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Marine bar stock

6060, 6061, 6005A and 6082 Marine Aluminium Round Bar

Round bar in the four main 6xxx alloys covers almost every machined aluminium part on a vessel, from light trim pins in 6060 to load-carrying shafts and bolts in 6082-T6. All four are heat-treatable, machine well in T6, take a protective anodised finish and resist marine atmospheres. Metline supplies them from about 6 mm to 250 mm diameter, cut to length and certified, to shipyards and machine shops worldwide.

By Metline Technical Team · Updated

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Aluminium deck fittings and railings on a modern vessel
Alloys
6060 · 6061 · 6005A · 6082
Tempers
O, T4, T5, T6, T3511, T8511
Diameter
about 6 – 250 mm
Standard
EN 755-2 · ASTM B221 · GB/T 3191
Overview

How the four 6xxx round bar grades differ

Every 6xxx alloy gets its strength the same way: silicon and magnesium dissolve during solution heat treatment and then precipitate as fine Mg2Si particles during ageing. What separates the grades is how much of each element they contain and which grain-controlling additions they carry. More silicon and magnesium mean more strength; manganese or chromium keeps the grain fine in large diameters.

For a marine buyer, that translates into a simple ladder. 6060 has the least alloy content, extrudes fastest and gives the best anodised surface, but its T6 proof strength is only about 150 MPa. 6005A raises that to about 215 – 225 MPa. 6061, with a copper and chromium addition, reaches about 240 MPa minimum and is the grade most drawings from the Americas and Asia call for. 6082, with the most silicon and a manganese addition, is the strongest at about 260 MPa minimum in mid-range diameters and is the European structural default.

None of them should be treated as fully equivalent to 5xxx alloys in constant seawater immersion. On deck, in superstructures, in engine rooms and inside the hull, though, anodised or painted 6xxx round bar gives long service with very little maintenance.

Chemical composition

Chemical composition (wt %)

Element606060616005A6082
Silicon (Si)0.30 – 0.600.40 – 0.800.50 – 0.900.70 – 1.30
Iron (Fe)0.10 – 0.30≤ 0.70≤ 0.35≤ 0.50
Copper (Cu)≤ 0.100.15 – 0.40≤ 0.30≤ 0.10
Manganese (Mn)≤ 0.10≤ 0.15≤ 0.500.40 – 1.00
Magnesium (Mg)0.35 – 0.600.80 – 1.200.40 – 0.700.60 – 1.20
Chromium (Cr)≤ 0.050.04 – 0.35≤ 0.30≤ 0.25
Zinc (Zn)≤ 0.15≤ 0.25≤ 0.20≤ 0.20
Titanium (Ti)≤ 0.10≤ 0.15≤ 0.10≤ 0.10
Others, each / total≤ 0.05 / ≤ 0.15≤ 0.05 / ≤ 0.15≤ 0.05 / ≤ 0.15≤ 0.05 / ≤ 0.15
Aluminium (Al)RemainderRemainderRemainderRemainder

Note the copper content of 6061 (0.15 – 0.40 %). It adds strength but slightly lowers resistance to pitting in chloride environments, which is one reason European marine designers lean towards 6082 (copper ≤ 0.10 %) for exposed structure.

Mechanical properties

Mechanical properties of extruded round bar

EN 755-2 minimum values, D = diameter. GB/T 3191 sets essentially the same minimums for these grades, and treats T3511 like T4 and T8511 like T6.

Alloy-temperSize D (mm)Tensile Rm (min)Proof Rp0.2 (min)Elongation A
6060-T4≤ 150120 MPa60 MPa≥ 16 %
6060-T5≤ 150160 MPa120 MPa≥ 8 %
6060-T6≤ 150190 MPa150 MPa≥ 8 %
6061-O≤ 200≤ 150 MPa≤ 110 MPa≥ 16 %
6061-T4≤ 200180 MPa110 MPa≥ 15 %
6061-T6≤ 200260 MPa240 MPa≥ 8 %
6005A-T6≤ 25270 MPa225 MPa≥ 10 %
6005A-T6> 25 – 50270 MPa225 MPa≥ 8 %
6005A-T6> 50 – 100260 MPa215 MPa≥ 8 %
6082-O≤ 200≤ 160 MPa≤ 110 MPa≥ 14 %
6082-T4≤ 200205 MPa110 MPa≥ 14 %
6082-T6≤ 20295 MPa250 MPa≥ 8 %
6082-T6> 20 – 150310 MPa260 MPa≥ 8 %
6082-T6> 150 – 200280 MPa240 MPa≥ 6 %
6082-T6> 200 – 250270 MPa200 MPa≥ 6 %

For cold-finished 6061-T6 rod to ASTM B211, the minimum tensile strength is higher, 290 MPa (42 ksi), with 240 MPa (35 ksi) yield.

Supply range

Diameters and weights

Supply range

Diameter
About 6 – 250 mm extruded; drawn rod in small diameters; larger sizes by arrangement
Length
Standard 3 – 6 m; fixed lengths and cut blanks to order
Temper
O, T4, T5 (6060), T6, T3511, T6511, T8511
Finish
Mill, peeled, turned, ground or anodised
Diameter (mm)kg per metrekg per 3 m barkg per 6 m bar
60.0760.230.5
80.1360.410.8
100.2120.641.3
120.3050.921.8
160.5431.633.3
200.852.545.1
251.333.988.0
301.915.7311.5
403.3910.1820.4
505.3015.9031.8
607.6322.9045.8
8013.5740.7281.4
10021.2163.62127.2
12030.5491.61183.2
15047.71143.14286.3
20084.82254.47508.9
250132.54397.61795.2
Tolerances

Diameter tolerances

All four alloys sit in the easier-to-extrude group of EN 755-3 and GB/T 14846. The usual diameter tolerances for extruded bar:

Diameter (mm)Permitted deviation (mm)
over 8 to 18±0.22
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
over 120 to 150±0.80
over 150 to 180±1.00
over 180 to 220±1.15

Beyond 220 mm the tolerance widens to about ±1.3 mm. Straightness is typically within 0.8 mm per 300 mm up to 80 mm diameter. Drawn, peeled or ground bar can be supplied to h9 – h11 for automatic lathes.

Fabrication

Machining, joining and protecting 6xxx round bar

Turning

Use T6 or T6511 for production turning. 6061 and 6082 break chips best; 6060 is softer and can smear without sharp tools.

Welding

ER5356 is the usual marine filler; ER4043 for crack-sensitive joints. Allow for about 50 % strength loss next to welds in T6 material.

Anodising

Sulphuric anodising (15 – 25 µm, sealed) for marine exposure. Hard anodising for wear parts such as pins and bushes.

Galvanic contact

Isolate from stainless and bronze; use aluminium or coated fasteners where possible.

Applications

Marine applications

  • Shafts and pins: hinge pins, davit pins, pulley axles and roller spindles (6082, 6061)
  • Stanchions and posts: machined bases and solid posts for railings and canopies
  • Fasteners: aluminium bolts and studs for aluminium structures, avoiding galvanic couples
  • Bushes and sleeves: turned from larger bar, often hard anodised
  • Handles and trim: door handles, grab rails and decorative parts (6060)
  • Mast and rigging fittings: tangs, end plugs and sheave housings
Comparison

Side-by-side comparison

Property6060-T66005A-T66061-T66082-T6
Min. proof strength (bar)150 MPa215 – 225 MPa240 MPa250 – 260 MPa
MachinabilityFairGoodVery goodVery good
Anodised appearanceExcellentGoodVery goodGood
Copper content≤ 0.10 %≤ 0.30 %0.15 – 0.40 %≤ 0.10 %
Typical marketEuropeEuropeAmericas, AsiaEurope, India
Ordering

How to order

  1. SpecifyAlloy, temper, diameter, length, quantity, tolerance and standard.
  2. QuoteAvailability, certificate and terms (EXW, FOB, CIF or DAP).
  3. PrepareCutting, marking and inspection.
  4. ShipEN 10204 3.1 certificate with export packing.
Sources

References and standards

  1. EN 755-2 – Extruded rod/bar, tube and profiles: mechanical properties
  2. EN 755-3 – Extruded round bar: tolerances on dimensions and form
  3. ASTM B211 – Aluminum and Aluminum-Alloy Rolled or Cold Finished Bar, Rod, and Wire
  4. ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
  5. The Aluminum Association – International Alloy Designations and Chemical Composition Limits
FAQ

Marine 6xxx aluminium (aluminum) round bar: FAQs

Which 6xxx round bar is best for marine shafts?

6082-T6 for European drawings or 6061-T6 for ASTM drawings. Both give about 240 – 260 MPa minimum proof strength; hard-anodise wear surfaces.

Is 6061 or 6082 better in seawater?

6082 has less copper and is usually considered slightly better in chloride environments, but both need anodising or coating for long exposure.

What diameters are available?

Extruded bar typically from about 6 mm to 250 mm; larger diameters and cold-finished small diameters on request.

How heavy is a 50 mm aluminium round bar?

About 5.30 kg per metre in any 6xxx alloy.

What is the difference between T6 and T6511?

Both have the same strength. T6511 is stretched to relieve stress and lightly straightened, so it distorts less during machining.

Need marine round bar?

Send alloy, temper, diameter, length, quantity and destination for availability, certification and a delivered price.

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