Aluminum 6060: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

Alloy 6060 is a member of the 6xxx series aluminum-magnesium-silicon family, positioned close to 6063 and 6061 in chemistry and application space. It is principally an Al-Mg-Si alloy where silicon and magnesium combine to form Mg2Si precipitates that provide age-hardening response during thermal treatment.

The strengthening mechanism for 6060 is precipitation hardening (heat-treatable) rather than pure work-hardening, although some mechanical properties can be adjusted via strain hardening in H-temper conditions. Key traits include moderate-to-good strength, very good corrosion resistance in atmospheric environments, good extrudability and weldability, and favorable formability in the annealed condition.

Typical industries using 6060 include architectural and building systems, general-purpose extrusions, automotive trim and low-load structural components, and some electronics housings and heat-sink elements. The alloy is often chosen over similar alloys when a balance of extrudability, surface finish, corrosion resistance and economical strength is required rather than maximum peak strength.

Designers tend to select 6060 when extrusion profile quality, anodizing appearance, or tight dimensional control are priorities, or when the application benefits from lower alloying content that simplifies welding and surface finishing. Its combination of ease of forming and controlled age-hardening makes it a practical choice for medium-duty structural profiles and architectural components.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed condition, best for forming and bending
H14	Medium-Low	Moderate	Good	Excellent	Strain-hardened to half-hard condition, limited shaping possible
T5	Medium	Moderate	Fair	Good	Cooled from extrusion and artificially aged, common for extrusions
T6	Medium-High	Moderate-Low	Limited	Good	Solution heat-treated and artificially aged for peak strength
T651	Medium-High	Moderate-Low	Limited	Good	T6 with stress-relief by stretching; improved dimensional stability

Temper has a strong influence on mechanical and forming behavior since 6060 is age-hardenable and responds to both solution treatment plus artificial aging and to cold work. Annealed (O) material offers the best ductility and minimum yield strength, making it the preferred starting state for extensive forming operations.

Tempered conditions like T5 and T6 increase yield and tensile strengths via controlled precipitation of Mg2Si, while H-temper variants provide intermediate properties by cold work; choose temper based on whether forming, welding, or dimensional stability is the primary requirement.

Chemical Composition

Element	% Range	Notes
Si	0.30–0.60	Silicon forms Mg2Si precipitates with Mg to enable age hardening.
Fe	≤0.35	Iron is an impurity that forms intermetallics; higher Fe reduces extrusion finish.
Mn	≤0.10	Minor role; can affect grain structure and strength marginally.
Mg	0.35–0.60	Magnesium combines with Si to form strengthening precipitates.
Cu	≤0.10	Small amounts may increase strength but reduce corrosion resistance.
Zn	≤0.20	Limited; higher zinc is uncommon and can affect precipitation behavior.
Cr	≤0.05	Trace amounts help control grain structure and recrystallization.
Ti	≤0.10	Often used as grain refiner in small amounts during casting/billet production.
Others	≤0.15 each; total ≤0.35	Includes Ni, Pb, Sn, Bi and other residuals with limited influence at low levels.

Silicon and magnesium are the functional pair for precipitation hardening; their ratio controls the volume fraction and distribution of Mg2Si precipitates. Iron and other impurities influence extrusion surface quality and can form coarse intermetallics that slightly reduce toughness and aesthetics.

Trace elements such as chromium and titanium are used mainly to modify grain size and recrystallization during billet production and thermo-mechanical processing, which can affect final surface finish and mechanical uniformity.

Mechanical Properties

6060 exhibits a wide spectrum of mechanical behavior depending on temper and section thickness, typical of heat-treatable Al-Mg-Si alloys. In annealed condition the alloy offers excellent ductility with low yield strength, enabling deep drawing and complex bending operations. With solution heat treatment and appropriate artificial aging (T6), tensile and yield strengths increase substantially, but elongation and formability decrease accordingly.

Hardness tracks the precipitation state and generally increases as the alloy moves from O to T6, with corresponding improvements in yield and ultimate tensile strength. Fatigue performance is moderate and is strongly dependent on surface finish, residual stress state and the presence of stress concentrators or coarse intermetallic particles. Thickness has a pronounced effect: extrusion profiles and thin sheets can be more uniformly aged and achieve consistent properties, while thicker plates may show gradient microstructures and require adjusted heat treatment.

Designers must account for HAZ softening when welding precipitation-hardened tempers, and for potential over-aging when components are exposed to elevated temperatures during service or secondary processing.

Property	O/Annealed	Key Temper (T6)	Notes
Tensile Strength	~100–130 MPa	~170–230 MPa	Tensile range depends on cross-section and exact tempering cycle.
Yield Strength	~30–70 MPa	~120–170 MPa	Yield increases markedly with T5/T6; H-temper values fall between.
Elongation	~20–30%	~6–12%	Ductility decreases with increased strength and reduced precipitate size.
Hardness (HB)	~25–40 HB	~55–75 HB	Brinell hardness correlates with aging; values depend on temper and mill practice.

Physical Properties

Property	Value	Notes
Density	2.70 g/cm³	Typical for aluminum alloys, used for mass and weight calculations.
Melting Range	~610–650 °C	Alloyed aluminum exhibits a melting interval below pure Al melting point.
Thermal Conductivity	~160–180 W/m·K	Lower than pure Al but still high; good for heat dissipation components.
Electrical Conductivity	~30–35 %IACS	Reduced relative to pure aluminum due to alloying elements.
Specific Heat	~900 J/kg·K	Temperature-dependent but useful for thermal management calculations.
Thermal Expansion	~23–24 µm/m·K	Moderate coefficient; must be considered in assemblies with dissimilar metals.

6060 offers good thermal and electrical conductivity among structural aluminum alloys, which supports uses in heat sinks and electrical housings where moderate strength and heat transfer are required. The relatively high thermal conductivity combined with acceptable stiffness affords good thermal cycling behavior for many non-critical high-temperature applications.

Designers should account for thermal expansion in multi-material assemblies and consider that conductivity and thermal capacity vary with temper and impurity content.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.3–6 mm	Uniform in thin gauge; easy to cold-form	O, H14, T4	Used for panels, facades, thin structural parts
Plate	>6 mm up to 50 mm	May show tempered gradients after heat treatment	O, T6	Less common; used where thicker extruded sections are required
Extrusion	Profile cross-sections variable	Excellent homogeneity in extrusions	T5, T6, T651	Widely used for architectural and structural profiles
Tube	Ø small to 200+ mm	Good consistency; welded or seamless	O, T6	Used for frames, conveyors, and fluid handling structures
Bar/Rod	Ø few mm to 100 mm	Typical bar stock behavior; machinable	O, T6	Used for machined fittings and small structural elements

Forming operations and downstream processing differ across product forms because of cooling rates, section thickness and residual stresses introduced during extrusion and rolling. Extrusions tend to have superior surface finish and dimensional control, making them common for architectural applications that require anodizing and tight tolerances.

Sheets are preferred for cold forming and panel work due to better bendability, while thicker plates and bars require more aggressive heat treatment and may be more difficult to bring to uniform tempers because of quench limitations.

Equivalent Grades

Standard	Grade	Region	Notes
AA	6060	USA	American Aluminum Association designation for wrought alloy.
EN AW	AlMgSi0.5	Europe	Common European designation; approximate chemistries align with 6060/6063 family.
JIS	A6060	Japan	Japanese wrought designation with similar composition and uses.
GB/T	6060	China	Chinese standard often aligned with international 6060 chemical and mechanical limits.

Equivalent grades reflect comparable compositions and processing practices but small differences in impurity limits, required mechanical properties and permitted element ranges can affect extrusion finish and aging response. European EN AW designations often reference nominal Mg and Si contents by mass fraction and may group 6060 with alloys such as 6063 for commercial use.

When substituting material across regions or standards, check specific mill certificates for critical tolerances such as Fe content, residual impurities, and mechanical properties in the intended temper.

Corrosion Resistance

6060 provides good atmospheric corrosion resistance due to the formation of a stable aluminum oxide film and modest alloying content that minimizes galvanic activity relative to higher-alloyed systems. In rural and urban environments the alloy performs well, especially when anodized or painted, and it typically resists general corrosion without extensive maintenance.

In marine or chloride-rich atmospheres 6060 is serviceable for many structural applications but is less resistant to pitting than 5xxx magnesium-rich alloys; surface treatments such as anodizing, coatings and sealants markedly improve performance. Stress corrosion cracking is uncommon in 6060 at typical service strengths, but localized corrosion can be exacerbated at painted or sealed joints where crevices trap chlorides.

Galvanic interactions must be considered when joining 6060 to more noble materials such as stainless steels or copper alloys; insulating layers or sacrificial anodes are commonly used to mitigate galvanic attack. Compared with high-strength 7xxx series alloys, 6060 typically has superior corrosion resistance but lower peak strength and fatigue resistance.

Fabrication Properties

Weldability
6060 welds readily using common fusion processes such as TIG and MIG, and it shows low susceptibility to hot cracking compared with certain high-alloy systems. Recommended filler alloys include ER4043 (Al‑Si) and ER5356 (Al‑Mg) depending on the need for corrosion resistance or higher strength in the weld. Heat-affected zones in previously aged tempers will soften as precipitates coarsen, so weld design and post-weld heat treatment or mechanical restoration should be considered for load-bearing joints.

Machinability
Machinability of 6060 is moderate; it is not a free-machining alloy but responds well to carbide tooling, sharp geometries and rigid setups. Cutting speeds and feeds for turning and milling are intermediate relative to pure aluminum and to harder aluminum alloys, and lubrication with oil-based coolants reduces built-up edge and improves surface finish. Chip formation tends to be continuous and ductile; proper chip control measures such as segmented tooling or chipbreakers are beneficial in production machining.

Formability
Formability is excellent in the annealed (O) temper, allowing tight bends, deep draws and complex extruded shapes with minimal risk of cracking. In T5/T6 tempers formability is significantly reduced, and springback must be accounted for in tooling design; small bend radii are feasible in O but require larger radii or intermediate annealing for T‑tempers. When cold working to H tempers, incremental forming is recommended to avoid surface defects and to control final dimensional tolerances.

Heat Treatment Behavior

6060 is a heat-treatable Al-Mg-Si alloy and follows the general solutionizing and aging path common to the series. Solution treatment is typically carried out at approximately 520–560 °C to dissolve Mg2Si into a supersaturated solid solution, followed by rapid quenching (usually water quench) to retain the solute atoms in solution. Artificial aging cycles vary but commonly occur between 160–220 °C for several hours to precipitate finely dispersed Mg2Si particles that increase strength; T5 refers to cooling from processing followed by artificial aging, while T6 indicates full solution treatment plus artificial aging.

T651 indicates T6 with a controlled stretching or stress relief to minimize residual stresses and distortion. Natural (room temperature) aging also occurs to some degree after quenching and can change mechanical properties over days to weeks; in production this is controlled by specifying appropriate tempers and aging schedules. Over-aging at elevated temperatures will coarsen precipitates, reduce yield strength and increase ductility.

High-Temperature Performance

Strength of 6060 declines with increasing temperature as precipitates coarsen and solute diffusivity increases; the useful sustained temperature for mechanical loading is generally limited to about 100–150 °C. Above these temperatures, significant reduction in yield and tensile strength occurs and dimensional stability may be compromised by recovery and over-aging phenomena. Oxidation of aluminum is minimal relative to ferrous alloys due to formation of a protective Al2O3 film, but long-term exposure at high temperatures can affect surface appearance and anodizing characteristics.

Welded zones and heat-affected regions are particularly susceptible to strength loss under thermal exposure due to precipitate dissolution or coarsening, so design for elevated temperature service should consider thicker sections, alternative alloys, or controlled post-weld heat treatments to restore mechanical properties.

Applications

Industry	Example Component	Why 6060 Is Used
Architectural / Building	Window and door frames, curtain wall profiles	Good extrudability, anodize appearance and dimensional control
Automotive	Trim, rails, low-load structural extrusions	Balance of manufacturability and moderate strength
Marine	Non-critical structural members, railings	Reasonable corrosion resistance and surface finish options
Electronics	Enclosures and heat-dissipating housings	Thermal conductivity and extrudability for complex profiles
General Fabrication	Tubing, handrails, furniture frames	Formability and finish quality for consumer applications

6060 is widely used where profile appearance, anodizing behavior and economical production of complex extrusions are important. Its moderate strength combined with excellent surface finish and corrosion performance makes it versatile for non-high-strength structural components and decorative building elements.

Selection Insights

When selecting 6060, prioritize applications that require good extrudability, consistent anodizing quality and moderate strength rather than peak mechanical performance. Choose annealed O temper for forming-intensive components and T5/T6 when post-processing dimensional stability and higher strength are needed.

Compared with commercially pure aluminum (1100), 6060 trades some electrical and thermal conductivity and slightly reduced formability for substantially higher strength and improved mechanical stability. Compared with work-hardened alloys such as 3003 or 5052, 6060 provides higher potential strength via precipitation hardening while maintaining competitive corrosion resistance, though 5xxx alloys retain better marine corrosion resistance in highly chloride-laden environments. Compared with closely related heat-treatable alloys such as 6061 or 6063, 6060 is often preferred for extrusion surface finish and dimensional control even though peak attainable strength is lower than 6061; select 6060 when extrudability and anodizing aesthetics outweigh maximum strength requirements.

Closing Summary

Alloy 6060 remains a relevant and practical aluminum choice for extruded profiles and moderate-load applications due to its combination of good extrudability, surface finish, corrosion resistance and predictable age-hardening response. Its balanced set of properties makes it a cost-effective solution for architectural, automotive trim and general fabrication tasks where formability and finish are as important as mechanical performance.