNS R07031, WRe, electron devices, lamp wire, filament, alloy wire, finishes, tensile, ductility.