EN 4024:2009

Overview

EN 4024:2009 - Aerospace series - Pipe coupling 8°30' in titanium alloy - Elbows 45° welded end with thrust wire nut is a CEN standard that specifies the physical, material and quality requirements for 45° titanium alloy elbows with welded ends and thrust wire nuts used in aerospace fluid systems. The standard covers nominal pressure up to 28 000 kPa and an operating temperature range of −55 °C to 135 °C, and is intended for high-reliability aerospace applications where a pipe coupling 8°30' geometry is required.

Key topics and requirements

• Configuration, dimensions and mass: Detailed geometric data and mass values are defined by Figure 1 and Table 1 of the standard; dimensions apply before lubrication and unspecified dimensions may be at the manufacturer’s option when EN 3275 (type II) acceptance is met.
• Material: Titanium alloy per the referenced aerospace material standards (EN 3311 / EN 3312 / EN 3314 / EN 3315) for bars and forgings; selection follows the normative references.
• Surface roughness and internal finish:
  • External and internal surface roughness per Figure 1 and design documentation.
  • Internal finishing must achieve a radius R = 0.3–1.0 mm and surface roughness of 0.8 µm. Hand deburring is not permitted.
• Surface treatment and lubrication:
  • Welded end: no surface treatment for at least 10 mm (outside and bore).
  • Lubrication on the thrust wire/coupling contact area per EN 2491; prior to lubrication the surface must be abrasive blasted using non‑metallic grit. Lubricant film thickness: 0.005 mm to 0.013 mm.
• Threading and connections: Thread dimensions follow ISO 5855-3 (MJ threads) and thrust wire/nut geometry references (EN 3264, EN 4032).
• Designation, marking and QA:
  • Designation format and marking per EN 4024 (example: EN4024-0806) and EN 2424 (marking style A).
  • Technical specification cross-reference: EN 3275 (type II).
  • Quality assurance and qualification: EN 9133.

Applications and users

EN 4024:2009 is used by:

• Aerospace component designers and system engineers specifying pipe fittings for aircraft fluid systems.
• Manufacturers and machinists producing titanium 45° elbows with welded ends and thrust wire nuts to aerospace standard parts.
• Procurement, conformity assessment and quality engineers ensuring parts meet pressure, temperature and finish requirements.
• Certification bodies and inspectors performing acceptance testing and verification to EN 3275 and EN 9133.

Typical applications include high-pressure aerospace fluid lines and assemblies requiring lightweight, corrosion‑resistant titanium fittings with precise mating geometry (8°30' pipe coupling).

Related standards

Key normative references: EN 2424, EN 2491, EN 2656, EN 3264, EN 3273, EN 3275, EN 3311/3312/3314/3315, EN 4032, EN 9133, ISO 5855-3. These define marking, lubrication, geometric configuration, material grades, thrust-wire components, dynamic seals and qualification procedures.