Selecting the Most Appropriate Aluminium Alloy for Your Extrusion Process

Aluminium extrusions refer to a process employed to create and manufacture aluminium sections with various cross-section shapes by filling a forming die with the soft metal.” It is among the most utilized processes in many industries, such as construction, automotive, aerospace, and manufacturing, due to its lightweight, resistance to corrosion, and versatility. The type of aluminium extrusion alloys is important as it determines the strength, durability, and performance of the final products.

Understanding Aluminium Alloys

Aluminium alloys are primarily categorized into series based on their main alloying elements, with each series offering specific advantages for applications. The most used series for aluminium extrusion include:

• Pure Aluminium- 1000 Series
• Aluminium-Copper Alloys- 2000 Series
• Aluminium-Manganese Alloys- 3000 Series
• Aluminium-Silicon Alloys- 4000 Series
• Aluminium-Magnesium Alloys- 5000 Series
• Aluminium-Magnesium-Silicon Alloys- 6000 Series
• Aluminium-Zinc Alloys- 7000 Series
• Miscellaneous Elements- 8000 Series

Key Properties to Consider When Choosing an Aluminium Extrusion Alloy

When it comes to selecting an aluminium alloy for extrusion, several factors are to be put into consideration when making this decision:

1. Tensile and Yield Strength Levels

Tensile and yield strength levels of aluminium alloys vary with changes in adhering elements. For instance, if your project requires a lot of strength, the 7000 series alloys (7075, for example) are used most often in the aerospace sector. In structural applications where both strength and formability are required, the 6000 series alloys (6061, for instance) are preferred.

2. Resistance to Corrosion

Aluminium has a natural ability to protect itself against oxidative environments due to its innate ability to form an oxide layer. However, this is only true for certain types of alloys, while others are resistant to this wear and tear. In marine or harsh climatic conditions, the 5000 series alloys, especially aluminium alloy 5083, are highly prized due to their strong resistance against corrosion. As a result, this type of alloy is preferred for manufacturing boat hulls or any coastal architectural cladding.

3. Forming and Functionality

How easily an alloy can be extruded or fabricated is very important, particularly for those complex profiles. The further extrusion series, such as two thousand alloys, for example, 6061, are famously known for their improved workability and enhanced ability to take on forms, thus they can be put in frames and even make industrial elements. Work can also be done with alloys of the first series (one hundred percent aluminium) as they are also very well drawn and, depending on the work, require more creative shapes with less thickness.

4. Weldable Metal

Welding is one of the common processes that involve aluminium extrusion in many projects. Some alloys, for example, 6061, which is in a set of alloys known as the 6000 series, have high weldability, making them the preferred materials for regions that require the elements to be joined by welding. On the other hand, alloys of the 2000 series, for example, 2024, are dense and can carry high loads, but their copper content makes them quite a challenge to weld.

5. Weight and Density

Light metal provides density advantages, which is the primary reason aluminium is highly utilized in industrial design. In case there is a need to control the weight of the item being designed, the 1000 alloys, which are high-grade commercial and therefore low in density pure aluminium, are suitable. On the contrary, if weight is secondary and stronger materials are required, especially when the applications of 7000 alloys, which are slightly heavy linear clevises, are needed, the 7000 series of alloys are preferable.

Common Aluminium Extrusion Alloys and Their Applications

Let’s look at some of the most used aluminium alloys for extrusion and where they excel:

1. 6061 Aluminium (6000 Series)

6061 is one of the most widely used aluminium varieties thanks to a very well-judged selection of mechanical properties, processability, and resistance to corrosion. Contains mainly magnesium and silicon, both weldable and subject to heat treatment for strength. Appropriate for parts where high durability is necessary and thus widely used in elements of aircraft, cars, and structures, including frame structures and hulls of ships and boats.

2. 5083 Aluminium (5000 Series)

5083 has been one of the most well-received marine-grade aluminium alloys due to its amazing property of resistance to corrosion, specifically saltwater. This allows for more applications of 5083 aluminium sheets as it has too High strength weight ratio and avoids pitting and stress corrosion cracking, making it the best metal for shipbuilding, boat hull construction, ocean-based structures, and even building facades in extreme environmental conditions.

3. 7075 Aluminium (7000 Series)

7075 is a type of aluminium alloy that is primarily zinc aluminium alloyed and has been known to be high in strength, also approaching steel in terms of weight and strength class; this is why most high-strength alloys are preferred in aeroplane structural applications. However, it is more difficult to weld and form than most other alloys.

4. 1100 Aluminium (1000 Series) 

1100 is noted as one of the most chemically pure aluminium grades, having good forming characteristics and corrosion resistance. These types of applications may involve components with complex shapes and variations but do not require immense structural strength; thus these applications are mostly restrained to the food and chemical industries and those involving heat exchangers and decorative coatings, particularly in aggressive environments with visual and functional demands.

5. 2024 Aluminium (2000 Series)

2024 is a high-strength aluminium alloy which is heat-treatable; this alloy is mainly copper-based and has very high fatigue resistance. Although its ability to defend against corrosion is lower, it is extensively applied in the aerospace sector and the military in tough elements such as the framework of aircraft and armoured detachments. There is usually a need for an extra layer of protection outside for use in such conditions for a longer period.

There are various types of aluminium alloys, and each has its own properties. The wrong choice of aluminium alloy for extrusion or the aluminium extrusion manufacturer can lead to the failure of a project. A careful examination of the project’s requirements makes it possible to select the best performing, longest lasting, and most affordable alloy for the project.