Aluminum EN AW-1100: Composition, Properties, Temper Guide & Applications

Comprehensive Overview

EN AW-1100 belongs to the 1xxx series of wrought aluminum alloys, representing commercially pure aluminum with a minimum aluminum content of approximately 99.0%. Its principal distinguishing feature is very low intentional alloying content; trace elements such as silicon and iron are present at sub‑percent levels and control impurity-related properties.

Strengthening in EN AW-1100 is achieved almost entirely by work hardening (strain hardening) rather than by heat treatment, since it is a non-heat-treatable alloy. As a result, its mechanical strength is modest compared with 2xxx, 6xxx or 7xxx series alloys, but it offers excellent ductility, high electrical and thermal conductivity, superior corrosion resistance and outstanding formability.

Key traits include very high corrosion resistance in atmospheric and many chemical environments, excellent weldability and very good formability in the annealed condition; its strength can be raised through cold working to H‑tempers for specific applications. Typical industries using EN AW-1100 encompass chemical processing, food and beverage equipment, signage and nameplates, heat exchangers, and electrical conductors where conductivity and formability outrank peak strength.

Engineers often choose EN AW-1100 when maximum conductivity, surface finish, or corrosion resistance is required and when tight bend radii or deep drawing operations mandate a very ductile material. It is also favored where fabrication simplicity and recyclability are important, and where cost sensitivity favors low‑alloyed aluminium over more complex alloy systems.

Temper Variants

Temper	Strength Level	Elongation	Formability	Weldability	Notes
O	Low	High (30–50%)	Excellent	Excellent	Fully annealed condition for maximum ductility
H12	Moderate-low	Medium (20–35%)	Very Good	Excellent	Light strain hardening; retains good formability
H14	Moderate	Reduced (10–30%)	Good	Excellent	Common cold-worked temper for increased strength
H16	Moderate	Lower (5–20%)	Fair to Good	Excellent	Higher work hardening for stronger parts
H18	Higher	Low (3–10%)	Limited	Excellent	Severe cold work, for highest strength without heat treatment
H112	Moderate	Variable	Good	Excellent	Non-heat-treated, strain-hardened by process control

Temper selection in EN AW-1100 is primarily a balance between ductility and strength obtained by controlled cold working stages. Annealed O temper maximizes formability and surface finish, while H‑tempers progressively raise tensile and yield strength at the expense of elongation, with no change in metallurgical heat-treatment capability.

Chemical Composition

Element	% Range	Notes
Si	≤ 0.95	Impurity; controlled to limit effects on corrosion and castability
Fe	≤ 0.95	Common impurity that slightly reduces ductility and conductivity
Mn	≤ 0.05	Minimal, little strengthening effect in 1100
Mg	≤ 0.05	Negligible; low levels prevent precipitation hardening
Cu	≤ 0.05	Kept very low to preserve corrosion resistance
Zn	≤ 0.10	Small amounts tolerated; larger amounts reduce corrosion resistance
Cr	≤ 0.05	Trace control limits grain structure changes
Ti	≤ 0.03	Possible grain refiner; present in trace amounts
Others	≤ 0.15 combined	Combined residuals include V, Ni, etc.; aluminum makes up the balance (~99.0%)

The near‑purity of EN AW-1100 means physical and electrochemical properties are dominated by the aluminum matrix rather than alloy precipitates. Trace elements and residuals primarily influence electrical/thermal conductivity, grain structure and minor variations in mechanical behavior; therefore composition control focuses on keeping impurity levels low to preserve the alloy’s signature properties.

Mechanical Properties

Tensile behavior in EN AW-1100 is characterized by low ultimate and yield strengths in the annealed condition combined with long uniform elongation. Yields are low and work hardening is the primary route to raising strength; cold rolling and drawing can significantly increase tensile properties but reduce ductility. Hardness correlates directly with temper, with HB values remaining low in annealed material and increasing with H‑tempers; fatigue endurance is modest and strongly affected by surface finish and cold work.

Thickness affects mechanical response: thin gauges can be cold-rolled to higher H‑tempers with little loss of ductility relative to thicker sections where surface and interior strain distributions differ. Fatigue performance is sensitive to surface defects and galvanic corrosion exposure; polished or anodized surfaces improve fatigue life. Fracture behavior remains ductile with significant plastic deformation before failure in ductile tempers, while heavily cold-worked conditions show reduced toughness.

Property	O/Annealed	Key Temper (e.g., H14)	Notes
Tensile Strength	~65–95 MPa	~95–140 MPa	Broad ranges depend on thickness and exact cold work level
Yield Strength	~25–45 MPa	~60–110 MPa	Yield rises with strain hardening; measurement sensitive to specimen orientation
Elongation	~30–50%	~10–30%	Elongation drops as temper increases; thinner gauges often retain higher elongation
Hardness	~20–30 HB	~35–60 HB	Hardness increases with cold work; typical Rockwell or Vickers conversions possible

Physical Properties

Property	Value	Notes
Density	2.71 g/cm³	Typical density for near‑pure aluminum alloys
Melting Range	~ 640–660 °C	Solidus-liquidus range near pure Al melting point
Thermal Conductivity	~ 215–240 W/m·K (at 25 °C)	Very high; excellent for heat transfer applications
Electrical Conductivity	~ 58–62 % IACS	High electrical conductivity, suitable for conductors and busbars
Specific Heat	~ 900 J/kg·K	Similar to pure aluminum; useful for thermal mass calculations
Thermal Expansion	~ 23.6 ×10⁻⁶ /K (20–100 °C)	Typical aluminum expansion coefficient for design allowances

The physical property set for EN AW-1100 emphasizes heat and charge transfer rather than high mechanical strength. Thermal conductivity and specific heat make it ideal for heat exchanger plates, cladding and radiators, while electrical conductivity supports busbars and low-voltage conductors. Designers must account for relatively high thermal expansion compared with steels when integrating 1100 parts into mixed‑material assemblies.

Product Forms

Form	Typical Thickness/Size	Strength Behavior	Common Tempers	Notes
Sheet	0.1–6.0 mm	Ductile; easily cold-worked	O, H12, H14	Widely used for deep drawing, cladding, and decorative finishes
Plate	>6.0 mm	Lower cold work potential; thicker sections harder to form	O, H112	Used for chemical tanks and structural panels where conductivity is needed
Extrusion	Profiles up to large cross-sections	Can be strained during extrusion for H‑tempers	O, H112	Limited alloying allows continuous extrusions with smooth surfaces
Tube	Varied diameters and wall thicknesses	Formed by drawing/rolling; can be work-hardened	O, H14	Common for heat exchanger tubing and architectural tubing
Bar/Rod	Diameters up to 200 mm	Typically lower permeability to work hardening	O, H16	Machinable in O temper; strengthening via cold drawing possible

Sheets and thin gauges provide the best formability and are commonly deep drawn or roll-formed; plates and thicker extrusions are processed more by mechanical cutting and welding. Extrusion processing benefits from the alloy’s simple composition for consistent flow and surface finish, while tubes and rods are often produced by seamless or welded methods followed by sizing and annealing to control properties.

Equivalent Grades

Standard	Grade	Region	Notes
AA	1100	USA	Commonly referenced American designation for commercially pure Al
EN AW	1100	Europe	Equivalent European alloy; EN AW prefix denotes wrought aluminum
JIS	A1050	Japan	Close equivalent with similar impurity limits and properties
GB/T	1100	China	Chinese standard designating similar composition and property ranges

Subtle differences between standards are primarily in maximum residual impurity limits and permitted trace elements, which can slightly affect conductivity and corrosion resistance. Processing history and temper specifications in each region can also change mechanical ranges; engineers should confirm temper and guaranteed properties from the mill certificate rather than relying solely on nominal grade equivalence.

Corrosion Resistance

EN AW-1100 exhibits excellent atmospheric corrosion resistance due to its high aluminum content and minimal active alloying additions. It naturally forms a protective oxide film that resists general oxidation and provides good long-term outdoor performance in industrial and urban environments.

In marine environments EN AW-1100 performs well against general corrosion in unstressed conditions, but attention must be paid to pitting in chloride-containing environments and to crevice corrosion where stagnant seawater can accumulate. Anodizing and appropriate surface treatments significantly improve both appearance and localized corrosion resistance for marine use.

Stress corrosion cracking (SCC) susceptibility is low in EN AW-1100 because SCC is typically associated with higher‑strength alloys; however, heavily cold-worked conditions can slightly increase sensitivity under tensile stress in corrosive media. Galvanic interaction with more noble metals (e.g., copper, stainless steel) can accelerate local corrosion; electrical isolation or compatible fasteners are recommended when dissimilar metals are in contact.

Fabrication Properties

Weldability

EN AW-1100 is among the most weldable aluminum alloys and responds well to TIG, MIG and spot welding processes. Filler alloys such as ER4043 (Al‑Si) or ER5356 (Al‑Mg) are commonly used depending on desired ductility and corrosion behavior; thin gauges weld with minimal distortion. Hot‑cracking risk is low compared with higher‑strength aluminum alloys, and the heat‑affected zone experiences little loss of mechanical property because the alloy is non‑heat‑treatable.

Machinability

Machining in the annealed condition is straightforward due to high ductility and low work hardening tendency; machinability index is moderate and better than many pure Al grades. Carbide tooling with positive rake angles and higher feed rates are recommended to avoid built-up edge; chip control can be an issue as the material creates long, stringy chips if not segmented. Surface finish machines to a high lustre, but attention to fixture design is necessary due to low stiffness relative to steels.

Formability

Formability is excellent in the O condition, allowing very tight bend radii and deep drawing operations without cracking. Recommended minimum bend radii are small—often down to one times thickness or less depending on tooling and temper—while H‑tempers require larger radii and incremental forming or anneal steps. Springback is moderate and predictable; designers should plan for it in tooling or perform stress-relief anneals after heavy forming.

Heat Treatment Behavior

EN AW-1100 is a non-heat-treatable alloy; it does not respond to solution heat treatment and precipitation hardening the way 6xxx or 7xxx series alloys do. Mechanical property increases are accomplished by cold working (strain hardening) and reversed by annealing processes.

Annealing is performed at temperatures typically between 300–400 °C depending on section thickness and desired softness, with slow cooling to restore full ductility; this resets the material to the O temper. Because hardening is mechanical, multiple cycles of work and intermediate anneals are common in fabrication sequences to achieve complex shapes without cracking.

High-Temperature Performance

At elevated temperatures EN AW-1100 experiences relatively rapid loss of strength compared with heat-treatable alloys; usable service temperatures are typically limited to well below 200 °C for structural applications. Oxidation resistance is reasonably good because of protective alumina formation, but creep resistance is poor relative to specialty high‑temperature alloys.

Welding thermal cycles produce an HAZ but do not cause precipitation-driven softening; however, prolonged exposure to elevated temperatures can anneal cold-worked strength and reduce hardness. For continuous high-temperature service, engineers should consider alloys designed for creep resistance rather than 1100.

Applications

Industry	Example Component	Why EN AW-1100 Is Used
Automotive	Decorative trim and nameplates	Excellent formability and surface finish
Marine	Heat exchangers and non-structural fittings	Corrosion resistance and thermal conductivity
Aerospace	Interior brackets and fairings	Low weight and good formability for non-structural parts
Electronics	Heat sinks and busbars	High thermal and electrical conductivity

EN AW-1100 is often selected where superior conductivity and formability are the overriding priorities, and where structural loads are low. Its clean surface and compatibility with finishing processes such as anodizing also make it a go-to alloy for visible components and chemically sensitive environments.

Selection Insights

When choosing EN AW-1100, prioritize electrical and thermal conductivity, excellent formability and the highest corrosion resistance available in common wrought alloys. Select O temper for maximum ductility and deep drawing, and H‑tempers when modest strength gains are required via cold work; always check mill certificates for conductivity and mechanical properties.

Compared with common work‑hardened alloys such as 3003 or 5052, EN AW-1100 offers slightly higher electrical and thermal conductivity and generally better surface finish, but it provides lower intrinsic strength than 5052 which contains magnesium for higher strength. Compared with heat‑treatable alloys like 6061 or 6063, EN AW-1100 is preferred where conductivity, corrosion resistance and formability are more important than peak strength; choose 6061 when structural strength and hardness are essential despite reduced conductivity.

Consider cost and availability: EN AW-1100 is widely available and generally lower cost than specialized alloys, but if a design requires higher strength, fatigue life or elevated temperature resistance, selecting a differently alloyed material may be more cost effective in the long run.

Closing Summary

EN AW-1100 remains a foundational alloy for modern engineering where purity-driven properties—excellent conductivity, superior formability and robust corrosion resistance—are required more than high strength. Its simplicity makes it economical, highly recyclable and easy to fabricate across a wide range of product forms, ensuring continued relevance in chemical, electrical and consumer applications.