ASTM B344-20 (2025) PDF

Full title and description

Standard Specification for Drawn or Rolled Nickel-Chromium and Nickel-Chromium-Iron Alloys for Electrical Heating Elements — designation ASTM B344-20 (reapproved/updated 2025). The standard specifies composition, form (drawn or rolled), and basic properties for nickel-chromium and nickel-chromium-iron alloys used as electrical heating-element materials.

Abstract

This standard defines the nominal alloy compositions and product forms (annealed, drawn, or rolled shapes) intended for electrical resistance heating applications, and references test methods and acceptance criteria relevant to resistivity, oxidation resistance, and chemical analysis. It consolidates prior editions and reapproval information into the B344-20 designation with a 2025 reapproval/update.

General information

• Status: Active / current (B344-20 with 2025 reapproval/update).
• Publication date: July 1, 2025 (reapproval/updated information listed July 2025).
• Publisher: ASTM International.
• ICS / categories: 77.150.40 (Nickel and chromium products).
• Edition / version: B344-20 (original 2020 edition; reapproved/updated 2025 — sometimes shown as B344-20R25).
• Number of pages: 4.

(Publication date, page count, designation and publisher details as recorded in ASTM's and recognised standards catalogues.)

Scope

This specification covers annealed, drawn, or rolled shapes intended for electrical heating purposes made from nickel-chromium and nickel-chromium-iron alloys. It lists nominal compositions (for example 80Ni–20Cr; 60Ni–16Cr–remainder Fe; 38Ni–21Cr–remainder Fe; 35Ni–20Cr–remainder Fe), establishes required material characteristics (chemical composition limits, basic mechanical and electrical characteristics), and references test methods for resistivity, change of resistance with temperature, and oxidation/accelerated-life evaluations.

Key topics and requirements

• Specified nominal alloy compositions for common heating-resistance grades (80/20 NiCr, 60/16 NiCrFe, 38/21 NiCrFe, 35/20 NiCrFe).
• Permitted product forms: annealed, drawn wire and rolled strip/flat wire suitable for heating elements and resistance applications.
• Basic mechanical criteria (elongation limits by gauge/size) and dimensional acceptability for routine acceptance.
• Nominal resistivity and reference conditions for measuring resistivity (quenched or specified thermal history where applicable).
• Referenced test methods for electrical and life/oxidation performance (e.g., tests for resistivity and change of resistance with temperature, accelerated life/oxidation tests) and chemical analysis practices for acceptance and verification.

Typical use and users

Used by manufacturers and suppliers of heating-element wire and strip, designers and fabricators of industrial and domestic electric heating equipment, materials engineers, procurement/specification writers, and testing laboratories that verify composition and electrical properties of resistance alloys.

Related standards

References and related documents commonly cited with B344 include ASTM test methods and practices such as B63 (resistivity of metallically conducting resistance and contact materials), B70 (change of resistance with temperature), B76 (accelerated life / oxidation resistance testing for NiCr and NiCrFe heating alloys), and chemical analysis practices such as A751. Earlier editions/revisions of B344 (for example B344-14, B344-11) are also related historical documents.

Keywords

nickel-chromium, NiCr, nickel-chromium-iron, NiCrFe, heating element, resistance alloy, flat wire, drawn wire, rolled strip, electrical heating, resistivity.

FAQ

Q: What is this standard?

A: ASTM B344-20 (reapproved/updated 2025) is a specification that defines compositions, product forms, and basic property/acceptance guidance for drawn or rolled nickel-chromium and nickel-chromium-iron alloys used as electrical heating elements.

Q: What does it cover?

A: It covers annealed, drawn, or rolled shapes for electrical heating purposes and lists nominal alloy compositions, dimensional/product form requirements, and references to relevant test methods for electrical and oxidation performance.

Q: Who typically uses it?

A: Manufacturers and suppliers of heating-element materials, equipment designers and fabricators using resistance alloys, materials engineers, testing labs, and procurement/specification teams.

Q: Is it current or superseded?

A: The B344-20 designation is current and has a 2025 reapproval/update (commonly cited as B344-20R25); earlier editions such as B344-14 and B344-11 are superseded by the 20-series edition and its 2025 reapproval/update.

Q: Is it part of a series?

A: It is part of ASTM Committee B02's portfolio on nonferrous metals and alloys (subcommittee B02.10 for thermostat metals and electrical resistance heating materials) and is used alongside related ASTM test methods for resistivity, temperature-coefficient characterization, and life/oxidation testing.

Q: What are the key keywords?

A: nickel-chromium, NiCr, nickel-chromium-iron, NiCrFe, heating element, resistance alloy, flat wire, drawn wire, rolled strip, resistivity.