EN 4471:2007

Overview

EN 4471:2007 is a European standard specifying technical requirements for Steel FE-PM1505 (X1CrNiMoAlTi12-9-2), a high-strength stainless steel used in aerospace applications. The steel is produced via vacuum induction melting and consumable electrode remelting, followed by solution treatment and precipitation hardening. This standard covers forgings with thickness or diameter (a or D) up to 150 mm and mandates a minimum tensile strength (Rm) of 1,300 MPa. EN 4471:2007 ensures consistent quality and performance for critical aerospace components requiring exceptional mechanical properties and corrosion resistance.

Key Topics

• Material Composition: Defines chemical limits for elements including Carbon (C), Silicon (Si), Manganese (Mn), Phosphorus (P), Sulfur (S), Chromium (Cr), Molybdenum (Mo), Nickel (Ni), Aluminum (Al), Titanium (Ti), and Nitrogen (N₂).
• Melting Process: Specifies vacuum induction melting combined with consumable electrode remelting to ensure superior purity and homogeneity.
• Heat Treatment: Covers solution treatment at 820–860 °C with quenching (oil, air, or water) plus precipitation treatment at 525–545 °C for at least 4 hours to enhance strength and toughness.
• Mechanical Properties: Requires tensile strength (Rm) ≥ 1,300 MPa, yield strength (Rp0,2) ≥ 1,200 MPa, elongation (A) ≥ 9-11%, and reduction of area (Z) ≥ 45-50% after heat treatment.
• Forgings Dimensions: Applies to forged parts having thickness or diameter ≤ 150 mm.
• Testing and Verification: Includes mechanical testing (tensile, impact, hardness), grain size evaluation, and inspection for surface and internal defects per EN 4700-6.

Applications

Steel FE-PM1505 forged according to EN 4471:2007 is tailored for aerospace structural components that demand high strength, durability, and corrosion resistance. Typical applications include:

• Landing gear parts and critical load-bearing elements
• High-stress aerospace fasteners and fittings
• Structural frames and components subject to fatigue and harsh environmental exposure
• Engine and airframe components requiring exceptional toughness and mechanical performance

The standard ensures components meet stringent aerospace industry reliability and safety requirements, enabling manufacturers to produce parts with predictable and certified material behavior under operating conditions.

Related Standards

EN 4471:2007 complements and links with several other aerospace metallic material standards:

• EN 4258: General organization of aerospace metallic material standardization.
• EN 4346: Specification for softened forging stock of Steel FE-PM1505 with thickness or diameter up to 300 mm.
• EN 4500-5: Rules for drafting and presentation of material standards for steels.
• EN 4700-6: Technical specifications for pre-production and production forgings in aerospace steel and heat-resistant alloys.

These interconnected standards facilitate the consistent production, testing, and certification of high-performance aerospace steel forgings, supporting international harmonization and quality assurance in the aerospace supply chain.

Keywords: EN 4471:2007, Steel FE-PM1505, aerospace steel, vacuum induction melted steel, consumable electrode remelted, solution treated, precipitation hardened, aerospace forgings, high strength steel, tensile strength 1300 MPa, aerospace materials standard, CEN aerospace standards.