SIST EN 3820:2017

Overview

SIST EN 3820:2017 is a European standard established by CEN that defines the specifications for aerospace-grade metric bolts made from titanium alloys. These bolts feature a normal hexagon head, coarse tolerance normal shank, and short threads. They are anodized and lubricated with molybdenum disulfide (MoS2) to enhance performance and durability. The standard classifies these bolts as capable of withstanding a tensile strength of 1,100 MPa at ambient temperature and operational limits up to 315 °C.

This aerospace series standard ensures high reliability, precision, and consistency in the production and application of titanium bolts critical to aerospace components and assemblies.

Key Topics

• Configuration and Dimensions
  The bolts comply with ISO 3193 for dimensions and tolerances, expressed in millimeters. Dimensions account for anodizing but are measured prior to lubrication. Detailed dimensional tables specify thread sizes, head diameters, and lengths essential for accurate fit and function.

• Material Specifications
  Titanium alloy materials conform to strength class 1,100 MPa as per TR 3775, supporting high-strength requirements while maintaining lightweight properties crucial for aerospace applications.

• Surface Treatment
  Bolts are anodized to provide corrosion resistance and surface hardness. They are MoS2 lubricated according to EN 2491 with a precise coating thickness from 5 to 10 micrometers to reduce friction and wear during installation and service.

• Tolerance and Form
  Form and position tolerances follow ISO 7913 to maintain assembly integrity and bolted joint performance. Sharp edges are chamfered between 0.1 to 0.4 micrometers to prevent stress concentrations.

• Marking and Identification
  Bolts are marked in accordance with EN 2424 for aerospace products, enabling traceability and quality control. Marking styles depend on the bolt diameter range.

• Manufacturer Approval and Qualification
  Manufacturers must comply with aerospace quality management systems per EN 9100 and certify bolts via EN 9133 to ensure product quality and performance reliability.

Applications

SIST EN 3820:2017 titanium bolts are primarily designed for aerospace engineering where strength-to-weight ratio, corrosion resistance, and temperature endurance are critical. Typical applications include:

• Aircraft structural assemblies
• Engine components subject to elevated temperatures
• Spacecraft and satellite structural fastenings
• High-performance aerospace manufacturing requiring reliable bolt performance under dynamic loads and temperature fluctuation

Their combination of titanium alloy, anodizing, and MoS2 lubrication ensures long service life with minimal maintenance, optimized for aerospace environments where safety and durability are paramount.

Related Standards

• EN 2424 – Marking standards for aerospace products, essential for traceability of parts.
• EN 2491 – Specification for molybdenum disulfide dry lubricant coatings and application methods.
• EN 9100 – Quality management system requirements tailored for aerospace, space, and defense organizations.
• EN 9133 – Qualification procedure for aerospace standard parts to certify manufacturing processes and product quality.
• ISO 3193 – General specification for metric aerospace bolts including dimensions and thread series.
• ISO 7913 – Tolerances of form and position applicable to aerospace bolts for optimal assembly precision.

Adopting SIST EN 3820:2017 helps aerospace manufacturers maintain compliance with stringent quality standards, ensuring bolt components meet operational durability, safety, and performance requirements in aerospace applications. Its focus on titanium alloy bolts with advanced surface treatment supports lightweight and robust fastener solutions essential for modern aerospace engineering.