Aluminum 3004: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

Alloy 3004 is part of the 3xxx series of wrought aluminum alloys, classified specifically within the 3xxx Mn-Mg group. Its primary alloying elements are manganese (Mn) and magnesium (Mg), with small controlled amounts of iron, silicon and trace elements.

3004 is a non-heat-treatable, strain-hardened alloy; strengthening is achieved primarily through cold work (work-hardening) rather than precipitation hardening. This mechanism enables selectable combinations of strength and ductility by varying the temper (degree of strain and/or anneal).

Key traits of 3004 include moderate-to-good strength for a 3xxx alloy, improved formability in annealed conditions, acceptable corrosion resistance in typical atmospheric environments, and generally good joining characteristics. It is commonly used in beverage can bodies, heat exchangers, architectural sheet and other sheet-form applications where a balance of formability and strength is required.

Engineers select 3004 when a step-up in strength over 3003 is needed without abandoning the deep-draw/formability characteristics of the 3xxx family. It is chosen over higher-strength heat-treatable alloys when severe forming or cost-sensitive, highly manufacturable sheet is required.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High (20–30%)	Excellent	Excellent	Fully annealed condition for maximum formability
H14	Medium	Low–Moderate (6–12%)	Good	Good	Strain-hardened one-quarter hard; common for drawn/formed parts
H18	High	Low (3–8%)	Limited	Good	Fully hard; used where higher strength and stiffness are required
H24	Medium	Moderate (10–18%)	Good	Good	Strain-hardened then partially annealed; balance of formability and strength
H26	Medium-High	Moderate (8–14%)	Fair	Good	Two-step temper to achieve intermediate mechanical properties
H28	High	Low (4–10%)	Limited	Good	Heavier cold work for greater yield and tensile strength

Temper has a pronounced effect on 3004 properties because the alloy relies on deformation for strengthening. Moving from O to the H-series increases yield and ultimate tensile strength while reducing ductility and stretch formability, which must be considered for deep-draw or complex bending processes.

Weldability remains robust across most tempers because 3004 is non-heat-treatable; however, localized annealing in the heat-affected zone and reduced post-weld strength in strain-hardened tempers should be factored into joint design.

Chemical Composition

Element	% Range	Notes
Si	0.05–0.6	Controlled to limit brittle intermetallics; higher Si can improve castability in other alloys.
Fe	0.2–0.7	Common impurity; higher Fe forms intermetallic particles that slightly reduce ductility.
Mn	1.0–1.5	Primary strengthener; promotes grain stability and increases strain-hardening capacity.
Mg	0.8–1.3	Contributes to work-hardening and modest solid-solution strengthening.
Cu	0.05–0.2	Kept low to preserve corrosion resistance; small amounts marginally increase strength.
Zn	0.05–0.2	Minor; limited impact at these levels but monitored to avoid intergranular corrosion issues.
Cr	0.05–0.20	Trace levels can refine grain structure and improve corrosion resistance slightly.
Ti	≤0.15	Deoxidant and grain refiner in some mill practice; small amounts control grain size.
Others	≤0.05 each, ≤0.15 total	Residuals and trace elements; aluminum balance (~96.2–98.8%).

Manganese and magnesium are the principal performance drivers: Mn stabilizes and refines the microstructure and enhances recrystallization resistance, while Mg enhances strain-hardening and provides modest solid-solution strengthening. Impurity elements such as iron and silicon form intermetallic phases that can reduce ductility and influence surface appearance; tight control of these is important for sheet that will undergo deep drawing or decorative finishing.

Mechanical Properties

Tensile behavior of 3004 is characteristic of cold-worked, non-heat-treatable aluminum alloys. In the annealed state the alloy shows relatively low yield and tensile strengths with high uniform elongation, enabling deep drawing and forming; after moderate cold work the yield rises markedly and elongation falls, producing a useful strength window for structural sheet components.

Yield and ultimate tensile strengths are sensitive to gauge and temper. Thin gauges typically respond with higher apparent yield due to surface work-hardening and processing-induced texture; conversely, thicker plate or extrusions may show lower work-hardening response and slightly reduced strength for equivalent tempers.

Fatigue performance is moderate and dependent on surface finish and residual stresses from forming or welding; surface scratches and notches reduce fatigue life substantially. Hardness follows tensile response and is useful as a quick field check for temper condition and degree of cold work.

Property	O/Annealed	Key Temper (H14)	Notes
Tensile Strength (UTS)	110–145 MPa	170–230 MPa	Range depends on thickness, processing history and exact temper.
Yield Strength (0.2% offset)	35–75 MPa	120–170 MPa	H14 yields show substantial increase from annealed values due to strain hardening.
Elongation (A50 mm)	20–30%	6–12%	Elongation decreases markedly with increased cold work.
Hardness (Brinell, approx.)	30–45 HB	55–85 HB	Hardness correlates with temper; useful for QC and in-service checks.

Physical Properties

Property	Value	Notes
Density	2.70–2.73 g/cm³	Typical for wrought aluminum alloys; impacts mass and stiffness calculations.
Melting Range	~640–650 °C	Solidus and liquidus are close; melting behavior similar to commercial Al alloys.
Thermal Conductivity	~120–160 W/m·K	Lower than pure aluminum due to alloying elements; still good for heat transfer applications.
Electrical Conductivity	~30–40 % IACS (~17–23 MS/m)	Reduced from pure Al; design circuits should account for increased resistivity.
Specific Heat	~900 J/kg·K	Typical value for aluminum alloys used in thermal modeling.
Thermal Expansion	~23–24 µm/m·K (20–100 °C)	Relatively high coefficient; important for joint design with dissimilar materials.

These physical constants reflect 3004's utility where thermal transport and low density matter but where no extreme thermal resistance is required. The thermal and electrical conductivities are lower than pure Al but remain favorable compared with many steels, making 3004 suitable for heat exchanger fins and conductive enclosures where strength and formability are needed.

Thermal expansion and conductivity data are critical for multi-material assemblies; designers should account for differential expansion when bonding or mechanically fastening 3004 to metals with significantly different coefficients.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.2–4.0 mm	Good cold-work response; thin gauges easily formed	O, H14, H24	Widely used for beverage can bodystock and architectural panels.
Plate	>4.0 mm up to ~12 mm	Reduced work-hardening per thickness; may be stress-relieved	O, H18, H26	Plate used where larger panels or shallow-drawn components are acceptable.
Extrusion	Profiles up to moderate cross-sections	Work-hardening limited compared to wrought sheet; needs post-extrusion temper	H14, H26	Less common than other alloys for complex extrusions; good for simpler profiles.
Tube	Typical OD 6–200 mm	Cold drawing and annealing control wall properties	O, H14	Used in heat exchanger tubing and structural applications; corrosion performance matters.
Bar/Rod	Diameters up to ~100 mm	Strength increases with cold drawing; machinability variable	H14, H18	Used for fabricated fittings and mechanical components requiring moderate strength.

Formed product selection is governed by the alloy’s susceptibility to work-hardening and the intended forming operations. Sheet and thin gauge products are predominant because they leverage 3004’s excellent drawability in the annealed condition and controllable strengthening by cold work.

Thicker products such as plate and bar often require different processing approaches (hot rolling, solutionizing/annealing cycles) to achieve uniform properties; such forms are chosen where geometry and stiffness requirements outweigh deep formability.

Equivalent Grades

Standard	Grade	Region	Notes
AA	3004	USA	Aluminum Association designation commonly used in procurement.
EN AW	3004	Europe	EN AW-3004 equivalent; chemical tolerances and mechanical test methods follow EN standards.
JIS	A3004 (or similar)	Japan	Japanese standards list aluminium-manganese-magnesium alloys with minor naming differences.
GB/T	3A04 / 3004	China	Chinese designation commonly expressed as 3A04; composition tolerances may differ slightly.

Equivalent standards are broadly interoperable but can vary in allowable impurity limits, specified tempers, and testing procedures. Buyers should always request the specific standard (AA, EN, JIS, GB/T) and temper certification because mechanical property acceptance criteria and sheet thickness ranges may differ between regions.

Mill process routes (rolling schedule, anneal parameters, final surface treatments) can also cause measurable differences in texture and formability even when chemical composition meets the same nominal grade.

Corrosion Resistance

In atmospheric service 3004 exhibits good general corrosion resistance comparable to other Al-Mn alloys; it forms a self-healing oxide that protects the underlying metal under normal environmental exposure. The presence of magnesium slightly alters localized corrosion tendencies but does not significantly compromise general atmospheric performance for intended uses such as architectural cladding or beverage can bodies.

In marine or chloride-containing environments 3004 is more susceptible to pitting and crevice corrosion than Al-Mg (5xxx) alloys; exposed edges, welds and crevices require attention to design and, where practical, protective coatings or anodizing. For prolonged marine immersion, alloys with higher magnesium (5052) or protective cladding are usually preferred.

Stress corrosion cracking (SCC) is not a major concern for 3004 compared with high-strength heat-treatable alloys; the non-heat-treatable nature and relatively low strength lower SCC susceptibility. When galvanically coupled, 3004 is anodically reactive relative to stainless steels and noble metals, so electrical isolation or compatible fasteners and coatings are recommended to mitigate galvanic corrosion.

Compared with 1xxx commercial-pure aluminum, 3004 trades slightly reduced conductivity for higher strength while maintaining similar general corrosion behavior. Versus 5xxx alloys, 3004 usually has lower pitting resistance but better formability in annealed tempers.

Fabrication Properties

Weldability

3004 is readily welded by common fusion processes including GTAW (TIG) and GMAW (MIG); solid-state joining methods such as resistance spot welding are also feasible for sheet assemblies. Typical filler wires used include Al-Mg-Si or Al-Si fillers (e.g., ER4043 or ER5356) chosen to balance weldability, corrosion resistance and mechanical compatibility with the base metal.

Hot-cracking tendencies are low compared with high-strength heat-treatable alloys, but care must be taken with joint design and heat input to avoid excessive local annealing of strain-hardened tempers. Post-weld mechanical properties will reflect HAZ softening where base material was cold-worked; designers should allow for local reduction in yield in heavily worked parts.

Machinability

Machinability of 3004 is fair to moderate and generally lower than aluminum alloys containing lead or bismuth free-machining additives. The alloy tends to be more ductile and can produce long, stringy chips unless chips are broken by tooling geometry and interrupted cuts; carbide tools with positive rake and chip-breakers are recommended.

Cutting speeds and feeds should be tuned for the selected temper and section; lubricants and flood coolant improve tool life and surface finish. For precision components where high machining rates are required, heat-treatable alloys with engineered machinability grades or additions may be preferred.

Formability

Formability is one of 3004’s strengths in the annealed O condition, enabling deep drawing, ironing and complex stamping operations commonly used in container manufacturing. Minimum internal bend radii depend on temper and thickness, but O temper typically accommodates radii of 1–2× thickness (t), while strain-hardened H14 may require larger radii of 2–4×t to avoid cracking.

Cold-work increases strength but reduces elongation; springback is moderate and must be accounted for in die design. Techniques such as intermediate anneals, controlled lubrication and stretch-forming improve outcomes for complex geometries.

Heat Treatment Behavior

3004 is non-heat-treatable and does not respond to solution treatment and artificial aging in the way 6xxx or 7xxx alloys do. Attempts at solution heat treatment provide limited strengthening because the Mn and Mg content primarily contribute to work-hardening and solid-solution effects rather than age-hardening precipitates.

Control of properties is achieved by cold work and annealing cycles: full anneal (O) is typically accomplished by heating to appropriate temperatures (often in the 300–420 °C range depending on mill practice), holding to recrystallize and then cooling to achieve maximum ductility. Partial anneals (H2x, H3x tempers) are used to set intermediate strength/ductility balances after cold deformation.

T-type temper nomenclature (e.g., T5/T6) is not generally applicable or effective for 3004 because precipitation hardening is minimal; the specification and selection of tempers should be limited to H and O families for predictable results.

High-Temperature Performance

Strength of 3004 degrades with increasing temperature and significant softening occurs well below typical alloy melting points; above roughly 100–150 °C sustained strength drops and creep becomes more significant. For intermittent elevated-temperature exposure, 3004 can be used up to modest temperatures but continuous structural service above ~150 °C is not recommended.

Oxidation is minimal at common elevated service temperatures because aluminum forms a protective oxide; however, protective coatings and joint seals are prudent where prolonged hot humidity or corrosive atmospheres are present. Thermal exposure can also relieve cold work and alter mechanical properties in previously strained tempers, so thermal history must be considered for components used near their thermal limits.

The heat-affected zone from welding will exhibit local softening where prior cold work was present; this localized reduction in strength should be accounted for when designing weldments intended for elevated-temperature environments.

Applications

Industry	Example Component	Why 3004 Is Used
Packaging / Beverage	Can bodies and shells	Excellent deep-drawability and strength balance for thin-gauge can manufacture
HVAC / Heat Exchange	Fins, coils, tubing	Good thermal conductivity and formability for fin stock and tubes
Architectural	Cladding, soffits	Formability, surface finish potential and moderate corrosion resistance
Automotive	Interior panels, non-structural trim	Formability and weight savings in stamped components
Electronics	Heat spreaders, enclosures	Thermal management combined with manufacturability and cost-effectiveness

3004 is widely used where sheet formability and a modest increase in strength over 3003 are required without sacrificing manufacturability or significantly increasing cost. Its use in beverage can bodies exemplifies a demanding production environment where consistent drawability, surface finish and cost per kilogram are critical.

For components requiring higher corrosion resistance or higher sustained elevated-temperature strength, other alloy families may be selected, but for high-volume, formed sheet applications 3004 remains an economical, robust choice.

Selection Insights

Choose 3004 when you need higher formable strength than commercially-pure aluminum (1100) while retaining much of 1100’s workability and superior surface finish. Compared with 1100, 3004 sacrifices some electrical conductivity and maximum ductility to deliver improved yield and tensile strength, which enables thinner gauges in formed parts.

Relative to nearby work-hardened alloys like 3003 and 5052, 3004 sits between them: it offers higher strength than 3003 for similar forming operations and typically better general corrosion resistance than some 3003 lots, while 5052 provides superior marine corrosion resistance and higher strength at the expense of some drawability. Compared with heat-treatable alloys such as 6061 or 6063, 3004 is chosen when forming and low-cost sheet production are priorities and ultimate peak strength is not required; it is preferred for deep-drawn components and continuous production runs where thermal treatments would be impractical.

Closing Summary

Alloy 3004 remains relevant because it fills a practical niche: a work-hardenable Al-Mn-Mg alloy that combines reliable deep-draw formability with a useful uplift in strength versus basic 3xxx alloys. Its balanced corrosion resistance, good joining performance and favorable production economics make it a mainstay for beverage containers, HVAC components and formed architectural sheet where manufacturability and cost control are paramount.