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EN AW 6082 / UNS A96082

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BS L115 / AlSi1MgMn / 6082 / T651

EN AW 6082 (also known as AlMgSi1) is an aluminium alloy offering high strength, high corrosion resistance and good machinability. 6082 is one of the most widely specified members of the aluminium-silicon-magnesium (Al-Si-Mg) alloys for structural applications. Its properties are close to those of alloy 6061, and in some cases it provides better mechanical properties and higher strength.​‌​​‌​

6082 T651 sheet and plate is a moderate strength aerospace material, and it has higher strength than 6061.

Machinability: Although EN AW 6082 is an aluminium alloy with high mechanical properties, it also offers good machinability. That matters particularly for cold and hot forming operations.​‌​​‌​

Turning and milling: Cutting speed — despite its high strength, 6082 can be machined at medium cutting speeds, and excessively high cutting speeds are not recommended. Cutting tools — it can be machined successfully using carbide inserts and hardened steel tooling. Cooling — cutting fluid should be used during high speed machining, which helps prevent high temperatures in the cut and improves machining efficiency.

Weldability: It can readily be welded by the TIG and MIG processes, but thermal stress in the weld zone must be carefully controlled. Surface cleanliness before welding is important, because the oxide layer can affect weld quality, and the cooling rate must be controlled during welding.​‌​​‌​

Heat treatment: EN AW 6082 is generally given the T6 temper, which raises the strength of the alloy. Because hardness increases during heat treatment, this makes the alloy widely used in high performance structural applications.

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What EN AW-6082 Is — and Why It Is Not the Same Thing as 6061

EN AW-6082 (chemical symbol EN AW-AlSi1MgMn / W.Nr. 3.2315 / AA 6082 / old DIN name AlMgSi1 / in the British tradition HE30 · BS H30) is Europe’s structural 6xxx alloy. Its nominal composition is 0.70-1.3 % Si, 0.60-1.2 % Mg and — the distinguishing element — 0.40-1.0 % Mn. That manganese band is the single fact that separates this alloy from everyone else in the family.​‌​​‌​

The honest one-line definition: 6082 is the highest-strength standard member of the 6xxx family, and it buys that strength by giving up surface quality and decorative anodizing. Under EN 485-2 the minimum proof stress of a 6082-T6 plate sits in the 240-260 N/mm² band; in the same system EN AW-6060 T6 profile gives 140-150 N/mm². Almost double.

And the most expensive commercial misunderstanding starts here: treating 6082 and 6061 as equivalent. Both are “structural 6xxx”, both run at a similar strength level in T6, and many distributor tables list them side by side as though they were interchangeable. Their chemistries exclude one another.​‌​​‌​

The real divide is the code: 6061 is in ASME, 6082 is not​‌​​‌​

This matters more than the mechanical difference and it almost never comes up in a sales conversation. On the pressure-equipment side, 6061 is accepted as a pressure-boundary material in ASME II Part D (through SB-209 plate and SB-221 extrusions). 6082 is not. So if you are designing an ASME Section VIII vessel and you have 6082 in hand, there is no allowable stress to use — the material is stronger and still cannot be code-stamped. America uses 6061 because the code recognises 6061; Europe uses 6082 because Eurocode 9 and EN 485 / EN 755 recognise 6082. This is not a technology gap, it is a code geography.

Standards by Product Form

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The second big fact separating 6082 from 6060 is the breadth of product forms. Where 6060 is an extrusion alloy only, 6082 is standardised as sheet, plate, extrusion, cold drawn product and forging. That is what makes it Europe’s general-purpose structural aluminium.

Product Forms With NO Standard

The standards coverage of 6082 is broad but not unlimited. The gaps below cost money if they are not known at quotation stage.​‌​​‌​

Chemical Composition​‌​​‌​

A direct consequence of the chemistry: quench sensitivity​‌​​‌​

The manganese in 6082 is the source of everything that separates it from 6060 — the strength and the problems alike. Manganese (and chromium) dispersoids act as nucleation sites for early, coarse precipitation of Mg₂Si during the quench. If the cooling is not fast enough, the Mg and Si that should have provided strength are already spent before the ageing treatment begins.

The practical consequence: 6082 can be brought to T6 by a press quench in thin sections; but in heavy sections and in plate form that is not enough and a separate solution furnace with an intense water quench is required. That means three things: higher cost, distortion and high residual stress. The third item is precisely why the T651 temper exists.​‌​​‌​

The Temper System — T4, T6 and T651

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The temper system of 6082 is narrower than that of 6060 but each entry carries a sharper commercial meaning. There are no European intermediate tempers such as T64/T66 here; the key distinction is what T651 actually is, and for a manufacturer that is not a one-line difference.

Mechanical Properties

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Every value below is a MINIMUM. There are two counter-intuitive points in 6082 that deserve attention, and both are visible in the tables.​‌​​‌​

COUNTER-INTUITIVE POINT — in extrusion the THIN section gets the LOWER minimum. The EN 755-2 table gives 6082-T6 Rp0.2 ≥250 / Rm ≥290 at ≤5 mm but Rp0.2 ≥260 / Rm ≥310 at 5-25 mm. That is not a typographical error. The reason is that thin-walled extrusions undergo more surface recrystallisation at the press exit and lose the strength contribution of the retained substructure; in addition, the recrystallised coarse-grain layer occupies a proportionally larger share of a thin section. In plate the trend reverses (it falls as thickness rises) — because there the governing factor is quench rate, not recrystallisation. The two tables describe two different physics and must not be mixed.

CONFLICT NOTICE. A widely mirrored mill datasheet prints Rm 310 / Rp0.2 260 N/mm² for 6082 T4 sheet (3-6 mm). Those values cannot belong to T4 — they are identical to that same sheet’s own T6 row, and the same sheet gives 205 / 110 for T4 bar and tube. This is a row shift and it is the most common datasheet error we have seen for 6082. The right order of magnitude for T4 is the 205 / 110 N/mm² band; confirm the exact sheet minimum from the EN 485-2 table itself. No number for T4 sheet is given on this page.

MINIMUM vs TYPICAL. All the numbers above are the minima of the standard. Measured typical values run higher: in one welding study the measured tensile strength of the 6082-T6 parent metal was 289.88 N/mm² with an elongation at fracture of 19.2 % — against a standard minimum elongation of 8-10 %. Use the minimum in design and the typical in process planning, and never confuse the two.​‌​​‌​

Physical Properties

Heat Treatment and Thermal Stability

Solution treatment and quench​‌​​‌​

6082 follows the general heat-treatment route of the AlMgSi family: solution treatment in the region of 525-540 °C, then quench, then artificial ageing. But in 6082 the quench is an entirely different engineering problem from 6060.

The reason is manganese. The 0.40-1.0 % Mn of 6082 produces a fine distribution of Al-Mn(-Fe,Si) dispersoids through the matrix. These dispersoids offer ready-made surfaces for nucleation; if the quench is not fast enough, Mg and Si are spent as coarse, ineffective precipitates on those surfaces and are not left in solution for the subsequent ageing. The measured result is visible directly in the EN 485-2 table: the tensile minimum of 150 mm plate is 11 % below that of 6 mm sheet.​‌​​‌​

Practical consequences:
· In thin extrusions a press quench (water mist / intense air) can be enough for T6.
· In heavy extrusions and in plate a separate solution furnace plus an intense water quench is required.
· That means high residual stress, which is exactly why T651 exists: 1.5-3 % controlled stretching after the quench erases it.
· If a polymer quenchant is used — sometimes chosen to reduce distortion — there is a strength penalty. On 7075 that effect has been measured as a 5-10 % strength penalty; no comparable published number was found for 6082, but the mechanism and the direction are the same.

Artificial ageing​‌​​‌​

The published artificial-ageing band for the AlMgSi family is 155-190 °C for 4-16 hours. The exact plant-specific cycle for 6082 could not be verified in this research and will not be given here as a recipe. Common industrial practice sits in the 175-185 °C band. The softening anneal for the AlMgSi family is given as 360-400 °C for 1-2 hours, then slow cooling at 30 °C per hour down to 250 °C — a fast cool defeats the anneal, because the material is partially re-solutionised and hardens again.

Thermal stability and powder coating​‌​​‌​

6082-T6 begins to soften permanently above roughly 120-135 °C. This is not a capability limit but a precipitate stability limit, and it is irreversible. Three places matter in practice:
1. The powder-coat oven (180-200 °C, 10-20 minutes). Usually harmless on T6 material; but it partially ages a T4 part. Do the forming before the coating line.
2. Post-weld straightening heat. Local heating applied out of steel habit softens 6082 while straightening it. Do not do it.
3. Continuous hot service. Around engines, on power-electronics heat sinks, near steam lines, reduce the design strength against the 120 °C limit — that is a Eurocode 9 topic and the numerical reduction factors come from the standard’s own table.

Welding​‌​​‌​

6082 welds very well — and it loses roughly half its strength where it is welded. The second of those sentences is the most expensive fact in aluminium structural design.

HAZ loss — with numbers, and why two different numbers circulate

The measured number. In a 6082-T6 MIG joint made with ER5356 filler, 1.2 mm wire and 2.57 kJ/mm heat input: parent metal 289.88 N/mm², joint 222.09 N/mm² — a 76.62 % joint efficiency. Elongation at fracture fell from 19.2 % to 11.4 % (59.38 % of the parent metal).​‌​​‌​

The design number. A mill datasheet for the same alloy states something far more pessimistic: “mechanical properties reduce approximately 50 % after welding.” The two do not contradict each other; they measure different quantities:
· 76.6 % is a ratio of ultimate tensile strengths measured in a tensile test.
· ~50 % corresponds to the fall in proof strength and is close to the reduction logic Eurocode 9 applies to the HAZ. A T6 material with 260 N/mm² proof stress has a HAZ at T4 level, around 110 N/mm² — that alone is a 58 % loss.
The number to design with is the proof-strength one. Designing a welded 6082 structure with the parent metal’s T6 proof stress means breaking the structure next to the weld bead.

Where is the HAZ? In the same measured study the minimum-hardness zone was found 9.5-10.5 mm from the weld centre. So the fracture is not at the bead; it is about a centimetre away from it. The design consequence is critical: strengthening the bead (thicker weld, more passes) does not strengthen the structure — it only widens the HAZ and makes matters worse. The right move is to lower the heat input and to move the weld into a low-stress region.​‌​​‌​

Recovery after welding

Partial recovery is real. After welding, natural ageing restores some strength in the HAZ over weeks; re-ageing artificially (around the 175 °C band) gives more. But it does not return to T6, because the precipitates in the HAZ have already coarsened and will not refine without re-solutionising. Full recovery means re-solution treatment, re-quench and re-ageing after welding, which on a welded assembly is usually impractical because of distortion.​‌​​‌​

Machining

Unlike 6060, 6082 machines well — but only in the right temper. One mill sheet rates it 2 (good) in the heat-treated condition and 4 (poor) in the soft-annealed condition on a 1-5 scale. On one extruder’s 0-3 scale 6082 scores 2 points — above 6060’s 1 point — and the note observes that it “maintains mid-range machinability despite being the highest-strength standard alloy”.​‌​​‌​

Corrosion — Where It Is Good, Where It FAILS​‌​​‌​

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The corrosion record of 6082 is good but not as clean as that of 6060, and the difference comes from the chemistry. On one mill’s 1-5 scale: 1 (very good) in normal atmosphere, 2 (good) in seawater. On the anodizing side: protective anodizing 1 (very good), but decorative anodizing 3 (moderate).

Why it is good: the absence of copper​‌​​‌​

The copper ceiling of 6082 is ≤0.10 %, and that is the main source of its corrosion resistance. Compare: 6061 requires copper at 0.15-0.40 %, which is why 6061 sits slightly below 6082 in corrosion resistance. In 7075 copper runs 1.2-2.0 % and that alloy behaves entirely differently — see EN AW-7075.

And the greatest advantage of the 6xxx family applies here too: stress corrosion cracking is practically ABSENT. In NASA’s MSFC-STD-3029 classification, 6061 sits in the “high resistance” class (Table I) in all tempers — no cracking in 30 days at 75 % of yield. 6082 is not explicitly listed in that standard, and we say so honestly; but the metallurgy is the same (copper-free, low Zn, Mg₂Si hardening) and in practice SCC is not treated as a design constraint for 6082 either.​‌​​‌​

WHERE IT FAILS — 1: intergranular corrosion (IGC) and free silicon

This is the genuine weakness of 6082 that 6060 does not have, and most datasheets never mention it. The silicon band of 6082 is 0.70-1.3 % and the magnesium band 0.60-1.2 %. When silicon remains in excess of the ratio Mg₂Si requires — which in 6082 is typical — free silicon precipitates on the grain boundaries. Silicon is cathodic relative to the aluminium matrix; the result is a continuous micro-galvanic path along the grain boundary, and that is intergranular corrosion.​‌​​‌​

Conditions that raise the risk: slow quenching (heavy section — it feeds the grain-boundary precipitates), improper ageing (under or over), the weld HAZ and a chloride environment. Conditions that lower it: fast quenching, a correct T6 cycle, and — most effectively — isolation from the environment by coating or anodizing.
Practical consequence: for heavy-section and/or welded 6082 going into seawater or a chloride process, surface protection is not optional. The alternative for the same environment is the copper-free, silicon-free 5xxx family — see EN AW-5083 and EN AW-5754.

WHERE IT FAILS — 2: decorative anodizing​‌​​‌​

This is an appearance failure rather than a corrosion failure — but in façade work it causes more rejections than corrosion does. 6082 scores 1 (very good) for protective anodizing and 3 (moderate) for decorative anodizing on a 1-5 scale. The cause is the 0.40-1.0 % manganese and ≤0.25 % chromium: these leave light-scattering second-phase particles in the anodic film and it comes out grey, hazy and variable from batch to batch.
What can be done: protective (clear, technical) anodizing is unproblematic. If a visible surface is wanted, powder coating or wet paint is the answer. For a decoratively anodized visible façade the right alloy is not 6082 but EN AW-6060 or 6063.

WHERE IT FAILS — 3: the weld bead and the HAZ​‌​​‌​

Welding creates two separate corrosion problems in 6082. The first is the intergranular corrosion risk in the HAZ: grain-boundary precipitation concentrates there and the micro-galvanic path created by free silicon becomes pronounced. The second is the galvanic difference between filler and parent metal: 5xxx fillers (5356/5183) are slightly more active than 6082 and in a chloride environment the bead can corrode preferentially. And a measured warning: in the same study, the heat input that gave the best mechanical result (2.57 kJ/mm) produced the worst corrosion resistance. When a welding parameter is optimised, the objective it was optimised for must be stated.

WHERE IT FAILS — 4: galvanic couples and alkaline media​‌​​‌​

Galvanic: like all aluminium, 6082 becomes the ANODE against stainless steel, carbon steel, copper, brass and graphite. In structural work this means an aluminium joint with stainless bolts, and a small aluminium area against a large steel area is the worst ratio. Isolating washers, coated fasteners and keeping the joint dry are mandatory.
Alkaline: the passive film on aluminium is stable roughly between pH 4 and 9. Fresh concrete and cement mortar (pH 12-13) will pit 6082 within hours. On bridges, scaffolding and construction sites this is a daily risk — surfaces splashed with concrete must be washed immediately.
Crevice corrosion: under gaskets, in lap joints and around fasteners, where oxygen cannot reach and chloride accumulates, deep pitting begins. That is the practical meaning of a seawater rating of 2 rather than 1.

Frequently Asked Questions​‌​​‌​

Our American customer wants 6061-T6 and we have 6082-T6 in stock. Can we ship it?

Technically 6082 is stronger. As a specification you cannot ship it. Those are two different questions and you have to answer both.
1. The chemistries exclude each other. The manganese of 6082 is 0.40-1.0 % mandatory; the 6061 ceiling is ≤0.15 %. So no 6082 heat can meet 6061 chemistry. The same holds in reverse: 6061 requires copper at 0.15-0.40 % while the 6082 ceiling is ≤0.10 %; no 6061 heat can meet 6082 chemistry. The two alloys are not “equivalents”; they exclude one another.
2. The mechanical values favour 6082. Common minima for 6061-T6 are Rm 290 / Rp0.2 240 N/mm²; for 6082-T6 (extrusion 5-25 mm) Rm ≥310 / Rp0.2 ≥260. So the structure would be stronger with 6082 — but that does not mean you met the customer’s specification.
3. The real obstacle is on the code side. The customer may want 6061 for a reason: ASME II Part D accepts 6061 as a pressure-boundary material and does not accept 6082. If the job is an ASME vessel or a B31.3 line, it cannot be code-stamped with 6082 and the “it is stronger” argument means nothing.
4. The machinability difference. The copper in 6061 gives it slightly better chip breaking. On a high-volume automatic-lathe part that difference is felt.
The honest quotation sentence: “We can supply 6082-T6; its mechanical properties exceed 6061-T6 and it is certified to EN 485-2 / EN 755-2. However 6082 is not a 6061, it does not meet the ASTM/ASME specifications, and substitution can only be made with the customer’s written approval.” Do not ship it without that approval.​‌​​‌​

We are designing a welded 6082 frame. Which strength should we calculate with?

NOT the parent metal’s T6 values. This is the most expensive mistake made in aluminium structural design.
What happens: welding effectively re-solutionises a narrow band beside the fusion line and cools it without control. In that band the Mg₂Si precipitates coarsen and the strength the temper provided is gone. The HAZ typically falls to around T4 level: the 260 N/mm² proof stress of T6 drops toward 110 N/mm² in the HAZ.
The numbers: in a measured 6082-T6 MIG joint (ER5356, 2.57 kJ/mm) parent metal 289.88 N/mm², joint 222.09 N/mm² — 76.6 % efficiency; elongation fell from 19.2 % to 11.4 %. A mill datasheet for the same alloy states “approximately 50 % reduction” on the design side. The first describes ultimate strength, the second proof strength. Design uses proof strength; use the pessimistic one.
Where it breaks: in the same study the minimum-hardness zone was 9.5-10.5 mm from the weld centre. The fracture is not at the bead but a centimetre away from it. The design consequence: thickening the bead does not strengthen the structure; it only widens the HAZ.
The correct route: design to EN 1999-1-1 (Eurocode 9). It treats the HAZ as a separate region and defines reduction factors and a HAZ width. The numerical factor table of Eurocode 9 is not reproduced on this page because it could not be independently verified — use the standard’s own table.
Designer’s moves: move the weld into a low-stress region; lower the heat input; thicken the section at the HAZ; where possible switch to friction stir welding or mechanical joining. Post-weld re-ageing gives partial recovery but does not bring T6 back.​‌​​‌​

Parts machined from our 80 mm T6 plate bow as they come off the machine. Why?

The material is not defective; the wrong temper was purchased.
The mechanism: 6082 is a quench-sensitive alloy (because of the manganese dispersoids), so heavy plate must be solution treated in a separate furnace and quenched intensely. During the quench the plate surface cools far faster than the core, and what remains is a self-balanced but very high residual stress field — compression at the surface, tension in the core. The plate is flat, because the stresses balance. The moment you remove material asymmetrically that balance breaks and the part bows toward its new equilibrium.
The fix: buy T651. Its definition is solution heat treated → quenched → stress relieved by CONTROLLED STRETCHING → artificially aged. The stretch runs 1.5-3 % for plate and 0.5-3 % for sheet. The mechanical values are identical to T6 — what you buy is not strength but dimensional stability.
Additional measures: between roughing and finishing, release the part, let it rest and re-fixture it; remove material symmetrically from both faces; keep clamping forces low (a tightly clamped part looks flat on the machine and bows when released).
And a caution: because T6 and T651 share the same mechanical table, some distributor pages write them as a single “T6/T651” row. That does not mean you are getting stretched plate. Write T651 into the order and look for it on the certificate.​‌​​‌​

Can 6082 be in contact with food? And up to what temperature can it be used?

Food contact: one mill datasheet states explicitly that 6082 is “suitable for the food industry according to DIN EN 602”, and the alloy’s classic applications include beer barrels and milk churns. The metallurgical reason is that copper is effectively forbidden (≤0.10 %). Compare: the same statement is not given for 7075, and one European mill sheet explicitly marks 7075 as NOT suitable for food contact — because of its 1.2-2.0 % copper.
But food contact is a surface question: if there is an anodic film, sealing must be complete; if there is a weld, the filler metal must be suitable too. And the final declaration of conformity belongs to the part manufacturer, not to the alloy choice.
Temperature: one mill sheet gives about 120-135 °C long term and about 155-170 °C short term. That is a stability limit, not a capability: above it the Mg₂Si precipitates coarsen, the material softens permanently and does not recover on cooling. Pasteurisation (~70 °C) and CIP cleaning (~80-85 °C) are below the limit; steam sterilisation at 121 °C sits right on it and the strength loss over repeated cycles should be measured. A few hours at 200 °C effectively takes a T6 part down to T4 level.​‌​​‌​

Common datasheet errors — check these before you order

1. Treating 6082 and 6061 as EQUIVALENT — THE MOST COMMON AND MOST EXPENSIVE ERROR. Their chemistries exclude one another: 6082 Mn 0.40-1.0 % mandatory / 6061 Mn ≤0.15 %; 6061 Cu 0.15-0.40 % mandatory / 6082 Cu ≤0.10 %. No heat can satisfy both. And 6061 is accepted in ASME II Part D while 6082 is not — that matters more than the mechanical difference.
2. T4 sheet values printed identically to the T6 row. A widely mirrored mill sheet shows Rm 310 / Rp0.2 260 for T4 sheet (3-6 mm); that is identical to its own T6 row, while the same sheet gives 205 / 110 for T4 bar and tube. It is a clear row shift. There is no T4 with a 260 N/mm² proof stress.
3. Writing “T6/T651” as a single row. The mechanical values are identical, but T651 is stretched and T6 is not. If you will machine precision parts from heavy plate, they are not the same product. Write T651 into the order.
4. Assuming the thin extruded section is stronger. In EN 755-2, 6082-T6 gives ≤5 mm: 290/250 and 5-25 mm: 310/260 — the thin one gets the LOWER minimum. In plate the trend is the opposite. Do not mix the two tables.
5. Calculating heavy plate with thin-plate values. EN 485-2 gives 6-12.5 mm: 300/255 and 100-150 mm: 275/240. Quench sensitivity makes heavy plate weaker, and that 11 % gap is real in design.
6. Inconsistent hardness values. For the same T4, one source gives 70 HBW, another 65 HBW and a third gives 35 HBW for extruded T4. 35 HBW is most likely wrong — the expected order for 6082-T4 is the 60-70 HBW band. Hardness is not a mandatory acceptance criterion of EN 485 / EN 755; it is informative.
7. Melting temperature given as a single number. Two independent sources give the range 585-650 °C while one distributor page prints a single value of 555 °C. That is almost certainly wrong. Take 585 °C as the lower bound for welding and hot-forming planning.
8. Leaving “welds very well” standing alone. It is true — but the HAZ proof stress falls to T4 level. Measured joint efficiency is 76.6 %; the mill sheet’s design statement is “approximately 50 % reduction”. Do not design a welded structure with the T6 proof stress.
9. Promising decorative anodizing. 6082 scores 1 (very good) for protective anodizing and 3 (moderate) for decorative anodizing. Manganese and chromium grey the film. For a visible façade use 6060 or 6063, not 6082.
10. Never mentioning the intergranular corrosion risk. 6082 can carry free silicon in excess of Mg₂Si stoichiometry, and that silicon forms a cathodic path along the grain boundaries. The combination of slowly quenched heavy section + chloride environment + welding is a real risk. This is a weakness 6060 does not have.
11. Applying EN 12020-2 tolerances to 6082. EN 12020 is for 6060 and 6063 only. The tolerance standard for a 6082 profile is EN 755-9; anything tighter is by agreement.
12. Conflicting thermal expansion coefficient. 23.4 × 10⁻⁶ K⁻¹ and 23.1 × 10⁻⁶ K⁻¹ both appear for the same alloy on different pages. In precision assembly, record which value you used.
13. “New alloy” marketing. One distributor page introduces 6082 as “a relatively new alloy” and says it “has replaced 6061 in many applications”. It did not replace it — it became the standard in a geographically different market. America still uses 6061 because the code recognises 6061.​‌​​‌​

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