Aluminum 5050: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

5050 is a member of the 5xxx series aluminum alloys, which are magnesium-bearing, wrought alloys characterized by non-heat-treatable strengthening. The alloy is formulated around aluminum with magnesium as the principal alloying addition, augmented by controlled amounts of manganese, chromium and trace elements to tune strength and corrosion resistance. 5050 gains its strength primarily through solid solution strengthening and work hardening rather than precipitation heat treatment, making temper history and cold working the dominant means of property control. Typical traits include moderate to good strength for a non-heat-treatable alloy, very good atmospheric corrosion resistance, good weldability, and reasonable formability depending on temper and thickness.

Industries that commonly adopt 5xxx-series alloys like 5050 include marine and shipbuilding, transportation and automotive components, pressure vessels and piping, architectural panels, and general fabrication where corrosion resistance and moderate strength are prioritized. Designers choose 5050 where a balance of corrosion resistance, formability and weldability is needed without the complexity of heat-treatable processing. It is selected over lower-strength, higher-conductivity alloys when improved mechanical performance is required and over heat-treatable alloys when reduced distortion, better weldability and service corrosion resistance are more important than maximum peak strength.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed condition for easiest forming
H111	Low–Moderate	High	Very Good	Excellent	Slight work-hardened with minimal mechanical properties increase
H14	Moderate	Moderate	Good	Excellent	Single-step strain-hardened, commonly used for formed components
H24	Moderate–High	Moderate	Fair	Excellent	Strain-hardened and stabilized; better strength, reduced ductility
H32	High	Lower	Limited	Good	Strain-hardened and partially annealed to achieve balanced properties
H34	High	Lower	Limited	Good	Higher work-hardening level for maximum strength in cold-worked parts
T5 / T6 / T651	Not applicable	Not applicable	Not applicable	Not applicable	Heat-treatable tempers are not effective for 5xxx series alloys

The temper has a primary influence on yield and tensile strength through accumulated plastic strain and the resulting dislocation density. Annealed tempers (O) maximize ductility and formability while H- and Hx-tempers progressively increase strength at the expense of elongation and bendability.

Selection of temper should be matched to forming operations; deep drawing and severe bending need annealed or H111 conditions, while panels and structural members that require higher as-fabricated strength often use H32/H34 tempers.

Chemical Composition

Element	% Range	Notes
Si	≤ 0.25	Impurity; controlled to limit brittle intermetallics
Fe	≤ 0.40	Common impurity; excess reduces ductility and corrosion resistance
Mn	0.10–0.50	Adds strength and controls grain structure via dispersoid formation
Mg	1.5–3.5	Principal strengthening element; improves corrosion resistance and work-hardenability
Cu	≤ 0.10	Low levels to preserve corrosion resistance; higher Cu reduces SCC resistance
Zn	≤ 0.10	Minor; kept low to avoid hot-cracking and galvanic issues
Cr	0.05–0.25	Grain structure control, improves corrosion resistance and limits grain growth
Ti	≤ 0.15	Grain refiner in cast products and ingots
Others	Balance Al	Trace elements (V, Zr) may be present in small amounts for special variants

Magnesium is the defining alloying element for 5050 and it increases both strength and seawater corrosion resistance through solid solution strengthening. Manganese and chromium are deliberate microalloying elements that refine grains and form dispersoids, improving strength and resistance to recrystallization while keeping the alloy non-heat-treatable. Iron and silicon are residual elements that must be controlled to maintain ductility and to prevent the formation of brittle intermetallic phases during casting and thermomechanical processing.

Mechanical Properties

In tensile behavior 5050 shows classic non-heat-treatable alloy response: low initial strength in the annealed condition with pronounced gains through cold working. Yield and ultimate tensile strengths are highly dependent on temper; O condition yields modest values suitable for forming while H-tempers can achieve two- to three-fold increases in yield through strain hardening. Elongation decreases as temper progresses from O to H32/H34 due to increased dislocation density and possible texturing effects in rolled products.

Hardness follows tensile strength trends and is a practical proxy for estimating formability and bending behavior during fabrication. Fatigue performance is acceptable for many structural applications but is influenced by surface finish, thickness, and environment; corrosion fatigue resistance in chloride environments is better than many copper-bearing alloys but inferior to some 6xxx aerospace aluminums. Thickness has a marked effect on forming and strength retention; thicker sections are harder to cold-form and exhibit higher as-fabricated strength due to less homogeneous cold work through the cross-section.

Property	O/Annealed	Key Temper (H32)	Notes
Tensile Strength	95–140 MPa (14–20 ksi)	240–320 MPa (35–46 ksi)	Tensile rises strongly with strain hardening; values depend on product form and thickness
Yield Strength	35–70 MPa (5–10 ksi)	150–260 MPa (22–38 ksi)	Yield can vary widely with temper designation and work history
Elongation	20–30%	6–15%	Elongation decreases as temper and strength increase; thickness influences ductility
Hardness (HV)	25–45	60–95	Hardness correlates with tensile and yield; used for QC in production

Physical Properties

Property	Value	Notes
Density	2.68 g/cm³	Typical for aluminum alloys; important for strength-to-weight calculations
Melting Range	~600–650 °C	Alloyed aluminum shows a mushy solidus-liquidus interval; exact range depends on composition
Thermal Conductivity	~130–160 W/m·K	Lower than pure Al but still high enough for many heat-transfer applications
Electrical Conductivity	~35–45% IACS	Reduced from pure aluminum by alloying; acceptable for some conductor or bus applications
Specific Heat	~900 J/kg·K	Typical value used in thermal mass and transient heat calculations
Thermal Expansion	~23.5 µm/m·K	High expansion compared with steels; important for thermal joint design

The physical constants indicate 5050 is lightweight with favorable thermal conductivity and specific heat compared with steels, making it attractive for transport and heat dissipation roles. The combination of low density and moderate thermal/electrical conductivities supports use in structures where thermal management and weight savings are key, but designers must account for higher thermal expansion and lower stiffness relative to ferrous materials.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.3–6.0 mm	Good surface finish; strength varies with temper	O, H111, H14, H32	Widely used for panels, enclosures and formed components
Plate	6–150+ mm	Thickness-dependent strength; limited deep drawability	O, H111, H32	Used for structural parts, hull plating and thicker fabricated components
Extrusion	Sections up to several meters	Strength depends on extrusion ratio and subsequent cold work	O, H112, H34	Extruded shapes allow complex profiles for structural and architectural parts
Tube	Seamless/welded, diameters variable	Strength controlled by wall thickness and temper	O, H32	Used in fluid handling, lightweight frames and structural tubing
Bar/Rod	Diameters up to 150 mm	Cold-drawn to increase strength	H112, H14, H32	Supply for machined parts, fasteners, and axles where corrosion resistance is useful

Sheet and plate are the most common forms for 5050, produced by rolling operations that set grain structure and residual stress prior to tempering or cold work. Extrusions allow customized cross-sections and often require specific homogenization and quench strategies in the billet to deliver uniform properties. Forging and cold drawing for bars and rods increase strength through further work hardening, while welded tubular components may be furnished in tempers that balance formability with post-weld strength retention.

Equivalent Grades

Standard	Grade	Region	Notes
AA	5050	USA	Allied/Alcoa/AA designations commonly used in procurement
EN AW	5050	Europe	EN AW-5050 nomenclature aligns with AA series chemistry and tempers
JIS	A5050	Japan	JIS grade mapping often follows AA composition with regional tolerances
GB/T	5050	China	Chinese GB/T standards provide similar chemistry but may have different mechanical acceptance criteria

Equivalency across standards is nominally straightforward because 5050 is a well-defined wrought magnesium alloy, but caution is required: regional standards may differ in allowable trace elements, testing protocols and temper nomenclature. Buyers should specify the source standard and required mechanical/corrosion performance rather than relying solely on grade name to ensure consistent delivered properties.

Corrosion Resistance

5050 exhibits robust atmospheric corrosion resistance typical of magnesium-bearing 5xxx-series alloys, forming a protective oxide film that provides long service life in urban and mildly industrial environments. Its resistance to pitting and uniform corrosion in chlorinated environments (such as seawater) is good compared with Cu-bearing and many heat-treatable alloys, but local anodic dissolution can occur at high chloride concentrations or under stagnant seawater conditions. Alloy purity, temper, surface finish and residual stress (including from welding) will substantially influence service life in aggressive environments.

Stress corrosion cracking (SCC) susceptibility for 5xxx alloys increases with higher magnesium content and with certain tempers; alloys with Mg > 3.5% are more at risk for SCC under tensile stress in saltwater. 5050, with moderate Mg levels and controlled impurity content, typically shows low to moderate SCC risk when specified and processed appropriately, but designers should avoid tensile overload and consider cathodic protection in marine structures. Galvanic interactions must be considered when mating 5050 to more noble metals like stainless steel or copper; proper isolation, fastener selection and coating strategies will mitigate accelerated corrosion at interfaces.

Compared with 6xxx series (Mg + Si) alloys, 5050 offers improved marine corrosion performance and weldability but at the expense of lower maximum achievable strength through heat treatment. Versus 3xxx series (Mn) alloys, 5050 provides higher strength and often better seawater resistance thanks to the magnesium content.

Fabrication Properties

Weldability

5050 welds readily by common fusion processes including MIG (GMAW) and TIG (GTAW) with minimal hot-cracking tendency compared with some high-copper alloys. Recommended filler metals are 5xxx or 4xxx series matching filler wires that preserve corrosion resistance; for welded marine applications, low-copper fillers (e.g., 5183, 5554 where appropriate) are commonly used. Heat-affected zone (HAZ) softening is limited because there is no precipitation hardening, but localized overaging is not applicable; residual stresses and distortion must be controlled with fixturing and post-weld mechanical tempering if needed.

Machinability

Machinability of 5050 is moderate and similar to other 5xxx alloys; it machines cleaner than some higher-strength alloys but does not reach the ease of pure aluminum. Carbide tooling with positive rake and good chip evacuation is recommended; cutting speeds and feeds should be set to prevent built-up edge and to control work hardening near the surface. Typical behavior produces short to moderately long chips depending on cutting geometry and temper; oils and coolants help ensure dimensional accuracy and surface finish.

Formability

Forming characteristics are excellent in the O and H111 tempers where the alloy exhibits high elongation and deep drawability; minimum bend radii in sheet applications can be tight depending on thickness and tooling. In H32/H34 tempers the formability decreases as work hardening raises yield; designers should allow for springback and may need to anneal parts prior to severe forming. Best results for complex shapes are obtained by specifying an annealed or lightly worked temper and controlling tool radii, lubricant and strain distribution.

Heat Treatment Behavior

As a non-heat-treatable alloy, 5050 does not respond to solution- and precipitation-age heat treatments used for 6xxx and 7xxx families to raise strength substantially. Thermal processing is therefore focused on annealing to soften the material and on stabilizing (or stress-relief) operations to reduce residual stresses after forming or welding. Typical annealing cycles are performed at temperatures sufficient to recrystallize the microstructure and restore ductility; careful cooling avoids excessive distortion.

Strength increases are achieved primarily through cold working (strain hardening) such as rolling, drawing or controlled bending. Temper designations in the H series indicate the degree and type of cold work and any stabilization steps; partial anneals (e.g., H32) are used to balance ductility and strength for specific forming or structural needs. For repair and rework, localized annealing or mechanical re-tempering can be used to restore formability at small areas.

High-Temperature Performance

5050 maintains usable mechanical properties at moderate temperatures but shows progressive strength loss as service temperature approaches a significant fraction of aluminum’s melting range. Practical continuous service temperatures are usually limited to below ~150–200 °C for structural load-bearing applications where strength retention is required. Oxidation is not a major limiting issue at these temperatures, but creep resistance is limited relative to specialized high-temperature alloys.

Exposure to elevated temperatures during welding or post-weld heat processes will not precipitate strengthening phases but can relieve work hardening and reduce yield strength locally in the HAZ. Designers should account for thermal softening in joints and consider mechanical design or post-process work hardening to recover lost strength if elevated temperatures are part of service or fabrication.

Applications

Industry	Example Component	Why 5050 Is Used
Automotive	Body panels, decorative trim	Good formability and corrosion resistance with moderate strength
Marine	Hull plating, deck fittings	Superior seawater corrosion resistance and weldability
Aerospace	Secondary structures, fairings	High strength-to-weight for non-primary structures and corrosion durability
Transportation	Tankers, trailers	Lightweight structural members with good fatigue and chloride resistance
Architecture	Facade panels, roofing	Weathering resistance and ease of fabrication
Electronics	Enclosures, thermal spreaders	Adequate thermal conductivity and electrical grounding with low density

5050 is found in applications that require a balance of corrosion resistance, moderate strength and excellent fabricability. It is particularly popular where welding and forming are integral parts of the manufacturing route and where the service environment includes exposure to humid or chloride-laden atmospheres.

Selection Insights

5050 is a pragmatic choice when engineering priorities are corrosion resistance, weldability and good formability without the need for high-temperature aging treatments. It trades off peak heat-treatable strength for better weldability and reduced susceptibility to distortion and residual stress compared with 6xxx-series alloys.

Compared with commercially pure aluminum (1100), 5050 offers substantially higher strength while retaining reasonable electrical and thermal conductivities; expect a reduction in conductivity versus 1100 but a useful gain in mechanical performance. Versus work-hardened alloys such as 3003 or 5052, 5050 sits slightly higher in strength and generally offers superior marine corrosion resistance, although formability may be comparable depending on temper. Versus common heat-treatable alloys like 6061 or 6063, 5050 is preferred when in-service corrosion performance and weld distortion control are priorities despite lower achievable peak strength.

Select 5050 when the component will be welded extensively, exposed to marine or harsh atmospheres, or requires substantial forming in the annealed condition. If maximum stiffness or the highest possible strength-to-weight ratio is required, consider heat-treatable alternatives or higher-strength 5xxx/6xxx alloys with appropriate joining strategies.

Closing Summary

5050 remains a relevant aluminum alloy for modern engineering where a robust combination of seawater corrosion resistance, weldability and formability is required without reliance on precipitation heat treatment. Its position within the 5xxx family makes it a dependable choice for structural and marine applications where predictable, work-hardened strength and long-term durability are more important than achieving the absolute maximum tensile strength.