EN 3324:2007

Overview

EN 3324:2007 is a European standard established by CEN, specifically designed for aerospace applications. It defines the specifications for hexagon head bolts with relieved shank and long thread, manufactured from heat-resisting steel type FE-PM1708 (also known as FV535). These bolts are characterized by their exceptional mechanical properties, including a tensile strength classification of 1,000 MPa and operational temperature capacity up to 550 °C. The standard emphasizes bolts that are unplated, ensuring compliance with aerospace industry requirements for durability and heat resistance.

Key Topics

• Material Specifications: The bolts adhere to the FE-PM1708 heat-resistant steel standard, providing excellent strength and thermal stability suitable for high-temperature aerospace environments.
• Mechanical Classification: Rated at a minimum tensile strength of 1,000 MPa and capable of withstanding temperatures up to 550 °C, these bolts meet rigorous aerospace performance criteria.
• Bolt Design Features: The specification covers a hexagon head for easy tool engagement, a relieved shank to reduce stress concentration, and a long threaded portion for versatile fastening applications.
• Dimensions and Tolerances: Detailed dimensions, thread pitch, diameters, lengths, and tolerances are defined, complying with ISO thread standards to ensure interchangeability and precision.
• Marking and Identification: The standard specifies clear marking requirements according to EN 2424, facilitating traceability and quality assurance in aerospace manufacturing.
• Technical References: Compliance with related aerospace standards like ISO 3353-1 for threads and EN 3302 for technical specifications ensures comprehensive quality control.

Applications

EN 3324:2007 bolts are specifically engineered for the aerospace sector where reliability under extreme conditions is crucial. Their applications include:

• Aircraft Structural Assemblies: Securing key structural components exposed to high mechanical loads and elevated temperatures.
• Engine Components: Fastening parts within jet engines where heat resistance and tensile strength are mandatory.
• High-Temperature Systems: Use in aerospace subsystems that operate in environments approaching or exceeding 550 °C.
• Repair and Maintenance: Replacement bolts for aerospace components that require uncoated, heat-resistant fasteners.
• Aerospace Manufacturing: Integration in the production of aerospace hardware and assemblies demanding consistent performance under strict norm compliance.

Related Standards

EN 3324:2007 is part of a broader aerospace fastener quality framework and references or aligns with several complementary standards, including:

• ISO 3353-1: Aerospace external threads, specifying rolled external threads critical for bolt-thread compatibility.
• ISO 5855-2: Defines limit dimensions for bolts and nuts in aerospace MJ thread series.
• EN 2424: Governs aerospace product marking standards ensuring product traceability.
• EN 3302: Provides detailed technical specifications relevant to bolts made from heat resisting steel FE-PM1708.
• EN 2493: Specifies material requirements for heat-resisting steel FE-PM38 bars used in aerospace applications.
• EN 4244 / EN 4245: Address related aspects of heat-resisting alloy FE-PM1708 including manufacturing and treatment methods.

Keywords: aerospace bolts, hexagon head bolts, relieved shank, long thread, heat resisting steel, FE-PM1708, tensile strength 1000 MPa, temperature resistance 550 °C, aerospace fasteners standards, EN 3324, unplated aerospace bolts, CEN standards aerospace, aerospace hardware fastening

By adhering to EN 3324:2007, aerospace manufacturers and maintenance teams ensure the use of high-quality, reliable bolts ideal for critical high-temperature and high-stress aerospace environments, supporting safety and performance in demanding applications.