Aluminum 5182: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

5182 is a member of the aluminum 5xxx series, an alloy class dominated by magnesium as the primary alloying element. The 5xxx family is categorized as non-heat-treatable, deriving strength mainly from solid-solution strengthening and strain hardening rather than precipitation heat treatments.

Major alloying additions in 5182 are magnesium (the principal strengthening element), with minor controlled additions of manganese, chromium and trace elements to control grain structure and improve resistance to recrystallization. The alloy leverages the Al-Mg system to provide a balance of elevated strength, good ductility, and superior corrosion resistance relative to many other wrought aluminum series.

Strengthening in 5182 is predominantly via solid solution of Mg in the Al matrix and by work hardening during forming; it cannot be substantially strengthened by conventional quench-and-age cycles. Key traits include moderate-to-high strength for a non-heat-treatable alloy, excellent resistance to general and marine corrosion, good formability in annealed conditions, and generally good weldability when proper filler metals are used.

Industries that commonly specify 5182 include automotive (body closures, inner panels), packaging (specialty closures), marine and transport sectors where corrosion resistance and formability are required, and some electrical/thermal applications where aluminium’s conductivity and stiffness-to-weight ratio are needed. Engineers select 5182 where an optimized trade-off of formability, elevated Mg-strength, and corrosion performance is required instead of higher-strength heat-treatable alloys or softer commercially-pure grades.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High (20–40%)	Excellent	Excellent	Fully annealed, best for heavy forming and deep drawing
H12	Low–Medium	Moderate (10–25%)	Good	Good	Lightly strain-hardened for moderate stiffness
H14	Medium	Moderate (8–20%)	Good	Good	Common for sheet where some stiffness is required
H16	Medium	Lower (6–15%)	Fair	Good	Higher work hardening, reduced stretchability
H22 / H24	Medium–High	Moderate	Fair–Good	Good	Strain-hardened then partially annealed, trade-off between strength and formability
H32 / H34	High	Lower (3–12%)	Reduced	Good	Strain-hardened and stabilized; common for structural applications
T4 (rare)	Low–Medium	High	Excellent	Good	Solution heat treated and naturally aged; uncommon for 5xxx series

Temper selection strongly modifies the balance between formability and strength. Annealed O temper provides the best drawability and ductility, while progressive H-temper levels increase yield and tensile strength at the expense of elongation and deep-drawability.

Thickness and processing history also interact with temper: thinner gauges attain higher strain-hardening from processing and often can be delivered in higher H-tempers, whereas thicker product forms are more commonly supplied in softer tempers to permit forming.

Chemical Composition

Element	% Range	Notes
Si	≤ 0.25	Impurity control; excessive Si forms hard intermetallics that reduce ductility
Fe	≤ 0.5	Common impurity; promotes intermetallics that can affect surface finish and toughness
Mn	0.2–0.7	Controls grain structure and improves strength and resistance to recrystallization
Mg	4.0–5.0	Primary strengthening element; raises strength and improves corrosion resistance
Cu	≤ 0.10	Kept low to preserve corrosion resistance and weldability
Zn	≤ 0.25	Minor; higher Zn can reduce corrosion resistance
Cr	≤ 0.25	Grain structure control, limits grain growth on thermomechanical processing
Ti	≤ 0.15	Grain refiner when present in small amounts
Others (each)	≤ 0.05	Trace elements and residuals; balance Al (~remainder)

Magnesium dominates the alloy’s mechanical and corrosion behavior, providing solid-solution strengthening and improving resistance to seawater and atmospheric attack. Manganese and chromium at low levels refine recrystallization behavior and maintain strength after thermomechanical processing. Iron and silicon must be controlled to avoid coarse intermetallics that can impair surface and mechanical performance, especially in drawn or anodized components.

Mechanical Properties

5182 exhibits a tensile/yield behavior typical of medium-strength, non-heat-treatable aluminum alloys. In annealed condition the alloy demonstrates good elongation and energy absorption capability, making it suitable for deep drawing and forming operations. In strain-hardened tempers the yield and ultimate tensile strengths rise substantially, with a corresponding reduction in elongation and stretch formability.

Hardness correlates with temper and work history: annealed material shows low hardness values while H-temper material increases hardness via strain hardening. Fatigue performance is influenced by surface finish, residual stresses from forming or welding, and thickness; thicker sections and smoother finishes will typically yield improved high-cycle fatigue life. The presence of Mg improves low-temperature toughness relative to some other wrought alloys and offers stable performance in cyclic loads when properly processed.

Thickness has a significant effect on both strength and ductility for 5182. Thin gauges typically exhibit higher apparent yield and tensile strength because of residual cold work from rolling and faster quench-equivalent cooling during processing, whereas thicker plates may be supplied in softer tempers to facilitate forming and welding.

Property	O/Annealed	Key Temper (e.g., H32/H34)	Notes
Tensile Strength	~110–170 MPa	~240–360 MPa	Wide range depends on temper and thickness; H-tempers significantly higher
Yield Strength	~35–95 MPa	~150–260 MPa	Yield increases markedly with strain hardening; values vary with gauge and temper
Elongation	~20–40%	~3–15%	Formability drops as temper moves toward higher H-designations
Hardness (HB)	~30–60 HB	~70–120 HB	Brinell approximations; hardness correlates with tensile strength and temper

Physical Properties

Property	Value	Notes
Density	2.66–2.70 g/cm³	Typical for wrought Al-Mg alloys; good stiffness-to-weight ratio
Melting Range	~555–650 °C	Solidus/liquidus depend on exact composition; bulk melting near pure Al but depressed by Mg
Thermal Conductivity	~120–150 W/m·K	Lower than pure Al due to alloying; still good for heat dissipation
Electrical Conductivity	~25–40 % IACS	Reduced versus pure aluminum; conductivity decreases with increasing Mg content
Specific Heat	~880–900 J/kg·K	Typical aluminum-specific heat enabling effective heat storage and dissipation
Thermal Expansion	~23–24 µm/m·K (20–100 °C)	Typical thermal expansion for aluminium alloys; consider for tight tolerance assemblies

5182 retains many of aluminum’s favorable physical attributes: low density, high thermal conductivity, and good specific heat. These properties make it useful where weight reduction and thermal management are important, although Mg alloying reduces conductivity relative to purer alloys.

Designers must account for the alloy’s thermal expansion in joined structures and for the temperature dependence of mechanical properties, especially when operating close to its elevated-temperature service limits.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.2–6.0 mm	Higher apparent strength on thin gauges	O, H14, H24, H32	Used for body panels, closures, and formed components
Plate	>6.0 mm up to ~25 mm	Lower work-hardening from rolling; often softer	O, H112	Structural components and fabricated parts requiring thickness
Extrusion	Cross-sections variable	Strength depends on section and cooling	Tolerances ±	Less common; Mg content affects extrusion temperatures
Tube	0.5–10 mm wall	Good formability for welded/seamless tubes	H32/H34	Used for fuel lines, structural tubes with corrosion resistance
Bar/Rod	Diameter variable	Good combination of strength and ductility	O, H12	Forged or drawn products for fittings and fasteners

Processing route (rolling, cold drawing, extrusion) and final temper determine the strength and anisotropy of 5182 products. Sheets and coils are most common for automotive and packaging markets, with careful control of surface finish and work hardening to enable forming and secondary operations like welding and adhesive bonding.

Plate and heavier-section forms are often supplied softer to allow machining and forming, while thinner-sheet coils are frequently provided in partially-hardened H-tempers for stamping applications where springback control is important.

Equivalent Grades

Standard	Grade	Region	Notes
AA	5182	USA	Aluminum Association designation commonly used in North America
EN AW	5182	Europe	EN AW-5182 corresponds closely; European processing and temper designations apply
JIS	A5182	Japan	Japanese Industrial Standard designation; chemical and mechanical tolerances align closely
GB/T	5182	China	Chinese national standard uses similar designation; specification variations may exist by mill

Cross-references between standards are generally straightforward because the alloy designation 5182 is widely recognized, but minor differences in impurity limits, recommended tempers, and certification practices exist. Buyers should always verify mill certificates and mechanical property requirements for the target standard and intended application.

Corrosion Resistance

5182 offers excellent general atmospheric corrosion resistance and performs well in marine environments due to its relatively high magnesium content combined with low copper content. The naturally forming aluminum oxide film provides a protective barrier; alloying and temper can influence film stability and localized corrosion behavior.

In chloride-rich environments, pitting and crevice corrosion remain possible, particularly at welds, edges, or sites with coarse intermetallic particles. Proper surface preparation, coatings, and design to avoid stagnant crevices mitigate these risks.

Stress corrosion cracking (SCC) susceptibility for 5xxx-series alloys increases with higher Mg content and with certain tempers that concentrate residual stresses; 5182 can be susceptible to SCC under sustained tensile stresses in aggressive environments, especially if cold-worked or improperly welded. Galvanic interactions with more noble metals (e.g., copper, stainless steel) can accelerate local corrosion of 5182, so insulation or sacrificial design is recommended in mixed-metal assemblies.

Compared to 3xxx and 1xxx series, 5182 provides substantially higher strength while retaining similar or better corrosion resistance. Versus 6xxx heat-treatable alloys, 5182 generally offers better marine corrosion resistance but lower peak strength, which drives its selection for exterior and marine-exposed components.

Fabrication Properties

Weldability

5182 welds well with common aluminum welding processes (TIG, MIG, resistance), and it is frequently welded in automotive and marine fabrication. Recommended filler alloys for welding 5182 include Al-Mg fillers such as 5183 and 5356, which help preserve corrosion resistance and ductility in the weld metal. Hot cracking risk is generally low for Al-Mg alloys, but welding leads to localized softening in the heat-affected zone and potential loss of strength; post-weld mechanical design should account for HAZ effects.

Machinability

Machining 5182 is classed as fair; it is more difficult to machine than pure aluminum due to higher strength and work-hardening tendency. Carbide tooling with positive rake and rigid setups yields best results, with moderate cutting speeds and ample coolant to manage chip packing and built-up edge. Fine surface finish requires sharp tooling and control of feed to avoid smearing and excessive work hardening at the cut surface.

Formability

Formability is excellent in annealed (O) condition, enabling deep drawing and complex stamping. For bending, recommended minimum internal bend radii are typically on the order of 0.5–1.0× thickness for mild bends in annealed sheet, increasing for higher H-tempers. Cold working produces predictable strain-hardening response that can be used to tailor strength, but excessive work hardening may lead to cracking during severe forming and therefore intermediate anneals are sometimes required.

Heat Treatment Behavior

5182 is a non-heat-treatable alloy and will not respond to conventional solution-and-age treatments used for 2xxx, 6xxx, or 7xxx alloys. Attempts to apply precipitation hardening treatments do not produce substantial increases in strength relative to work hardening.

Strength changes are achieved by cold working (strain hardening) and by thermal treatments that promote recovery or recrystallization. Full annealing to restore ductility is performed by heating into the 300–420 °C range (typical anneal temperatures depend on section size and desired microstructure) followed by controlled cooling to avoid warpage.

Stabilization tempers (e.g., H32/H34) are produced by controlled mechanical working and thermal treatments to set a balanced combination of strength and reduced residual stress. For welded assemblies, localized heating produces HAZ softening rather than age hardening, so temper recovery rather than strengthening must be expected.

High-Temperature Performance

Mechanical strength of 5182 degrades noticeably with increasing temperature, with appreciable loss of yield and tensile strength above roughly 100 °C and accelerating at higher temperatures. For continuous structural service, designers commonly limit operating temperatures to below approximately 65–100 °C depending on load and environment to avoid creep and loss of mechanical integrity.

Oxidation is not generally a limiting factor because aluminium forms a thin protective Al2O3 layer rapidly; however, elevated temperatures can coarsen microstructure and accelerate grain boundary effects that influence corrosion and mechanical performance. Welding and any local thermal cycling can cause HAZ softening and reduced creep resistance in the vicinity of joints.

For transient high-temperature exposure, 5182 can tolerate short excursions but prolonged exposure will reduce strength and may exacerbate stress corrosion phenomena. For applications where sustained high-temperature strength is required, heat-treatable or special high-temperature alloys are preferable.

Applications

Industry	Example Component	Why 5182 Is Used
Automotive	Closure panels, inner body sheets	Combination of formability, corrosion resistance, and moderate strength for stamped parts
Marine	Hull fittings, trim, structural brackets	Excellent seawater corrosion resistance and good strength-to-weight
Aerospace	Secondary fittings, brackets	Good strength with low density and acceptable corrosion resistance for non-primary structures
Electronics	Heat spreaders, chassis	Thermal conductivity and light weight useful for thermal management and EMI enclosures

5182 is frequently chosen where a balance of formability, corrosion resistance and cost-effective strength is required rather than maximum attainable strength. Its capabilities for stamping, welding and post-forming joining make it a practical choice for high-volume manufacturing in transportation and marine sectors.

Selection Insights

5182 is an appropriate selection when engineers need better strength than commercially-pure alloys (e.g., 1100) while still preserving much of aluminum’s formability and corrosion resistance. Compared with 1100, 5182 sacrifices some electrical and thermal conductivity but gains substantial mechanical strength and improved resistance to seawater corrosion.

Against other work-hardened Mg-bearing alloys such as 3003 or 5052, 5182 sits toward the higher-strength end for non-heat-treatable alloys, offering superior tensile/yield performance with comparable or often superior marine corrosion resistance. This makes 5182 attractive where slightly higher strength is needed without moving to heat-treatable systems.

Compared with heat-treatable alloys like 6061 or 6063, 5182 is selected when corrosion resistance in marine or chloride-prone environments and superior formability are prioritized over maximum peak strengths. Use 5182 when welding and forming dominate the process chain and where exposure conditions favor Al-Mg alloys.

Closing Summary

5182 remains a widely used aluminum alloy because it combines Mg-induced solid-solution strength, excellent corrosion resistance, and good formability in a manufacturable, weldable package. Its balance of properties and availability in common sheet and coil forms keep it relevant for automotive, marine and general engineering applications where durability and manufacturability are paramount.