A guide to aluminium grades and their uses.

A Guide To Aluminium Grades

Aluminium is one of the most widespread elements found on earth, and one of the most popular in metalwork. The following article will cover the different grades of aluminium available, their physical and mechanical properties, and some of their most common uses.

When working with aluminium there are currently eight series of grades used to categorise the different types of alloy available. An alloy is created by mixing two or more types of metal to offer more desirable features such as greater strength or a higher melting temperature. Different grades of aluminium have different properties, and each has specific applications and uses. They are identified using four-digit numbers with the first number denoting the series of grade, indicating the primary alloying element. This is known as the International Alloy Designation System.

Some alloys can have their properties modified further through heat-treatment or other types of working.

1000 Series – “Pure” Aluminium

The 1000 series metals are the purest available, comprised of 99% or above aluminium content. Generally, these aren’t the strongest options available, but have fantastic workability and are a versatile choice, suitable for hard forming, spinning, welding and more.

These alloys remain highly resistant to corrosion and have excellent thermal and electrical conductivity, making them a popular choice for a number of uses such as food processing and packaging, chemical storage and electrical transmission applications.

2000 Series – Copper Alloys

These alloys use copper as their primary element in addition to aluminium and can be heat-treated to give them outstanding toughness and hardness, comparable to some steels. They have excellent machinability and a great strength-to-weight ratio; the combination of these characteristics makes them a popular choice in the aerospace industry.

One downside to these alloys is their low corrosion resistance, so they are often painted or clad with a higher purity alloy when their application means they will be exposed to the elements.

3000 Series – Manganese Alloys

The 3000 series of primarily manganese alloys are suitable for all-round general purpose uses and are among the most popular choices available today. They have moderate strength, corrosion resistance and good workability. This series contains one of the most widely used aluminium alloys of all, 3003, popular due to its versatility, excellent weldability and aesthetically pleasing finish.

This series of materials can be found in various everyday objects such as cooking utensils, signs, treads, storage and numerous other sheet-metal applications such as roofing and guttering.

4000 Series – Silicon Alloys

Alloys in this series are combined with silicon, its primary use being to lower the melting point of material whilst keeping its ductility. For this reason, Alloy 4043 is a well-known choice for welding wire, suitable for use in elevated temperatures and offering a smoother finish than many other options.

The 4000 series generally offer good thermal and electrical conductivity and have good corrosion resistance, making these alloys a popular choice in automotive engineering.

5000 Series – Magnesium Alloys

5000 series alloys are combined with magnesium, but many contain additional elements such as manganese or chromium. They offer exceptional corrosion resistance, making them a popular choice for marine applications such as boat hulls and other industry-specific uses including storage tanks, pressure valves and cryogenic tanks.

These highly versatile alloys maintain moderate strength, weldability and respond well to working and forming. Another commonly used welding wire is made from Alloy 5356, often chosen for aesthetic purposes as it keeps its colour after anodising.

6000 Series – Magnesium and Silicon Alloys

These alloys are combined with both magnesium and silicon (forming magnesium silicide) and are extremely common alloys for general purpose uses in a huge variety of industries such as construction, architecture, automobile and more.

With above-average strength, strong corrosion resistance and good machinability, materials in this series also respond well to heat-treatment and maintain their workability after tempering or annealing. One of the most popular alloys for the UK market is 6082, which is available in several profiles including sheet, box section, bars, I beam, and channel.

7000 Series – Zinc Alloys

The strongest alloys available, even stronger than many types of steel, the 7000 series contain zinc as their primary agent, with a smaller ratio of magnesium or other metals included to help retain some workability. This combination results in an extremely hard, strong, stress-resistant metal.

These alloys are commonly used in aerospace industries due to their superb strength-to-weight ratio, as well as within everyday items such as sports equipment and car bumpers.

8000 Series – Other Alloy Categories

The 8000 series are alloyed with a variety of other elements such as iron and lithium. Generally, they are created for very specific purposes within specialist industries such as aerospace and engineering. They offer similar properties to the 1000 series but with higher strength and formability.

As one of the top aluminium suppliers in the UK, at metals4U we offer a wide variety of aluminium alloys for whatever your project requires. For expert advice, support, and to find out more about our aluminium product range, get in touch now.