SIST EN 3979:2005

Overview

EN 3979:2005 is a CEN (Aerospace series) standard that defines requirements for aluminium alloy AL‑P8090‑O2 supplied as sheet for superplastic forming (SPF). It covers rolled, thermomechanically processed sheets of nominal thickness 0.8 mm ≤ a ≤ 6 mm intended for aerospace applications, including delivery condition, mechanical properties, and SPF capability testing.

Key topics and requirements

• Material and form
  • Aluminium alloy designation: AL‑P8090‑O2 in sheet form, produced and processed to enhance superplastic forming capability.
  • Thickness range: 0.8–6 mm.
• Delivery and heat treatment
  • Delivery condition: O2 (thermomechanically processed).
  • Reference heat treatment for release testing: solution heat treatment at 525–535 °C with water quench (to ≤40 °C), followed by artificial aging at 165–185 °C for 20–40 hours.
• Mechanical properties (manufacturer release tests)
  • Proof stress R_p0.2 ≥ 330 MPa (longitudinal directions).
  • Tensile strength R_m ≥ 410 MPa.
  • Elongation A ≥ 4% (50 mm gauge).
• Superplastic forming capability
  • SPF capability assessed by elevated-temperature tensile testing with specified test temperature and soak conditions.
  • Test temperature: 520–540 °C, soak 15–45 minutes.
  • Required elongation for SPF capability: A ≥ 300% under the specified test conditions.
• Other inspections
  • Density limit (batch verification): ρ ≤ 2.56 kg/dm³.
  • Dimensional, marking, microstructure and defect acceptance criteria referenced to EN 4400‑2.

Applications and users

• Primary use: Manufacture of superplastically formed aerospace components where complex shapes and high formability are required (e.g., skins, complex structural panels).
• Who uses EN 3979:2005
  • Aerospace material purchasers and procurement specialists specifying SPF aluminium sheet.
  • Materials and process engineers designing SPF operations.
  • Quality, inspection and testing laboratories performing release and SPF capability testing.
  • OEMs and suppliers qualifying batches and establishing product acceptance criteria.

Practical value

• Provides a clear, traceable specification for sourcing AL‑P8090‑O2 SPF sheet with defined mechanical and forming performance.
• Helps ensure consistency between manufacturers and purchasers for critical aerospace components produced by superplastic forming.
• Facilitates product qualification and batch acceptance by referencing standardized test conditions and heat treatments.

Related standards

• EN 4400‑2 - Aluminium and aluminium alloy wrought products: technical specification (sheet and strip).
• EN 4258 - Organisation of aerospace metallic material standards.
• EN 4500‑2 - Rules for drafting/presentation of aluminium alloy material standards.

Keywords: EN 3979:2005, AL‑P8090‑O2, superplastic forming, SPF sheet, aerospace aluminium, sheet 0.8–6 mm, proof stress 330 MPa, tensile 410 MPa, SPF capability.