Precision drawn aluminium tube is extruded and then cold drawn over a mandrel to tight diameter and wall tolerances with a smooth, bright surface. The clearest way to see how it is specified is through real-world specification types. Below are seven typical orders, from thin-wall 2024-T3 aerospace tube to large-diameter 5083 marine tube, with what each specification line means and why it was chosen.
A drawn tube starts as an extruded or pierced hollow. It is then pulled through a die while a mandrel or plug supports the bore, reducing diameter and wall in one or more passes. Cold drawing tightens dimensions, improves surface finish and, in non-heat-treatable alloys, raises strength by cold work.
The result is tube that is rounder, straighter and more uniform in wall than extruded tube, with a surface that often needs no further finishing. It is the right material when the tube is a precision component in its own right: a telescopic section, a hydraulic or pneumatic barrel, an instrument housing, an aircraft fluid line or a part that will be machined with minimal stock removal.
Tightest tolerances and finishes depend on alloy, size and wall; confirm on the quotation.
Each example below is a typical specification pattern for its application, not a particular customer order. Weights are calculated from nominal dimensions at the density of each alloy.
Seamless drawn tube to ASTM B210 and AMS-WW-T-700/3 for aircraft structures and fittings. T3 (solution treated, cold worked, naturally aged) gives high strength and good fatigue resistance. Cut to short lengths for machining.
Thin-wall seamless tube with a diameter-to-wall ratio of 34. Used for UAV arms and frames where stiffness per gram matters. Wall tolerance is the key line: thin walls must stay uniform for consistent stiffness.
Free-machining Al-Cu tube for turned sleeves and housings. Close OD and wall tolerances reduce the stock that must be removed and make automated bar-fed machining reliable.
Heavy-wall cold drawn seamless tube for marine fittings, railings and offshore equipment. 5083 resists seawater and keeps strength after welding; long 6 m lengths reduce joints.
A family of three diameters with the same 3.5 mm wall, drawn to EN 754 for mechanical components. 6005A combines good strength with excellent surface finish after drawing.
Annealed thin-wall tube for formed ducts and fluid lines. The O temper allows bending, flaring and swaging without cracking.
Large-diameter thin-wall seamless tube for housings and structural shells. Roundness and straightness over long lengths are the hardest requirements at this size.
| Example | Alloy and temper | OD × wall (mm) | Weight (kg/m) | Key specification line |
|---|---|---|---|---|
| 1 | 2024-T3 | 25 × 2.5 | 0.49 | Aerospace certification |
| 2 | 2024-T4 | 34 × 1 | 0.29 | Wall uniformity |
| 3 | 2017-T4 | 42 × 1 | 0.36 | OD tolerance for bar feeders |
| 4 | 5083 | 60 × 5 | 2.30 | Seamless, long length |
| 5 | 6005A-T6 | 90 × 3.5 | 2.57 | Surface finish |
| 6 | 5052-O | 90 × 1.5 | 1.12 | Formability |
| 7 | 5083-O | 166 × 3 | 4.09 | Roundness and straightness |
Example 5 weight is for the 90 mm size of the family; weights for other sizes follow the same formula: kg/m = π × (OD − wall) × wall × density ÷ 1000.
| Specification line | What it controls | Common mistake |
|---|---|---|
| Alloy and temper | Strength, corrosion resistance, formability, machinability | Ordering T6 when the tube must be bent; order O or T4 and heat treat after forming |
| Seamless vs structural (porthole) | Whether the tube has extrusion weld seams | Using porthole-extruded tube for pressure or critical fatigue parts |
| OD and wall (or OD and ID) | Fit and stiffness | Specifying OD, ID and wall together, which over-constrains the tube |
| Tolerances | Fit, interchangeability, machining stock | Asking for tight tolerances on every dimension when only one matters |
| Surface roughness | Appearance, sealing, anodising result | Not stating whether inside, outside or both |
| Straightness and length | Telescoping, machining, assembly | Forgetting the length over which straightness is measured |
| Standard | Test methods, tolerances, certification | Mixing ASTM tolerances with EN property tables |
| Family | Typical alloys | Typical features | Applications |
|---|---|---|---|
| High-strength drawn tube | 6061, 6082, 7075, 2024 | T6, T6511, T3 tempers | Bicycle frames, aircraft fluid lines, seat structures, optical instruments |
| Ultra-thin-wall tube | 6061, 6063, 7075 | Wall from about 0.5 mm; OD/wall ratio above 30 | Lightweight frames, sports equipment, drone arms |
| High-surface-finish tube | 6060, 6061, 6063, 6082, 3003, 7075 | Surface down to about Ra 0.2 µm | Medical parts, outdoor equipment, decorative parts |
| Drawn tube in coil | 1070, 1100, 3003, 3103 | OD about 4 – 28 mm, wall 0.3 – 1.5 mm | Air conditioning, fuel and cooling lines |
| Telescopic tube | 6063, 6005, 7075 | Matched OD/ID pairs, close straightness | Tripods, trekking poles, tent poles, fishing rods, antennas |
| Small-diameter tube | Various | OD about 3 – 10 mm, wall 0.3 – 2 mm | Headphone parts, cosmetic tubes, precision pins and sleeves |
Extruded tube is formed hot through a die and has wider tolerances. Drawn tube is extruded and then cold drawn over a mandrel, giving tighter diameter and wall tolerances, a smoother surface and, in non-heat-treatable alloys, higher strength.
Standard tolerances follow ASTM B210 or EN 754-7. By agreement, small-diameter tube can be held to a few hundredths of a millimetre on OD, with wall tolerance around ±0.05 mm or tighter, depending on alloy and size.
Yes for pressure lines, hydraulic or pneumatic barrels and fatigue-critical parts. Seamless tube has no extrusion weld seams, so properties are uniform around the circumference.
Yes. The smooth drawn surface anodises evenly. 6060, 6063 and 6061 give the best decorative results; 2024 and 7075 anodise but with a less uniform colour.
They are typical specification patterns we see for each application, used here to explain how drawn tube is specified. Your own drawing and standard always govern the order.
Send your alloy, size, tolerance, finish and quantity. Our team will confirm feasibility and reply with a delivered price.
