5052 Aerospace Aluminium Tube

Why 5052 is the standard aircraft line tube

5052 is a medium-strength aluminium alloy with about 2.5 % magnesium and 0.25 % chromium. It cannot be heat treated, so its strength comes from cold drawing; in exchange it is ductile, weldable and very resistant to corrosion, including in marine air.

Aircraft fluid systems need tube that can be bent to tight radii, flared or beaded for fittings, and left in service for decades without corroding inside or out. Annealed 5052-O does this better than almost any other aluminium alloy. It is stronger than 3003, which it largely replaced for fuel and oil lines, yet far more forgiving to form than heat-treated 6061-T6 or 2024-T3. Where pressure is high, as in main hydraulic systems, designers move to 6061-T6, 2024-T3 or titanium and stainless steel; for fuel, oil, vent, drain, pneumatic, instrument and low-pressure hydraulic return lines, 5052-O remains the default.

The same alloy drawn in harder tempers, H32 to H38, is used for light frames, handrails, antenna masts, ducting and fixtures where some strength is needed and the tube is welded or mechanically joined. Compared with high-manganese alloys, 5052 also has better resistance to stress-corrosion cracking, which matters in tubes that are bent and then held under clamp loads.

The page below covers composition, properties by temper, the AMS and ASTM specifications buyers most often quote, sizes and weights, tolerances, fabrication advice, testing, finishes and how 5052 compares with the alternatives.

5052 tube chemical composition (wt %)

All 5052 tubing specifications use the same registered composition. Magnesium provides solid-solution strength; chromium controls grain growth during annealing and improves resistance to stress corrosion. Copper is held to 0.10 % maximum, which is one reason the alloy performs so well in corrosive service.

Values follow the Aluminum Association registration used by ASTM B210, B241, AMS 4069/4071 and EN 573-3.

Mechanical properties of 5052 tube by temper

For drawn tube, ASTM B210 sets minimum tensile and yield strength for each temper, with a maximum tensile strength for O so the tube stays soft enough to form. The AMS tubing specifications for 5052-O use comparable limits and add tighter dimensional and inspection requirements.

Minimums summarised from ASTM B210 for drawn 5052 tube; elongation limits depend on wall thickness and specimen type. Always design to the values in the edition named on your order.

Which 5052 tube temper should you order?

• Bending, flaring or beading? Order O. Stabilised H3x tempers crack at the small radii typical of aircraft plumbing.
• Welded frame or enclosure? H32 or H34; remember the weld zone will soften towards O properties.
• Vibration or handling loads on straight tube? H36 gives more stiffness against denting.
• Maximum strength, no forming? H38, or consider 6061-T6 if the part needs still more.

5052 tube specifications for aerospace and industry

Aircraft drawings usually call an AMS specification; industrial and marine buyers use ASTM or EN. The table lists the documents most often quoted for 5052 tube. Older drawings may cite WW-T-700/4, the federal specification for 5052 tube, which has been superseded and is not recommended for new designs.

5052 tube sizes, shapes and weights

Weight of round tube in kg per metre is π × (OD − wall) × wall × 2.68 ÷ 1000, with dimensions in millimetres. Use the tube weight calculator for any other size.

Dimensional tolerances for 5052 drawn tube

Commercial drawn tube follows the standard tolerance tables in ASTM B210 (ANSI H35.2). AMS close-tolerance specifications such as AMS 4069 tighten diameter and wall limits further, which is why they are preferred for flared hydraulic and fuel lines where fit with fittings is critical.

Typical mean-diameter tolerances for drawn round tube per ANSI H35.2. Tolerances at any single point are wider, especially for annealed tube, which can go slightly oval in handling. Confirm against the edition named on your order.

Pressure rating and design notes for 5052 lines

A first estimate of burst pressure for a thin-walled tube comes from Barlow's formula, P = 2 × S × t ÷ OD, where S is the tensile strength, t the wall and OD the outside diameter. For a 3/8 in × 0.035 in 5052-O line using the 25 ksi minimum tensile strength, estimated burst is about 4,700 psi (32 MPa). Aircraft practice applies a substantial factor of safety, often four, giving a working pressure in the region of 1,100 – 1,200 psi for that size.

That calculation explains why 5052-O is used for fuel, oil, pneumatic and return lines, while 3,000 psi and 5,000 psi hydraulic pressure lines use 6061-T6, 2024-T3, titanium or corrosion-resistant steel. The figures here are only a first estimate; the governing design manual, the fitting manufacturer's data and qualification testing control the final rating.

• Bend radius: 5052-O tube bends well at centreline radii of about 2 – 3 × OD on a mandrel bender; thin walls need closer-fitting mandrels and wiper dies to avoid wrinkling.
• Flaring: 37° single flares (AN/MS style) are routinely made on 5052-O; harder tempers are prone to splitting at the flare.
• Support spacing: clamp lines often enough to keep vibration frequencies away from engine and propeller excitation.
• Galvanic contact: separate from stainless or titanium fittings with sealant or anodised and primed surfaces; never let carbon-fibre structure touch bare tube.
• Chafing: use cushioned clamps and sleeves where lines pass through structure.

Bending, welding, machining and finishing

Surface treatments for 5052 tube

Note that colour identification of aircraft fluid lines is normally done with tape or band markings rather than by anodising colour, so the finish should be chosen for protection and fatigue performance first.

Where 5052 tube is used

• Aircraft fuel systems: feed, transfer, vent and drain lines in O temper
• Oil and lubrication: engine and gearbox oil lines on light aircraft and helicopters
• Pneumatic and instrument lines: pitot-static, vacuum and low-pressure air lines
• Hydraulic return and low-pressure lines where the system design allows aluminium
• Environmental-control ducting and cooling-air ducts in welded assemblies
• Ground support equipment: handrails, platforms, stands and refuelling equipment
• Marine and offshore: seawater-spray piping, railings, masts and canopy frames
• Transport and industry: fuel and oil lines, HVAC conduits, pneumatic systems and machine frames

A representative case is a light-aircraft fuel system: wing-tank feed lines in 3/8 in × 0.035 in 5052-O tube, bent on a mandrel bender, 37°-flared, joined with anodised aluminium fittings and supported in cushioned clamps. The same alloy in H32 sheet forms the tanks, giving consistent corrosion behaviour across the system.

5052 tube compared with 3003, 6061, 5083 and 2024

3003 is cheaper and slightly more formable but has little more than half the strength, so it is now used mainly for ducting and very low-pressure lines. 6061-T6 and 2024-T3 take over when pressure rises. 5083 is stronger than 5052 but must not run above about 65 °C because of sensitisation, which rules it out of many engine-bay locations.

Common mistakes when buying 5052 tube

• Ordering a hard temper for bent lines. H32 and H34 look attractive for their strength, but they split at flares and tight bends. If the tube will be formed, order O and let the design use O allowables.
• Accepting seamed tube for pressure service. Porthole-die extruded tube is cheaper but has extrusion welds along its length. Fuel and hydraulic lines should be drawn seamless, and the order should say so.
• Leaving out the specification revision. AMS documents change over time. Quoting the revision letter avoids disputes over test requirements and tolerances at receiving inspection.
• Ignoring internal cleanliness. Drawing lubricant and debris inside tube can contaminate fuel and hydraulic systems. Ask for cleaned and capped tube if lines go straight into assembly.
• Mixing imperial and metric sizes. Aircraft fittings are sized to imperial tube (for example 3/8 in OD). A 10 mm tube will not seal in a 3/8 in fitting, so state the unit system clearly.
• Forgetting galvanic isolation. Bare 5052 in contact with stainless fittings or carbon-fibre structure will corrode at the joint; plan sealant, primer or anodised interfaces in the design.

Related 5052 products and aerospace tubing

How to order 5052 aerospace tube

1. SpecifyAlloy and temper, OD and wall (or schedule), length or coil, quantity and the governing specification with its revision (AMS 4069, AMS 4071, ASTM B210 or EN 754).
2. ConfirmWe confirm the specification can be met, the tolerance class, any extra tests and the delivery terms (EXW, FOB, CIF or DAP).
3. InspectMaterial is checked for dimensions, straightness and surface condition; tests named on the order are carried out or arranged with a third party.
4. DocumentEach lot ships with a mill test certificate to EN 10204 3.1 showing chemistry and mechanical results, traceable to the cast or lot number.
5. Pack and shipExport packing in sealed, moisture-protected wooden cases or on pallets, shipped by sea or air to your port or door.

5052 aerospace aluminium (aluminum) tube: FAQs