SIST EN 3330:2009

Overview

SIST EN 3330:2009 is a European standard developed by CEN that specifies the technical requirements for Steel FE-PL1503 (commonly known as 35CrMo4) in an annealed condition. This standard covers steel supplied as bars and wires with an external diameter (De) up to 40 mm. Its primary focus is on applications in the aerospace industry, particularly for the manufacture of prevailing torque nuts.

The standard ensures high-quality steel material tailored for critical aerospace components, supporting the industry's demand for reliable and consistently high-performance materials. SIST EN 3330:2009 is part of the EN aerospace metallic material series and follows rigorous criteria for chemical composition, mechanical properties, heat treatment, and dimensional tolerances.

Key Topics

• Material Specification
  Steel FE-PL1503 (35CrMo4), annealed condition
  Chemical composition limits for Carbon, Silicon, Manganese, Chromium, Molybdenum, Nickel, Phosphorus, and Sulfur
  Air melting method for steel production

• Form and Dimensions
  Bars and wires with diameters ≤ 40 mm
  Dimensional tolerances comply with EN 2034 (for drawn and descaled bars) and EN 2036 (for ground bars)
  Delivery condition code: U (Annealed)

• Mechanical and Physical Properties
  Hardness range (HB ≤ 217, HV5 ≤ 228 for annealed condition)
  Iron-based alloy steel with controlled impurity levels and minimal decarburization
  Test procedures and sample preparation according to EN 4700-2 and EN 4700-4

• Heat Treatment and Quality Control
  Reference heat treatments include salt bath quenching and air cooling processes
  Inspection for external defects, surface conditions, and marking as per aerospace industry standards
  Manufacturer and purchaser agree on qualification programs for product acceptance

Applications

SIST EN 3330:2009 steel is primarily intended for prevailing torque nuts in aerospace applications. These nuts are essential for securing critical fasteners that must resist loosening under vibration and stress conditions typical in aerospace environments. The chemical and mechanical properties defined in this standard ensure that the nuts made from this steel deliver:

• High strength and durability to maintain preload in fastening systems
• Resistance to wear and fatigue under demanding operational stresses
• Reliable performance with consistent dimensions and material quality
• Compatibility with aerospace manufacturing processes and standards

The steel's use in aerospace prevailing torque nuts contributes to overall safety, longevity, and maintenance efficiency in aircraft and other aerospace vehicles.

Related Standards

SIST EN 3330:2009 references and works in conjunction with several other aerospace and material standards to define comprehensive requirements and testing methods:

• EN 4258 – General organization of aerospace metallic material standardization
• EN 4500-5 – Rules for drafting and presentation of steel material standards
• EN 2034, EN 2036 – Dimensional tolerances for steel bars
• EN 2600 – Designation rules for metallic semi-finished aerospace products
• EN 4700-2, EN 4700-4 – Technical specifications for steel bars and wires
• ASD-STAN regulations for aerospace and defense industry materials

These related standards ensure seamless integration of SIST EN 3330:2009 within aerospace quality management systems and industrial processes.

Keywords: SIST EN 3330:2009, Steel FE-PL1503, 35CrMo4 steel, aerospace steel standard, annealed steel bar, aerospace prevailing torque nuts, aerospace material specifications, steel wire aerospace, dimensional tolerances aerospace steel, aerospace fasteners steel, CEN steel standards