Achieving the right-sized product is crucial for all die-casting manufacturers. It often involves the proper shaping of metals or alloys into cross-sectional products. Extrusion is specifically suited for the task.
Sufficient malleability and superior stability make aluminum alloys a great option for extrusion. Hence, aluminum extrusion is widely implemented to obtain the required shape based on client requirements.
The article takes a short yet enlightening dive into the necessary details of aluminum extrusion alloys.
What is Extrusion Alloy?
Extrusion refers to a mechanical metal formation process to shape a metal alloy or the metal itself. This process involves forcing a billet of the alloy/metal through a die. The specified die must have an opening.
Alloys that can undergo the process are termed extrusion alloys. There are two methods to extrude Al alloys – cold heading and hot heading. Cold heading offers more durable products whereas hot heading is a faster process. It’s the most acclaimed cost-effective manufacturing process in aluminum die casting.
Extrusion imparts compression and shear without tension. The absence of tensile stress makes extruded alloy products exclusively resistant to tear/crack. The same goes for several aluminum die casting alloys.
Property Comparison for Different Alloy Series
Aluminum alloy series based on their principal constituent(s) hold great importance in extrusion. The suitable extrusion properties of different Al alloy series are tabulated as follows –
| Aluminum Alloy Designation | Major Alloy Element | Typical Characteristics Regarding Extrusion |
| 1xxx | Aluminum (at least 99%) | High corrosion resistance, good finishing, excellent workability |
| 2xxx | Copper (Cu) | High mechanical strength, superior machinability, completely heat-treatable |
| 3xxx | Manganese (Mn) | Moderate strength, good corrosion resistance, sufficient workability |
| 4xxx | Silicon (Si) | Not satisfying properties to match the required extrudability |
| 5xxx | Magnesium (Mg) | Moderate strength, high resistance to marine corrosion, excellent weldability |
| 6xxx | Silicon (Si) + Magnesium (Mg) | Sufficient strength, high machinability, good corrosion resistance, superb weldability, balanced formability |
| 7xxx | Zinc (Zn) | Superb strength, heat treatable, good machinability |
The 6xxx series has been the most popular aluminum extrusion alloy class. It’s because they offer a perfect balance of desired properties. Several alloys of other series exhibit satisfactory performance.
Best Aluminum Extrusion Alloys
Only a few extrusion alloys of aluminum have widespread adoption due to having favorable properties. The noteworthy preferences include –
- 1060 –High formability with superb weldability makes the alloy suitable for standard commercial uses. Its typical application lies in chemical equipment, pharmaceuticals, food handling, and liquid containers.
- 3003 –The non-heat treatable alloy develops strength from cold working, providing good machinability. Its superior resistance to chemical corrosion is highly favored in making condensers and heat exchangers.
- 6042 –Excellent consistency with high tolerance control makes the alloy a favorite for machine shops. Electrical connectors, AC components, valve blocks, brake parts, and hardware utilize its low lead level.
- 6061 –Great strength, matching toughness, and superb finishing suits brazing or welding requirements. It’s an extensively common alloy for construction supports, including marine and automobile products.
- 6063 –A finer grain structure effectively delivers the best possible surface finishing upon anodization. Apart from architectural applications, electrical conductors and cylinder tubing benefit from its use.
- 6262 –A special alloy specifically developed for superior machinability and resistance to wear and tear. Its acceptance of all coating types with great weldability is suitable for automotive and marine uses.
Alloys like 1100, 2014, 2024, 5083, 6101, and 7075 have good extrudability to a limited extent. That’s why these alloys have specific applications instead of widespread usability.
Extrudability of Wrought Aluminum Alloys
The term extrudability indicates the optimum relative speed of the extrusion process. It’s the upper limit at which the desired extrusion profiles can be obtained. The profile must not contain any crack or tear.
An alloy’s overall extrudability depends on –
- Product shape
- Billet temperature
- Micro-structure casting
- Extrusion ratio
- Alloy composition
- Micro-segregation level
In general, 1060, 3003, 5052, and 6xxx grade (except 6066) have good extrudability. 6066 and 5xxx grade exhibit moderate extrudability. 2xxx, 5xxx (>4% Mn), and 7xxx are the ones with poor extrudability.
Which Aluminum Extrusion Alloy to Use?
Aluminum alloys are almost second to none due to highly advantageous mechanical properties. However, extrudable Al alloys are the ones to contemplate the best of those features. Choosing the right extrusion alloy needs the following factors taken into account –
- Intended applications
- Finishing requirements
- Strength consideration
- Electrical conductivity
- Thermal specifications
There are multiple extrusion processes available to meet the demands. Each process concerns distinct parameters for optimum output. And the factors listed above play the key role in deciding the process.
Sunrise Metal has been an industry-leading pioneer for over 10 years. The Chinese aluminum die casting manufacturer has everything to deliver satisfaction. Contact us now to get suggestions from our experts.