Aluminum EN AW-5086: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

EN AW-5086 is a member of the 5xxx series of aluminum alloys, characterized primarily by magnesium as the principal alloying element. This family is classed as non-heat-treatable alloys whose mechanical strength is obtained by solid-solution strengthening from Mg and by plastic deformation (work hardening) and strain aging in certain tempers.

Major alloying elements in EN AW-5086 are magnesium with significant additions of manganese and minor controlled levels of iron, silicon, chromium and trace elements. The Mg level provides the principal increase in strength and improves corrosion performance in chloride environments, while Mn refines grain structure and helps retain strength after processing.

Key traits of EN AW-5086 include a favorable combination of moderate-to-high strength for a non-heat-treatable aluminum, very good resistance to seawater and marine atmospheres, excellent weldability with conventional fusion methods, and reasonable formability when supplied in softer tempers. These properties make it common in marine, transportation, pressure-vessel, and cryogenic applications.

Engineers select EN AW-5086 over other alloys when a balance of corrosion resistance, weldability and toughness is more important than the absolute peak strength achievable with heat-treatable alloys. It is preferred where structural integrity in saltwater or aggressive environments is required without complex heat-treatment cycles.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed; best for complex forming and drawing
H111	Medium-Low	Moderate	Very Good	Excellent	Slightly strain hardened; often natural temper after rolling
H32	Medium	Moderate	Good	Excellent	Strain-hardened and stabilized; common for structural sheet
H34	Medium-High	Moderate-Low	Fair	Excellent	Higher strain hardening for increased strength
H36	High	Low-Moderate	Reduced	Excellent	Stronger strain-hardened condition for heavy sections
H116	Medium	Moderate	Good	Excellent	Stabilized for improved corrosion and weld properties; marine grade
H321	Medium	Moderate	Good	Excellent	Stabilized by low-temperature aging to resist sensitization

Temper choice strongly affects mechanical response and forming behavior because EN AW-5086 is non-heat-treatable; all higher strength tempers are produced by plastic deformation and natural or controlled stabilization. Designers must balance desired yield/tensile strength against required bend radii and elongation, choosing softer tempers for deep drawing and harder H‑tempers for structural stiffness and reduced springback.

Chemical Composition

Element	% Range	Notes
Si	≤ 0.40	Controlled low silicon to reduce intermetallics and maintain toughness
Fe	≤ 0.50	Iron is an impurity that forms hard intermetallics; limited to preserve ductility
Mn	0.20–0.7	Refines grain structure and offsets some Mg embrittlement; improves strength
Mg	3.5–4.5	Primary strengthening element; critically influences corrosion resistance and weldability
Cu	≤ 0.10	Kept low to avoid reduced corrosion resistance and stress corrosion susceptibility
Zn	≤ 0.25	Minor; excessive Zn can promote galvanic and local corrosion
Cr	0.05–0.25	Added for grain control and to improve strength retention after hot working
Ti	≤ 0.15	Grain refiner in small additions; improves mechanical consistency
Others (each)	≤ 0.05	Trace elements controlled to maintain predictable properties

The composition of EN AW-5086 positions it between the lower-strength 3xxx series and the higher-Mg 5xxx variants; magnesium provides solid-solution strengthening while manganese and chromium control grain size and mitigate recrystallization. Tight control of Fe, Si and Cu is important to prevent brittle intermetallics and to preserve pitting resistance and weldment performance in chloride-bearing environments.

Mechanical Properties

Tensile behavior of EN AW-5086 is typical of non-heat-treatable Al-Mg alloys: strain-hardening increases strength but reduces ductility. The alloy shows favorable toughness and retains elongation at low temperatures; thickness and temper significantly influence the measured tensile curve and ductility.

Yield strength varies with temper and thickness; H‑tempers produced by controlled cold work typically have higher yield and tensile strengths than O or H111 tempers. Hardness follows the same trend, with strain hardened conditions showing increases in Vickers/Brinell measures; however, work hardening reduces formability and increases springback.

Fatigue performance is generally good for welded and unwelded structures because of the alloy’s ductility and resistance to corrosion-fatigue in seawater when properly detailed. Thicker sections can retain higher absolute stiffness but may display different aging and residual stress patterns after welding and cold working, requiring qualification testing for critical components.

Property	O/Annealed	Key Temper (H32 / H116)	Notes
Tensile Strength	~120–200 MPa	~220–330 MPa	Wide ranges due to thickness and strain-hardening; select temper per design requirement
Yield Strength	~55–120 MPa	~140–260 MPa	Yield increases substantially with strain hardening/stabilization
Elongation	~20–35%	~8–18%	Softer tempers provide higher elongation for forming operations
Hardness	~30–45 HV	~60–95 HV	Hardness correlates with strain-hardening level and affects machining and forming

Physical Properties

Property	Value	Notes
Density	2.66 g/cm³	Typical for Al-Mg alloys; beneficial strength-to-weight ratio
Melting Range	~570–650 °C	Solidus-liquidus range varies with composition and impurities
Thermal Conductivity	~140–165 W/m·K	Lower than pure Al but still good for heat spreading
Electrical Conductivity	~30–40 %IACS	Reduced vs pure Al due to Mg in solid solution
Specific Heat	~0.90 kJ/kg·K	Typical aluminum specific heat near ambient temperature
Thermal Expansion	~23–24 µm/m·K	Moderate thermal expansion; important for joint design with dissimilar metals

The physical properties show EN AW-5086 retains many of aluminum’s advantages: low density yields high specific stiffness and energy absorption per mass. Thermal and electrical conductivities are lower than pure aluminum but remain adequate for heat-sinking and thermal management tasks; design must account for expansion when joining to steel or composites.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.5–6.0 mm	Behavior varies strongly with temper	O, H111, H32, H116	Widely used for hull panels, structural skins, and pressure vessels
Plate	6–200+ mm	Thick sections need heavier strain-hardening or tempering via processing	H34, H36, H116	Heavy-gauge plate often used in marine and armor; limited cold forming
Extrusion	Variable cross-sections	Extruded profiles can be cold finished to H‑tempers	O, H111, H32	Common for framework, railings, and stiffeners
Tube	Ø10 mm–300 mm	Welded or seamless; wall thickness affects strength and buckling	H32, H111	Used in fluid systems, structural members, and pressure lines
Bar/Rod	Ø3 mm–200 mm	Bars can be drawn/rolled then strain hardened	H111, H34	Used for fittings, fasteners and machined components

Processing varies by product form: sheet and plate are typically rolled and then cold-worked or stabilized to meet specified tempers, while extrusions require control of billet temperature and quench to retain homogeneous Mg distribution. Plate tends to be less formable and more often welded and machined, while sheet is used where complex forming and joining are needed.

Equivalent Grades

Standard	Grade	Region	Notes
AA / ASTM	5086	USA	Common commercial designation; covered in multiple ASTM specifications
EN AW	5086	Europe	AlMg4.5Mn equivalent under EN standards with similar composition controls
JIS	A5086 (or Al-Mg series)	Japan	Equivalent Al–Mg–Mn family designation; process standards vary
GB/T	5086	China	Chinese national standard grade with comparable composition ranges

Equivalency is close across major standards, but there are small differences in allowed impurity levels, temper definitions and testing protocols. Buyers should reference the specific specification sheet (ASTM, EN, JIS, GB/T) used in procurement to confirm exact composition limits, mechanical test requirements and surface finish standards.

Corrosion Resistance

EN AW-5086 exhibits excellent atmospheric corrosion resistance and is widely used in marine environments due to beneficial Mg levels that form stable oxide/hydroxide films. Pitting corrosion resistance in chloride-bearing environments is good compared with many Al alloys, although localized corrosion can still occur at stress concentrators or poorly prepared surfaces.

In seawater and splash zones, EN AW-5086 resists general and localized corrosion better than many heat-treatable Al alloys because it avoids the anodic precipitates that promote pitting. Stress corrosion cracking (SCC) susceptibility is generally low for 5086 compared with high-strength Al alloys, but SCC risks increase with higher Mg contents and with specific tempers following certain thermal exposures.

Galvanic interactions must be managed when 5086 is coupled to cathodic metals such as copper or stainless steel; the alloy is anodic to many steels and can be protected or isolated by coatings and insulating gaskets. Compared to 3xxx series (Al-Mn) alloys, 5086 typically offers higher strength while maintaining similar or improved corrosion behavior; compared to 6xxx and 7xxx heat-treatable alloys, 5086 is far superior in marine corrosion resistance.

Fabrication Properties

Weldability

EN AW-5086 welds very well with common fusion processes including TIG and MIG; joints typically achieve properties close to the parent metal when appropriate filler and procedures are used. Recommended fillers are Al‑Mg alloys (e.g., 5183, 5356) selected for matched strength and corrosion performance; filler choice and pre/post-weld treatment control HAZ behavior. Hot‑cracking risk is low for 5086 compared with high-copper alloys, but hydrogen porosity and contamination must be controlled with good shielding and cleaning practices.

Machinability

Machinability of EN AW-5086 is moderate and not as favorable as 2xxx or 6xxx-series wrought alloys designed for high-speed machining. The alloy machines best in softer tempers; chip formation tends to produce continuous, ductile chips requiring controlled feeds and chip breakers. Carbide tooling is recommended for higher-throughput machining, with cutting speeds and feeds reduced for harder H‑tempers to limit tool wear and thermal work-hardening.

Formability

Forming is excellent in annealed (O) and lightly worked tempers such as H111, enabling deep drawing, stretching and complex stamping. Bend radii should be chosen according to temper and thickness; typical minimum internal bend radii range from 1× to 3× thickness for softer tempers, increasing for H32/H36 conditions. Cold work increases strength but reduces stretch and increases springback; warm forming or staged deformation is sometimes used to achieve tight radii in heavier-gauge material.

Heat Treatment Behavior

EN AW-5086 is a non-heat-treatable alloy; it does not respond to solution heat treatment and artificial aging to develop higher strength in the same manner as 6xxx or 7xxx alloys. Instead, strength increases are obtained by cold work (strain hardening) followed by natural or controlled stabilization to reduce residual stresses and limit further strain aging.

Annealing (O temper) is used to remove work hardening and restore ductility; typical anneal cycles are at elevated temperatures followed by controlled cooling to avoid distortion and grain growth. Stabilization treatments (e.g., H116) involve low-temperature aging or controlled storage to achieve a balanced combination of strength, corrosion resistance and weldability without introducing deleterious precipitates.

High-Temperature Performance

EN AW-5086 retains useful mechanical properties up to modest elevated temperatures, but elevated service dramatically reduces yield and fatigue strength relative to ambient conditions. Significant strength loss occurs as temperature approaches 100–150 °C depending on temper, so long-term structural applications should be limited to moderate temperatures or require empirical qualification.

Oxidation and scaling are minimal for aluminum alloys in air; however, prolonged exposure to hot chloride-bearing atmospheres can accelerate corrosion processes. The HAZ of welds can experience softening and reduced strength at elevated service temperatures, so design and post-weld treatments should consider the combined effects of temperature, stress and corrosive species.

Applications

Industry	Example Component	Why EN AW-5086 Is Used
Marine	Hull plates, decks, superstructure	Excellent seawater corrosion resistance and good strength-to-weight
Automotive / Transportation	Trailer panels, fuel tanks, structural members	Good weldability, impact resistance and corrosion behavior
Aerospace	Secondary structures, fittings	Good toughness, weldability and moderate structural strength
Pressure Vessels / Cryogenics	Storage tanks, cryogenic vessels	Low temperature toughness and weldability
Industrial / Heat Transfer	Heat exchangers, manifolds	Adequate thermal conductivity and corrosion resistance

EN AW-5086 is selected where a balance of corrosion resistance, weldability and moderate structural strength is required, particularly in marine and transportation sectors. Its formability in softer tempers and capability to be jointed by common welding methods broaden its application envelope for fabricated assemblies.

Selection Insights

Choose EN AW-5086 when a design requires durable corrosion resistance in chloride-rich environments combined with good weldability and moderate structural strength. It is a practical choice for marine structures and welded fabrications where heat-treatable alloys may suffer corrosion or hydrogen-related issues.

Compared with commercially pure aluminum (1100), EN AW-5086 trades some electrical and thermal conductivity and slightly reduced formability for significantly higher strength and better structural performance. Compared with common work-hardened alloys such as 3003 or 5052, EN AW-5086 typically offers higher strength and comparable or improved marine corrosion resistance, at a modest cost premium.

When contrasted with heat-treatable alloys like 6061, EN AW-5086 will not reach the same peak tensile strengths but is preferred where superior seawater corrosion resistance, weldability without quench/temper cycles, and better toughness are required.

Closing Summary

EN AW-5086 remains a widely used aluminum alloy because it delivers a robust mix of weldability, corrosion resistance and strain-hardening strength without the complexity of heat treatment, making it especially valuable in marine, pressure vessel and structural fabrication contexts.