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The processing

How aluminium is combined with other metals to give it its desired properties.

abstract close up image of aluminium

When we have refined the alumina into aluminium, we get a liquid metal that is cast into extrusion ingots, sheet ingots or foundry alloys, all depending on the product. The aluminium is mixed with other materials to give it its desired property, typically copper, magnesium, manganese, silicon, tin or zinc. Depending on the use, we make the aluminium easily malleable or strong and energy absorbing. The metal is then shipped to production facilities, where it’s pressed into sheets or extruded into all shapes and sizes – materializing the ideas of the engineers and designers. 

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Aluminium vocabulary

The world of aluminium is full of technical expressions. But don’t worry, we’ve translated them for you:

Anodizing is an electrochemical process that converts the surface of aluminium into a long-lasting, high performance aluminium oxide finish. Because it is integrated into the metal rather than just applied to the surface, it cannot peel or chip. This protective finish is very hard and durable and enhances the product’s resistance to corrosion, so it can withstand extreme wear and tear. In fact, the anodized finish is the second hardest substance known to man, exceeded only by the diamond. The metal is also porous, so it can be coloured and sealed, or undergo additional processing, if desired.

Aluminium pieces with different finishes

A billet is an aluminium log that is used when extruding the aluminium into parts and products.

Aluminium billets

Cast-house products are all the products we make in the cast-house like extrusion ingots, sheet ingots, foundry alloys and high-purity aluminium.

Man woking with liquid aluminium in a casthouse

Aluminium reacts with the oxygen in the air to form an extremely thin layer of oxide. This layer is dense and provides excellent corrosion protection. It’s even self-repairing if damaged.

Close up of aluminium surface

The extrusion process starts by heating a billet of aluminium alloy and then forcing it under high pressure through a special steel die using a hydraulic press or ram. Sort of like squeezing toothpaste out of a tube. The result is a piece of aluminium – an extrusion or profile – that will maintain the specific shape of the die and hence has almost unlimited possibilities for design.

Extruded aluminium pieces

After the profile has been extruded it can be fabricated into different shapes and fitted with various features, like holes for screws etc.

Aluminium machinery

There are a variety of techniques to join aluminum such as fusion welding, friction stir welding, bonding and taping. Features that facilitate easy joining are often incorporated into the design of the extrusions.

Hands holding aluminium pieces

Milling, drilling, cutting, punching and bending are all common methods for shaping aluminium. The energy input during machining is low, meaning a more sustainable final product.

Milling in aluminium

Aluminium is 100 % recyclable and does not lose any of its original properties in the process. As it is recycled aluminium only uses 5 % of the energy that is used to make primary aluminium. Hydro’s goal is to enable a more circular economy through our re-melt facilities. Here we sort and recycle used and scrapped aluminium, so the metal can be used again and again.

Crushed scrap aluminium in blocks


The flexible metal

What makes aluminium so versatile is that it can be tailored to fit your exact needs. While pure aluminium is relatively soft, we can add other elements to the mix to change its properties – a process called alloying. 

The exact composition of chemicals gives the alloy different properties, meaning every alloy has its own unique characteristics. With more than 540 different alloys to choose from, you need to consider qualities such as strength, corrosion, surface treatment, weldability and cost to find the one that’s right for your needs. And our experts are here to help you, contact us to hear more.