SIST EN 2221:2018

Overview

EN 2221:2017 (published by CEN / ASD‑STAN) is a European aerospace material standard that specifies requirements for Steel FE‑PL31 hollow bars, intended for aerospace use. The standard covers hollow bar forms with wall dimension a in the range 3.5 mm ≤ a ≤ 55 mm, produced by air melting and supplied in defined delivery and heat‑treatment conditions. EN 2221 sets chemical composition limits, production form, heat‑treatment references, microstructure expectations and inspection/qualification arrangements for reliable use in aerospace components.

Key topics and technical requirements

• Material designation: Steel FE‑PL31 (a high‑carbon, chromium‑bearing steel formulated for hardened & tempered conditions).
• Chemical composition (typical limits in the standard):
  • C: 0.95 – 1.10 %
  • Si: 0.15 – 0.35 %
  • Mn: 0.25 – 0.45 %
  • P: ≤ 0.030 %
  • S: ≤ 0.020 %
  • Cr: 1.35 – 1.65 %
  • Ni: ≤ 0.40 %
    (Full composition and tolerances are given in EN 2221.)
• Melting and form: Air melted; product form specified as hollow bars.
• Dimensional range: Applicable for hollow bars where wall dimension a satisfies 3.5 mm to 55 mm.
• Heat treatment / delivery conditions:
  • Options include spheroidised, cold‑rolled, hardened & tempered, or softened states as specified.
  • Reference heat treatment: austenitise around 830 °C (±10 °C) followed by oil quench (OQ) and tempering in the range 150–190 °C (reference temper ~180 °C ±5 °C).
• Microstructure: Carbides shall be fine and non‑aligned, supporting fatigue and bearing performance.
• Inspection & qualification:
  • Marking and dimensional inspection required.
  • Product qualification program is agreed between manufacturer and purchaser.
  • Mechanical and other tests are referenced within the standard (see EN 2221 for details).
• Typical use: Bearings and other aerospace components requiring hardened, wear‑resistant hollow bar sections.

Applications and users

• Primary users: aerospace manufacturers, parts suppliers, metallurgists, procurement and quality engineers working on structural and rotating components.
• Typical applications: bearing race blanks, bushings, sleeves, and other hollow components where high hardness, controlled microstructure and dimensional accuracy are required.
• Benefits: Ensures material consistency, repeatable heat treatment and traceability for safety‑critical aerospace parts.

Related standards

• EN 4258 - organization of aerospace metallic material standards
• EN 4500‑005 - rules for drafting/presentation of steel material standards
• EN 4700‑002 - technical specification for steel bars and sections

For specification, procurement or design use, consult the full EN 2221:2017 text to access exact test methods, acceptance criteria and contractual requirements.