Aluminum EN AW-3103: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

EN AW-3103 is a member of the 3xxx series of wrought aluminum alloys, which are predominantly alloyed with manganese as the principal strengthening element. This family is classified as non-heat-treatable and gains strength through controlled cold work (strain hardening) rather than through solution and precipitation heat treatments typical of the 6xxx and 7xxx series.

The principal alloying element in EN AW-3103 is manganese, typically at sub‑percent to low‑percent levels, with small controlled amounts of iron, silicon and trace elements that influence forming and surface finish. As a result, EN AW-3103 offers a balance of moderate strength, very good formability, and decent corrosion resistance in many atmospheric environments.

Key traits of EN AW-3103 include medium strength (higher than commercially pure Al but lower than many work‑hardened or heat‑treatable alloys), excellent cold formability in the annealed condition, reliable weldability with standard aluminum processes, and good resistance to general corrosion. Typical industries using EN AW-3103 include building and architectural components, decorative trim and cladding, signage and lighting fixtures, and general sheet metal work where formability and surface finish are important.

Engineers select EN AW-3103 over purer grades for its improved mechanical performance while retaining good forming characteristics and over higher‑strength alloys when superior ductility, surface quality and cost are prioritized. It occupies a practical trade‑off position for parts made from sheet and thin‑gauge product that require bending, drawing and welding without the need for peak age‑hardened strength.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	20–35%	Excellent	Excellent	Fully annealed, maximum ductility for deep drawing
H11 / H111	Low–Moderate	15–30%	Very good	Excellent	Slight work hardening; commonly used for light forming
H14	Moderate	6–18%	Good	Excellent	Quarter‑hard; common temper for moderate strength/forming balance
H16	Moderate–High	4–12%	Fair–Good	Excellent	Half‑hard; improved stiffness and springback control
H18	High	2–8%	Limited	Excellent	Full hard from cold working; used when higher yield is required

EN AW-3103 is predominantly supplied in annealed (O) and various H tempers obtained by controlled rolling and cold working. The temper controls the dislocation density and microstructure, so moving from O to H18 increases strength and decreases elongation and drawability.

Weldability remains good across these tempers because the alloy is non‑heat‑treatable; however, cold‑worked tempers will show localized softening in heat‑affected zones after welding and may require post‑weld mechanical or thermal treatments to restore properties.

Chemical Composition

Element	% Range	Notes
Si	≤ 0.6	Silicon is kept low to preserve ductility and surface quality.
Fe	≤ 0.7	Iron is an impurity; controlled levels affect anisotropy and strength.
Mn	0.6–1.5	Primary alloying element; imparts solid‑solution and dispersive strengthening.
Mg	≤ 0.10	Magnesium is minimal in 3103 and not used for precipitation strengthening.
Cu	≤ 0.20	Copper content is low; helps strength marginally but can reduce corrosion resistance if high.
Zn	≤ 0.20	Zinc is a minor impurity with limited effect on properties at these levels.
Cr	≤ 0.10	Chromium may appear in trace amounts to control grain structure.
Ti	≤ 0.15	Titanium is used rarely as a grain refiner in small amounts.
Others (each)	≤ 0.05	Other elements controlled to protect ductility and formability.

The Mn content is the defining compositional driver for EN AW-3103, enabling work‑hardening response and improved strength relative to commercially pure aluminum. Iron and silicon are kept at low levels to avoid embrittlement and to maintain excellent surface finish and rollability for sheet production.

Mechanical Properties

In tensile behavior EN AW-3103 shows classic non‑heat‑treatable alloy performance: ductility and low yield in the annealed condition with progressive increases in yield and tensile strength as cold work is introduced. Yield strength is strain‑rate dependent and can be elevated substantially by moderate cold working, delivering predictable springback characteristics useful for formed components.

Elongation in O temper is high, supporting deep drawing and stretch forming, while H‑tempers trade ductility for stiffness and higher 0.2% proof strengths. Hardness correlates with temper and is commonly low in O (soft), rising through H11/H14 to H18 where work hardening produces the highest hardness levels; hardness scales are used for production QA.

Fatigue performance of EN AW-3103 is moderate and typically correlates with surface condition and temper; polished surfaces and compressive residual stresses from forming improve fatigue life. Sheet thickness influences mechanical response: thin gauges are more easily strained and will reach work‑hardened strength earlier during forming, whereas thicker sections retain higher energy absorption but reduce formability.

Property	O/Annealed	Key Temper (e.g., H14)	Notes
Tensile Strength	95–140 MPa (typical)	140–200 MPa (typical)	Values depend on gauge, processing history and exact temper
Yield Strength (0.2% proof)	30–50 MPa	90–140 MPa	Yield increases significantly with cold work
Elongation	20–35%	6–18%	Annealed provides maximum ductility; cold work reduces elongation
Hardness (HB)	20–40	40–80	Hardness tracks cold work; used for process control

Physical Properties

Property	Value	Notes
Density	2.70 g/cm³	Typical density for wrought Al‑Mn alloys; useful for mass and stiffness calculations.
Melting Range	640–655 °C	Solidus/liquidus close to pure aluminum; melting range depends on minor constituents.
Thermal Conductivity	120–160 W/m·K	Good thermal conductor; lower than high‑purity aluminum but suitable for heat spreaders.
Electrical Conductivity	~30–40 % IACS	Lower than pure aluminum; conductivity decreases with cold work and alloying.
Specific Heat	~0.90 kJ/kg·K (900 J/kg·K)	Typical specific heat used for transient thermal calculations.
Thermal Expansion	23–24 µm/m·K (20–100 °C)	Coefficient of thermal expansion typical for Al alloys; important for bimetallic joints.

The physical property set places EN AW-3103 as a lightweight material with favorable thermal conduction and predictable thermal expansion, making it suitable for components where heat spreading and dimensional stability over moderate temperature ranges are required. Electrical conductivity is sufficient for non‑critical conductive applications but is usually inferior to commercially pure grades used in electrical conductors.

Designers must account for thermal expansion when mating EN AW‑3103 to dissimilar materials and for conductivity when specifying it for thermal management; surface treatments and coatings commonly used in architectural applications do not drastically alter bulk thermal properties but can affect emissivity and heat transfer.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.3–6.0 mm	Strength increases with cold rolling/temper	O, H11, H14, H16, H18	Most common form; used for panels, trim, facades
Plate	6–25 mm	Limited; generally supplied in softer tempers	O, H111	Less common due to primary use as thin gauge sheet
Extrusion	Variable cross‑sections	Extrusions of 3103 are uncommon; workability varies	H111	Possible for simple profiles but 3xxx series extrusions less typical
Tube	Ø 6–120 mm	Cold working during tube manufacturing raises strength	O, H14	Used for decorative tubing and light structural elements
Bar/Rod	Ø 5–50 mm	Bars are available; strength via work hardening	H11, H14	Used for fasteners, trims, and formed components

Sheet production is the core processing route for EN AW‑3103 with rolling and annealing sequences selected to produce uniform surface quality and controlled mechanical properties. Extrusions and heavier sections are less frequent because other series (6xxx for extrusions, 5xxx for marine plate) generally provide better strength and performance for those product categories.

Cold forming operations such as bending, stamping and drawing are the dominant fabrication routes; temper selection is used to balance springback, drawability and final in‑service strength. For architectural components where surface finish and anodizing quality are required, rolling and annealing practices are optimized to minimize surface defects and maintain uniform alloy chemistry.

Equivalent Grades

Standard	Grade	Region	Notes
AA	3103	USA	Often referred to in American Aluminum Association literature as AA 3103.
EN AW	3103	Europe	EN AW‑3103 is the common European designation under EN standards.
JIS	A3103 (approx.)	Japan	Japanese specifications may reference similar Al‑Mn alloys with local designations.
GB/T	3103 (approx.)	China	Chinese standards include 3xxx family equivalents; exact compositions may vary slightly.

Equivalent grade designations across regions are broadly interchangeable for many commercial applications, but engineers should verify specific composition limits and mechanical property tables for ordering. Slight differences in impurity limits, allowable tolerances and temper designations may exist between AA, EN, JIS and GB/T specifications; these can affect formability, surface finish and qualification for coatings or structural acceptance.

Corrosion Resistance

EN AW-3103 exhibits good atmospheric corrosion resistance similar to other Al‑Mn alloys, forming a stable oxide film that limits uniform corrosion in rural and urban environments. The manganese content does not substantially reduce general corrosion resistance and the alloy performs well for exterior architectural components and trim where periodic maintenance or coatings are applied.

In marine environments the alloy shows reasonable resistance to salt spray and moderate chloride exposure, but prolonged immersion or splash zones with heavy chloride attack will accelerate pitting and surface degradation compared with more resistant alloys like 5xxx series (Al‑Mg). For persistent marine applications designers often specify anodic coatings or select higher Mg alloys depending on structural and exposure demands.

EN AW‑3103 has a low susceptibility to stress corrosion cracking because it is non‑heat‑treatable and does not form detrimental precipitates; however, welded or cold‑worked regions with tensile residual stresses should be assessed for localized corrosion behavior. Galvanic interaction with more noble metals (stainless steel, copper) can accelerate corrosion of EN AW‑3103; insulating layers, sealants or sacrificial anodes are recommended when dissimilar metal joints are unavoidable.

Fabrication Properties

Weldability

EN AW‑3103 welds readily by TIG and MIG processes with standard aluminum practice, showing low tendencies for hot cracking due to its simple alloy chemistry. Typical filler materials include Al‑Mn compatible wires and rods (for example Al‑5xx6 or Al‑4xxx grades depending on joint requirements), chosen to balance mechanical properties, corrosion resistance and filler availability. Welds will produce a local HAZ softening in cold‑worked tempers because the alloy is non‑heat‑treatable; post‑weld mechanical treatment or over‑matching filler may be used to recover performance.

Machinability

Machining EN AW‑3103 is generally straightforward but not exceptional; machinability indices are lower than free‑machining aluminum alloys that include lead or bismuth. Carbide or coated high‑speed tool steels with positive rake and high feed rates produce the best chip control, and coolant can help avoid built‑up edge and improve surface finish. When designing for machining, engineers typically prefer thicker sections and appropriate tempering to increase rigidity and reduce chatter.

Formability

EN AW‑3103 is one of the more formable Mn‑containing alloys, particularly in the O temper where deep drawing and stretch forming are excellent. Recommended minimum bend radii depend on temper and thickness but are generally small in O—allowing tight bends—and must be increased for H‑tempers to prevent cracking. Cold‑work hardening raises yield and reduces elongation, so progressive forming schedules and intermediate anneals are common production strategies for complex parts.

Heat Treatment Behavior

As a non‑heat‑treatable alloy, EN AW‑3103 does not respond to solutionizing and artificial aging treatments for strengthening; such processes will not produce the precipitate hardening seen in 6xxx or 7xxx series. The primary metallurgical control route is cold work (rolling, drawing, bending) which increases dislocation density and imparts higher yield and tensile strengths.

Annealing (reversion to O) is performed to restore ductility and reduce residual stresses; anneal temperatures are selected to recrystallize without causing surface oxide issues—typical industrial anneal cycles are carefully controlled in commercial furnaces. For applications requiring localized property tailoring, combinations of cold work, stress relieving and surface finishing are used instead of classic heat treatment sequences.

High-Temperature Performance

EN AW‑3103 exhibits gradual strength loss with increasing temperature, with meaningful reductions above ~100–150 °C and rapid softening as temperatures approach the recrystallization regime. Long‑term exposure to elevated temperatures can lead to recovery and recrystallization, reducing work‑hardened strength and altering dimensional stability; therefore, service temperatures are typically limited to well below 200 °C for load‑bearing applications.

Oxidation at elevated temperature is minimal compared with steels; aluminum forms a protective oxide but high temperature exposure can change surface appearance and interfere with coatings or adhesives. Welded joints and HAZs can suffer strength reductions under thermal cycling; designers must account for annealing of cold work and possible changes in fatigue performance if operating temperatures approach tempering thresholds.

Applications

Industry	Example Component	Why EN AW-3103 Is Used
Automotive	Interior trim panels, decorative molding	Good formability and surface finish at moderate strength
Architectural / Building	Facade cladding, soffits, guttering	Corrosion resistance and anodizing quality for visible surfaces
Signage & Lighting	Reflector housings, sign faces	Sheet formability, surface finish, and dimensional stability
Consumer Appliances	Cookware trim, cabinet faces	Ease of forming, weldability and economic availability
HVAC / Ducting	Lightweight duct panels	Good formability and corrosion resistance in indoor environments

EN AW‑3103 is favored for components that require a balance of formability, acceptable mechanical performance and a high quality surface finish, particularly where anodizing or painting is part of the specification. Its combination of properties also makes it economical for medium‑duty architectural and consumer applications where extreme strength is not required.

Selection Insights

For selection engineers considering EN AW‑3103, prioritize it when you need superior formability and surface quality with moderate strength and good corrosion resistance at economical cost. If the design demands deep drawing and tight radii with subsequent light welding or brazing, EN AW‑3103 in O temper often provides the best trade‑off between manufacturability and in‑service performance.

Compared with commercially pure aluminum (e.g., 1100), EN AW‑3103 sacrifices a small amount of electrical and thermal conductivity to gain higher yield and tensile strength, making it preferable where structural integrity and forming are required. Compared with similar work‑hardened alloys (e.g., 3003, 5052), 3103 sits close to 3003 in properties and typically offers comparable strength with similar corrosion resistance; for marine or high‑load cases, Mg‑bearing alloys like 5052 may be chosen instead.

Compared to heat‑treatable alloys (e.g., 6061/6063), EN AW‑3103 will not reach the same peak strengths but is often selected for superior formability, ease of fabrication and better surface finish for architectural or decorative parts where maximum strength is not the primary requirement.

Closing Summary

EN AW‑3103 remains a relevant and widely used aluminum alloy because it combines reliable Mn‑based strengthening with excellent formability, good corrosion resistance and straightforward fabrication in sheet and thin‑gauge forms. Its balance of properties, surface quality and cost efficiency makes it a pragmatic choice for architectural, decorative and general sheet metal applications in modern engineering.