prEN 3723
(Main)Aerospace series — Nuts, hexagonal, self-locking, in heat resisting steel FE-PA92HT (A286), MoS2 coated Aerospace — Classification : 1 100 MPa (at ambient temperature) / 425 °C
General Information
- Abstract
This document specifies the characteristics of self-locking hexagonal nuts in FE-PA92HT, MoS2 coated, for aerospace applications.
Classification: 1 100 MPa1/425 °C2.
- Status
- Not Published
- Publication Date
- 19-Oct-2027
- Technical Committee
- ASD-STAN - Aerospace
- Drafting Committee
- ASD-STAN/D 3/S 2 - Fasteners
- Current Stage
- 4060 - Closure of enquiry - Enquiry
- Start Date
- 16-Jul-2026
- Completion Date
- 16-Jul-2026
Overview
prEN 3723 is a draft European standard developed by CEN for the aerospace sector, focusing on the specifications of self-locking hexagonal nuts made from heat-resisting steel FE-PA92HT (A286) with a MoS2 (molybdenum disulphide) coating. These nuts are designed for aerospace applications where high strength and resistance to elevated temperatures are required. Classified for 1 100 MPa at ambient temperature and up to 425 °C, this standard ensures compatibility with demanding environments commonly encountered in aircraft and aerospace systems.
prEN 3723 supersedes the earlier EN 3723:1996 and introduces editorial updates and clarifications, including material references and technical specification revisions.
Key Topics
- Material Requirements: Nuts are produced using high-performance, heat-resisting steel FE-PA92HT (A286) to meet the stringent needs of aerospace applications.
- Surface Coating: The application of a MoS2 coating provides effective dry lubrication, essential for reliable performance under high-load and high-temperature conditions.
- Mechanical Classification: Components are specified for 1 100 MPa strength at ambient temperature and validated for use up to 425 °C, ensuring suitability for thermal cycling and mechanical stress.
- Dimensional Specifications: Clear detailing of thread codes, sizes, tolerances, and mass per size based on ISO and EN standards, ensuring interchangeability and consistency across the industry.
- Marking and Traceability: Mandatory marking according to EN 2424, supporting traceability and quality control throughout the product lifecycle.
- Quality Management: Manufacturers must adhere to recognized quality management systems, such as EN 9100, maintaining product reliability and safety for aerospace operations.
- Product Qualification: Comprehensive qualification procedures as per EN 9133, ensuring all nuts meet required aerospace standards before deployment.
Applications
The nuts specified in prEN 3723 have wide-ranging use in:
- Aircraft Structures: Applied in primary and secondary structural assemblies where high strength and temperature resistance are vital.
- Engines and Powertrains: Suitable for fastening components in aircraft engines exposed to elevated thermal and mechanical stresses.
- Aerospace Systems: Used in critical systems such as landing gear, control surfaces, and electronic equipment mounts where vibration resistance and self-locking capabilities are essential.
- Satellite and Spacecraft Assemblies: Due to their resistance to high temperatures and reliable self-locking mechanism, these nuts are suitable for demanding space applications.
These self-locking hexagonal nuts are designed specifically to address the stringent demands for reliability and durability, minimizing the risk of loosening due to vibration or thermal expansion in flight-critical areas.
Related Standards
For comprehensive implementation and compliance, prEN 3723 is intended to be used alongside the following aerospace and fastening standards:
- EN 2399: Heat resisting steel for aerospace bolts.
- EN 2424: Marking requirements for aerospace products.
- EN 2491: Specifications for MoS2 dry lubricant coatings.
- EN 3638, EN 3639: Specifications for heat-resisting alloys in various forms.
- EN 3752: Self-locking nuts, MJ threads, heat-resisting steel, MoS2 coated.
- ISO 5855-2, ISO 7995: MJ thread dimension standards.
- TR 3791, SAE AMS5525: Material and process requirements for self-locking nuts.
- EN 9100, EN 9133: Quality management and product qualification procedures for aerospace components.
By following prEN 3723 in conjunction with these references, manufacturers and engineers ensure robust, reliable fastening solutions for aerospace systems, improving safety and service life in mission-critical applications.
Relations
- Effective Date
- 20-Jan-2026
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Frequently Asked Questions
prEN 3723 is a draft published by the European Committee for Standardization (CEN). Its full title is "Aerospace series — Nuts, hexagonal, self-locking, in heat resisting steel FE-PA92HT (A286), MoS2 coated Aerospace — Classification : 1 100 MPa (at ambient temperature) / 425 °C". This standard covers: This document specifies the characteristics of self-locking hexagonal nuts in FE-PA92HT, MoS2 coated, for aerospace applications. Classification: 1 100 MPa1/425 °C2.
This document specifies the characteristics of self-locking hexagonal nuts in FE-PA92HT, MoS2 coated, for aerospace applications. Classification: 1 100 MPa1/425 °C2.
prEN 3723 is classified under the following ICS (International Classification for Standards) categories: 49.030.20 - Bolts, screws, studs; 49.030.30 - Nuts. The ICS classification helps identify the subject area and facilitates finding related standards.
prEN 3723 has the following relationships with other standards: It is inter standard links to EN 3723:1996. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
prEN 3723 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2026
Aeronavtika - Matice, šestrobe, samozapiralne, iz toplotnoodpornega jekla FE-
PA92HT (A286), prevlečene z MoS2 za letalstvo - Klasifikacija: 1100 MPa (pri
temperaturi okolice)/425 °C
Aerospace series - Nuts, hexagonal, self-locking, in heat resisting steel FE-PA92HT
(A286), MoS2 coated Aerospace - Classification : 1 100 MPa (at ambient temperature) /
425 °C
Luft‑ und Raumfahrt - Sechskantmutter, selbstsichernd, aus hochwarmfesten Stahl
FE‑PA92HT (A286), MoS2‑beschichtet - Klasse: 1 100 MPa (bei Raumtemperatur)/425
°C
Ta slovenski standard je istoveten z: prEN 3723
ICS:
49.025.10 Jekla Steels
49.030.30 Matice Nuts
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2026
ICS 49.030.20 Will supersede EN 3723:1996
English Version
Aerospace series - Nuts, hexagonal, self-locking, in heat
resisting steel FE-PA92HT (A286), MoS2 coated Aerospace
- Classification : 1 100 MPa (at ambient temperature) /
425 °C
Luft- und Raumfahrt ¿ Sechskantmutter,
selbstsichernd, aus hochwarmfesten Stahl FE-PA92HT
(A286), MoS2 beschichtet ¿ Klasse: 1 100 MPa (bei
Raumtemperatur)/425 °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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 3723:2026 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 5
4 Required characteristics . 5
4.1 Configuration – Dimensions – Tolerances – Mass . 5
4.2 Materials . 5
4.3 Surface Treatment . 5
5 Designation . 8
6 Marking . 8
7 Technical specification . 8
7.1 General. 8
7.2 Approval of manufacturers . 8
7.3 Qualification of products . 8
Bibliography . 9
European foreword
This document (prEN 3723:2026) 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 3723:1996.
— Clause 3, “Terms and definitions”, added;
— 4.2, “Materials”, standards TR 3791 and SAE AMS5525 added;
— Clause 7, “Technical specification”, editorially revised.
oSIST prEN 3723:202
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