Aluminum EN AW-1070A: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

EN AW-1070A is a member of the 1xxx series of aluminium alloys, specifically in the commercially pure family where aluminium content is typically 99.7% by mass. Alloys in the 1xxx series are characterized by minimal intentional alloying; the principal alloying elements in EN AW-1070A are trace amounts of iron, silicon and small additions of copper, manganese, zinc and titanium that occur as impurities or controlled microalloying.

Strengthening of EN AW-1070A is achieved almost exclusively through work-hardening (strain hardening) and grain refinement; it is not heat-treatable to increase strength via precipitation hardening. Key traits are excellent electrical and thermal conductivity, very good corrosion resistance in ambient environments, superior formability in the annealed condition, and generally excellent weldability.

Industries that commonly use EN AW-1070A include chemical processing, architectural cladding, electrical and thermal management (busbars, heat sinks), packaging and certain decorative applications where high formability and surface finish are valued. The alloy is chosen over higher-strength series when conductivity, surface quality, ease of forming, or maximum corrosion resistance in mild environments are priorities rather than peak mechanical strength.

Designers select EN AW-1070A when low residual alloying content benefits electrical or thermal performance, or when deep drawing and complex forming operations are primary production steps; the alloy trades off higher strength for better ductility, lower cost and broader availability in thin-gauge products.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High (30–45%)	Excellent	Excellent	Fully annealed, maximum ductility for deep drawing
H12	Moderate	Moderate (20–30%)	Very good	Very good	Light strain hardening, limited strengthening
H14	Moderate-High	Moderate (15–25%)	Good	Very good	Common cold-worked temper used for lightweight formed parts
H16	High	Lower (10–20%)	Fair	Good	Higher strain-hardening, greater strength at cost of formability
H18	Very High	Low (5–12%)	Limited	Good	Near-maximum work-hardened strength; used where no further forming is required
H24	Moderate	Moderate (15–30%)	Very good	Very good	Strain hardened and partially annealed for balance of formability and strength

Temper has a primary influence on the balance between strength and ductility for EN AW-1070A because the alloy cannot be precipitation hardened. Work hardening increases yield and tensile strengths but reduces elongation and formability. Choosing O for deep drawing or H14/H16 for parts requiring dimensional stability after forming is the typical engineering strategy.

Chemical Composition

Element	% Range	Notes
Si	≤ 0.05	Silicon kept very low to maximize conductivity and prevent hard intermetallics
Fe	≤ 0.30	Iron is the principal impurity; limits control grain structure and surface appearance
Mn	≤ 0.03	Minimal manganese; has negligible strengthening effect at these levels
Mg	≤ 0.03	Magnesium negligible in effect; kept low to preserve corrosion resistance
Cu	≤ 0.05	Copper present only in trace amounts; higher Cu would reduce corrosion resistance
Zn	≤ 0.05	Zinc low to avoid embrittlement and preserve electrical performance
Cr	≤ 0.01	Chromium typically very low or not intentionally added
Ti	≤ 0.03	Titanium may be present as a grain refiner in small quantities
Others	≤ 0.05 each / balance Al	Remainder is aluminium; strict impurity control preserves conductivity and ductility

The chemistry of EN AW-1070A is designed to prioritize aluminium as the dominant constituent, which directly governs its high electrical and thermal conductivity and excellent ductility. Trace elements such as iron and silicon are controlled to minimize coarse intermetallic particles that would reduce formability, surface quality and conductivity; intentional microalloying (Ti) can be used for grain refinement without compromising the alloy’s primary properties.

Mechanical Properties

Tensile behavior in EN AW-1070A is governed by the cold work state and thickness: annealed sheet shows low yield and moderate ultimate tensile strength with high elongation, while strain-hardened tempers reach higher yield and tensile strengths but with reduced ductility. The alloy exhibits a relatively smooth stress-strain curve with limited strain aging phenomena; plastic deformation is uniform until necking due to good ductility in softer tempers.

Hardness in EN AW-1070A is low compared with alloyed series and correlates closely with temper; Brinell and Vickers values increase with work hardening. Fatigue strength is modest and scales with mean stress and temper; surface finish, machining damage, and cold work history strongly influence fatigue performance. Thickness effects are pronounced for formability and strength measurements: thinner gauges permit higher apparent elongation and more uniform properties after cold work.

Property	O/Annealed	Key Temper (H14)	Notes
Tensile Strength	90–125 MPa	120–155 MPa	Values depend on gauge and test direction; H14 increases strength via strain hardening
Yield Strength	35–60 MPa	80–120 MPa	Yield rises significantly with work-hardening; O has low proof stress enabling forming
Elongation	30–45%	15–25%	Ductility drops with increased cold work; O is preferred for deep drawing
Hardness (HB)	20–35 HB	35–55 HB	Hardness correlates with temper and cold work history

Physical Properties

Property	Value	Notes
Density	2.71 g/cm³	Typical for commercially pure aluminium alloys; important for mass-sensitive designs
Melting Range	655–660 °C	Narrow melting range typical of nearly pure aluminium
Thermal Conductivity	220–237 W/m·K	Very high thermal conductivity; ideal for heat-transfer components
Electrical Conductivity	~60–63 %IACS	Excellent electrical conductivity, slightly below oxygen-free copper but superior among structural alloys
Specific Heat	~900 J/kg·K	High specific heat supports thermal buffering in heat sinks and thermal management
Thermal Expansion	23.6 ×10⁻⁶ /K (20–100°C)	Relatively high thermal expansion; must be considered in assemblies with dissimilar materials

The physical property set of EN AW-1070A makes it an excellent choice for thermal management and electrical conductor applications, where conductivity and low density are valuable. Thermal expansion and relatively low stiffness compared with steel must be accounted for in multi-material assemblies and high-temperature applications to avoid dimensional distortion.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.2–6.0 mm	Consistent with temper; thin gauges often supplied O or H14	O, H12, H14, H16	Widely used for forming and cladding
Plate	6–25 mm	Reduced formability; often supplied O or light H tempers	O, H18	Less common; used where thickness needed but formability limited
Extrusion	Cross-sections from small to large	Limited alloying restricts high-strength extrusions	O, H14	Used for profiles where conductivity and surface finish matter
Tube	Thin- to medium-wall	Strength varies with cold work (drawn tubes often Hxx)	O, H16, H18	Common for decorative and heat-exchanger tubes
Bar/Rod	Diameters up to 100 mm	Typically supplied O or slightly worked	O, H12	Used for machined components requiring high conductivity

Sheet and thin-gauge products dominate commercial use because the alloy’s excellent formability and surface finish are most useful in those geometries. Extrusions and drawn tubes are feasible but limited by the alloy’s lack of precipitation hardening; designers often rely on cold work and geometry to meet strength requirements. Processing differences (rolling vs extrusion vs drawing) affect residual stress, surface condition and final temper selection.

Equivalent Grades

Standard	Grade	Region	Notes
AA	1070 / 1070A	USA	Aluminium Association designation for commercially pure Al with similar limits
EN AW	EN AW-1070A	Europe	European normative designation; commonly used in European supply chains
JIS	A1070	Japan	Japanese equivalent for high-purity Al, similar chemical and mechanical characteristics
GB/T	1070	China	Chinese standard grade equivalent; may have slight differences in impurity limits or tempers

Subtle differences between standards often reside in allowable impurity maximums, surface finish requirements, and published temper and mechanical property data for specific product forms. When specifying EN AW-1070A across regions, engineers should reference the applicable standard’s temper tables and mechanical requirements to avoid inadvertent discrepancies in properties or supply obligations.

Corrosion Resistance

EN AW-1070A exhibits excellent general corrosion resistance in atmospheric and mildly corrosive industrial environments due to the rapid formation of a protective aluminium oxide layer. The passive film offers long-term protection, and in many environments the alloy performs comparably to higher-alloyed aluminium grades for general exposure conditions.

In marine and chloride-rich environments, EN AW-1070A is vulnerable to localized pitting and crevice corrosion if protective coatings or design details are inadequate; compared with 5xxx and 6xxx series alloys, it has lower resistance to chloride-induced pitting in active seawater. Stress corrosion cracking is uncommon in high-purity 1xxx alloys because they lack the high-strength microstructures that promote SCC, but residual stresses combined with corrosive environments can still cause localized failures.

Galvanic interactions position EN AW-1070A anodic to many common engineering metals including stainless steels and copper alloys; when coupled directly in seawater or damp environments, the aluminium will corrode preferentially unless electrically isolated or protected. Compared with 3xxx or 5xxx series, the 1xxx group generally offers superior overall corrosion resistance in neutral pH atmospheres but sacrifices localized chloride resistance versus certain marine-grade alloys.

Fabrication Properties

Weldability

Welding behaviour for EN AW-1070A is excellent with common fusion processes such as TIG and MIG; good weld puddle fluidity and low susceptibility to hot cracking are typical because of the low alloy content. Recommended fillers are often from the 1100 series or other low-alloy fillers to preserve corrosion resistance and conductivity; use compatible filler wire and control heat input to minimize distortion. Weld HAZ will locally soften any work-hardened temper because the alloy cannot be precipitation hardened; designers must account for loss of strain-hardening near welded seams.

Machinability

Machinability of EN AW-1070A is fair to moderate and generally lower than engineered free-machining alloys because the high ductility promotes long, continuous chips that can clog tooling. Sharp carbide tools, positive rake geometry, and ample coolant/air blow-off are recommended to control chip formation and surface finish. Preferred cutting speeds are moderately high with light feeds to avoid built-up edge; surface finish can be excellent when tooling and lubrication are optimized.

Formability

Formability is one of the strongest attributes of EN AW-1070A in the annealed O condition; the alloy supports deep drawing, complex stamping and stretch forming with low springback. Recommended minimum bend radii depend on temper and thickness but are typically small in O temper (e.g., internal radius ≥ 0.5–1.0× thickness for mild reductions), while H tempers will require larger radii and may need preheating or multiple incremental bends. Designers commonly use O temper for multi-stage forming operations and switch to H tempers when post-forming strength or dimensional stability is required.

Heat Treatment Behavior

EN AW-1070A is not heat-treatable by solution and precipitation hardening routes; attempts to age this alloy will not produce the strength increases seen in 2xxx, 6xxx or 7xxx series alloys. The principal thermal processing route is annealing: an anneal (softening) is achieved by heating into the recrystallization range (typically 320–420 °C depending on section thickness) followed by controlled cooling to produce the O temper and restore maximum ductility.

Because strengthening is achieved by cold work, repeated thermal exposure or welding will reduce as-processed strength by allowing recovery and recrystallization. Controlled stress-relief anneals (lower temperature) can reduce residual stresses without fully restoring the O temper, which is useful when retaining some work-hardened strength is desirable.

High-Temperature Performance

Mechanical strength in EN AW-1070A falls off rapidly with increasing temperature relative to its ambient properties; usable structural strength for sustained loads is generally limited to temperatures below approximately 100–150 °C. Oxidation resistance at elevated temperature is good due to alumina formation, but scale formation and softening limit use in continuous high-temperature applications.

Thermal excursions during welding and fabrication create local HAZ softening in work-hardened tempers and may alter dimensional stability; for cyclic high-temperature exposure designers should validate creep, relaxation and fatigue behavior for the specific temper and geometry.

Applications

Industry	Example Component	Why EN AW-1070A Is Used
Automotive	Decorative trim, heat shields	Excellent formability and surface finish; adequate corrosion for non-structural trim
Marine	Architectural fittings, non-structural panels	Good atmospheric corrosion resistance and low density
Aerospace	Non-structural fittings, fairings	High conductivity, good formability, and low weight for secondary structures
Electronics	Heat sinks, busbars	Very high thermal and electrical conductivity combined with low density

EN AW-1070A is most often specified where conductivity, formability and surface appearance take precedence over high strength. Its role is strongest in non-structural or secondary load-bearing components and in applications that exploit the alloy’s thermal and electrical properties.

Selection Insights

EN AW-1070A is an optimal choice when high electrical or thermal conductivity, maximum ductility and excellent surface quality are the design drivers. Select 1070A for deep-drawn parts, heat-spreading components and where lightweight, corrosion-resistant cladding is required.

Compared with commercially pure aluminium such as AA1100, EN AW-1070A delivers very similar conductivity and formability while being standardized under EN designations; in practice, the two trade very little, with 1070A sometimes having tighter impurity limits. Compared with work-hardened alloys like 3003 or 5052, 1070A offers higher conductivity and marginally better formability in annealed conditions but sacrifices strength and strain hardening potential. Compared with heat-treatable alloys such as 6061 or 6063, 1070A will be chosen when conductivity and formability outweigh the need for high peak strength; it is preferred for thermal management and forming operations even though it cannot reach the same tensile/yield levels.

Closing Summary

EN AW-1070A remains relevant because it uniquely balances extremely high conductivity, superior formability and excellent corrosion resistance in a low-cost, widely available aluminium product. For engineers designing thermal, electrical or highly formed components, 1070A provides predictable, easily processed performance where high strength is not the primary requirement.