Machining
T6 machines with short chips and a good finish using carbide tools and coolant.
Marine extrusions
6005A-T6 Marine Grade Aluminium Square Bar
6005A-T6 square bar is a heat-treated aluminium-magnesium-silicon extrusion with a guaranteed proof strength of about 215 – 225 MPa, sitting between 6060 and 6082 in strength while extruding more easily than 6082. It is a class-recognised alloy for ship extrusions and suits frames, stiffeners, deck fittings and machined blocks. Metline supplies 6005A square bar cut to length and certified to EN 755, worldwide.
- Alloy
- EN AW-6005A (Al-Si-Mg)
- Temper
- T6
- Side length
- about 10 – 120 mm
- Min. proof strength
- 215 – 225 MPa
Why 6005A is a marine extrusion alloy
Aluminium ships are built from two families of material: rolled 5xxx plate for the shell and decks, and extruded 6xxx sections for stiffeners, frames, deck planks and outfitting. 6005A is one of the extrusion alloys class rules most often accept, alongside 6061 and 6082. It is a medium-strength, heat-treatable Al-Si-Mg alloy with a little manganese and chromium, designed to extrude into thin-walled and hollow shapes that 6082 struggles to produce.
As a solid square bar in T6 temper, 6005A gives a minimum tensile strength of 260 – 270 MPa and proof strength of 215 – 225 MPa under EN 755-2, depending on size. That is roughly 40 % more proof strength than 6060-T6, and only modestly below 6082-T6. Corrosion resistance in marine atmospheres is good because copper is limited to 0.30 % and the alloy is normally used above the waterline or protected by paint or anodising.
One note on naming: you will see this product sold as "6005 square bar". 6005 and 6005A are separate registrations; 6005A permits more manganese and chromium and is the version standardised in Europe and listed in marine rules. Unless your drawing specifies 6005, we supply and certify 6005A.
6005A chemical composition (wt %)
| Element | 6005A |
|---|---|
| Silicon (Si) | 0.50 – 0.90 |
| Iron (Fe) | ≤ 0.35 |
| Copper (Cu) | ≤ 0.30 |
| Manganese (Mn) | ≤ 0.50 |
| Magnesium (Mg) | 0.40 – 0.70 |
| Chromium (Cr) | ≤ 0.30 |
| Zinc (Zn) | ≤ 0.20 |
| Titanium (Ti) | ≤ 0.10 |
| Others, each / total | ≤ 0.05 / ≤ 0.15 |
| Aluminium (Al) | Remainder |
EN 573-3 also requires manganese plus chromium to total 0.12 – 0.50 %. Those two elements form dispersoids that keep the grain structure fine after extrusion, which supports toughness and a uniform anodised finish. Some catalogue tables show 6005A with 6082-like silicon and manganese ranges; the limits above are the registered ones.
Mechanical properties of 6005A-T6 square bar
EN 755-2 minimums for extruded bar are shown. For square bar, D is the side length.
| Alloy-temper | Size D (mm) | Tensile Rm (min) | Proof Rp0.2 (min) | Elongation A |
|---|---|---|---|---|
| 6005A-T6 | ≤ 25 | 270 MPa | 225 MPa | ≥ 10 % |
| 6005A-T6 | > 25 – 50 | 270 MPa | 225 MPa | ≥ 8 % |
| 6005A-T6 | > 50 – 100 | 260 MPa | 215 MPa | ≥ 8 % |
Physical properties (T6, typical)
- Density
- 2.70 g/cm³
- Elastic modulus
- about 69.5 GPa
- Thermal conductivity
- about 180 – 190 W/m·K
- Electrical conductivity
- about 47 – 50 % IACS
- Coefficient of thermal expansion
- about 23.5 µm/m·°C
- Melting range
- about 605 – 655 °C
Welding reduces strength in the heat-affected zone to roughly half the T6 proof value. Class rules and EN 1999 (Eurocode 9) provide reduced design values for welded 6005A, and connections are usually placed in lower-stress areas.
Standards and designations
| System | Designation |
|---|---|
| EN 573-3 | EN AW-6005A / EN AW-AlSiMg(A) |
| German Werkstoff | 3.3210 |
| Bar properties | EN 755-2 |
| Square bar tolerances | EN 755-4 |
| China (GB/T 3190) | 6005A; bar to GB/T 3191 |
| Marine | Listed among extrusion alloys in major class society rules (T5 / T6) |
For class-approved structure, specify the society and ask for the material certificate to be issued accordingly.
Sizes and weights
Supply range
- Side length
- About 10 – 120 mm (larger sizes by arrangement)
- Temper
- T6; T5 for sections air-quenched at the press
- Length
- 3 – 6 m standard; cut pieces on request
- Surface
- Mill finish, anodised or powder coated
| Side (mm) | kg per metre | kg per 3 m bar | kg per 6 m bar |
|---|---|---|---|
| 10 | 0.270 | 0.81 | 1.6 |
| 12 | 0.389 | 1.17 | 2.3 |
| 15 | 0.608 | 1.82 | 3.6 |
| 20 | 1.08 | 3.24 | 6.5 |
| 25 | 1.69 | 5.06 | 10.1 |
| 30 | 2.43 | 7.29 | 14.6 |
| 40 | 4.32 | 12.96 | 25.9 |
| 50 | 6.75 | 20.25 | 40.5 |
| 60 | 9.72 | 29.16 | 58.3 |
| 70 | 13.23 | 39.69 | 79.4 |
| 80 | 17.28 | 51.84 | 103.7 |
| 100 | 27.00 | 81.00 | 162.0 |
| 120 | 38.88 | 116.64 | 233.3 |
Tolerances
6005A is in the easier-to-extrude tolerance group. Side-length tolerances usually applied (EN 755-4 / GB/T 14846 pattern):
| Side length (mm) | Tolerance (mm) |
|---|---|
| over 18 to 25 | ±0.25 |
| over 25 to 40 | ±0.30 |
| over 40 to 50 | ±0.35 |
| over 50 to 65 | ±0.40 |
| over 65 to 80 | ±0.45 |
| over 80 to 100 | ±0.55 |
| over 100 to 120 | ±0.65 |
Form tolerances (typical)
- Corner radius
- About 1 mm up to 25 mm side, rising to 2.5 mm at 80 – 120 mm
- Twist
- About 1 – 2 mm per metre depending on size
- Straightness
- About 0.8 mm per 300 mm up to 80 mm side
Fabrication
Welding
MIG/TIG with ER5356 (preferred for marine use and colour match after anodising) or ER4043. Expect heat-affected zone softening.
Bending
Limited in T6; bend in T4 and age afterwards if tight radii are needed.
Finishing
Takes protective and decorative anodising well; powder coat over a chrome-free pretreatment.
Designing with 6005A in a marine environment
Most 6005A on a vessel sits in the superstructure, on deck or inside the hull, where it sees salt-laden air, condensation and occasional spray rather than constant immersion. In those conditions the alloy forms a stable oxide film and corrodes very slowly, and a sealed anodic film or a marine paint system extends life further. Problems almost always start at joints: crevices that trap seawater, and contact with more noble metals.
Detail joints so that water drains rather than pools, seal faying surfaces with a polysulphide or polyurethane sealant, and isolate stainless-steel fasteners with nylon washers and sleeves. Where a 6005A bar is welded to 5083 plate, the two alloys are galvanically compatible, and ER5356 or ER5183 filler suits both.
| Design point | Practical guidance |
|---|---|
| Welded strength | Design welded members to the reduced heat-affected-zone values in the class rules or EN 1999-1-1; keep welds out of peak-stress regions |
| Fatigue | Fatigue strength of welded aluminium details is much lower than parent metal; avoid abrupt section changes and intermittent welds in vibrating areas |
| Temperature | T6 properties are stable to about 100 °C; long exposure above roughly 150 °C over-ages the alloy |
| Fire protection | Aluminium structure in fire-rated divisions needs insulation to keep the core below about 200 °C under the rule fire test |
| Inspection | Visual checks at joints and drains during routine surveys catch crevice and galvanic corrosion early |
Marine applications
- Stiffeners and frames for superstructures and deckhouses
- Hatch coamings and frames, door frames and window surrounds
- Railings, ladders and gangways
- Machinery foundations and brackets
- Offshore walkways and handrail posts
6005A versus 6060, 6061 and 6082
| Alloy-T6 | Min. Rp0.2 (bar) | Extrudability | Typical role |
|---|---|---|---|
| 6060 | 150 MPa | Excellent | Outfitting, trim, low-load parts |
| 6005A | 215 – 225 MPa | Very good | Medium-strength structure, thin hollow sections |
| 6061 | 240 MPa | Good | Machined parts, ASTM markets |
| 6082 | 250 – 260 MPa | Fair | Highest strength structure, European markets |
Ordering
- SpecifyAlloy 6005A-T6, side length, length, quantity, standard and any class requirement.
- QuoteAvailability, certificate and terms (EXW, FOB, CIF or DAP).
- PrepareCut, mark and inspect.
- ShipWith EN 10204 3.1 certificate, in export packing.
References and standards
- EN 573-3 – Chemical composition and form of wrought products
- EN 755-2 – Extruded rod/bar, tube and profiles: mechanical properties
- EN 755-4 – Extruded square bar: tolerances on dimensions and form
- EN 1999-1-1 (Eurocode 9) – Design of aluminium structures
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
6005A marine aluminium (aluminum) square bar: FAQs
Is 6005 the same as 6005A?
No. They are separate registrations; 6005A allows more manganese and chromium and is the version standardised in Europe and listed in marine rules.
Is 6005A suitable for marine use?
Yes, for extrusions above the waterline or protected by coating. For permanently immersed parts, 5xxx alloys are preferred.
What is the minimum strength of 6005A-T6 bar?
Under EN 755-2, 270 MPa tensile and 225 MPa proof up to 50 mm, and 260 / 215 MPa for 50 – 100 mm.
How much does a 40 mm 6005A square bar weigh?
About 4.32 kg per metre.
Which filler wire suits 6005A in marine work?
ER5356 is preferred for marine structures and anodised parts; ER4043 reduces hot-cracking risk on restrained joints.
Need 6005A square bar?
Send size, length, quantity and destination for availability, certification and a delivered price.
