Aluminium Tube Coil (Coiled Aluminium Tubing)

What is aluminium tube coil?

Tube coil is a supply format, not a separate alloy. Long lengths of small round tube, hundreds or thousands of metres in one piece, are wound onto a coil so that a manufacturer can feed them continuously into straightening, cutting and bending machines with very little scrap and no joints.

There are two main routes to make it. Extruded coiled tube is pressed through a die and coiled directly at the press; ASTM B491 covers this product for general-purpose uses such as refrigeration service, gas lines, oil lines and instrument lines, in outside diameters from 6.00 to 20.00 mm (0.250 – 0.750 in). Drawn coiled tube starts as an extruded hollow that is cold-drawn through dies over a mandrel to reach thinner walls and tighter tolerances, then annealed; seamless drawn tube is covered by ASTM B210 and EN 754, and general-purpose drawn tube by ASTM B483.

Aluminium tube coil competes directly with copper coil in air conditioning and refrigeration. It is far lighter (aluminium is about 2.7 g/cm³ against about 8.9 g/cm³ for copper), its price is less volatile, and it removes galvanic corrosion problems where an aluminium fin coil meets a copper tube. The trade-offs are lower strength, which calls for slightly thicker walls, and the need for proper brazing or mechanical joints in place of simple soft soldering.

Which alloy for tube coil?

Coiled tube is almost always made from non-heat-treatable alloys, because the tube has to be soft enough to coil, uncoil and bend. Strength therefore comes from wall thickness and alloy choice rather than heat treatment.

For most refrigeration and HVAC work the choice is between 1100 and 3003. 3003 gives a useful margin of strength for higher-pressure refrigerants and is common in brazed heat exchangers; 1100 is chosen where maximum bendability or slightly better conductivity matters. See the 3003 tube and 1100 tube pages for full alloy data.

Mechanical properties of common tube coil alloys

Typical values for annealed (O temper) material from Aluminum Association data. H111 is slightly work-hardened after annealing, from coiling and straightening, and sits just above O. Tube supplied to ASTM B210 or B491 is tested against the minimum and maximum limits in the standard; the mill certificate reports the actual results.

Typical tube coil specification range

If your process uses an automatic decoiler and straightener, send us the machine’s coil inner diameter, maximum outer diameter, maximum weight and winding direction. A level-wound coil that suits the line saves hours of set-up and prevents tangles. For installers, pancake coils of a fixed length (for example 15 m or 50 ft) are easier to carry and unroll on site.

Weight per metre of common tube coil sizes

Weight per metre = π × (OD − wall) × wall × density. The table uses 2.71 g/cm³ (1100); 3003 is about 0.7 % heavier. The last column shows roughly how many metres of tube make up 10 kg of coil.

Estimating pressure capability

Pressure rating is the question buyers ask most, and it cannot be answered by the alloy alone. A first estimate uses Barlow’s formula: burst pressure P ≈ 2 × S × t / OD, where S is the tensile strength, t the wall thickness and OD the outside diameter. Working pressure is the burst pressure divided by a safety factor, and refrigeration codes set those factors.

As an illustration, a 9.52 × 1.0 mm tube in 3003-O, taking a conservative tensile strength of 95 MPa, gives an estimated burst pressure of about 2 × 95 × 1.0 / 9.52 ≈ 20 MPa (200 bar). With a safety factor of 3 to 5 the allowable working pressure would sit between about 40 and 65 bar. Treat this as a screening calculation only; brazed joints, bends that thin the outer wall, temperature and the code you design to (for example ISO 5149 or EN 378 for refrigerating systems) all reduce the real figure, and qualified systems must be pressure-tested.

Bending, joining and surface treatment

Where aluminium tube coil is used

• HVAC and refrigeration: refrigerant line sets, evaporator and condenser circuits, heat-pump coils and dehumidifiers
• Domestic appliances: refrigerator evaporators and freezer coils, often in 1100 or 3003
• Automotive thermal management: A/C lines, oil-cooler and battery-cooling circuits (alongside microchannel tube)
• Gas, oil and instrument lines: compressed air, pneumatic control and lubrication lines where light weight and easy routing matter
• Solar thermal: absorber circuits and storage-tank heat exchangers
• Medical and laboratory: oxygen-concentrator and analytical-instrument tubing
• Industrial heat exchangers: serpentine coils for process cooling and heat recovery

Aluminium tube coil compared with copper coil

In practice the tube’s thermal resistance is a small part of a heat exchanger’s total, so the lower conductivity of aluminium has little effect on coil performance when the design accounts for it. The bigger engineering tasks are jointing and wall thickness. All-aluminium coils also simplify end-of-life recycling.

How to order aluminium tube coil

1. Specify the tubeAlloy and temper (for example 3003-O), OD, wall thickness and the governing standard (ASTM B491, B210 or EN 754).
2. Specify the coilLevel-wound or pancake, coil ID and OD, coil weight or length, winding direction and end sealing.
3. TestingState any eddy-current, pressure, cleanliness or flaring and expansion tests you need.
4. DocumentsMill test certificate to EN 10204 3.1 with chemical and mechanical results, plus packing list.
5. Packing and shippingCoils packed on pallets or in wooden cases with moisture protection, shipped on EXW, FOB, CIF or DAP terms worldwide.

Related tube products and guides

Aluminium (aluminum) tube coil: FAQ