Understanding Aluminum Temper Designations: A Guide for Manufacturers

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Understanding Aluminum Temper Designations: A Guide for Manufacturers

Aluminum is one of the most widely used materials in manufacturing due to its many desirable properties, such as strength, lightness, and corrosion resistance. However, aluminum comes in many different forms depending on how it has been processed and treated. One key aspect of aluminum’s properties is its temper designation, which provides valuable information about the material’s strength, hardness, and formability. In this article, we will explore the different aluminum temper designations and their significance for manufacturers.

What is an Aluminum Temper Designation?

Aluminum temper designations are alphanumeric codes that indicate the composition and treatment of the metal. These designations are part of the Aluminum Association (AA) system, which is commonly used in the aluminum industry to classify different types of aluminum alloys. The temper designation typically consists of a letter followed by one or more numbers, with each component providing specific information about the material’s properties.

Understanding Aluminum Temper Designations

There are many different temper designations used in the aluminum industry, but some of the most common ones include:

– F: As fabricated
– O: Annealed
– H: Strain hardened
– T: Heat treated

Each of these temper designations represents a different stage in the manufacturing process and has a specific impact on the properties of the aluminum alloy. Let’s take a closer look at these designations and what they mean for manufacturers.

As Fabricated (F)

The as-fabricated temper designation indicates that the aluminum has been shaped or formed but has not undergone any further treatment. This means that the material is in its natural state after being processed, with no additional heat treatment or cold working. As-fabricated aluminum is generally soft and malleable, making it suitable for forming and shaping processes. However, it may lack the strength and hardness required for certain applications, which is why further treatment may be necessary.

Annealed (O)

The annealed temper designation (O) indicates that the aluminum has been heated to a specific temperature and then allowed to cool slowly to relieve internal stresses and improve ductility. Annealing helps to soften the material and increase its formability, making it easier to bend, stretch, and shape. Annealed aluminum is often used in applications where high ductility is required, such as deep drawing or spinning processes.

Strain Hardened (H)

The strain-hardened temper designation (H) indicates that the aluminum has been cold worked to increase its strength and hardness. This process involves stretching or compressing the material to introduce dislocations in the crystal structure, which effectively strengthens the metal. Strain-hardened aluminum is commonly used in applications where high strength is crucial, such as automotive components or structural parts. The level of strain hardening is denoted by a number following the H designation, with higher numbers indicating greater strength.

Heat Treated (T)

The heat-treated temper designation (T) indicates that the aluminum has been subjected to a specific heat treatment process to achieve desired properties. Heat treatment can involve processes such as solution heat treatment, quenching, and aging, which can improve strength, hardness, and corrosion resistance. Heat-treated aluminum alloys are commonly used in aerospace, military, and automotive applications where high performance is required. The specific letter and number following the T designation indicate the type of heat treatment and its effects on the material.

Other Temper Designations

In addition to the four main temper designations mentioned above, there are several other variations that manufacturers should be aware of, including:

– W: Solution heat treated
– H1 through H19: Strain hardened to various levels
– T1 through T10: Heat treated to various levels
– H32, H34, H36, H38: Strain hardened and partially annealed
– H112, H116: Strain hardened and stabilized

Each of these temper designations provides valuable information about the material’s properties and processing history, helping manufacturers select the right aluminum alloy for their specific applications.

Considerations for Manufacturers

When selecting an aluminum alloy for a particular application, manufacturers should consider several factors related to temper designations, including:

– Strength requirements: Determine the level of strength and hardness needed for the application and select an alloy with an appropriate temper designation.
– Formability: Consider the formability and ductility of the material, especially for shaping and forming processes.
– Corrosion resistance: Evaluate the material’s resistance to corrosion and ensure that it meets the requirements of the application.
– Cost considerations: Balance the cost of the material with its performance characteristics to achieve the most cost-effective solution.

By understanding the significance of aluminum temper designations and how they impact the properties of the material, manufacturers can make informed decisions when selecting aluminum alloys for their products.


Aluminum temper designations play a crucial role in determining the properties and performance of aluminum alloys. By understanding the meaning of these designations and their significance for manufacturing processes, manufacturers can select the right aluminum alloy for their specific applications. Whether strength, formability, or corrosion resistance is the primary concern, the temper designation provides valuable information to guide material selection and processing. With this knowledge in hand, manufacturers can optimize the performance and cost-effectiveness of their products using the right aluminum temper designations.

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