EN 3740:2026

• Abstract:

  This document specifies the characteristics of bolts, shouldered, thin hexagonal head, close tolerance shank, short thread, in titanium alloy, anodized, MoS2 dryfilm coated, for aerospace applications.; Classification: 1 100 MPa1/315 °C2..

• Status: Not Published
• Publication Date: 01-Sep-2026
• ICS: 49.030.20 - Bolts, screws, studs
• Technical Committee: ASD-STAN - Aerospace
• Drafting Committee: ASD-STAN/D 3/S 2 - Fasteners
• Current Stage: 6055 - CEN Ratification completed (DOR) - Publishing
• Start Date: 03-Aug-2026
• Completion Date: 03-Aug-2026
• Ref Project: kSIST FprEN 3740:2026 - Aerospace series - Bolts, shouldered, thin hexagonal head, close tolerance shank, short thread, in titanium alloy, anodized, MoS2 coated - Classification: 1 100 MPa (at ambient temperature)/315 °C

• Revises: EN 3740:2019 - Aerospace series - Bolts, shouldered, thin hexagonal head, close tolerance shank, short thread, in titanium alloy, anodized, MoS2 coated - Classification: 1 100 MPa (at ambient temperature)/315 °C
• Effective Date: 20-Nov-2024

Overview

EN 3740:2026 - Aerospace Series Bolts specifies the characteristics and requirements for shouldered bolts with a thin hexagonal head, close tolerance shank, and short thread, manufactured in titanium alloy. These bolts are designed for aerospace applications and feature anodized surfaces with MoS2 (molybdenum disulphide) dry film coating, offering reliable performance under demanding conditions, namely at a minimum tensile strength of 1 100 MPa at ambient temperature and operational suitability up to 315 °C.

Developed by CEN (European Committee for Standardization), this standard ensures compatibility, quality, and safety for bolts used in aerospace structures. EN 3740:2026 supersedes EN 3740:2019, reflecting updates in surface treatment processes and editorial revisions.

Key Topics

• Product Characteristics: Defines bolts with a shouldered, thin hexagonal head, precise close tolerance shank, and short thread design, all fabricated in high-performance titanium alloys.
• Surface Treatments: Specifies anodizing and MoS2 dry film coating for enhanced corrosion resistance, reduced friction, and improved longevity in aerospace environments.
• Dimensions & Tolerances: Details standardized dimensions and mass for various diameter codes, expressed in millimetres, including requirements for post-treatment measurements.
• Mechanical Properties: Ensures a minimum tensile strength of 1 100 MPa at ambient temperature and temperature resistance up to 315 °C without altering the bolt’s original characteristics.
• Marking & Identification: Requires clear product marking per EN 2424 for traceability, including both nominal and coating codes.

Applications

EN 3740:2026 bolts are specifically tailored for the aerospace industry, where component integrity and material performance are critical to safety and efficiency. Typical applications include:

• Aircraft Structures: Used in critical assemblies where reliability under variable loads and temperatures is essential.
• Aerospace Engines and Systems: Suitable for mounting parts within engines and subsystems experiencing elevated temperatures.
• Spacecraft: Application in structures where weight reduction and corrosion resistance are vital through the use of titanium alloy and advanced coatings.
• Maintenance and Repairs: Ensures replacement bolts meet consistent European standards, assisting in regular MRO (Maintenance, Repair, and Overhaul) operations.

These bolts are intended to be used in conjunction with washers compliant with EN 2414 and nuts according to EN 3230.

Related Standards

Organizations seeking comprehensive standardization benefit from considering the following related documents:

• EN 2424 - Aerospace series: Marking of aerospace products.
• EN 2491 - Molybdenum disulphide dry lubricants: Coating methods.
• EN 2414 - Washers, chamfered, with counterbore, in alloy steel, cadmium plated.
• EN 3230 - Nuts, hexagon, slotted/castellated, reduced height, normal across flats, steel, cadmium plated.
• EN 4016 - Oversized bolts for aerospace use.
• ISO 3353-1 and ISO 5855-2 - Threads and tolerances for aerospace fasteners.
• ISO 7913 - Tolerances of form and position for bolts and screws, metric.
• ISO 9152 - Aerospace bolts with MJ threads in titanium alloy, procurement specification.
• EN 9100 and EN 9133 - Aerospace quality management and qualification procedures.

Practical Value

By conforming to EN 3740:2026, aerospace manufacturers and maintenance providers are assured of:

• Interchangeability and Reliability: Standardized dimensions and properties ensure consistent quality and fitment across the aerospace sector.
• Enhanced Performance: Titanium alloy and specialized coatings extend component service life in harsh operating environments.
• Regulatory Compliance: Meeting European and global requirements for aerospace hardware, supporting safety-critical operations.
• Supply Chain Assurance: Facilitates sourcing from multiple approved suppliers, fostering competition and reducing costs while maintaining quality.

EN 3740:2026 strengthens product consistency, safety, and technological advancement in aerospace fastening solutions.

SLOVENSKI STANDARD
oSIST prEN 3740:2025
01-september-2025
Aeronavtika - Sorniki, vezi, tanka šesterokotna glava, ozka toleranca, kratek navoj,
iz titanove zlitine, anodizirani, mazani z MoS2 - Klasifikacija: 1 100 MPa (pri
temperaturi okolice)/315 °C
Aerospace series - Bolts, shouldered, thin hexagonal head, close tolerance shank, short
thread, in titanium alloy, anodized, MoS2 coated - Classification: 1 100 MPa (at ambient
temperature)/315 °C
Luft- und Raumfahrt - Sechskant-Passschrauben, kleiner Kopf, enge Schafttoleranz,
kurzes Gewinde, aus Titanlegierung, anodisiert, MoS2‑geschmiert - Klasse: 1 100 MPa
(bei Raumtemperatur)/315 °C
Série aérospatiale - Vis épaulées, à tête hexagonale fine, tige à tolérance serrée, filetage
court, en alliage de titane, anodisées, revêtues MoS2 - Classification : 1 100 MPa (à
température ambiante)/315 °C
Ta slovenski standard je istoveten z: prEN 3740
ICS:
49.025.30 Titan Titanium
49.030.20 Sorniki, vijaki, stebelni vijaki Bolts, screws, studs
oSIST prEN 3740:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 3740:2025
oSIST prEN 3740:2025
DRAFT
EUROPEAN STANDARD
prEN 3740
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2025
ICS 49.030.20 Will supersede EN 3740:2019
English Version
Aerospace series - Bolts, shouldered, thin hexagonal head,
close tolerance shank, short thread, in titanium alloy,
anodized, MoS2 coated - Classification: 1 100 MPa (at
ambient temperature)/315 °C
Luft- und Raumfahrt - Sechskant-Passschrauben,
kleiner Kopf, enge Schafttoleranz, kurzes Gewinde, aus
Titanlegierung, anodisiert, MoS2-geschmiert - Klasse: 1
100 MPa (bei Raumtemperatur)/315 °C
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee ASD-
STAN.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 3740:2025 E
worldwide for CEN national Members.

oSIST prEN 3740:2025
prEN 3740:2025 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Required characteristics . 4
4.1 Configuration — Dimensions — Masses . 4
4.2 Tolerances of form and position . 5
4.3 Materials . 5
4.4 Surface treatment . 5
5 Designation . 9
6 Marking . 9
7 Technical specification . 9
8 Oversized bolts . 9
Bibliography. 10

oSIST prEN 3740:2025
prEN 3740:2025 (E)
European foreword
This document (prEN 3740:2025) has been prepared by ASD-STAN.
After enquiries and votes carried out in accordance with the rules of this Association, this document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 3740:2019.
This document includes the following significant technical changes with respect to EN 3740:2019:
— 4.4 “Surface treatment” updated;
— document editorially revised.
oSIST prEN 3740:2025
prEN 3740:2025 (E)
1 Scope
This document specifies the characteristics of bolts, shouldered, thin hexagonal head, close tolerance
shank, short thread, in titanium alloy, anodized, MoS dryfilm coated, for aerospace applications.
1 2
Classification: 1 100 MPa /315 °C .
These bolts are intended to be used with washers according to EN 2414 and nuts according to EN 3230.
2 Normative references
T
...