5052-O
Fully annealed. The softest condition, with the highest elongation. Choose O when the hex will be flared, swaged, crimped or cold headed after machining.
Marine hexagon bar
5052 Marine Grade Aluminium Hexagon Bar
5052 hexagon bar is a medium-strength aluminium-magnesium bar that resists seawater and salt spray without coating, which makes it a practical stock for nuts, spacers, fittings and small machined parts on boats and coastal equipment. Metline supplies 5052 hex bar in O and H112 tempers, extruded or drawn, cut to length and certified, to customers worldwide.
- Alloy
- 5052 (Al-Mg 2.5)
- Tempers
- O, H112
- Sizes
- Hex across flats, cut lengths
- Standards
- ASTM B221 · EN 755-6
What is 5052 hexagon bar used for at sea?
5052 contains about 2.5 % magnesium and a small chromium addition. It gains its strength from magnesium in solid solution and from cold work, not from heat treatment, so it keeps a stable structure in service and is not prone to the sensitisation that can affect alloys with more than 3 % magnesium.
The hexagonal section gives six flats for a spanner or a lathe collet, which is why hex bar is the starting stock for nuts, couplings, standoffs, through-hull spacers and threaded fittings. In 5052 those parts sit happily in salt spray, bilge water and fuel, provided they are isolated from copper alloys and stainless steel.
It is worth being clear about what 5052 is not. It is a moderate-strength alloy, roughly half the strength of 6061-T6, and it is not one of the alloys that classification societies approve for hull structure. For highly loaded or class-inspected parts, 5083 hex bar or a 6xxx alloy with a protective finish is the better choice.
5052 chemical composition
Limits are the registered Aluminum Association values, followed by ASTM B221 and EN 573-3. The mill certificate shows the actual analysis of each cast.
| Element (wt %) | 5052 |
|---|---|
| Silicon (Si) | 0.25 |
| Iron (Fe) | 0.40 |
| Copper (Cu) | 0.10 |
| Manganese (Mn) | 0.10 |
| Magnesium (Mg) | 2.2 – 2.8 |
| Chromium (Cr) | 0.15 – 0.35 |
| Zinc (Zn) | 0.10 |
| Others, each / total | 0.05 / 0.15 |
| Aluminium (Al) | Remainder |
Single figures are maximums. Magnesium is the main strengthening element; chromium controls grain structure and helps stress-corrosion resistance.
Mechanical properties of 5052 hex bar
Extruded hexagon bar is normally supplied in O or H112. The values below are the specified limits for extruded 5052 bar in ASTM B221 and EN 755-2. Drawn (cold-finished) hex in H32 or H34 is stronger and is available on request to ASTM B211 or EN 754-2.
| Temper | Tensile strength Rm | Yield Rp0.2 min | Typical use |
|---|---|---|---|
| O (annealed) | 170 – 240 MPa (25 – 35 ksi) | 70 MPa (10 ksi) | Maximum ductility for bending, swaging and cold heading |
| H112 (as extruded) | 170 MPa (25 ksi) min | 70 MPa (10 ksi) | General machining stock; properties from the extrusion process |
Elongation minimums depend on size and on gauge length (A50 mm or A5d); see the certificate for the lot. Typical H112 bar exceeds the minimum tensile figure by a useful margin.
Physical properties of 5052
- Density
- 2.68 g/cm³ (0.097 lb/in³)
- Modulus of elasticity
- about 70 GPa
- Thermal conductivity
- about 138 W/m·K (H32)
- Electrical conductivity
- about 35 % IACS
- Coefficient of thermal expansion
- about 23.8 µm/m·°C (20 – 100 °C)
- Melting range
- about 607 – 649 °C
O or H112: which temper to order
5052-H112
As extruded, with properties that come from hot working. The normal choice for machined nuts, couplings and spacers where moderate strength is enough.
5052-H32 / H34 (drawn)
Cold-drawn hex with higher proof strength and tighter tolerances across flats. Useful for automatic-lathe work and where the flats must fit tooling closely.
Standards and international equivalents
Hexagon bar is covered by extruded and drawn bar standards rather than by marine-specific rules. Quote the standard on your drawing; dimensions and tolerances follow the shape-specific part of the standard.
| Standard | Scope |
|---|---|
| ASTM B221 / B221M | Extruded bars, rods, profiles and tubes: chemistry and mechanical properties |
| ASTM B211 / B211M | Rolled or cold-finished bar, rod and wire (drawn hex) |
| ANSI H35.2 | Dimensional tolerances for aluminium mill products |
| EN 755-2 / EN 755-6 | Extruded bar: mechanical properties / hexagonal bar dimensions and tolerances |
| EN 754-2 / EN 754-6 | Cold-drawn bar: mechanical properties / hexagonal bar tolerances |
| EN 573-3 | Chemical composition |
| System | Designation |
|---|---|
| Aluminum Association / ASTM | 5052 |
| UNS | A95052 |
| European (EN 573-3) | EN AW-5052 / EN AW-AlMg2.5 |
| German Werkstoff | 3.3523 |
| ISO | AlMg2.5 |
| Japan (JIS) | A5052 |
| China (GB/T 3190) | 5052 |
| Former French (NF) | AG2.5C |
5052 hex bar sizes and weights
Supply range
- Across flats
- Common metric sizes from 6 mm upward; imperial sizes in fractions of an inch; large sections extruded to order
- Length
- 3 m and 6 m standard; cut pieces and other lengths on request
- Production route
- Extruded (O, H112) or extruded and cold drawn (H32, H34)
- Ends
- Saw cut, deburred; chamfered blanks on request
- Packing
- Bundled, paper or film wrapped, in wooden cases for sea freight
A regular hexagon measured across flats (s) has a cross-section of 0.866 × s². With 5052 at 2.68 g/cm³, weight per metre is 0.00232 × s² kg. Use the bar weight calculator for other sections.
| Size (mm) | kg per metre | 3 m bar (kg) | 6 m bar (kg) |
|---|---|---|---|
| 8 | 0.149 | 0.45 | 0.9 |
| 10 | 0.232 | 0.70 | 1.4 |
| 12 | 0.334 | 1.00 | 2.0 |
| 13 | 0.392 | 1.18 | 2.4 |
| 14 | 0.455 | 1.36 | 2.7 |
| 17 | 0.671 | 2.01 | 4.0 |
| 19 | 0.838 | 2.51 | 5.0 |
| 22 | 1.12 | 3.37 | 6.7 |
| 24 | 1.34 | 4.01 | 8.0 |
| 27 | 1.69 | 5.08 | 10.2 |
| 30 | 2.09 | 6.27 | 12.5 |
| 32 | 2.38 | 7.13 | 14.3 |
| 36 | 3.01 | 9.02 | 18.0 |
| 41 | 3.90 | 11.70 | 23.4 |
| 46 | 4.91 | 14.73 | 29.5 |
| 50 | 5.80 | 17.41 | 34.8 |
| 55 | 7.02 | 21.06 | 42.1 |
| 60 | 8.36 | 25.07 | 50.1 |
| 65 | 9.81 | 29.42 | 58.8 |
| 70 | 11.37 | 34.12 | 68.2 |
| 80 | 14.85 | 44.56 | 89.1 |
| 90 | 18.80 | 56.40 | 112.8 |
| 100 | 23.21 | 69.63 | 139.3 |
Tolerances and inspection
Across-flats tolerance, corner radius, straightness and twist all follow the ordering standard: EN 755-6 for extruded hex, EN 754-6 for drawn hex, or ANSI H35.2 for ASTM orders. Tolerances widen as section size grows, and drawn hex holds noticeably tighter limits than extruded hex of the same size, which matters if parts are fed through a collet.
- Dimensional check of across flats, across corners and length on each lot
- Visual inspection for die lines, scratches and corrosion staining
- Straightness and twist measured on full-length bars where the standard requires it
- Mill test certificate to EN 10204 3.1 with chemistry and tensile results
- Third-party inspection on request before shipment
Machining, welding and finishing hex bar
Machining
Fair to good. Softer tempers produce long, gummy chips; H112 and drawn tempers machine more cleanly. Use sharp, polished high-rake carbide or HSS tools, generous coolant and chip breakers on automatic lathes.
Threading
Roll or cut threads readily. For threads that are assembled and disassembled often, consider a thread insert or a harder alloy, because aluminium threads gall against stainless fasteners.
Welding
TIG and MIG weld well with ER5356 filler. The weld zone returns to roughly annealed strength, which for 5052 is close to the H112 condition anyway.
Anodising
Takes a clear protective anodic film. It is not a bright-anodising alloy, and the film is slightly yellow-grey on higher-magnesium stock.
Galvanic isolation
Separate 5052 parts from bronze, copper and stainless steel with nylon or PTFE washers and sleeves, especially below the waterline.
Temperature
Suitable for continuous service up to about 65 – 100 °C. Strength rises slightly at cryogenic temperature.
Typical uses of 5052 hexagon bar
- Fasteners and nuts for aluminium hatches, covers and fittings where a matching alloy avoids galvanic pairs
- Spacers and standoffs for consoles, electronics mounts and deck equipment
- Fuel and water fittings welded into 5052 tanks on small craft
- Rail and stanchion bases, cleat bodies and small deck hardware
- Couplings and adaptors for low-pressure hose and drainage lines
- Coastal equipment: fish-farm cages, pontoon hardware and dock fittings
5052 hex bar compared with 5083 and 6061
| Property | 5052-H112 | 5083-H112 | 6061-T6 |
|---|---|---|---|
| Minimum tensile strength (extruded) | 170 MPa | 270 MPa | 260 MPa |
| Minimum yield strength (extruded) | 70 MPa | 110 MPa | 240 MPa |
| Seawater resistance | Very good | Excellent | Fair; needs protection |
| Welded strength retention | High (non-heat-treatable) | High | Low in heat-affected zone |
| Machinability | Fair | Fair | Very good |
| Class-approved for hull structure | No | Yes (UR W25) | Yes, with protection |
Choose 5052 for moderately loaded parts that must sit in seawater without coating; 5083 when you need more strength or class acceptance; 6061-T6 when machinability and strength matter more than immersion resistance and the part will be anodised or painted.
How to order 5052 hex bar
- SpecifyAcross-flats size, temper (O, H112, or drawn H32/H34), length, quantity and the standard (ASTM B221, B211, EN 755-6).
- QuoteWe confirm availability, tolerance class, certification and delivery terms: EXW, FOB, CIF or DAP.
- Cut and inspectBars are cut to length if required, checked for dimensions and surface, and bundled.
- DocumentEN 10204 3.1 mill certificate and packing list with each shipment.
- ShipExport packing in wooden cases by sea or air to your port or site.
References and standards
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles and Tubes
- ASTM B211 – Aluminum and Aluminum-Alloy Rolled or Cold Finished Bar, Rod, and Wire
- 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)
- EN 573-3 – Chemical composition and form of wrought products
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
5052 aluminium (aluminum) hex bar: FAQ
Is 5052 hex bar suitable for saltwater?
Yes. 5052 resists seawater and salt spray very well without coating. Isolate it from stainless steel and copper alloys to avoid galvanic corrosion.
What is the difference between 5052-O and 5052-H112 hex bar?
O is fully annealed and most ductile, for parts that are formed after machining. H112 is the as-extruded condition, with the same specified minimums in most standards but usually higher actual strength, and is the normal machining temper.
How much does 5052 hex bar weigh?
Weight per metre is 0.00232 × (across flats in mm)². A 20 mm hex weighs about 0.93 kg/m and a 50 mm hex about 5.8 kg/m.
Can 5052 hex bar be anodised?
Yes. It takes a clear protective anodic film well. It is not used for bright decorative anodising.
Is 5052 approved by classification societies for ship structure?
No. IACS UR W25 lists 5083, 5383, 5059, 5086 and others, but not 5052. Use 5083 bar for class-inspected structural parts.
Do you supply cut lengths?
Yes. Hex bar can be supplied in standard lengths or cut to your lengths, with an EN 10204 3.1 certificate.
Need 5052 hex bar?
Send size, temper, length and quantity. Metline will reply with availability, certification and a delivered price.
