Aluminium Grades Explained: Which Do I Need?

There are eight grade series of aluminium. Each grade is associated with a particular alloy. Alloys refer to metals which have been made by combining two or more types of metal...

Different grades are associated with different strengths and applications, so you’ll need to choose carefully.

Aluminium grades are categorised using a series of four numbers:

The first number denotes the primary alloying element, which is how alloys are split into series

The second number refers to specific modifications to one of the alloying elements

Digits 3 and 4 are random numbers associated with specific alloys

So, what are the eight series of aluminium grades you can choose from?

1000 Series

Whilst there’s no such thing as 100% pure aluminium, the 1000 series is as close as it gets. This grade features alloys that are made up of at least 99% aluminium content.

These alloys are highly workable, with a variety of options for working the aluminium, including everything from welding to hard forming. Other benefits include corrosion resistance and strong conductivity. The Metal Store stocks aluminium sheet metal in grade 1050.

Applications

Thanks to its high electrical and thermal conductivity, these grades are frequently used for electrical and chemical applications.

2000 Series

This grade is combined with copper. Through specialist heat treatment, it’s possible to optimise the toughness of these alloys. They feature fantastic machinability and good strength. On the other hand, they suffer from poor corrosion resistance, so may require painting with a higher quality alloy in some circumstances.

Applications

2000 series grade aluminium is frequently used for aerospace applications.

3000 Series

Alloys from this grade feature manganese and are great all-rounders that can be applied to a variety of uses. They feature good strength, temperature stability, and workability, and are also resistant to corrosion. This means that as well as everyday uses, they can also be used in extreme conditions.

Applications

3000 series alloys are used in day-to-day applications, including kitchen utensils. They are also used in a variety of sheet-metal applications, and in heat exchanger components.

4000 Series

Combined with silicon, 4000 grade aluminium alloys have a lower melting point, making them a popular option for welding wire and brazing alloys. They also feature strong electrical and thermal conductivity, as well as resistance to corrosion.

Whilst silicon alone can’t be heat-treated, there are several 4000 alloys that are suitable for heat treatment.

Applications

These alloys are commonly used in the automotive industry.

5000 Series

This aluminium grade series is combined primarily with magnesium, but may also features other elements, including manganese. These alloys are strong, easy to weld and are very suitable for working and forming. We supply aluminium checker plate in grade 5754, due to its high strength and corrosion resistance.

Applications

Thanks to its corrosion resistant properties, this grade is a popular option for use in marine environments, and for storage tanks. With this being said, some 5000 series alloys containing magnesium shouldn’t be exposed to very high temperatures due to the potential for corrosion cracking.

6000 Series

This series of alloys features both magnesium and silicon, which forms magnesium-silicide. Known for being very workable and heat treatable, 6000 series aluminium is strong and corrosion resistant. You’ll also find they’re good to form, weld and machine. The highest strength alloy in this series is 6082, which we stock in several products, including aluminium angle, box section, flat bar and square bar.

Applications

Due to their broad strengths, these alloys are frequently used across a variety of industries, including construction, architecture and fabrication.

7000 Series

These alloys are predominantly combined with zinc, but may also contain magnesium, copper or chromium if you’re interested in heat-treating the metal. Incredibly strong, many of the alloys in this series match steel in their strength. They’re also tough and stress-resistant but can be at risk of corrosion.

Applications

Thanks to their exceptional strength, these alloys are commonly used in the aerospace industry and in the production of sports equipment.

8000 Series

8000 series aluminium alloys are combined with many other elements, including nickel, lithium and iron. These alloys are not commonly used but are developed for specific applications in certain industries.

Applications

This niche series of alloys is most commonly used in very specific applications within the engineering or aerospace industries.