Aluminum is one of the most versatile metals in use today, second only to iron in global consumption. Its combination of lightweight strength, corrosion resistance, thermal and electrical conductivity, and recyclability makes it ideal for applications across aerospace, automotive, manufacturing, power distribution, and more. To enhance its properties, aluminum is often alloyed with elements such as copper, magnesium, manganese, silicon, tin, and zinc, resulting in a wide range of alloys tailored for specific applications.

Common Applications for Aluminum

• Automotive components such as body structures, engine parts, and wheels
• Aerospace structures, including fuselages and wings
• Architectural elements like window frames, facades, and roofing
• Building and infrastructure projects, including bridges and structural frameworks
• Consumer electronics such as laptops, smartphones, and tablets
• Industrial and household appliances
• Marine vessels and shipbuilding
• Railway cars and high-speed trains
• Machinery and equipment manufacturing

With so many alloys available, understanding aluminum alloy numbering systems is essential. These systems communicate critical information about an alloy’s composition, properties, and performance potential. However, naming conventions can vary across regions and suppliers, making it challenging to select the right material without proper guidance.

This article explores the most widely used aluminum alloy designation systems worldwide—ANSI/AA, UNS, EN, and ISO—and compares how the same alloys are identified across each system. We’ll also review the two main alloy classifications, wrought and cast, the families within these classifications, and the key factors to consider when choosing an aluminum alloy. Understanding these systems will help you evaluate options, compare materials, and select the best fit for your application.

Aluminum Alloy Designations: ANSI, UNS, EN, and ISO

Aluminum alloys are classified using several standardized designation systems, each developed to provide consistency in identifying alloy compositions and properties. Familiarity with these systems allows you to quickly determine an alloy’s key characteristics and compare materials across regions.

ANSI/AA – The Aluminum Association

The ANSI/AA system, developed by the Aluminum Association, is the most widely used in North America. Alloy names begin with “AA” followed by four numbers (AA ####), with the first digit indicating the alloy’s primary alloying element.

UNS – Unified Numbering System

The UNS system is used throughout North America for metals and alloys. Designations begin with the letter “A” followed by five numbers (A#####). Some UNS numbers correspond to existing AA designations, while others provide additional information about chemical composition.

EN – European Norm

Developed by the European Union, the EN system unifies alloy designations across member states. It uses the prefix “EN,” followed by “AC” for cast alloys or “AW” for wrought alloys, and a four-digit code (EN AC/AW ####). Its structure is similar to the AA system.

ISO – International Organization for Standardization

The ISO system differs from the others. Designations begin with “Al,” followed by the percentages of the main alloying elements, making it easy to identify the primary metals in each alloy.

Comparison Across Systems

Below is an example showing how the same aluminum alloy is designated in each system:

Wrought vs. Cast: How Aluminum Alloys Are Classified

Aluminum alloys are grouped into two main categories: wrought alloys and cast alloys. Wrought alloys are mechanically worked through rolling, extrusion, or forging to improve strength, ductility, and grain structure. Cast alloys, by contrast, are melted and poured into molds, making them ideal for producing complex shapes.

Both wrought and cast alloys can be further classified as heat-treatable or non-heat-treatable, depending on whether heat treatment can enhance their mechanical properties.

At thyssenkrupp Materials NA Canada, alloys are identified using the ANSI/AA (Aluminum Association) designation system, which organizes them into families based on their primary alloying element. This provides a consistent framework for classifying both wrought and cast products, helping manufacturers easily match alloys to their application needs.

Wrought Aluminum Alloys

Wrought alloys are mechanically worked through rolling, extrusion, or forging, giving them higher strength, toughness, and ductility. They are used in applications where structural performance and reliability are critical.

They are categorized using a four-digit numbering system that reflects the primary alloying element and series.

• First digit: Indicates the alloy series (1xxx–7xxx) based on the primary alloying element.
• Second digit: Typically, a modification indicator (0 = original composition, 1–9 = variation).
• Last two digits: Identify the specific alloy within the series. For the 1xxx series (pure aluminum), they denote minimum aluminum purity above 99.0%; for other series (2xxx–8xxx), they are sequential identifiers.

Examples:

• 1100 Aluminum: 1 = 1000 series (pure aluminum), 1 = modified version, 00 = specific alloy
• 6061 Aluminum: 6 = 6000 series (magnesium & silicon alloy), 0 = original composition, 61 = specific alloy

Overview of Wrought Alloy Series:

• 1xxx – Pure Aluminum: ≥99% purity; excellent corrosion resistance and conductivity; common in electrical and chemical industries.
• 2xxx – Copper Alloys: High strength-to-weight ratio; ideal for aerospace components.
• 3xxx – Manganese Alloys: Moderate strength and good workability; used in roofing, cookware, and architectural applications.
• 4xxx – Silicon Alloys: Lower melting point, improved fluidity; used in welding rods, brazing sheets, and engine components.
• 5xxx – Magnesium Alloys: High tensile strength and corrosion-resistant; common in marine structures.
• 6xxx – Magnesium & Silicon Alloys: Balanced strength, machinability, and corrosion resistance; used in architectural extrusions and automotive components.
• 7xxx – Zinc Alloys: Extremely high strength; used in aerospace, military vehicles, and mobile equipment.
• 8xxx – Miscellaneous Alloys: Often contain iron, tin, or lithium.
• 9xxx – Reserved for future use.

Cast Aluminum Alloys

Cast alloys are formed by pouring molten aluminum into molds, which makes them ideal for complex shapes and parts that don’t need extensive mechanical working. They have good corrosion resistance, excellent machinability, and are cost-effective for high-volume production, but are less ductile and strong than wrought alloys.

They are classified using a four-digit numbering system followed by a decimal point, where the digit after the decimal indicates the product form: 0 = casting, 1 or higher = ingot.

Overview of Cast Alloy Series:

• 1xx.x: Pure aluminum
• 2xx.x: Primarily copper-alloyed
• 3xx.x: Primarily silicon-alloyed; covers ~90% of castings due to high fluidity and wear resistance
• 4xx.x: Silicon-based alloys
• 5xx.x: Magnesium-alloyed
• 6xx.x: Unused
• 7xx.x: Zinc-alloyed; may include copper and magnesium
• 8xx.x: Tin-alloyed
• 9xx.x: Unused

Factors to Consider When Selecting an Aluminum Alloy

Selecting the right aluminum alloy is not a one-size-fits-all decision; it requires balancing performance requirements, cost considerations, and environmental factors. The first step is to understand your application’s specific demands. For example, marine environments call for highly corrosion-resistant alloys such as 5083, while aerospace applications rely on ultra-strong grades like 7075 to withstand extreme stresses.

Weight is another critical consideration. Aluminum’s natural lightness makes it a top choice for industries where reducing mass improves efficiency, such as automotive and aerospace manufacturing. Corrosion resistance is equally important for components exposed to moisture, saltwater, or industrial chemicals; alloys in the 1000 and 5000 series excel in these conditions.

Manufacturing requirements also influence alloy selection. The 6000 series, for example, offers exceptional machinability and weldability, making it ideal for structural components and complex parts. Cost should be factored in as well; non-heat-treatable alloys are often more economical for general-purpose applications.

Maximizing Performance with the Right Aluminum Partner

Choosing the right aluminum alloy is only half the equation—having a trusted supplier ensures you get the performance, quality, and support your application demands. At thyssenkrupp Materials NA Canada, we combine deep technical expertise with a robust inventory to match you with alloys that deliver both immediate and long-term value.

Our team works closely with customers to navigate material options, balancing performance requirements, environmental conditions, and budget considerations. We stock a wide range of alloys for diverse industries, including:

• Aerospace and Defense: Alloys such as 2024, 7050, 7075, and 6013 are renowned for high strength, fatigue resistance, and performance under extreme conditions.
• Marine and Corrosion-Resistant Applications: Grades like 5083 and 5086 are engineered to withstand saltwater exposure and harsh environments.
• Electrical and Automotive: Alloys 6101, 6063, and 6020 offer excellent conductivity, formability, and surface finish.
• Precision Machining and Manufacturing: Alloys such as 2011, 6262, CASTMIC6, and CAST5000 deliver outstanding machinability, dimensional stability, and surface quality.

We also provide precision cutting and processing services to deliver aluminum sheets, plates, and extrusions to exact specifications, along with an easy-to-use online ordering system for quick quoting and purchasing. Whether your priority is corrosion resistance, lightweight strength, or precision machining, thyssenkrupp Materials NA Canada has the materials, expertise, and services to help you succeed.

Contact our aluminum specialists today to discuss your project, request a quote, or explore alternative alloys that could deliver even greater results.