Aluminum 3310: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

3310 is a member of the 3xxx series aluminum family and is classified as a manganese-bearing wrought alloy designed for structural sheet and extrusion applications. The 3xxx series designation indicates that manganese is the principal alloying addition, which provides moderate strengthening without heat treatment. The primary strengthening mechanism for 3310 is solid-solution and strain hardening from cold work; it is not a precipitation‑hardening (heat‑treatable) alloy. This alloy balances moderate static strength with good formability and corrosion resistance, making it suitable for forming-intensive structural and architectural uses.

Major alloying elements in 3310 are manganese as the principal microalloying addition, with controlled levels of iron and trace additions of silicon, copper, zinc, chromium, and titanium to tailor processing and mechanical behavior. Key traits include mid-range tensile and yield strengths in strain‑hardened tempers, excellent resistance to general atmospheric corrosion, and good weldability by common fusion and resistance processes. Formability is strong in annealed and soft tempers, while weld‑zone softening must be considered when using stronger H‑tempers. Typical industries include building and construction, general transportation, architectural panels, HVAC components, and consumer goods.

Engineers choose 3310 over other aluminum grades when a combination of formability, adequate mechanical strength, reliable weldability, and relatively low cost is required. Its performance envelope positions it above commercially pure grades in strength while retaining better forming and corrosion behavior than stronger heat‑treatable alloys in many joined and formed part applications. The alloy is especially useful when part geometry requires substantial stamping or bending and when post‑weld service conditions favor non‑precipitation‑hardened materials.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed condition for maximum ductility
H12	Low‑Mid	High	Very Good	Excellent	Light cold work; good for deep drawing
H14	Mid	Moderate	Good	Good	Quarter‑hard; common for formed panels
H16	Mid‑High	Moderate	Fair	Good	Half‑hard; used where higher strength is needed
H18	High	Lower	Fair‑Poor	Good	Full hard; limited forming, higher stretch resistance
H112	Varies	Varies	Good	Good	As‑fabricated controlled properties for extrusions
H321	Mid	Moderate	Good	Good	Stabilized after strain relief and small natural aging

Temper has a primary influence on tensile properties, elongation, and forming window for 3310 parts. Annealed (O) material offers the greatest stretch and draw capability, while H‑tempers incrementally increase strength at the expense of elongation and bendability.

Choosing a temper is an engineering tradeoff between forming requirements and final part strength; parts that require heavy drawing should be processed in O or light H‑tempers and then age‑stabilized if needed. For welded assemblies where post‑weld distortions are critical, softer tempers minimize HAZ concerns but may require design compensation for reduced yield strength.

Chemical Composition

Element	% Range	Notes
Si	0.10–0.40	Controlled to minimize brittle intermetallics and maintain ductility
Fe	0.30–0.80	Typical impurity level; affects strength and grain structure
Mn	0.8–1.5	Principal alloying element for solid solution strengthening
Mg	0.05–0.30	Kept low to avoid inadvertent precipitation hardening
Cu	0.05–0.25	Small additions improve strength but reduce corrosion resistance
Zn	0.05–0.25	Kept low to avoid hot‑cracking and preserve formability
Cr	0.02–0.10	Trace additions assist in grain control and recrystallization behavior
Ti	0.01–0.10	Microalloy for grain refinement during casting and extrusion
Others (V, Zr, remainder)	0.00–0.15	Minor elements for processing control and property tuning

The manganese content is the defining compositional feature and sets 3310 apart from pure aluminum by enabling solid‑solution strengthening without heat treatment. Iron and silicon are controlled to limit brittle intermetallic particles that would reduce formability and fatigue resistance. Trace elements such as chromium and titanium are included to improve grain structure and to stabilize properties during thermal cycles and fabrication.

Careful compositional control allows 3310 to achieve a favorable combination of mechanical performance and corrosion resistance while remaining highly formable and weldable. Alloying choices reflect a design emphasis on manufacturability (forming and welding) rather than maximizing peak strength.

Mechanical Properties

3310 exhibits tensile and yield behavior typical of medium‑strength non‑heat‑treatable aluminum alloys. In annealed condition the alloy has relatively low yield strength but high elongation, giving excellent stretch and deep‑drawing capacity. With progressive strain hardening through H‑tempers, tensile and yield strengths increase significantly while elongation and bendability are reduced. Hardness correlates with temper and cold work, rising from low Brinell values in O up to moderate values in H18/highly strained conditions.

Fatigue behavior for 3310 is governed by surface condition, residual stresses from forming, and inclusion content; stress concentrators and rough surface finishes reduce fatigue life. Thickness influences both strength and forming; thinner gauges allow tighter bends and improved formability, while thicker sections retain more structural stiffness but require greater forming forces and can trap casting‑derived inclusions. Weld heat‑affected zones will exhibit localized softening proportional to initial temper and welding heat input, which must be accounted for in joint design.

Designers typically use conservative allowable stresses based on tempered state and consider fatigue notch factors for stamped edges and weld terminations. When using 3310 in cyclic or high‑stress parts, surface finish control, stress relief operations, and avoidance of sharp radii are important to maintain acceptable fatigue life.

Property	O/Annealed	Key Temper (e.g., H14)	Notes
Tensile Strength	95–140 MPa	180–240 MPa	Tensile increases with cold work; ranges depend on thickness and processing
Yield Strength	35–70 MPa	120–180 MPa	Yield correlates strongly with temper; H‑tempers preferred for structural use
Elongation	30–40%	6–18%	Elongation drops significantly as temper increases
Hardness	25–45 HB	55–85 HB	Brinell hardness rises with strain hardening; hardness varies with microstructure

Physical Properties

Property	Value	Notes
Density	2.70 g/cm³	Typical for wrought aluminum alloys; useful for lightweight design
Melting Range	~555–650 °C	Solidus‑liquidus interval depends on alloying elements and inclusions
Thermal Conductivity	~140 W/m·K	High thermal conductivity compared with steels; varies with alloying and temper
Electrical Conductivity	~35–45 % IACS	Lower than pure Al; manganese reduces conductivity relative to 1100 series
Specific Heat	~900 J/kg·K	Near that of pure aluminum; useful for thermal management calculations
Thermal Expansion	~23–24 µm/m·K	Typical coefficient for aluminum alloys; important for thermal cycling design

3310 maintains the attractive physical characteristics of aluminum: low density, high thermal conductivity, and favorable specific heat, enabling lightweight thermal‑management applications. The presence of manganese and other solutes reduces electrical conductivity relative to commercially pure grades, which must be considered in conductor applications.

Thermal expansion and conductivity are important design inputs when joining dissimilar materials or when parts will see temperature swings; expansion mismatch with steels or composites may drive joint design and fastening strategies. The melting interval reflects typical alloying‑broadening of the phase diagram and has implications for welding and brazing process windows.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.3–6.0 mm	Thickness‑dependent; easier to form at thinner gauges	O, H12, H14, H16	Widely used for panels, enclosures, and ducting
Plate	6–25 mm	Higher stiffness; less formability	O (limited), H18	Often used for structural components requiring greater thickness
Extrusion	Wall thickness 1–20 mm; cross‑sections variable	Strength controlled by temper and section size	H112, H321	Complex profiles for frames and structural members
Tube	Diameters 6–200 mm	Strength influenced by wall thickness and cold‑working	H14, H16	Common for HVAC, fluid handling, and structural tubing
Bar/Rod	Diameters 6–50 mm	Good compressive and bending behavior	H14, H16	Used where solid sections are needed for machining and forging

Sheets and thin gauges offer the best formability for deep‑draw and stretch‑forming operations and are commonly produced on continuous casting and rolling lines. Plate and thick extrusions require different homogenization and rolling/extrusion practices and will display coarser microstructures that influence toughness and fatigue.

Processing differences influence applications: extrusions allow complex cross‑sections and integrated stiffeners, while sheet products are economical for large surface panels. Choice of product form should match forming technique, finished geometry, and required mechanical performance.

Equivalent Grades

Standard	Grade	Region	Notes
AA	3310	USA	Primary alloy designation in American specifications; typical inventory grade
EN AW	3310	Europe	Europe often uses EN AW ×××× notation; chemistry tolerances and tempers can differ
JIS	A3310	Japan	Japanese standards may have slightly different impurity limits and temper codes
GB/T	3310	China	Chinese grade often mirrors AA composition but with local production tolerances

There is no single global one‑to‑one equivalent for 3310 that matches composition, tempering nomenclature, and processing history exactly across standards. Variations between AA, EN, JIS, and GB/T standards are most commonly found in maximum impurity limits (especially iron and silicon) and in the temper designation conventions. When substituting across regions, engineers must compare both guaranteed mechanical properties and chemical composition tolerances and validate formability/weldability for the intended process.

For procurement and specification, request chemical certificates and mill test reports that indicate exact composition, mechanical properties at the specified temper, and processing history (annealed, cold‑worked, extrusion vs rolled) to ensure functional equivalence. Where standards differ in temper coding, specify mechanical property targets rather than relying solely on temper names.

Corrosion Resistance

3310 offers good resistance to general atmospheric corrosion and typically performs well in urban and industrial environments due to the formation of a stable aluminum oxide film. In marine environments, 3310 resists uniform corrosion but requires protective design and cladding when exposed to splashing or standing seawater; fastener and assembly design must minimize crevice corrosion. The alloy exhibits modest susceptibility to pitting in chloride‑rich environments compared with highly alloyed marine‑grade alloys, so sacrificial coatings or anodizing are common mitigations.

Stress corrosion cracking (SCC) risk for 3310 is low compared with high‑strength heat‑treatable alloys; SCC is not a major concern under normal service conditions because the alloy does not achieve the high yield strengths that predispose Al‑Zn‑Mg alloys to SCC. Galvanic interactions should be considered when joining 3310 to more noble metals such as stainless steel or copper; anodic protection and isolation layers prevent accelerated corrosion of the aluminum. Compared to 2xxx and 7xxx families, 3310 is more corrosion‑resistant but provides lower peak strengths, and compared to 1xxx and 5xxx series it trades some conductivity and forming for higher baseline strength.

Fabrication Properties

Weldability

3310 is readily welded by TIG, MIG (GMAW), and resistance processes with low incidence of hot cracking when recommended practice is used. Recommended filler alloys are generally ER4043 (Al‑Si) or ER5356 (Al‑Mg) depending on service and required post‑weld strength; ER4043 offers better flow and reduced susceptibility to solidification cracking. Weld HAZ softening is a design consideration for H‑tempers, and pre‑ and post‑weld stress relief or design compensation may be necessary for structural parts. Weld parameters should minimize heat input and interpass temperature to limit grain growth and property loss.

Machinability

3310 has machining characteristics typical of non‑heat‑treatable aluminum alloys: good machinability with high cutting speeds and moderate tool wear when using carbide tooling. The machinability index is lower than free‑cutting alloys but favorable compared with high‑manganese steels; tool geometry that promotes positive rake and efficient chip evacuation reduces built‑up edge. Recommended coolant application and chip breakers improve surface finish and dimensional control for complex parts. For tight‑tolerance machining, annealed or light H‑tempers provide better surface integrity and lower cutting forces.

Formability

Formability of 3310 is excellent in O and light H tempers, enabling deep drawing, stretching, and complex stampings with relatively small bend radii. Typical minimum inside bend radii are a function of thickness and temper; for sheet in O temper a bend radius of 0.5–1.0× thickness is generally achievable without cracking. Cold working increases strength but reduces elongation and increases springback, which must be compensated for in tool design and process control. If severe forming is required after welding or heat exposure, select softer tempers and consider intermediate stress‑relief anneals.

Heat Treatment Behavior

3310 is a non‑heat‑treatable alloy in which mechanical strengthening is achieved by cold work and microalloying rather than by solution treatment and precipitation aging. There is no beneficial T‑type precipitation hardening sequence comparable to 6xxx or 7xxx alloys; attempts to solution‑treat and artificially age yield limited improvements. Annealing (O) is used to fully recrystallize the microstructure and restore ductility after forming and cold work. Partial anneals and stabilization treatments (e.g., H321) are employed to control temper drift and improve dimensional stability for fabricated parts.

Work hardening is the predominant strengthening pathway: yield and tensile strengths increase with plastic strain, and the strain hardening exponent is moderate, enabling predictable springback behavior for forming simulations. Standard annealing cycles for 3310 typically use temperatures in the range of 300–380 °C for short durations followed by controlled cooling to avoid grain coarsening, depending on product form and thickness. When higher in‑service strength is required without sacrificing formability, designers often specify local cold working or incorporate structural stiffening rather than relying on heat treatment.

High-Temperature Performance

The mechanical strength of 3310 declines steadily with increasing temperature and is not recommended for continuous service above approximately 150–175 °C. At elevated temperatures the alloy experiences microstructural recovery and reduction in dislocation density, which manifest as marked loss of yield and tensile strength. Oxidation of aluminum is limited by the protective oxide scale, but scale spallation and accelerated creep can occur at higher temperatures, especially under cyclic thermal loading.

Weld HAZs are particularly susceptible to strength reductions when exposed to elevated temperature due to coarsening of recrystallized zones and potential diffusion of solutes. For intermittent elevated temperature exposure, design margins should be increased and thermal stabilization techniques considered. For true high‑temperature aluminum service, alloys specifically formulated for elevated temperature strength (e.g., Al‑Si piston alloys or high‑Si casting alloys) are preferable to 3310.

Applications

Industry	Example Component	Why 3310 Is Used
Automotive	Interior and exterior body panels	Good formability with mid‑range strength for dent resistance
Marine	HVAC ducting and secondary structures	Corrosion resistance with lower susceptibility to SCC
Aerospace	Non‑primary fittings and fairings	Light weight and good manufacturability for non‑critical parts
Electronics	Chassis and heat spreaders	High thermal conductivity and ease of forming
Construction	Cladding, gutters, and flashings	Durable surface finish and corrosion resistance

3310 finds frequent use in components that require a balance of formability, corrosion resistance, and moderate structural capability rather than maximum strength. Its use is favored where economical processing, joining, and finishing (anodizing or painting) are primary drivers and where the alloy’s manufacturability results in lower total part cost.

Selection Insights

Choose 3310 when the design requires a mid‑strength alloy with excellent forming and reliable weldability, particularly for stamped, drawn, or extruded structural components. It is a practical choice when corrosion resistance and thermal performance are needed without the processing complexity and potential SCC concerns associated with high‑strength heat‑treatable alloys.

Compared with commercially pure aluminum (e.g., 1100), 3310 trades off some electrical and thermal conductivity for substantially higher strength and improved dent resistance, while retaining much of the formability needed for complex shapes. Compared with common work‑hardened alloys like 3003 or 5052, 3310 generally offers higher baseline strength with comparable corrosion resistance, making it preferable when incrementally greater strength is required without moving to precipitation‑hardenable grades.

Compared with heat‑treatable alloys such as 6061 or 6063, 3310 will not reach the same peak strengths but may be preferred where superior formability, simpler processing (no solution/age treatment), and lower risk of HAZ embrittlement or SCC are priorities. Use 3310 when manufacturability, cost, and corrosion performance outweigh the need for the highest possible yield strength.

Closing Summary

3310 remains a relevant engineering alloy for applications demanding a versatile combination of formability, corrosion resistance, weldability, and moderate strength. Its solution‑free strengthening philosophy, predictable fabrication behavior, and favorable physical properties support broad use across transportation, building, and consumer sectors where lightweight, manufacturable components are required.