ASTM B392-18 PDF

Full title and description

ASTM B392-18 — Standard Specification for Niobium and Niobium Alloy Bar, Rod, and Wire. This specification defines four wrought grades of niobium and niobium‑zirconium alloy in bar, rod and wire forms, with chemical and mechanical property limits, temper designations, sampling, inspection and marking requirements for commercial and reactor grades.

Abstract

ASTM B392-18 specifies requirements for four grades of wrought niobium and niobium‑zirconium alloy finished as bar, rod, and wire: R04200 (Type 1, reactor grade unalloyed niobium), R04210 (Type 2, commercial grade unalloyed niobium), R04251 (Type 3, reactor grade niobium with 1% Zr) and R04261 (Type 4, commercial grade niobium with 1% Zr). The standard covers chemical composition limits, mechanical property requirements (hardness, tensile, yield, elongation), temper designations, optional additional chemical requirements, and provisions for sampling, inspection and documentation.

General information

• Status: Active (current edition B392‑18).
• Publication date: Approved April 1, 2018; published 2018 (B392‑18).
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: Reactive and refractory / non‑ferrous metals classifications (examples reported: ICS 77.150.99; related wire category 29.060.10).
• Edition / version: B392‑18 (current edition approved April 1, 2018).
• Number of pages: 4 pages (short specification).

Scope

This specification applies to wrought niobium and niobium‑zirconium alloy in bar, rod and wire forms in four designated types: R04200 (reactor grade unalloyed niobium), R04210 (commercial grade unalloyed niobium), R04251 (reactor grade niobium with ~1% Zr), and R04261 (commercial grade niobium with ~1% Zr). Units are inch‑pound as standard with SI conversions informational only. The standard includes purchaser‑specified optional requirements for additional chemical limits and finished‑product conditions, and notes the user’s responsibility for safety and regulatory compliance.

Key topics and requirements

• Chemical composition limits for each grade (including optional additional chemical requirements when specified by purchaser).
• Mechanical property limits: tensile strength, yield (0.2% offset), elongation, and Brinell hardness criteria.
• Temper and condition designations for wrought products and permissible dimensional/finish variations.
• Sampling, testing, inspection and reporting requirements, including rounding rules per Practice E29 for reported values.
• Optional purchaser‑specified tests and supplementary requirements (e.g., additional chemical or heat‑treatment requirements).

Typical use and users

Used by niobium producers, metallurgical fabricators, wire and bar manufacturers, suppliers and purchasing engineers specifying raw material for nuclear, vacuum, superconducting and high‑purity applications. Typical users include quality and materials engineers, procurement teams, and designers in aerospace, power generation, research laboratories and other industries that require reactor‑grade or high‑purity niobium forms.

Related standards

ASTM standards related to niobium and niobium alloys include ASTM B391 (ingots), ASTM B393 (strip, sheet and plate), ASTM B394 (seamless and welded tubes), and other B‑series documents covering processing and product forms for niobium and niobium‑hafnium alloys. These companion specifications define material requirements for other product forms and upstream ingots.

Keywords

niobium, columbium, niobium alloy, niobium‑zirconium, bar, rod, wire, reactor grade, commercial grade, R04200, R04210, R04251, R04261, mechanical properties, chemical composition.

FAQ

Q: What is this standard?

A: ASTM B392‑18 is the ASTM International specification that defines chemical and mechanical requirements, temper designations and inspection/sampling provisions for wrought niobium and niobium‑zirconium alloy bar, rod, and wire in four designated types.

Q: What does it cover?

A: It covers four grades/types of niobium/niobium‑Zr alloy in bar, rod and wire form, giving composition limits, tensile/yield/elongation/brinell hardness requirements, permissible variations, sampling, inspection and reporting requirements; purchasers may specify additional optional requirements.

Q: Who typically uses it?

A: Material suppliers, mills and wire manufacturers, procurement and quality engineers, designers and specifiers in aerospace, nuclear/reactor applications, research institutions and any buyer or fabricator needing certified niobium bar/rod/wire.

Q: Is it current or superseded?

A: The B392‑18 edition (approved April 1, 2018) is the current published edition. A revision work item (WK95489) to review/revise B392‑18 has been recorded (work item initiated June 26, 2025), indicating committee activity toward a future revision, but B392‑18 remains the active edition until officially superseded.

Q: Is it part of a series?

A: Yes — it is one of several ASTM B‑series specifications addressing niobium products (for example, B391 for ingots, B393 for strip/sheet/plate, B394 for tubes), produced under Committee B10 (Reactive and Refractory Metals and Alloys) and subcommittee B10.03.

Q: What are the key keywords?

A: Niobium, columbium, niobium alloy, niobium‑zirconium, bar, rod, wire, reactor grade, commercial grade, mechanical properties, chemical composition.