SIST EN 3294:2008

Overview

SIST EN 3294:2008 is a European standard developed by CEN for aerospace-grade T-head bolts. These bolts are manufactured from the heat-resistant nickel base alloy NI-P101HT, commonly known as Waspaloy. The standard specifies dimensions, tolerances, and technical requirements for uncoated, close tolerance T-head bolts designed specifically for use with increased height nuts. These bolts are engineered to withstand high temperatures up to 730 °C and are primarily employed in aerospace fastening systems subject to shearing forces.

This standard ensures uniformity and reliability of high-performance fastening components crucial for aerospace industry applications, where material integrity and temperature resistance are vital.

Key Topics

• Material Specification: Bolts use heat resisting nickel base alloy NI-P101HT (Waspaloy), ensuring enhanced high temperature strength and durability.
• Dimensions and Tolerances: Precise dimensions including thread lengths, diameters, and bolt configuration are strictly defined for interchangeability and safe aerospace applications.
• Thread Type: Close tolerance MJ-threads with thread length compatible for increased height nuts. Thread pitch and diameter details follow aerospace standards ISO 3353-1 and ISO 5855 (Parts 1 & 2).
• Temperature Rating: Components are tested to withstand temperatures up to 730 °C, making them suitable for use in hot aerospace environments such as engines or exhaust assemblies.
• Mechanical Classification: Designed for a strength classification of 1 210 MPa, suitable for high-stress scenarios particularly emphasizing shearing forces.
• Surface Treatment: Bolts are supplied uncoated to maintain compatibility with aerospace fastening systems requiring exact surface characteristics.
• Marking and Designation: Each bolt is marked following EN 2424 standard, and designated with standardized nominal diameter codes and length codes for traceability and quality assurance.
• Compliance: Bolts conform to additional aerospace standards EN 2582 related to mechanical specifications, reinforcing consistent quality.

Applications

• Aerospace Fastening Systems: These T-head bolts are optimized for aerospace assemblies requiring fasteners with excellent heat resistance and tight dimensional control.
• High Temperature Environments: Ideal for parts exposed to elevated temperatures-engines, turbine assemblies, and high-performance aerospace components.
• Structural Fastening: Particularly used in situations where bolts are subjected primarily to shearing forces, ensuring structural integrity in critical aerospace joints.
• Increased Height Nuts Compatibility: Designed specifically for use with increased height aerospace nuts, enhancing joint reliability and strength under extreme conditions.

Related Standards

• EN 2582: Aerospace series for bolts in heat resisting nickel base alloy NI-P101HT - technical specification and classification.
• EN 2424: Aerospace series marking requirements for aerospace products, ensuring standardized identification.
• EN 2959 & EN 3220: Standards covering the nickel base alloy materials (including bars and wire) used as raw materials for aerospace fasteners.
• ISO 3353-1: Aerospace lead and runout threads for rolled external threads-relevant for thread design.
• ISO 5855-1 & ISO 5855-2: Aerospace MJ threads standards providing general requirements and limit dimensions for bolts and nuts.

SIST EN 3294:2008 sets the benchmark for manufacturing and quality assurance of close tolerance T-head bolts used in extreme aerospace environments. Its rigorous specifications for dimensions, materials, and mechanical properties make it an indispensable standard for engineers and manufacturers aiming to meet the highest aerospace industry requirements. Adherence to this standard supports enhanced safety, reliability, and performance in critical aerospace fastening systems.