Welding
MIG and TIG weld readily with ER5356 or ER5183. As-welded strength approaches O-temper values, so H32 gains are lost only in the heat-affected zone.
Marine-grade seamless pipe
5086 Aluminium Pipe & Tube
5086 aluminium pipe is a 4 % magnesium, non-heat-treatable marine alloy that combines high strength with excellent resistance to seawater and keeps most of its strength when welded. It is widely used for boat and ship piping, rails and fittings, desalination plants, storage tanks and cryogenic lines. Metline supplies 5086 drawn seamless and extruded pipe in Schedule 40, 80 and 160, plus round and square tube, in H32, H111, H112 and O, worldwide.
- Alloy
- 5086 (Al-4Mg-Mn)
- Tempers
- O, H32, H34, H111, H112
- Pipe sizes
- NPS 1/4 – 12, Sch 40/80/160
- Standards
- ASTM B241 · B210 · B221
What is 5086 aluminium pipe?
5086 is an aluminium-magnesium alloy with about 4 % magnesium, slightly less than 5083. It is strengthened by cold work rather than heat treatment, so welding does not destroy a heat-treated temper and the welded joint keeps close to annealed parent-metal strength.
In pipe form, 5086 is most often supplied in H32: strain-hardened and stabilised, giving a useful jump in yield strength over the annealed condition while staying ductile enough to bend and flare. Drawn seamless pipe is produced in standard nominal pipe sizes and schedules; extruded seamless pipe and tube cover heavier walls and larger sizes, and square tube is available both drawn (H111) and extruded (H32).
Boatbuilders like 5086 because it matches the 5086 and 5083 plate used for hulls and decks, so pipe, rail and structure can be welded with the same filler and will corrode at the same rate. It is also chosen for desalination plant lines, fuel and chemical storage tank fittings, and low-temperature service, where its toughness increases as temperature falls.
5086 chemical composition (wt %)
Registered limits for 5086 (EN AW-5086, AlMg4). The certificate reports actual analysis per lot.
| Element | Minimum | Maximum | Role in the alloy |
|---|---|---|---|
| Silicon (Si) | — | 0.40 | Impurity |
| Iron (Fe) | — | 0.50 | Impurity |
| Copper (Cu) | — | 0.10 | Kept low for seawater resistance |
| Manganese (Mn) | 0.20 | 0.7 | Strength and grain control |
| Magnesium (Mg) | 3.5 | 4.5 | Main strengthening element |
| Chromium (Cr) | 0.05 | 0.25 | Stress-corrosion resistance |
| Zinc (Zn) | — | 0.25 | Impurity |
| Titanium (Ti) | — | 0.15 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder |
Mechanical properties of 5086 pipe and tube
Typical values are Aluminum Association and ASM data for comparison. Specified minimums depend on the tube standard and wall; for example, drawn 5086-H32 tube must reach about 276 MPa (40 ksi) tensile and 193 MPa (28 ksi) yield under ASTM B210. The certificate for each lot is the governing record.
| Temper | Condition | Tensile strength | Yield strength | Elongation | Hardness |
|---|---|---|---|---|---|
| O | Annealed | 262 MPa / 38 ksi | 117 MPa / 17 ksi | 22 % | — |
| H111 | Annealed with slight strain hardening | Close to O; slightly higher yield | — | — | — |
| H112 | As extruded | Close to O; minimums per ASTM B221 / B241 | — | — | — |
| H32 | Quarter hard, stabilised | 290 MPa / 42 ksi | 207 MPa / 30 ksi | 12 % | About 72 HB |
| H34 | Half hard, stabilised | 324 MPa / 47 ksi | 255 MPa / 37 ksi | 10 % | — |
Physical properties (typical)
- Density
- 2.66 g/cm³
- Modulus of elasticity
- 71 GPa
- Shear strength (H32)
- About 165 MPa
- Thermal conductivity
- 127 W/m·K
- Electrical conductivity
- 31 % IACS
- Thermal expansion (20 – 100 °C)
- 23.8 µm/m·°C
- Melting range
- 585 – 640 °C
Some published data sheets give inconsistent ranges for 5086 tube properties. Order to a named standard and temper, and design to the minimums in that standard.
5086 round pipe: Schedule 40 and 80 sizes
Aluminium pipe follows the nominal pipe sizes of ASME B36.10M (dimensions per ANSI H35.2). Smaller sizes (NPS 1/4 and 3/8) and Schedule 160 walls are also supplied. Weight uses 2.66 g/cm³.
| NPS | OD (in / mm) | Sch 40 wall (in / mm) | Sch 40 kg/m | Sch 80 wall (in / mm) | Sch 80 kg/m |
|---|---|---|---|---|---|
| 1/2 | 0.840 / 21.3 | 0.109 / 2.77 | 0.43 | 0.147 / 3.73 | 0.55 |
| 3/4 | 1.050 / 26.7 | 0.113 / 2.87 | 0.57 | 0.154 / 3.91 | 0.74 |
| 1 | 1.315 / 33.4 | 0.133 / 3.38 | 0.85 | 0.179 / 4.55 | 1.10 |
| 1-1/4 | 1.660 / 42.2 | 0.140 / 3.56 | 1.15 | 0.191 / 4.85 | 1.51 |
| 1-1/2 | 1.900 / 48.3 | 0.145 / 3.68 | 1.37 | 0.200 / 5.08 | 1.83 |
| 2 | 2.375 / 60.3 | 0.154 / 3.91 | 1.84 | 0.218 / 5.54 | 2.54 |
| 2-1/2 | 2.875 / 73.0 | 0.203 / 5.16 | 2.92 | 0.276 / 7.01 | 3.87 |
| 3 | 3.500 / 88.9 | 0.216 / 5.49 | 3.82 | 0.300 / 7.62 | 5.18 |
| 4 | 4.500 / 114.3 | 0.237 / 6.02 | 5.45 | 0.337 / 8.56 | 7.56 |
| 5 | 5.563 / 141.3 | 0.258 / 6.55 | 7.38 | 0.375 / 9.52 | 10.49 |
| 6 | 6.625 / 168.3 | 0.280 / 7.11 | 9.58 | 0.432 / 10.97 | 14.42 |
| 8 | 8.625 / 219.1 | 0.322 / 8.18 | 14.41 | 0.500 / 12.70 | 21.90 |
| 10 | 10.750 / 273.1 | 0.365 / 9.27 | 20.44 | 0.594 / 15.09 | 32.52 |
| 12 | 12.750 / 323.8 | 0.406 / 10.31 | 27.02 | 0.688 / 17.48 | 44.74 |
| NPS | OD (in) | Sch 40 wall (in) | Sch 80 wall (in) | Sch 160 wall (in) |
|---|---|---|---|---|
| 1/4 | 0.540 | 0.088 | 0.119 | — |
| 3/8 | 0.675 | 0.091 | 0.126 | — |
| 2 | 2.375 | 0.154 | 0.218 | 0.344 |
Sch 40 equals Standard (STD) up to NPS 10 and Sch 80 equals Extra Strong (XS) up to NPS 8; above those sizes the walls differ, so state the schedule rather than STD or XS.
5086 square tube sizes
Square 5086 tube is produced as drawn seamless tube (H111, traditionally to WW-T-700/5, now AMS-WW-T-700/5) and as extruded tube (H32 or H112 to ASTM B221). Weights assume sharp corners.
| Size (in) | Wall (in) | Size × wall (mm) | kg/m | Typical route |
|---|---|---|---|---|
| 1 × 1 | 0.125 | 25.4 × 3.17 | 0.75 | Drawn seamless H111 |
| 1.5 × 1.5 | 0.125 | 38.1 × 3.17 | 1.18 | Drawn seamless H111 |
| 2 × 2 | 0.250 | 50.8 × 6.35 | 3.00 | Extruded H32 |
| 2.25 × 2.25 | 0.125 | 57.1 × 3.17 | 1.82 | Drawn seamless H111 |
| 2.75 × 2.75 | 0.156 | 69.8 × 3.96 | 2.78 | Drawn seamless H111 |
| 3 × 3 | 0.250 | 76.2 × 6.35 | 4.72 | Extruded H32 |
| 4 × 4 | 0.250 | 101.6 × 6.35 | 6.44 | Extruded H32 |
| 6 × 6 | 0.375 | 152.4 × 9.52 | 14.48 | Drawn or extruded |
Standards for 5086 pipe and tube
| Standard | Covers |
|---|---|
| ASTM B241/B241M | Seamless pipe and seamless extruded tube for pressure use (replaced the withdrawn B345) |
| ASTM B210/B210M | Drawn seamless tube (O, H32, H34) |
| ASTM B221 | Extruded bar, rod, profiles and tube (including square tube) |
| ASTM B483 | Drawn tube for general purposes |
| ASTM B429 | Extruded structural pipe and tube |
| AMS-WW-T-700/5 | Drawn seamless 5086 tube (formerly Federal WW-T-700/5) |
| EN 754 / EN 755 | Cold drawn and extruded tube, EN AW-5086 (AlMg4) |
| Class rules | DNV, ABS, Lloyd's Register, BV for shipboard piping where required |
Equivalent designations: UNS A95086, ISO AlMg4, Werkstoff 3.3545, JIS A5086.
Welding, finishing and machining
Bending and forming
H32 bends well for rails and T-tops; O and H111 for tighter radii.
Surface finishing
Mill finish, polished, brushed, anodised or painted. Anodised 5086 has a slightly grey tone.
Machining and CNC
Cutting, drilling, threading and CNC machining to drawing; sharp tools and lubricant prevent smearing.
Service temperature
Avoid sustained service above about 65 °C to prevent sensitisation; 5086 is a little less sensitive than 5083.
Galvanic isolation
Separate from copper alloys and stainless steel in wet service.
Where 5086 pipe is used
- Shipbuilding and boats: seawater, fuel and fire-main piping, rails, stanchions, T-tops and arches
- Desalination: seawater intake and process lines
- Storage tanks: fill, vent and drain lines on fuel and chemical tanks
- Welded structures: frames and handrails exposed to coastal atmospheres
- Low-temperature service: cryogenic and refrigerated piping
5086 or 5083 pipe?
| Factor | 5086 | 5083 |
|---|---|---|
| Magnesium content | 3.5 – 4.5 % | 4.0 – 4.9 % |
| Typical tensile (O) | 262 MPa | 290 MPa |
| Typical H32 / H111 use | H32 common for pipe and rail | O / H111 common for pipe |
| Sensitisation tendency | Slightly lower | Slightly higher |
| Weldability | Excellent | Excellent |
| Choose it for | Marine pipe and rails, tanks | Highest annealed strength, LNG |
In practice the two are close. 5083 is marginally stronger annealed; 5086 is often preferred where H32 pipe or a lower sensitisation risk is wanted. See 5083 pipe.
How to order 5086 pipe
- SpecifyNPS and schedule or size × wall, temper (H32, H111, H112, O), standard, class approval, length (up to about 6 m or cut lengths) and finish.
- QuoteWe confirm availability, processing (cutting, drilling, CNC), certification and delivery terms (EXW, FOB, CIF or DAP).
- DocumentEN 10204 3.1 mill certificate; class-witnessed 3.2 certificate on request.
- ShipCapped, bundled or crated for sea or air freight.
References and standards
- ASTM B241/B241M – Seamless Pipe and Seamless Extruded Tube
- ASTM B210/B210M – Drawn Seamless Tubes
- ASTM B221 – Extruded Bars, Rods, Wire, Profiles, and Tubes
- ANSI H35.2 – Dimensional Tolerances for Aluminum Mill Products (The Aluminum Association)
- ASM International – Properties of Wrought Aluminium Alloys: 5086
5086 aluminium (aluminum) pipe: frequently asked questions
Which surface finishes are available for 5086 pipe?
Mill finish, brushed, polished, anodised and painted or powder coated. Tell us the finish, any film protection and whether the inside surface matters.
Can 5086 pipe be supplied machined?
Yes. Cutting to length, drilling, threading and CNC machining to drawing can be arranged; send the drawing, tolerances and quantity.
How is 5086 pipe made?
Seamless pipe is extruded from a hollow billet over a mandrel and, for smaller sizes and tighter tolerances, cold drawn. Square tube is either drawn (H111) or extruded (H32).
Is 5086 stronger than 5083?
No. 5083 has slightly more magnesium and is somewhat stronger in the annealed condition. 5086 is commonly supplied in H32, which raises its yield strength, and is slightly less prone to sensitisation.
What does Sch 40 mean for aluminium pipe?
It is the wall-thickness schedule from ASME B36.10M, the same as for steel pipe. A 2 in Sch 40 pipe has a 2.375 in OD and 0.154 in wall; Sch 80 has a 0.218 in wall.
What is 5086 pipe used for?
Ship and boat piping and rails, desalination plants, storage-tank lines, welded coastal structures and low-temperature service.
Need 5086 pipe or square tube?
Send sizes, schedule, temper and quantity. We will reply with availability, certification and a delivered price.
