SIST EN 3816:2009

Overview

SIST EN 3816:2009 is a European standard issued by CEN that specifies the technical requirements and quality criteria for the aerospace-grade steel FE-PA3601, also known as X6CrNiTi18-10. This grade of steel is characterized by its air-melted production process and softened, cold-rolled condition. It is supplied in sheet and strip forms with a maximum thickness of 3 mm and a minimum tensile strength (Rm) of 800 MPa. The standard is designed to ensure consistent material properties suitable for demanding aerospace applications, particularly where high strength, corrosion resistance, and precise dimensional control are required.

Key Topics

• Material Designation: Steel FE-PA3601 (X6CrNiTi18-10)
• Production Method: Air melted, softened, and cold rolled
• Product Form: Sheet and strip with thickness a ≤ 3 mm
• Mechanical Properties:
  • Tensile strength (Rm) ≥ 800 MPa
  • Proof stress (Rp0.2) ≥ 700 MPa
  • Elongation (A) ≥ 10%
  • Hardness HV between 250 and 350
• Chemical Composition: Controlled maximum limits for carbon (0.08%), silicon (1.00%), manganese (2.00%), phosphorous (0.035%), sulfur (0.025%), chromium (17.0-19.0%), nickel (9.0-11.0%), and titanium (up to 0.60%)
• Heat Treatment: Typically annealed at 1,050 °C to 1,100 °C with air quenching or water quenching to achieve the required properties
• Testing and Inspection: Complies with testing protocols of EN 4700-1 regarding sample preparation, heat treatment, dimensional, mechanical, and microstructural inspections
• Microstructure and Grain Size: Conforms to aerospace-quality standards for grain uniformity and absence of external defects
• Magnetic Permeability: Less than 1.2 at a field strength of 15,915 A/m, ensuring non-magnetic properties critical in aerospace use

Applications

SIST EN 3816:2009 steel FE-PA3601 is primarily intended for aerospace industry components where high performance under mechanical stress and corrosion resistance are essential. Usage includes:

• Components of self-locking nuts such as cages and washers
• Aerospace structural elements requiring thin, yet strong and reliable metallic materials
• Critical assemblies demanding close dimensional tolerances and stable mechanical properties after cold rolling and heat treatment
• Parts requiring resistance to oxidation and environmental exposure due to the stainless composition of the steel alloy

Related Standards

• EN 4258: General organization of aerospace metallic material standards, facilitating linkage between different aerospace material specifications
• EN 4500-5: Rules for drafting and presentation specific to aerospace steel standards like EN 3816
• EN 4700-1: Technical specification for steel and heat resisting alloy wrought products, especially plates, sheets, and strips, providing test methods referenced by EN 3816
• EN 2043: General requirements for semi-finished products for aerospace, important for qualification and procurement processes under the EN 3816 regime

SIST EN 3816:2009 ensures that steel FE-PA3601 meets stringent aerospace specifications through controlled chemical composition, precision manufacturing processes, and rigorous testing. This standard is essential for suppliers, manufacturers, and quality assurance professionals involved in aerospace materials to consistently achieve superior performance and safety in aerospace applications.