Aluminum EN AW-1350: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

EN AW-1350 is a 1xxx-series aluminum alloy and is classified among the commercially pure aluminum grades. It is characterized by very high aluminum content (typically ≥99.5%) with only trace additions of common impurities such as silicon, iron and copper.

The alloy relies on solid-solution behavior and strain hardening for property development rather than precipitation heat treatment; it is non-heat-treatable and strengthened primarily by cold work. Key traits include excellent electrical and thermal conductivity, outstanding corrosion resistance in many atmospheres, superior formability, and very good weldability, albeit at relatively low mechanical strength.

Typical industries using EN AW-1350 include electrical distribution (busbars, conductors), chemical and food-processing equipment, architecture, and heat-exchange hardware. Engineers select EN AW-1350 when maximum conductivity, surface quality and forming ease are prioritized over peak structural strength, or when very high purity is required for electrochemical or chemical compatibility.

The alloy is chosen over others when its combination of conductivity, corrosion resistance and ductility outweighs more strength-focused alloys; it is often preferred over 6xxx-series or 5xxx-series alloys when electrical performance and formability are dominant design drivers.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High	Excellent	Excellent	Fully annealed, maximum ductility and electrical conductivity
H12	Low–Moderate	Moderate	Very Good	Excellent	Some work hardening for light structural use
H14	Moderate	Moderate	Good	Excellent	Common commercial temper, balanced strength and formability
H16	Moderate–High	Lower	Fair	Excellent	Higher work hardening for sheet used in formed parts
H18	High	Low	Limited	Excellent	Strongly strain-hardened, limited formability
H19	Very High	Very Low	Poor	Excellent	Near-maximum cold work strength for supplier-specified shapes

Temper selection controls mechanical and electrical performance through the amount of cold work introduced. Annealed (O) is used when forming complexity or conductivity is critical, whereas H-series tempers are used when incremental increases in strength are needed at the cost of some ductility and conductivity.

Chemical Composition

Element	% Range	Notes
Al	Balance (typically ≥99.5)	Primary constituent; defines conductivity and corrosion resistance
Si	≤0.15–0.25	Trace impurity; slightly reduces conductivity when present
Fe	≤0.30–0.40	Common impurity; can form intermetallics that affect strength and surface finish
Mn	≤0.05–0.10	Minimal in this grade; not a strengthening element here
Mg	≤0.05–0.10	Usually very low; negligible age hardening potential
Cu	≤0.05–0.10	Kept very low to preserve conductivity and corrosion resistance
Zn	≤0.05–0.10	Trace; limited effect at low levels
Cr	≤0.05	Trace; minor microstructure modifier
Ti	≤0.03	Often present in microalloying amounts for grain refinement
Others	Each ≤0.05; total ≤0.15–0.20	Residuals and intentional microalloying kept minimal

EN AW-1350 is essentially a high-purity aluminum with tightly controlled impurity levels. The very high aluminum fraction ensures high electrical and thermal conductivity, with small residual elements primarily affecting surface characteristics, recrystallization behavior, and the potential for intermetallic particle formation that can influence forming and surface quality.

Mechanical Properties

In the annealed O condition EN AW-1350 exhibits low tensile and yield strengths with very high ductility; typical tensile strength is low compared with structural alloys, and elongation is generally high enough for deep drawing and complex forming. Work hardening (H tempers) raises yield and tensile strength while reducing elongation in a predictable way; the degree of cold work governs mechanical property increments.

Hardness in the annealed state is low and increases with H-number tempering; the material is soft relative to 5xxx and 6xxx alloys but retains excellent toughness. Fatigue performance is moderate and governed by surface condition and form-induced stresses; smooth surfaces and avoiding sharp notches are important to preserve fatigue life.

Thickness and sheet gauge significantly influence mechanical response—thin gages are more readily cold-rolled into higher H-temper strengths while thicker plates will exhibit lower work-hardening efficiency and larger grain sizes after processing.

Property	O/Annealed	Key Temper (e.g., H14)	Notes
Tensile Strength	Typically low (e.g., ~50–90 MPa)	Moderate (e.g., ~100–150 MPa)	Values vary with thickness and degree of cold work
Yield Strength	Very low (often ≤30–40 MPa)	Moderate (e.g., 60–110 MPa)	Yield increases substantially with H-tempers
Elongation	High (≥30–40% typical)	Moderate (10–25%)	Cold working reduces elongation progressively
Hardness	Low (soft)	Increased	Hardness rises with strain hardening; HB/HRB values depend on specific temper

Physical Properties

Property	Value	Notes
Density	~2.70–2.71 g/cm³	Typical for near-pure aluminum alloys
Melting Range	~660 °C (solidus/liquidus near pure Al)	Narrow melting range due to high Al content
Thermal Conductivity	~210–235 W/m·K	Very high; one of the advantages of 1xxx series
Electrical Conductivity	~55–63 % IACS (depending on temper)	High conductivity in O condition; reduced slightly by cold work
Specific Heat	~900 J/kg·K (0.9 J/g·K)	Typical value near room temperature
Thermal Expansion	~23–24 µm/m·K (23–24 ×10⁻⁶/K)	Matches typical aluminum thermal expansion behavior

The physical constants reflect the near-pure aluminum matrix and drive many application choices: thermal conductivity and electrical conductivity are among the best available in aluminum alloys. The relatively narrow melting point and high thermal conductivity also influence welding and thermal processing decisions.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.1–6.0 mm	Thin sheet can be strain hardened to H tempers	O, H12, H14, H16, H18	Widely available; used for forming and conductor strip
Plate	>6 mm	Limited cold-work hardening in thick plate; generally softer	O, H112	Used for non-structural thicker components and tankage
Extrusion	Various cross-sections	Strength depends on post-extrusion cold work	O, H12, H14	Good for profiles where conductivity and surface finish are important
Tube	OD from small to large	Behavior similar to sheet/plate; forming limit depends on wall thickness	O, H12, H14	Used for heat exchangers and architectural sections
Bar/Rod	Diameters up to several 10s mm	Can be supplied drawn to increase strength	O, H12, H14	Used where machinability and conductivity are important

Form factor and thickness determine achievable temper and performance. Sheets and extrusions allow efficient cold-work strengthening and tight tolerances, while plate and heavy sections are typically supplied in annealed or lightly worked tempers due to limitations of cold working thick material.

Equivalent Grades

Standard	Grade	Region	Notes
AA / ASTM	1350	USA	Commonly referenced US alloy designation corresponding to EN AW-1350
EN AW	1350	Europe	Standard European designation; chemically comparable to AA1350
JIS	A1050 / A1050P	Japan	Closely related commercial-purity Al grades used in Japan
GB/T	1350	China	Chinese standard marks broadly equivalent chemical composition

Equivalent grade tables show regional naming conventions rather than exact one-to-one performance matches; small differences in impurity limits, temper definitions, or mill testing can exist between standards. Engineers should review specific standard chemical and mechanical tables for cross-qualification in critical applications.

Corrosion Resistance

EN AW-1350 displays very good general atmospheric corrosion resistance thanks to a high aluminum fraction that forms a stable, protective Al2O3 film. In industrial and rural atmospheres its performance is excellent, and it resists oxidation and most mild chemical environments when not exposed to strong chlorides or aggressive acids.

In marine or chloride-containing environments the alloy performs reasonably well but is more susceptible to pitting and crevice corrosion than Al-Mg or Al-Mn alloys formulated for marine service; surface finish and coatings are often used to improve long-term behavior. Stress corrosion cracking is uncommon in this alloy class because of its low strength and absence of precipitation hardening, but residual stresses and aggressive environments can still initiate localized attack.

Galvanic interactions must be considered when mating EN AW-1350 to stainless steels or copper alloys; the high nobility of aluminum causes anodic behavior in some pairings and may require sacrificial protection or isolation. Compared with 5xxx or 6xxx series alloys, 1350 usually offers comparable or superior corrosion resistance due to fewer alloying elements that can form active intermetallic sites.

Fabrication Properties

Weldability

Welding EN AW-1350 is straightforward with fusion processes such as TIG and MIG given the alloy's high purity and low alloy content. Recommended fillers are aluminum fillers with similar chemistry (e.g., Al99.5 types) or Al-Si fillers (e.g., ER4043) when flowability and reduced cracking tendency are desired; filler choice should consider final conductivity and corrosion needs. Hot-cracking risk is low compared to higher-alloyed materials, but weld heat can locally alter mechanical properties due to recrystallization and loss of cold-work strength in the HAZ.

Machinability

Machining behavior is typical of soft, ductile aluminum alloys: excellent machinability with low cutting forces and good surface finish. Tooling of carbide grade or high-speed steel with positive rake geometry is preferred to avoid built-up edge; cutting speeds and feeds should be optimized to the temper and section to avoid smearing. Chip formation is usually continuous and care must be taken with chip evacuation; lubricants or air blast can improve surface quality and tool life.

Formability

Formability is one of the strongest attributes of EN AW-1350, especially in annealed O temper where deep drawing and complex bending are routine. Minimum bend radii are generous in O condition and become tighter with increasing H temper; typical practice uses larger radii for H16–H18 tempers to prevent cracking. Springback is modest but predictable; process engineers should calibrate tooling to the temper and thickness to achieve dimensional accuracy.

Heat Treatment Behavior

EN AW-1350 is non-heat-treatable and does not respond to solution-aging cycles to raise strength. Control of properties is accomplished by cold work levels and annealing: full anneal is used to restore ductility and conductivity after forming. Typical annealing (recrystallization) cycles are performed at temperatures in the range of roughly 300–415 °C (depending on section thickness) with controlled cooling; this dissolves dislocation structures and returns the microstructure to the soft O condition.

Because there is no precipitation hardening mechanism, attempts to artificially age the material do not produce the property jumps seen in 2xxx/6xxx/7xxx series alloys. Design and processing must therefore account for property limits achievable by mechanical work and thermal annealing cycles alone.

High-Temperature Performance

EN AW-1350 retains useful mechanical properties at moderately elevated temperatures but shows progressive strength loss above approximately 100–150 °C. Creep resistance is limited relative to alloyed aluminum grades designed for high-temperature service; long-term loads at elevated temperature will require conservative design margins. Oxidation of aluminum forms a thin protective alumina scale that provides good resistance to further high-temperature corrosion, but scale behavior and diffusion at very high temperatures can alter surface appearance and thermal contact resistance.

Welded joints exposed to high temperatures can show local softening in the HAZ and reduced electrical conductivity; designers should consider mechanical and electrical derating for components expected to see thermal excursions.

Applications

Industry	Example Component	Why EN AW-1350 Is Used
Electrical	Busbars, conductors, strip	High electrical conductivity and ease of forming
Marine / Chemical	Tank linings, piping, fittings	Corrosion resistance and purity for chemical compatibility
Architecture	Cladding, decorative panels	Surface finish, corrosion resistance, and formability
Heat Transfer	Heat sink fins, radiator fins	High thermal conductivity and good formability
Food / Packaging	Processing equipment, containers	Purity, corrosion resistance, and hygienic surfaces

EN AW-1350 is commonly selected for components where conductivity, surface quality and forming capacity are primary requirements rather than peak mechanical strength. Its ubiquity in electrical and heat-transfer hardware reflects the material’s optimized balance of thermal/electrical properties and manufacturability.

Selection Insights

Choose EN AW-1350 when electrical or thermal conductivity, high formability and corrosion resistance are more important than high structural strength. Its low alloy content makes it an economical choice for conductors, heat exchangers and formed architectural elements.

Compared with commercially pure aluminum such as 1100, EN AW-1350 typically offers similar or slightly higher purity with comparable formability and conductivity but may differ in mill tolerances and impurity limits; it trades off very little conductivity for modest strength gains from controlled cold work. Compared with work-hardened alloys like 3003 or 5052, 1350 sits lower in strength but often higher in conductivity and slightly better for certain chemical compatibility cases. Compared with heat-treatable alloys such as 6061 or 6063, EN AW-1350 is preferred when conductivity and formability trump peak strength and when simple processing (cold work/anneal) is desired over heat-treatment cycles.

Closing Summary

EN AW-1350 remains relevant because it delivers a rare combination of very high conductivity, excellent corrosion resistance and superb formability in a cost-effective, easily fabricated package. For designs prioritizing electrical or thermal performance and shaped by complex forming requirements, it remains a primary choice across multiple industries.