SIST EN 3969:2009

Overview

SIST EN 3969:2009 is a CEN aerospace material standard that defines the requirements for Steel FE-PL1507 (40CrMoV12) intended as forging stock for aerospace applications. The standard specifies that the material is air melted, supplied in the annealed condition, and limited to forging stock with a or D ≤ 350 mm. It is part of the EN aerospace metallic materials series and follows the drafting rules and organization described in related EN documents.

This standard ensures uniform material designation, delivery condition, basic mechanical targets and references to test methods and product qualification procedures required for aerospace use.

Key Topics

• Material designation: Steel FE-PL1507 (40CrMoV12)

• Melting method: Air melted

• Delivery condition: Annealed (delivery condition code U)

• Form: Forging stock

• Maximum dimension: a or D ≤ 350 mm

• Mechanical / characteristic data (as reported in the standard):

  • Proof stress Rp0,2: ≥ 1 030 MPa
  • Tensile strength Rm: 1 250 ≤ Rm ≤ 1 400 MPa
  • Elongation A: ≥ 10%
  • Reduction of area Z: ≥ 35%
  • Impact: KV ≥ 25 J (notch direction T)
  • Hardness references are provided in the standard and in the associated heat treatment notes

• Reference heat treatment: The standard records a reference hardened and tempered cycle and requires actual heat-treatment details to be reported on inspection/test reports.

• Testing and inspection: Macrographic test per EN 2003-7; sampling and specific tests per EN 2157-2 and EN 2957 where applicable.

Applications

SIST EN 3969:2009 is targeted at manufacturers, purchasers and quality engineers involved in aerospace forging processes. Typical practical applications include:

• Supply of forging billets and stock for structural and mechanical aerospace components
• Materials intended for nitriding and surface treatments (the standard identifies suitability for nitriding in its typical use notes)
• Situations demanding traceable delivery, documented heat treatment, and conformance to aerospace qualification programs

Benefits for users include consistent material chemistry and processing control, clear delivery condition requirements, and alignment with aerospace testing and qualification practices.

Related Standards

The standard references and links with other EN documents that define test methods, qualification and presentation rules. Key related standards include:

• EN 2003-7 - Steel test methods: Macrographic test
• EN 2157-2 - Forging stock technical specification
• EN 2957 - Method of preparation of forged samples
• EN 2043 - General requirements for semi-finished product qualification
• EN 4258 and EN 4500-5 - Series organization and rules for drafting steel material standards

For procurement, qualification programs and detailed inspection criteria, manufacturers and purchasers should refer to EN 2157-2 and agree product qualification per EN 2043.

Keywords: SIST EN 3969:2009, FE-PL1507, 40CrMoV12, air melted, annealed, forging stock, aerospace steel, nitriding, material qualification.