Welding
Weld with ER5356 by MIG or TIG. Clean and brush the joint immediately before welding to avoid porosity. 5052 does not need or respond to post-weld heat treatment.
Marine square bar
5052 Marine Grade Aluminium Square Bar
5052 square bar is a corrosion-resistant aluminium-magnesium bar for brackets, cleats, backing blocks and frames that sit in seawater or salt spray. It welds easily to 5052 sheet and needs no coating to survive marine exposure, though it is a moderate-strength alloy rather than a structural hull grade. Metline supplies 5052 square bar in O and H112, and drawn tempers on request, cut to length worldwide.
- Alloy
- 5052 (Al-Mg 2.5)
- Tempers
- O, H112; drawn H32
- Sizes
- Square sections, cut lengths
- Standards
- ASTM B221 · EN 755-4
Where square 5052 bar is used on boats
A square section gives flat faces for drilling, tapping and welding, and a strong, compact shape for brackets and frames. In 5052 those parts gain the alloy's very good resistance to seawater and its ability to be welded without heat treatment.
Boat builders use 5052 square bar for engine-bed packing, cleat and fairlead bases, backing blocks behind deck fittings, small frames, ladder treads and the edge stiffeners of hatches. Because the bar matches the 5052 sheet used for small-craft hulls and tanks, welded assemblies stay single-alloy, which simplifies welding procedures and avoids galvanic differences.
Square bar is normally extruded and supplied in O or H112. Smaller sizes can be cold drawn to H32 or H34 for higher strength, sharper corners and tighter tolerances. For heavily loaded or class-inspected structure, 5083 square bar is the stronger, class-listed option.
5052 square bar composition
| 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. Limits follow the Aluminum Association registration used by ASTM B221 and EN 573-3.
Mechanical properties of 5052 square bar
Values below are the specified limits for extruded 5052 bar under ASTM B221 and EN 755-2. Drawn bar in H32 or H34 to ASTM B211 or EN 754-2 is stronger; limits depend on size and are confirmed with the order.
| 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 |
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
Standards, tolerances and equivalents
| Standard | Scope |
|---|---|
| ASTM B221 / B221M | Extruded bar: chemistry and properties |
| ASTM B211 / B211M | Cold-finished bar |
| ANSI H35.2 | Dimensional tolerances for ASTM orders |
| EN 755-2 / EN 755-4 | Extruded bar: properties / square bar dimensions and tolerances |
| EN 754-2 / EN 754-4 | Drawn bar: properties / square bar tolerances |
Square bar tolerances cover more than the side length: corner radius, squareness of the corners, straightness over 300 mm and over the full length, twist and cut length are all controlled. Each limit widens with section size, and drawn bar holds tighter values than extruded bar. Quote the tolerance standard when ordering; if parts will be machined all over, standard extruded tolerances are usually sufficient.
| 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 square bar sizes and weights
Supply range
- Side length
- Common sizes from about 6 mm; larger sections extruded to order
- Length
- 3 m and 6 m standard; cut pieces on request
- Corners
- Sharp or radiused as extruded; drawn bar has smaller corner radii
- Finish
- Mill finish; protective film or paper interleaving for cosmetic parts
A square bar of side a weighs a² × density per unit length: for 5052, 0.00268 × a² kg per metre with a in millimetres.
| Size (mm) | kg per metre | 3 m bar (kg) | 6 m bar (kg) |
|---|---|---|---|
| 6 | 0.096 | 0.29 | 0.6 |
| 8 | 0.172 | 0.51 | 1.0 |
| 10 | 0.268 | 0.80 | 1.6 |
| 12 | 0.386 | 1.16 | 2.3 |
| 15 | 0.603 | 1.81 | 3.6 |
| 16 | 0.686 | 2.06 | 4.1 |
| 20 | 1.07 | 3.22 | 6.4 |
| 25 | 1.68 | 5.03 | 10.1 |
| 30 | 2.41 | 7.24 | 14.5 |
| 35 | 3.28 | 9.85 | 19.7 |
| 40 | 4.29 | 12.86 | 25.7 |
| 50 | 6.70 | 20.10 | 40.2 |
| 60 | 9.65 | 28.94 | 57.9 |
| 70 | 13.13 | 39.40 | 78.8 |
| 80 | 17.15 | 51.46 | 102.9 |
| 100 | 26.80 | 80.40 | 160.8 |
| 120 | 38.59 | 115.78 | 231.6 |
| 150 | 60.30 | 180.90 | 361.8 |
Fabrication tips for 5052 square bar
Machining
Drill and tap with sharp tools and cutting fluid. H112 and drawn tempers give cleaner holes and threads than annealed bar.
Bending
O temper bends easily; H112 bends to moderate radii. Heat is not normally needed and can soften strain-hardened tempers.
Fastening
Use aluminium or isolated stainless fasteners. Insulating washers stop galvanic attack where stainless bolts pass through 5052.
Finishing
Can be left bare, painted after etch priming, or anodised for a protective clear film.
Service temperature
Suitable for normal marine temperatures and cryogenic service; not for sustained use above about 100 °C.
Applications of 5052 square bar
- Backing blocks and pads behind cleats, winches and deck hardware
- Engine and equipment mounts on small craft, welded to hull stringers
- Hatch and door frames, edge stiffeners and lid hinges
- Ladders, steps and gangway parts
- Tank baffles and supports welded inside 5052 tanks
- Marina and pontoon hardware exposed to splash and spray
Choosing between 5052, 5083 and 6082 square bar
| Factor | 5052-H112 | 5083-H112 | 6082-T6 |
|---|---|---|---|
| Min yield strength (extruded) | 70 MPa | 110 MPa | 260 MPa |
| Seawater immersion | Very good | Excellent | Needs protection |
| Weld strength retention | High | High | Low in heat-affected zone |
| Class-approved for hulls (UR W25) | No | Yes | Yes, protected |
| Best for | Small-craft fittings, tanks | Structural marine parts | Machined parts above water |
Ordering 5052 square bar
- SpecifySide length, temper, length, quantity and standard (ASTM B221, B211 or EN 755-4).
- QuoteWe confirm availability, tolerance, certificates and EXW, FOB, CIF or DAP terms.
- PrepareCutting to length, deburring and dimensional inspection.
- ShipBundled in wooden cases with an EN 10204 3.1 mill certificate.
References and standards
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles and Tubes
- 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)
- ANSI H35.2 – Dimensional Tolerances for Aluminum Mill Products
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
5052 aluminium (aluminum) square bar: FAQ
Is 5052 square bar marine grade?
It is widely used in marine service because it resists seawater very well. It is not a class-approved structural hull alloy, so use 5083 or 5086 for class-inspected parts.
What temper is 5052 square bar supplied in?
Usually H112 (as extruded) or O (annealed). Small sizes can be drawn to H32 or H34 for higher strength and tighter tolerances.
How much does 5052 square bar weigh?
0.00268 × (side in mm)² kg per metre. A 25 mm square bar weighs about 1.68 kg/m; a 50 mm bar about 6.70 kg/m.
Can 5052 square bar be welded to 5083 plate?
Yes. Use ER5183 or ER5356 filler. The joint strength is governed by the weaker 5052 side.
Do you cut square bar to size?
Yes. Metline supplies standard lengths or cut pieces with mill certificates and export packing.
Need 5052 square bar?
Send size, temper, length and quantity. Metline will reply with availability and a delivered price.
