Welding
Use ER5183 for 5059 and for 5086 in structural joints; ER5356 is also used with 5086. Never use 4043 or 4047 filler on these alloys.
High-magnesium marine round bar
5059 and 5086 Marine Grade Aluminium Round Bar
5059 and 5086 are both high-magnesium marine alloys listed by IACS for extruded hull material, but they sit at opposite ends of the strength range. 5086-H112 is a widely available, easily welded bar with a 95 MPa minimum yield; 5059-H112 more than doubles that, at 200 MPa, for weight-critical structure. Metline supplies both as extruded round bar, cut to length and certified, worldwide.
- Alloys
- 5059, 5086
- Tempers
- 5059 H112 · 5086 O, H111, H112
- Min yield (H112)
- 200 MPa / 95 MPa
- Rules
- IACS UR W25 · ASTM B221
Two marine alloys, two different jobs
Both alloys are non-heat-treatable aluminium-magnesium grades that gain strength from magnesium in solid solution and resist seawater without coating. Their difference is magnitude: 5086 carries about 4 % magnesium; 5059 carries 5 – 6 % plus zinc and zirconium.
5086 round bar is the practical choice for marine shafts, pins, bushes, stanchion fittings and machined parts that need better strength than 5052 but must stay easy to weld and form. It is listed in ASTM B221 and IACS UR W25 and is readily produced by many extruders.
5059 round bar is a specialist product. Its extruded H112 minimum strength is close to that of many 6xxx alloys in T6, but unlike them it keeps a high proportion of that strength after welding and resists seawater uncoated. It is chosen when the designer of a fast craft or naval vessel needs welded fittings, pins or bosses that match 5059 hull plate. It is usually extruded to order, so plan lead times accordingly.
Chemical composition of 5059 and 5086
| Element (wt %) | 5059 | 5086 |
|---|---|---|
| Silicon (Si) | 0.45 | 0.40 |
| Iron (Fe) | 0.50 | 0.50 |
| Copper (Cu) | 0.25 | 0.10 |
| Manganese (Mn) | 0.6 – 1.2 | 0.20 – 0.7 |
| Magnesium (Mg) | 5.0 – 6.0 | 3.5 – 4.5 |
| Chromium (Cr) | 0.25 | 0.05 – 0.25 |
| Zinc (Zn) | 0.40 – 0.90 | 0.25 |
| Titanium (Ti) | 0.20 | 0.15 |
| Zirconium (Zr) | 0.05 – 0.25 | — |
| Others, each / total | 0.05 / 0.15 | 0.05 / 0.15 |
| Aluminium (Al) | Remainder | Remainder |
Single figures are maximums. For 5059, zirconium is excluded from the "others" total. Limits as in IACS UR W25 and the Aluminum Association registrations.
Minimum properties of extruded 5059 and 5086 bar
IACS UR W25 sets these minimums for extruded products 3 – 50 mm thick; ASTM B221 gives the same values for 5086. For bar over 50 mm, properties are agreed against a recognised standard.
| Alloy | Temper | Yield Rp0.2 min (MPa) | Tensile Rm (MPa) | Elongation A50 / A5 min (%) |
|---|---|---|---|---|
| 5086 | O | 95 | 240 – 315 | 14 / 12 |
| 5086 | H111 | 145 | 250 | 12 / 10 |
| 5086 | H112 | 95 | 240 | 12 / 10 |
| 5059 | H112 | 200 | 330 | — / 10 |
Source: IACS UR W25 Rev.4 Table 3. Elongation A50 up to 12.5 mm, A5 above. Actual values are reported on the mill certificate.
Physical properties (approximate)
- Density
- 5086: 2.66 g/cm³ · 5059: about 2.65 g/cm³
- Modulus of elasticity
- about 71 GPa
- Thermal conductivity, 5086
- about 125 W/m·K
- Electrical conductivity, 5086
- about 31 % IACS
- Coefficient of thermal expansion
- about 23.8 µm/m·°C
Standards and equivalents
| Standard | Scope |
|---|---|
| IACS UR W25 and class rules | Extruded 5059 and 5086 (and 5083, 5383) for hull and marine structure |
| ASTM B221 / B221M | Extruded bar, rod and profiles; includes 5086 tempers O, H111 and H112 |
| ASTM B928 / B928M | High-magnesium marine products, including extruded profiles, with corrosion testing |
| EN 755-2 | Mechanical properties of extruded bar, tube and profiles |
| EN 755-3 / -4 / -6 | Dimensions and tolerances of round, square and hexagonal extruded bar |
| EN 573-3 | Chemical composition |
| System | 5059 | 5086 |
|---|---|---|
| Aluminum Association / ASTM | 5059 | 5086 |
| UNS | A95059 | A95086 |
| European (EN 573-3) | EN AW-5059 / AlMg5.5MnZnZr | EN AW-5086 / AlMg4 |
| German Werkstoff | — | 3.3545 |
| Japan (JIS) | — | A5086 |
| Marine rules | IACS UR W25, rolled and extruded | IACS UR W25, rolled and extruded |
Round bar sizes and weights
Supply range
- Diameter
- 5086 from about 10 mm to large diameters; 5059 to order
- Length
- 3 m and 6 m standard, or cut to length
- Tempers
- 5086: O, H111, H112 · 5059: H112
- Tolerances
- EN 755-3 or ANSI H35.2 for extruded round bar
Weights below use 2.66 g/cm³ (5086); 5059 is about 0.4 % lighter. Weight per metre = 0.002089 × d² kg with d in mm.
| Size (mm) | kg per metre | 3 m bar (kg) | 6 m bar (kg) |
|---|---|---|---|
| 10 | 0.209 | 0.63 | 1.3 |
| 12 | 0.301 | 0.90 | 1.8 |
| 16 | 0.535 | 1.60 | 3.2 |
| 20 | 0.836 | 2.51 | 5.0 |
| 25 | 1.31 | 3.92 | 7.8 |
| 30 | 1.88 | 5.64 | 11.3 |
| 40 | 3.34 | 10.03 | 20.1 |
| 50 | 5.22 | 15.67 | 31.3 |
| 60 | 7.52 | 22.56 | 45.1 |
| 70 | 10.24 | 30.71 | 61.4 |
| 80 | 13.37 | 40.11 | 80.2 |
| 100 | 20.89 | 62.67 | 125.3 |
| 120 | 30.08 | 90.25 | 180.5 |
| 150 | 47.01 | 141.02 | 282.0 |
| 200 | 83.57 | 250.70 | 501.4 |
Machining, welding and service notes
Machining
Both are somewhat gummy. Sharp, polished carbide tools with high positive rake, high cutting speed and good coolant give the best results; 5059 machines a little more cleanly because it is harder.
Forming
5086-O and H111 bend and swage well. 5059 is stiffer and springs back more; form it with generous radii.
Sensitisation
Keep both alloys away from long exposure between about 65 °C and 200 °C to avoid grain-boundary beta phase and intergranular corrosion.
Galvanic contact
Isolate from stainless steel, bronze and carbon fibre with non-conductive washers and sleeves.
Finishing
Usually left bare or painted; clear anodising is possible but the film is slightly grey on high-Mg alloys.
Marine uses of 5086 and 5059 round bar
- Hinge pins, davit pins and shafts under moderate load in wet service
- Stanchion bases, rail fittings and bollard parts welded to hull or deck plating
- Bosses and inserts welded into 5059 or 5083 structure (5059 bar matches 5059 plate)
- Rudder and steering-gear fittings on small craft, subject to the designer's strength checks
- Offshore and aquaculture hardware, pontoon connectors and mooring fittings
- Turned parts such as bushes, spacers and adaptors
How they compare with 5083 and 5383 bar
| Extruded H112, UR W25 minimum | 5086 | 5083 | 5383 | 5059 |
|---|---|---|---|---|
| Yield strength | 95 MPa | 110 MPa | 190 MPa | 200 MPa |
| Tensile strength | 240 MPa | 270 MPa | 310 MPa | 330 MPa |
| Availability | Good | Very good | Limited | To order |
For most fittings 5083 bar is the best-known middle option. Step down to 5086 when formability matters more, and up to 5383 or 5059 when the welded parts must match high-strength hull plate.
Ordering 5059 or 5086 round bar
- SpecifyAlloy, temper, diameter, length, quantity, standard and any class-society requirement.
- QuoteWe confirm availability or production route, certificates and EXW, FOB, CIF or DAP terms.
- Inspect and packDimensional and surface checks, cutting to length, export packing.
- DocumentEN 10204 3.1 certificate, or class certificate where the producing mill is approved.
References and standards
- IACS Unified Requirement W25 – Aluminium alloys for hull construction and marine structure
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles and Tubes
- ASTM B928/B928M – High Magnesium Aluminum-Alloy Products for Marine Service and Similar Environments
- EN 755-2 – Extruded rod/bar, tube and profiles: mechanical properties (with EN 755-3, -4 and -6 for round, square and hexagonal bar tolerances)
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
5059 and 5086 aluminium (aluminum) round bar: FAQ
What is the strength of 5086-H112 round bar?
Minimum tensile strength 240 MPa and minimum yield 95 MPa under ASTM B221 and IACS UR W25 for extruded products up to 50 mm.
Is 5059 round bar readily available?
Less so than 5083 or 5086. It is a specialist alloy, usually extruded to order, so allow time in the project schedule.
Can 5086 bar be used underwater?
Yes. 5086 has excellent resistance to seawater and is widely used for immersed fittings, provided it is isolated from more noble metals.
Which filler wire suits 5059?
ER5183 is standard; zirconium-bearing fillers are also used. 4xxx fillers must not be used.
Why is 5059 bar stronger than 5086?
It contains more magnesium (5 – 6 % against 3.5 – 4.5 %) plus zinc and zirconium, which together raise strength and help retain it after welding.
Need high-magnesium marine bar?
Send alloy, size, temper and quantity. Metline will reply with availability, certificates and a delivered price.
