SIST EN 3903:2017

Aerospace series - Washers, laminated, in corrosion resisting steel

This European Standard specifies the characteristics of laminated washers, in corrosion resisting steel, for maximum operating temperature 120°C, for aerospace applications.

Luft- und Raumfahrt - Scheiben aus Schichtblech aus korrosionsbeständigem Stahl

Série Aérospatiale - Rondelles pelables, en acier résistant à la corrosion

Aeronavtika - Podložke, večplastne, iz korozijsko odpornega jekla

Ta evropski standard določa lastnosti večplastnih podložk iz korozijsko odpornega jekla za najvišjo delovno temperaturo 120 °C v aeronavtiki.

General Information

• Status: Published
• Publication Date: 30-Mar-2017
• ICS: 49.025.10 - Steels
• ICS: 49.030.50 - Washers and other locking elements
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 23-Mar-2017
• Due Date: 28-May-2017
• Completion Date: 31-Mar-2017
• Ref Project: EN 3903:2017 - Aerospace series - Washers, laminated, in corrosion resisting steel

Overview

SIST EN 3903:2017 is a European standard developed by CEN that specifies the characteristics of laminated washers made from corrosion resisting steel, tailored specifically for aerospace applications. These washers are designed to operate safely at a maximum temperature of 120°C. The standard ensures that laminated washers meet stringent dimensional, material, and performance criteria essential for aerospace industry requirements, promoting reliability, safety, and quality consistency across the supply chain.

Key Topics

• Scope and Application
  SIST EN 3903:2017 covers laminated washers constructed from austenitic corrosion resistant steel with a minimum tensile strength (R) of 440 MPa. It defines their dimensions, tolerances, material properties, and markings to address the specific needs of aerospace components subjected to corrosion and moderately high temperatures.

• Materials and Performance
  The washers are manufactured using corrosion resistant steel optimized for durability in aerospace environments. The standard highlights corrosion resistance and mechanical integrity at temperatures up to 120°C, ensuring washers maintain structural performance throughout their service life.

• Dimensional Specifications
  Precise dimensional requirements, including nominal diameters, thickness codes, and mass per 1000 pieces, are detailed to standardize washer design. These tolerances help ensure interchangeability and consistent mechanical behavior during assembly and operation.

• Designation and Marking
  The standard prescribes washer designation syntax combining the EN 3903 reference, thickness, and diameter codes. Marking follows EN 2424 style G, facilitating traceability and compliance verification throughout the aerospace manufacturing process.

• Quality Assurance
  Compliance with aerospace quality management systems under EN 9100 is mandated, reflecting the need for rigorous quality control, continuous improvement, and documentation in aerospace supply chains.

Applications

EN 3903 laminated washers find extensive use in various aerospace components where corrosion resistance and mechanical reliability under thermal stress are critical. Typical applications include:

• Aircraft structural assemblies requiring secure fastener locking elements with consistent load distribution.
• Engine compartments and equipment exposed to moderate temperature variations up to 120°C.
• Aerospace defense systems and space vehicle hardware requiring standardized locking washers for vibration resistance.
• Maintenance, repair, and overhaul (MRO) operations where standardized replacement washers ensure compatibility and safety compliance.

Utilizing EN 3903-compliant washers enables aerospace manufacturers and maintenance providers to improve joint integrity, reduce corrosion-related failures, and enhance overall operational safety.

Related Standards

• EN 2424 - Aerospace series: Marking of aerospace products, referenced for standardized marking requirements.
• EN 9100 - Aerospace series: Quality management systems requirements for aviation, space, and defense organizations, ensuring quality assurance in production.
• Other aerospace standards on fasteners and locking elements that complement the use of laminated washers in assembly processes.

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By adhering to SIST EN 3903:2017, aerospace manufacturers ensure that laminated washers meet strict industry benchmarks for corrosion resistance, dimensional accuracy, and quality management-key factors for dependable aerospace component performance and safety.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2017
$HURQDYWLND3RGORåNHYHþSODVWQHL]NRUR]LMVNRRGSRUQHJDMHNOD
Aerospace series - Washers, laminated, in corrosion resisting steel
Ta slovenski standard je istoveten z: EN 3903:2017
ICS:
49.025.10 Jekla Steels
49.030.50 Podložke in drugi blokirni Washers and other locking
elementi elements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 3903
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2017
EUROPÄISCHE NORM
ICS 49.030.50
English Version
Aerospace series - Washers, laminated, in corrosion
resisting steel
Série Aérospatiale - Rondelles pelables, en acier Luft- und Raumfahrt - Scheiben aus Schichtblech aus
résistant à la corrosion korrosionsbeständigem Stahl
This European Standard was approved by CEN on 11 March 2016.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 3903:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Required characteristics . 4
4 Designation. 6
5 Marking . 6
6 Quality assurance .
...