EN 3720:1995
(Main)Aerospace series - Nuts, bihexagonal, self-locking, in heat resisting steel FE-PA92HT (A286), MoS2 coated - Classification: 1 100 MPa (at ambient temperature) / 425 °C
General Information
- Abstract
This standard specifies the characteristics of self-locking bihexagonal nuts in FE-PA92HT, MoS2 coated, for aerospace applications. Classification: 1 100 MPa / 425 °C
- Status
- Published
- Publication Date
- 18-Jul-1995
- Withdrawal Date
- 30-Jan-1996
- Technical Committee
- ASD-STAN - Aerospace
- Drafting Committee
- ASD-STAN/D 3 - Mechanical
- Current Stage
- 6060 - Definitive text made available (DAV) - Publishing
- Start Date
- 19-Jul-1995
- Completion Date
- 19-Jul-1995
Overview
EN 3720:1995 is a CEN aerospace standard that specifies the characteristics of bihexagonal (12‑point), self‑locking nuts made from heat‑resisting steel FE‑PA92HT (A286) with a MoS2 (molybdenum disulfide) coating. The standard covers mechanical and material classification for aerospace use, with a strength classification shown as 1 100 MPa (at ambient temperature) / 425 °C. It is indexed under ICS 49.030.30 (Nuts) and has been adopted nationally as SIST EN 3720:2001.
Key topics and requirements
- Material designation: Heat‑resisting steel FE‑PA92HT (A286) specified for high‑temperature performance.
- Nut type: Bihexagonal (12‑point) geometry, self‑locking design to resist loosening under dynamic or vibratory loads.
- Coating: MoS2 solid‑film coating for friction control, assembly torque consistency and improved anti‑galling behavior.
- Classification: Strength/service classification indicated as 1 100 MPa (ambient) / 425 °C, denoting suitability for elevated temperature applications in aerospace assemblies.
- Intended aerospace use: Dimensional, material and performance expectations tuned to aerospace fastener quality and reliability.
- Conformity: Adoption and national identifications (e.g., SIST EN 3720:2001) for regulatory and procurement traceability.
Applications
- Aircraft structural and engine fastenings where high temperature resistance and reliable locking are required.
- Turbine engine accessories, exhaust and high‑temperature zones where A286 strength retention is needed.
- Assemblies exposed to vibration and thermal cycling that require self‑locking features and controlled friction from MoS2 coating.
- Use in design specifications, procurement documents, quality control and inspection plans for aerospace suppliers and maintenance organizations.
Who uses this standard
- Aerospace design and stress engineers selecting fasteners for high‑temperature service.
- Procurement and specification writers requiring standardized, certified fastener performance.
- Quality assurance, testing and inspection teams verifying material, coating and locking performance.
- Fastener manufacturers and heat‑treatment shops producing A286 (FE‑PA92HT) components to aerospace requirements.
Related information / keywords
- Related designations: A286, FE‑PA92HT
- Keywords for search: EN 3720:1995, aerospace nuts, bihexagonal nut, self‑locking nut, MoS2 coated fastener, high‑temperature fastener, A286 nut, CEN aerospace standard, 1100 MPa classification, 425 °C service.
This summary helps engineers, procurement specialists and fastener manufacturers quickly understand the scope and practical use of EN 3720:1995 when selecting or specifying high‑temperature, self‑locking aerospace nuts.
Relations
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
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Frequently Asked Questions
EN 3720:1995 is a standard published by the European Committee for Standardization (CEN). Its full title is "Aerospace series - Nuts, bihexagonal, self-locking, in heat resisting steel FE-PA92HT (A286), MoS2 coated - Classification: 1 100 MPa (at ambient temperature) / 425 °C". This standard covers: This standard specifies the characteristics of self-locking bihexagonal nuts in FE-PA92HT, MoS2 coated, for aerospace applications. Classification: 1 100 MPa / 425 °C
This standard specifies the characteristics of self-locking bihexagonal nuts in FE-PA92HT, MoS2 coated, for aerospace applications. Classification: 1 100 MPa / 425 °C
EN 3720:1995 is classified under the following ICS (International Classification for Standards) categories: 49.030.30 - Nuts. The ICS classification helps identify the subject area and facilitates finding related standards.
EN 3720:1995 has the following relationships with other standards: It is inter standard links to CEN ISO/TS 21189:2019, EN 16062:2015, EN 16062:2011. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN 3720:1995 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)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Aerospace series - Nuts, bihexagonal, self-locking, in heat resisting steel FE-PA92HT (A286), MoS2 coated - Classification: 1 100 MPa (at ambient temperature) / 425 °CLuft- und Raumfahrt - Zwölfkantmuttern, selbstsichernd, aus hochwarmfestem Stahl FE-PA92HT (A286), MoS2 beschichtet - Klasse: 1 100 MPa (bei Raumtemperatur) / 425 °CSérie aérospatiale - Ecrous bihexagonaux, a freinage interne, en acier résistant a cha
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