Aluminum EN AW-6082: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

EN AW-6082 is part of the 6xxx series of aluminum alloys, which are defined by the presence of magnesium and silicon as the principal alloying elements. This alloy class is heat-treatable and forms the intermetallic Mg2Si phase upon aging, which provides the primary strengthening mechanism in T-temper conditions.

6082 is characterized by a balanced combination of medium-to-high strength, good corrosion resistance in atmospheric and mildly corrosive environments, and favorable weldability compared with higher-strength Al–Zn or Al–Cu alloys. The alloy exhibits moderate formability in annealed or T4 conditions and retains good machinability and structural stability in extrusions and plates, making it a workhorse for structural applications.

Typical industries using EN AW-6082 include automotive structural components, transportation trailers, marine superstructures, general engineering fabrications, and architectural profiles. Engineers often choose 6082 over 6061 when higher strength and improved machinability are required in extruded sections, and they prefer it to 6xxx alloys with lower Mn/Mg content when improved resistance to stress-corrosion cracking and better mechanical stability at elevated sections is desired.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed condition for maximum ductility
T4	Moderate	High	Very Good	Very Good	Solution heat-treated and naturally aged
T6	High	Low–Moderate	Fair	Good	Solution heat-treated and artificially aged for peak strength
T651	High	Low–Moderate	Fair	Good	T6 with stress relief by stretching; used to minimize residual distortion
H14	Moderate	Moderate	Good	Good	Strain-hardened to a specified degree; retains some formability

Temper has a strong influence on both static and fatigue properties because it controls the precipitation state of Mg2Si and the dislocation density in the matrix. Selection between O/T4 and T6/T651 is a trade-off between ductility/formability and yield/tensile strength; machining and welding practices must account for HAZ softening and residual stress depending on temper.

Chemical Composition

Element	% Range	Notes
Si	0.7 – 1.3	Provides silicon for Mg2Si precipitation; essential for heat-treatable strengthening
Fe	≤ 0.50	Impurity that forms intermetallics (β-AlFeSi) affecting toughness and machining
Mn	0.4 – 1.0	Improves strength and toughness through dispersoids; controls grain structure
Mg	0.6 – 1.2	Combines with Si to form Mg2Si precipitates responsible for age-hardening
Cu	≤ 0.10 – 0.20	Small amounts increase strength but can reduce corrosion resistance and weldability
Zn	≤ 0.20	Low levels; excessive Zn raises susceptibility to SCC in certain environments
Cr	≤ 0.25	Controls grain structure and can limit recrystallization during processing
Ti	≤ 0.10	Grain refiner in cast or wrought products; used at low levels
Others	Balance / residuals	Includes trace elements and impurities controlled to meet standards

The balance of Mg and Si determines the potential volume fraction and distribution of Mg2Si precipitates, which in turn establish the peak mechanical properties after artificial aging. Minor elements like Mn and Cr tailor recrystallization behavior and grain size, improving toughness and toughness-to-weight in extruded profiles and thick sections.

Mechanical Properties

Tensile behavior of EN AW-6082 varies widely with temper and section thickness because the precipitation state and strain-hardening capacity determine both yield and ultimate tensile strength. In T6/T651 conditions the alloy typically displays linear-elastic behavior up to a defined yield followed by uniform plastic elongation and conventional necking; the alloy retains reasonable notch sensitivity compared with high-strength Al–Zn alloys.

Yield strength in peak-aged tempers is high for a 6xxx series alloy, giving good structural capacity without the weight penalty associated with higher-density steels. Ductility is a trade-off: annealed or T4 material exhibits high elongation suitable for forming, whereas T6 reduces elongation and increases hardness, which benefits machining and fatigue life in some design conditions.

Fatigue resistance is acceptable for structural applications and benefits from smooth surface finish and control of residual stresses; heat-affected zones created during welding can reduce fatigue life due to HAZ softening. Thickness effects are significant because coarse-grained microstructures in thick sections and slower cooling rates can lower strength and delay full precipitation hardening compared with thin extrusions.

Property	O/Annealed	Key Temper (e.g., T6/T651)	Notes
Tensile Strength	115 – 185 MPa	300 – 340 MPa	T6 achieves near-peak strength for structural use; ranges depend on section and supplier specifications
Yield Strength	55 – 130 MPa	260 – 300 MPa	Yield rises markedly with artificial aging and cold work
Elongation	15 – 30%	8 – 12%	Ductility drops with increased precipitation and strain-hardening
Hardness	40 – 70 HB	95 – 120 HB	Hardness correlates with precipitate density and dislocation density

Physical Properties

Property	Value	Notes
Density	2.70 g/cm³	Typical for wrought aluminium alloys; benefits strength-to-weight calculations
Melting Range	~555 – 650 °C	Solidus/liquidus range varies with composition and traces of eutectic constituents
Thermal Conductivity	~170 W/m·K	Lower than pure Al due to alloying; still good for heat dissipation applications
Electrical Conductivity	~28–34 % IACS	Reduced relative to pure aluminum; depends on temper and impurity content
Specific Heat	~0.90 J/g·K	Typical at room temperature for aluminium alloys
Thermal Expansion	~23.4 µm/m·K (20–100 °C)	High coefficient typical of aluminium; design must accommodate thermal movement

Thermal and electrical properties make 6082 suitable where moderate thermal conductivity and low mass are required, for example in heat-spreading structural components or housings. The combination of low density and reasonable conductivity is often exploited in transport and marine applications where weight savings are critical but some thermal management is still needed.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.5 – 6 mm	Uniform; thin-sheet reaching full precipitate homogeneity quickly	O, T4, T6	Used for panels, covers and light structural elements
Plate	6 – 200+ mm	Through-thickness gradients possible; coarser precipitates in thick sections	O, T651	Large plates require controlled cooling and furnace treatments
Extrusion	Wall thickness 1 – 50 mm; complex cross-sections	High directional strength along profile; microstructure controlled by profile design	T6, T651, T4	Widely used for structural profiles, railings, and frames
Tube	OD 10 – 300 mm	Strength depends on wall thickness and work-hardening	O, T6	Manufactured by extrusion or welded processes
Bar/Rod	Diameter up to 200 mm	Homogeneous; can be aged to T6 after section-size-dependent solutioning	O, T6	Used for machined components and fastener blanks

Forms differ because thermal mass and deformation history change cooling rates, recrystallization and precipitate distribution, which affects achievable properties after heat treatment. Extrusions are often supplied pre-aged to stable tempers to minimize distortion during machining, while thick plates may be stress-relieved (T651) to control residual stresses and dimensional stability in heavy fabrications.

Equivalent Grades

Standard	Grade	Region	Notes
AA	6082	International	Common wrought designation aligned with EN AW-6082; often used in industry literature
EN AW	6082	Europe	Standard European designation referring to the alloy under EN standards
JIS	~A6061 (approx.)	Japan	No exact one-to-one JIS equivalent; A6061 is somewhat similar but has different Mg/Si balance
GB/T	~6061 / 6063 (approx.)	China	Chinese standards often list 6xxx series alloys with similar properties but different composition limits

Equivalency tables are approximate because national standards and naming conventions differ in allowable impurity levels, mandatory testing, and temper definitions. Engineers should verify mechanical and chemical certificates rather than relying solely on nominal grade names when substituting across standards.

Corrosion Resistance

EN AW-6082 exhibits good atmospheric corrosion resistance in industrial and urban environments due to the protective aluminum oxide film and modest Cu content. In marine or chloride-containing atmospheres the alloy performs reasonably well, though pitting can occur on exposed surfaces if protective coatings are breached; anodizing or organic coatings are commonly specified for aggressive environments.

Stress-corrosion cracking (SCC) susceptibility in 6082 is lower than in some high-strength Al–Zn alloys, but it is not immune; high tensile stress combined with corrosive media and elevated temperatures can promote SCC, particularly for overaged or heavily cold-worked conditions. Galvanic interactions with more noble metals (stainless steel, copper) will accelerate localized corrosion if electrical continuity and electrolyte presence exist; designers typically avoid direct contact or employ insulating barriers.

Compared with 5xxx series (e.g., 5052) EN AW-6082 has generally lower intrinsic corrosion resistance in marine environments but higher strength and better machinability. Against 3xxx series alloys (e.g., 3003), 6082 offers higher strength at the cost of slight reductions in formability and corrosion resistance in highly aggressive environments.

Fabrication Properties

Weldability

EN AW-6082 welds readily with common fusion processes such as TIG and MIG using appropriate filler alloys; fillers in the 4043 (Al-Si) or 5356 (Al-Mg) families are commonly selected to balance strength and crack resistance. The heat-affected zone experiences overaging and softening in peak-aged tempers, which can reduce local strength; post-weld heat treatment (PWHT) or selecting T6 in non-critical regions helps mitigate strength loss. Hot-cracking risk is moderate and can be controlled by joint design, filler choice, preheat when necessary, and control of impurities and weld cooling rates.

Machinability

Machinability of 6082 is good for a structural aluminum alloy, with typical machinability indices around 70–85% of free-cutting aluminum standards depending on temper. Carbide tooling with positive rake and ample coolant at moderate speeds delivers good surface finishes and tool life; machinists should watch for built-up edge in softer tempers and adjust feeds accordingly. Chip control is generally favorable, producing continuous or segmented chips depending on cutting conditions and temper; deep cuts and interrupted cuts benefit from rigid fixturing to avoid chatter.

Formability

Formability is highly temper-dependent: O and T4 tempers enable tight bends and complex profiling with low risk of cracking, while T6 and H14 temper reduce allowable bend radii and increase springback. Typical minimum bend radii for sheet in annealed conditions may be as low as 1–2× thickness for air-bend operations, but designers should verify using coupon testing for profiles and gauge-dependent behaviors. Cold forming and extrusion bending benefit from pre-heating and controlled strain paths for thicker sections to prevent surface cracking and maintain dimensional tolerances.

Heat Treatment Behavior

As a heat-treatable alloy, EN AW-6082 responds predictably to solution treatment, quenching, and aging. Solution treatment is typically carried out near 535–565 °C to dissolve Mg2Si and homogenize the solid solution, followed by rapid quench to retain a supersaturated matrix; the effectiveness of quenching depends strongly on section thickness and tooling.

Artificial aging temperatures are commonly in the 160–185 °C range for T6 conditions, with aging times optimized to achieve a peak hardness/strength trade-off while avoiding overaging; T651 is T6 with an additional controlled stretching or straightening to reduce residual stresses. Improper or slow quenching and insufficient aging can cause underaged or heterogeneous microstructures, while excessive aging or high-temperature exposure can coarsen precipitates and reduce strength and toughness.

High-Temperature Performance

EN AW-6082 experiences progressive strength loss as temperature rises above typical service temperatures because Mg2Si precipitates dissolve or coarsen and dislocation mobility increases. Useful structural strength is retained up to roughly 100–150 °C for short durations, but prolonged exposure above ~150 °C will degrade mechanical properties and can induce overaging and softening.

Oxidation is limited in air due to the protective Al2O3 scale, but elevated temperatures accelerate diffusion-driven changes in precipitate chemistry and grain boundary films, which can affect properties such as creep and fatigue at temperature. Designers should account for HAZ softening in welded assemblies and avoid sustained elevated-temperature exposure in load-bearing components unless re-aging and stabilization procedures are implemented.

Applications

Industry	Example Component	Why EN AW-6082 Is Used
Automotive	Structural extrusions, chassis rails	High strength-to-weight, good machinability, weldability
Marine	Deck structures, superstructure profiles	Reasonable corrosion resistance, good extrudability for complex profiles
Aerospace	Secondary fittings, cargo fittings	Balance of strength, weight savings, and corrosion performance
Electronics	Heat-dissipating housings	Moderate thermal conductivity and ease of fabrication
Construction	Window frames, curtain walling	Dimensional stability in extrusions and aesthetic surface finishing

EN AW-6082 is selected in these markets because it offers an advantageous blend of mechanical capacity, fabricability and corrosion performance in a cost-effective alloy system. The ability to supply profiles in stable T651 tempers and to derive high-strength machined parts from bar stock makes it especially versatile for both small and large structural components.

Selection Insights

Choose EN AW-6082 when an application requires higher structural strength than commercially pure aluminum (e.g., 1100) while still benefiting from good thermal conductivity and relatively easy fabrication. Compared with 1100, 6082 sacrifices some electrical conductivity and extreme formability for a substantially higher strength and improved structural performance.

When evaluating against work-hardened alloys such as 3003 or 5052, EN AW-6082 delivers higher peak strength and often superior machinability but slightly reduced resistance to marine pitting; pick 6082 where strength and stiffness dominate the requirement, and consider 5xxx alloys if superior raw corrosion resistance without heat treatment is critical.

Against other heat-treatable alloys such as 6061 or 6063, 6082 can be preferred for thicker extrusions and applications demanding higher natural strength and better machinability; 6061 may provide more consistent weldability in some cases and 6063 may be chosen for superior surface finish and extrusion workability.

Closing Summary

EN AW-6082 remains a widely used structural aluminum alloy because it combines heat-treatable strengthening, good weldability, and practical corrosion resistance in a form that is readily extrudable and machinable. Its balanced chemistry and temper options allow designers to tailor strength, ductility, and dimensional stability for a broad range of transport, marine, and general engineering applications, keeping it highly relevant in modern manufacturing and construction.