EN 4031:2001

Aerospace series - Pipe coupling 8°30' in titanium alloy - Nut for welded ferrule

This standard specifies the characteristics of nuts for welded ferrules, for pipe couplings 8 30', in titanium alloy, for
aerospace applications.
Nominal pressure: up to 28 000 kPa
Temperature range:   55  C to 135  C

Luft- und Raumfahrt - Rohrverschraubung 8°30' aus Titanlegierung - Mutter für Anschweißstutzen

Diese Norm legt die Eigenschaften von Muttern für Anschweißstutzen, für Rohrverschraubungen 8 30', aus Titanlegierung,
zur Verwendung in der Luft- und Raumfahrt fest.
Nenndruck: bis 28 000 kPa
Temperaturbereich:   55  C bis 135  C

Série aérospatiale - Système de raccordement 8°30' en alliage de titane - Écrou pour olive soudée

La présente norme spécifie les caractéristiques d'écrous pour olive à souder, pour les systèmes de raccordement 8 30',
en alliage de titane, pour applications aérospatiales.
Pression nominale: jusqu'à 28 000 kPa
Plage de température:   55  C à 135  C

Aerospace series - Pipe coupling 8-30' in titanium alloy - Nut for welded ferrule

General Information

• Status: Published
• Publication Date: 18-Sep-2001
• Withdrawal Date: 30-Mar-2002
• ICS: 49.080 - Aerospace fluid systems and components
• Technical Committee: ASD-STAN - Aerospace
• Drafting Committee: ASD-STAN/D 3 - Mechanical
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 31-May-2017
• Completion Date: 11-Feb-2026
• Ref Project: SIST EN 4031:2002 - Aerospace series - Pipe coupling 8°30' in titanium alloy - Nut for welded ferrule

Relations

• Child: ISO 22437:2018 - Aerospace series — Pipe coupling 8°30' in titanium alloy — Nut for welded ferrule
• Effective Date: 12-Feb-2026
• Refers: prEN 415-2 - Packaging machines safety - Part 2: Pre-formed rigid container packaging machines
• Effective Date: 28-Jan-2026
• Refers: EN 2424:2008 - Aerospace series - Marking of aerospace products
• Effective Date: 28-Jan-2026
• Refers: EN 2497:1989 - Aerospace series - Dry abrasive blasting of titanium and titanium alloys
• Effective Date: 28-Jan-2026
• Refers: EN 3275:2019 - Aerospace series - Pipe coupling 8°30' up to 28 000 kPa Dynamic beam seal - Metric series - Technical specification
• Effective Date: 28-Jan-2026
• Refers: EN 3311:2023 - Aerospace series - Titanium alloy TI-P64001 (Ti-6Al-4V) - Annealed - Bars for machining - D ≤ 300 mm - 900 MPa ≤ Rm ≤ 1 160 MPa
• Effective Date: 28-Jan-2026
• Referred By: EN 4686:2014 - Aerospace series - Pipe coupling 8°30' in titanium alloy - Equipped blind ferrules
• Effective Date: 28-Jan-2026
• Referred By: EN ISO 13631:2002 - Petroleum and natural gas industries - Packaged reciprocating gas compressors (ISO 13631:2002)
• Effective Date: 28-Jan-2026

Overview

EN 4031:2001 is a European Standard developed by CEN (Comité Européen de Normalisation) as part of the Aerospace Series standards. It outlines the specific requirements for nuts used in welded ferrule pipe coupling systems with an 8°30' angle, constructed from titanium alloy. These aerospace-grade components are designed to operate at nominal pressures up to 28,000 kPa and within a temperature range of -55°C to 135°C. The standard is vital for ensuring high performance, durability, and safety in demanding aerospace environments.

Key Topics

• Scope of Application: EN 4031:2001 applies to nuts for welded ferrules in 8°30' pipe couplings specifically intended for aerospace fluid systems.
• Material Specifications: Nuts are manufactured from titanium alloys compliant with EN 3311 and EN 3314, ensuring high strength, corrosion resistance, and aerospace reliability.
• Performance Requirements:
  • Nominal pressure resistance up to 28,000 kPa.
  • Operational temperature range from -55°C to 135°C.
• Surface Properties:
  • Surface roughness and finish must conform to defined specifications, ensuring high-quality connections.
  • Lubrication is required: PTFE (e.g., suitable commercial coatings) is applied on the 110° contact area for optimal assembly and long-term performance.
  • Pre-lubrication cleaning with non-metallic abrasive blasting as per EN 2497.
• Dimensional Control: Threads, mass, and other dimensions are standardized for consistent fit and function, referencing ISO 5855-3 and ISO 8788 for thread and tolerance definitions.
• Marking Requirements: Products must be marked in accordance with EN 2424, style A, ensuring full traceability in aerospace supply chains.

Applications

EN 4031:2001 standardized nuts are integral to the assembly of welded ferrule pipe couplings in the following contexts:

• Aerospace Hydraulic and Fluid Systems: Used in fuel, hydraulic, and pneumatic lines where high pressure, high reliability, and temperature resistance are crucial.
• Aircraft Manufacturing and Maintenance: Provides manufacturers, MRO providers, and suppliers with a trusted specification for procurement and quality assurance.
• Military and Spacecraft Fluid Components: These nuts ensure mission-critical connections in both military and commercial craft.
• Titanium Alloy Structures: Preferred where weight savings, corrosion resistance, and structural integrity are required.

Key benefits of using EN 4031:2001-compliant nuts include enhanced safety, consistent performance under extreme conditions, and interoperability with other standardized aerospace pipe coupling components.

Related Standards

EN 4031:2001 references several important aerospace standards to ensure comprehensive quality and interoperability:

• ISO 5855-3: Aerospace - MJ threads - Limit dimensions for fittings for fluid systems.
• ISO 8788: Aerospace - Metric nuts - Tolerances of form and position.
• EN 2424: Aerospace series - Marking of aerospace products.
• EN 2497: Dry abrasive blasting of titanium and titanium alloys.
• EN 3275: Pipe coupling 8°30' up to 28,000 kPa - Dynamic beam seal - Metric series - Technical specification.
• EN 3311 / EN 3312 / EN 3314: Specifications for titanium alloy materials and processing for aerospace use.

To maximize integration and regulatory alignment, aerospace professionals should use EN 4031:2001 together with these related standards for all critical pipe coupling applications in high-pressure, safety-relevant environments.

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EN 4031:2001 sets essential requirements for aerospace nuts for welded ferrules, supporting high reliability, safety, and standardization across global aerospace supply chains.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Aerospace series - Pipe coupling 8-30' in titanium alloy - Nut for welded ferruleLuft- und Raumfahrt - Rohrverschraubung 8°30' aus Titanlegierung - Mutter für AnschweißstutzenSérie aérospatiale - Systeme de raccordement 8°30' en alliage de titane - Écrou pour olive soudéeAerospace series - Pipe coupling 8°30' in titanium alloy - Nut for welded ferrule49.080Aerospace fluid systems and componentsICS:Ta slovenski standard je istoveten z:EN 4031:2001SIST EN 4031:2002en01-januar-2002SIST EN 4031:2002SLOVENSKI
STANDARD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 4031September 2001ICS 49.080English versionAerospace series - Pipe coupling 8°30' in titanium alloy - Nut forwelded ferruleSérie aérospatiale - Système de raccordement 8°30' enalliage de titane - Ecrou pour olive soudéeLuft- und Raumfahrt - Rohrverschraubung 8°30' ausTitanlegierung - Mutter für AnschweißstutzenThis European Standard was approved by CEN on 29 December 2000.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the 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 translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2001 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 4031:2001 ESIST EN 4031:2002

ScopeThis standard specifies the characteristics of nuts for welded ferrules, for pipe couplings 8°30', in titanium alloy, foraerospace applications.Nominal pressure: up to 28 000 kPaTemperature range:
55 °C to 135 °C2
Normative referencesThis European Standard incorporates by dated or undated reference provisions from other publications. These normativereferences are cited at the appropriate places in the text and the publications are listed hereafter. Fo
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