SIST EN 3434:2023

Aerospace series - Nuts, hexagon, slotted/castellated, self-locking, in steel, cadmium plated, MoS2 lubricated - Classification: 900 MPa (at ambient temperature)/235 °C

This standard specifies characteristics of self-locking hexagonal slotted/castellated nuts, in steel, cadmium plated, MoS2 lubricated, for aerospace applications.
Classification: 900 MPa /235 °C .

Luft- und Raumfahrt - Sechskant-Kronenmuttern, selbstsichernd, aus Stahl, verkadmet, MoS2-geschmiert - Klasse: 900 MPa (bei Raumtemperatur)/235 °C

Dieses Dokument legt die Eigenschaften von selbstsichernden sechskantigen, mit Cadmiumbeschichteten und MoS2 geschmierten Stahlkronenmuttern für Anwendung in der Luft- und Raumfahrt fest.
Klasse: 900 MPa /235 °C .

Série aérospatiale - Écrous hexagonaux à créneaux, à freinage interne, en acier, cadmiés, lubrifiés au MoS2 - Classification : 900 MPa (à température ambiante)/235 °C

Le présent document spécifie les caractéristiques des écrous hexagonaux à créneaux, à freinage interne, en acier, cadmiés, lubrifiés au MoS2, pour les applications aérospatiales.
Classification : 900 MPa 1)/235 °C 2).

Aeronavtika - Matice, šestrobe, z zarezo/kronske, samozaporne, iz jekla, kadmirane, mazane z MoS2 - Klasifikacija: 900 MPa (pri okoljski temperaturi)/235 °C

Ta standard določa lastnosti samozapornih šestrobih matic, kronskih/z zarezo, iz jekla, kadmiranih, mazanih z MoS2 za uporabo v aeronavtiki.
Klasifikacija: 900 MPa/235 °C.

General Information

• Status: Published
• Public Enquiry End Date: 24-Feb-2021
• Publication Date: 22-Jan-2023
• ICS: 49.025.10 - Steels
• ICS: 49.030.30 - Nuts
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 04-Jan-2023
• Due Date: 11-Mar-2023
• Completion Date: 23-Jan-2023
• Ref Project: EN 3434:2022 - Aerospace series - Nuts, hexagon, slotted/castellated, self-locking, in steel, cadmium plated, MoS2 lubricated - Classification: 900 MPa (at ambient temperature)/235 °C

Overview

SIST EN 3434:2023 (CEN) defines the required characteristics for aerospace hexagon slotted/castellated self-locking nuts made in steel, with cadmium plating and molybdenum disulfide (MoS2) lubrication. Classified as 900 MPa (ambient) / 235 °C, the standard sets configuration, material, surface treatment, marking and quality system expectations for nuts intended for aviation and space applications.

Key features specified in the standard include:

• Self-locking hexagonal slotted (castellated) design
• Steel material selection in accordance with referenced material guidance
• Cadmium plating on threads and contact surfaces (minimum 5 µm where applicable)
• MoS2 dry-lubricant coating (thickness not specified in EN 2491)
• Classification: minimum tensile stress class of 900 MPa at ambient temperature and maximum exposure temperature of 235 °C

Key Topics

• Configuration, dimensions and mass: Dimensions and tolerances are defined (metric MJ thread series) and apply after cadmium plating but before MoS2 lubrication. Details such as chamfers, radii and removal of sharp edges (0.1 mm to 0.4 mm) are covered. Finished nuts must fit a standard socket wrench.

• Surface treatments: Cadmium plating requirements are given according to EN 2133 (5 µm minimum on threads and surfaces contactable by a 20 mm ball). MoS2 coating methods follow EN 2491; coating thickness for MoS2 is not specified in this standard.

• Functional limits: The classification denotes the minimum tensile stress the nut must withstand when tested with a higher-strength bolt. The maximum temperature rating (235 °C) is conditioned by the cadmium plating process.

• Assembly lifecycle: Self-locking torque allowance is limited to five assemblies and disassemblies at ambient temperature as an operational constraint.

• Quality & traceability: Marking follows EN 2424 (style N). Manufacturers must operate an approved production organisation and maintain an aerospace-quality management system (for example EN 9100) and document qualification activities (e.g., EN 9133) as required.

Applications

These nuts are intended for critical aerospace fastenings where reliable locking, high tensile capacity and defined thermal performance are required. Typical uses include:

• Aircraft structural assemblies
• Aerospace mechanisms requiring repeated securement within defined reassembly limits
• Installations where corrosion protection and dry lubrication (MoS2) are necessary

Related Standards

Relevant normative references cited by SIST EN 3434:2023 include:

• EN 2133 (cadmium plating)
• EN 2491 (MoS2 dry lubricants)
• ISO 5855-2 (MJ threads limit dimensions)
• ISO 5858 (self-locking nuts procurement specification)
• ISO 8788 (tolerances of form and position)
• TR 3791 (materials for self-locking nuts)

For procurement, design and certification work, reference SIST EN 3434:2023 along with the listed standards to ensure compliance with material, surface treatment, dimensional and quality management requirements.

Standards Content (Sample)

SLOVENSKI STANDARD
01-marec-2023
Aeronavtika - Matice, šestrobe, z zarezo/kronske, samozaporne, iz jekla,
kadmirane, mazane z MoS2 - Klasifikacija: 900 MPa (pri okoljski temperaturi)/235
°C
Aerospace series - Nuts, hexagon, slotted/castellated, self-locking, in steel, cadmium
plated, MoS2 lubricated - Classification: 900 MPa (at ambient temperature)/235 °C
Luft- und Raumfahrt - Sechskant-Kronenmuttern, selbstsichernd, aus Stahl, verkadmet,
MoS2-geschmiert - Klasse: 900 MPa (bei Raumtemperatur)/235 °C
Série aérospatiale - Écrous hexagonaux à créneaux, à freinage interne, en acier,
cadmiés, lubrifiés au MoS2 - Classification : 900 MPa (à température ambiante)/235 °C
Ta slovenski standard je istoveten z: EN 3434:2022
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.

EN 3434
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2022
EUROPÄISCHE NORM
ICS 49.030.30
English Version
Aerospace series - Nuts, hexagon, slotted/castellated, self-
locking, in steel, cadmium plated, MoS2 lubricated -
Classification: 900 MPa (at ambient temperature)/235 °C
Série aérospatiale - Écrous hexagonaux à créneaux, à Luft- und Raumfahrt - Sechskant-Kronenmuttern,
freinage interne, en acier, cadmiés, lubrifiés au MoS2 - selbstsichernd, aus Stahl, verkadmet, MoS2-geschmiert
Classification : 900 MPa (à température ambiante)/235 - Klasse: 900 MPa (bei Raumtemperatur)/235 °C
°C
This European Standard was approved by CEN on 26 March 2021.

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. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists 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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 3434:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Required characteristics . 5
4.1 Configuration — Dimensions — Masses . 5
4.2 Tolerances of form and position . 7
4.3 Materials . 7
4.4 Surface treatments . 7
5 Designation . 7
6 Marking . 7
7 Technical specification . 7
8 Quality management systems. 7
Bibliography. 8

European foreword
This document (EN 3434:2022) has been prepared by the Aerospace and Defence Industries
Association of Europe - Standardization (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 European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by June 2023, and conflicting national standards shall be
withdrawn at the latest by June 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
...