Aluminum is a popular material for extrusion and shaping profiles due to its excellent mechanical properties and versatility. Its high ductility allows it to be easily shaped, while its lower melting point compared to steel makes the processing more energy-efficient. Additionally, aluminum has a high strength-to-weight ratio, making it suitable for industrial applications where both strength and lightweight characteristics are required.
When it comes to aluminum profiles, designations like 6061-T4, 6063-T5, or 6063-T6 refer to both the grade of aluminum and the tempering process it has undergone. The temper (T4, T5, T6) indicates the heat treatment process, which significantly affects the material’s mechanical properties and suitability for specific applications. Here we will explain the differences between T4, T5, and T6 aluminum and help you decide which one is best suited for your project.
What is T4 Aluminum?
T4 aluminum has undergone solution heat treatment followed by natural aging. In this state, the material is cooled after extrusion but does not undergo artificial aging in a furnace. As a result, T4 aluminum has relatively lower hardness but better deformability, making it suitable for applications that require subsequent bending or forming.
Properties of T4 Aluminum:
- Yield Strength: Approximately 110 MPa
- Tensile Strength: Approximately 240 MPa
- Hardness: Lower hardness, around HB 60-70
- Deformability: High, suitable for bending, forming, and other deformation processes
- Corrosion Resistance: Good
Applications of T4 Aluminum:
Ideal for products that need further shaping or deformation, such as automotive body panels or aerospace parts that require flexibility.
What is T5 Aluminum?
T5 aluminum undergoes solution treatment followed by incomplete artificial aging. After extrusion, the aluminum is air-cooled and then transferred to an aging furnace for a few hours at around 200°C. This process increases the material’s hardness while maintaining some degree of deformability. T5 aluminum is commonly used in applications where moderate strength is required, such as architectural profiles.
Properties of T5 Aluminum:
- Yield Strength: Approximately 160 MPa
- Tensile Strength: Approximately 270 MPa
- Hardness: Moderate hardness, around HB 75-85
- Deformability: Lower than T4, but still allows for some flexibility
- Corrosion Resistance: Moderate to good
Applications of T5 Aluminum:
Suitable for architectural profiles (e.g., windows, doors, curtain walls) and other components requiring a balance of strength and deformability.
What is T6 Aluminum?
T6 aluminum goes through solution treatment followed by complete artificial aging. The aluminum is water-quenched and then aged at a higher temperature for a longer duration. This results in a material with maximum hardness and strength, making it ideal for applications that require high durability and rigidity.
Properties of T6 Aluminum:
- Yield Strength: Approximately 240 MPa
- Tensile Strength: Approximately 310 MPa
- Hardness: High hardness, around HB 90-100
- Deformability: Low, very rigid
- Corrosion Resistance: Good, but slightly lower than T4 due to higher hardness
Applications of T6 Aluminum:
Used in high-strength applications such as aerospace components, automotive parts, and structural applications that demand high tensile strength and rigidity.
T4 vs T5 vs T6 Aluminum: What are the Differences?
The main differences between T4, T5, and T6 aluminum tempers lie in their heat treatment processes, which affect their strength, hardness, and deformability.
| Property | T4 | T5 | T6 |
|---|---|---|---|
| Heat Treatment | Solution treatment + natural aging | Solution treatment + incomplete aging | Solution treatment + full aging |
| Cooling Method | Air-cooled, no artificial aging | Air-cooled, then artificially aged | Water-cooled, then fully artificially aged |
| Yield Strength | ~ 110 MPa | ~ 160 MPa | ~ 240 MPa |
| Tensile Strength | ~ 240 MPa | ~ 270 MPa | ~ 310 MPa |
| Hardness | HB 60-70 | HB 75-85 | HB 90-100 |
| Deformability | High (suitable for bending) | Moderate (some flexibility) | Low (rigid, high hardness) |
| Corrosion Resistance | Good | Moderate to good | Good |
| Applications | Bending, forming, deformable parts | Curtain walls, standard profiles | Aerospace, automotive, structural components |
- T4: Softer and more deformable, suitable for parts that need to be bent or shaped further after extrusion.
- T5: Balanced between strength and flexibility, ideal for architectural applications such as doors, windows, and curtain walls.
- T6: Strongest and most rigid, ideal for high-stress applications like aerospace and automotive parts.
T4 vs T5 vs T6 Aluminum: Which is Better?
The best temper depends on your specific application:
- T4 Aluminum is better for applications requiring bending or additional deformation after extrusion. Its lower hardness allows for more flexibility in shaping.
- T5 Aluminum offers a balance between strength and flexibility, making it ideal for architectural applications where moderate strength and aesthetic finish are important.
- T6 Aluminum provides maximum hardness and strength, making it the best choice for heavy-duty applications like aerospace and automotive components, where high tensile strength and minimal deformability are essential.
The choice between T4, T5, and T6 aluminum tempers depends on the desired mechanical properties for your project. If you prioritize flexibility, go with T4. If you need moderate strength, T5 is a good middle ground. For maximum strength and hardness, T6 is the best choice.
By understanding the differences between these aluminum tempers, you can make an informed decision that ensures your project achieves the right balance of strength, flexibility, and cost.
Mechanical Properties of T1/T4/T5/T6 Aluminum Alloys
To provide a more detailed comparison of the mechanical properties of different aluminum alloys and tempers, the table below outlines the yield strength, tensile strength, elongation, and hardness for various aluminum profiles in the T4, T5, and T6 tempers.
This table highlights the mechanical differences between aluminum profiles in different temper states. For example, 6061-T6 has higher tensile strength and hardness compared to 6063-T6, making it more suitable for applications requiring higher strength, such as in aerospace or automotive components.
Understanding these properties helps in selecting the right aluminum alloy and temper for your specific needs, ensuring the material’s performance aligns with the demands of your project.