SIST EN 2503:2020

Overview

SIST EN 2503:2020 is a European standard developed by CEN (European Committee for Standardization) that specifies requirements for Steel X5CrNoMoCuNb14-5 (1.4594) forgings used primarily in aerospace applications. This steel grade features a tensile strength (Rm) range between 930 MPa and 1080 MPa, and the forgings covered by this standard have a maximum dimension (De) of 150 mm. The standard assures consistency in material properties, chemical composition, heat treatment, mechanical performance, and delivery conditions to meet the stringent demands of the aerospace industry.

The ASD-STAN designation for this material is FE-PM66, and the standard applies to forged components manufactured via air melting methods, heat-treated by solution annealing and precipitation hardening.

Key Topics

• Material Specification: Defines the chemical composition limits for elements such as Carbon (max 0.07%), Chromium (13.2%-14.7%), Molybdenum (1.2%-2.0%), Nickel, Niobium, Copper, and others to optimize corrosion resistance, strength, and toughness.

• Mechanical Properties: Ensures minimum proof stress of 780-1030 MPa and tensile strength between 930 MPa and 1080 MPa depending on test conditions. Elongation requirements exceed 10-15%, with hardness values ranging from 277 to 429 HB depending on temper.

• Heat Treatment: Specifies precise thermal processing conditions including solution annealing between 1000°C and 1050°C with air quenching, followed by precipitation hardening at temperatures between 530°C and 760°C for optimal mechanical and microstructural properties.

• Dimensions and Form: Focuses exclusively on forged products with diameters up to 150 mm, suited for aerospace structural and functional components.

• Testing and Inspection: Mandates dimensional inspections, marking, and mechanical testing using standardized bar samples to verify conformance. Optional tests and qualification programs can be negotiated between manufacturer and customer.

Applications

SIST EN 2503:2020 materials are widely applied in the aerospace sector for critical forged parts that require:

• High strength combined with superior corrosion resistance provided by stainless steel grades.
• Structural components in aircraft engines, landing gear, and airframe assemblies.
• Safety-critical parts subject to cyclic loads, high stress, and demanding environmental conditions.
• Parts where reliability and traceability according to European aerospace standards are mandatory.

The standard’s strict requirements ensure performance consistency for manufacturers and purchasers engaged in aerospace materials supply chains, contributing to overall flight safety and operational reliability.

Related Standards

• EN 2157-1: Aerospace series - Steel forgings - Technical specification - Part 1: General requirements. This standard is referenced within SIST EN 2503:2020 for forging stock and forging process guidelines.

• EN 4258: Aerospace series - Metallic materials - General organization of standardization, which outlines the framework governing the series of aerospace metallic material standards.

• EN 4500-005: Aerospace series - Metallic materials - Rules for drafting and presentation of material standards, providing standardized methodologies and format for steel specifications in aerospace.

For additional terminology and definitions relevant to the aerospace steel domain, users can consult the ISO Online Browsing Platform and the IEC Electropedia.

Keywords: SIST EN 2503:2020, aerospace steel standard, X5CrNoMoCuNb14-5, 1.4594 steel, precipitation hardened stainless steel, aerospace forgings, steel tensile strength, forging standards, aerospace material certification, steel heat treatment aerospace, forged aerospace components.