Physically, chemically and mechanically, aluminum is a metal, like steel, brass, copper, zinc, lead and titanium. Aluminum belongs to the group of light metals along with magnesium and titanium. It is the most abundant metal in nature and accounts for about 8% of the mass of the Earth's crust.
To a large extent, it can be melted, cast, shaped and machined in the same way as the other metals, and it conducts electric current.
Aluminum and aluminum alloys have many properties that make them highly competitive in a wide range of applications in almost every type of industry. Without aluminum, we cannot fly, travel by fast trains, fast and light cars or fast ferries. Aluminum is used in everything from vehicles, aircraft, ships, food storage, electronic parts, buildings, interior design and furniture, to name a few.
At Nordic Steel, we use a lot of aluminum to manufacture various products and equipment. Some of the things we make for our customers are facades, inspection and control racks, pallet racks and storage boxes.
We make fish attenuators to stop pink salmon. They are made of aluminum, partly because low weight is an advantage when they have to be portable.
Mobile fast chargers for the construction site are manufactured by Nordic Steel. Car trailer fast chargers are suitable for construction sites where contractors move around or are on short assignments. The car trailer chargers are manufactured in aluminum.
For the CarEye Capture project , we have designed and manufactured a flexible system with a technology that checks cars for damage in seconds. It is manufactured in aluminum, with precise laser cutting and bending, before surface treatment and assembly.
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For the Bussveien project in Stavanger, we have been responsible for the creation, design and production of a 140 square meter art wall, as part of the decoration of an underpass. The plates for the steel wall are produced in aluminum, the pattern is punched out in the plates.
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The properties that make aluminum and aluminum alloys attractive alternatives for many types of use are in particular:
1. Low weight
The density of aluminum is about one third (2.7 g / cm3) of the density of steel (7.83 g / cm3), copper (8.93 g / cm3) and brass (8.53 g / cm3). An aluminum component of one cubic meter weighs 2.7 tonnes, while a similar steel component weighs 7.8 tonnes. The specific gravity of aluminum is therefore relatively low.
The combination of strength and lightness in aluminum reduces the weight of cars, buses, trucks and boats, which in turn leads to less energy consumption and pollution from means of transport. Not unexpectedly, the use of aluminum in trains, trams, subway cars, buses and boats is increasing rapidly, especially when it comes to body and hull.
2. Corrosion resistant
Aluminum is resistant to the continuous oxidation that causes steel to rust. The unprotected aluminum surface combines with oxygen to form an oxide film that inhibits further oxidation. Unlike iron rust, the oxide film does not peel off so that the next layer is exposed to oxidation. If you scrape off the protective layer on aluminum, it is immediately restored.
The thin oxide layer is tightly bonded to the metal, and is colorless and transparent - making it invisible to the naked eye.
3.Physical properties
Aluminum surfaces can be highly reflective. Radiant energy, visible light, radiant heat and electromagnetic waves are effectively reflected, while anodized and dark surfaces can be reflective or absorptive. This is why aluminum is often chosen for decorative and functional purposes, such as in building facades.
Aluminum has excellent electrical and thermal conductivity. It is neither ferromagnetic, self-igniting, nor toxic, and looks attractive in its natural finish.
The metal itself is not toxic, it does not give off any aroma or flavoring. Aluminum is therefore ideally suited for use in the food and aquaculture industries, among others.
4.Mechanical properties
Formability is one of the most important properties of aluminum and many of its alloys. Some aluminum alloys have almost the same strength level as structural steel.
While aluminum has a specific modulus of elasticity similar to steel, the absolute modulus of elasticity is about one-third of that of steel. In construction technology, this means major shape changes, but this can be corrected by optimizing advanced construction of the cross section.
As such optimization usually involves a weight reduction in relation to steel, the areas of use may in fact be greater than for steel. Unlike steel, many aluminum alloys can be extruded, giving a wider range of possible applications.
5. Reuse of the material
Aluminum is 100 percent recyclable and during the recycling process, like steel, it retains all its original properties. During production, it is more cost-effective to use recycled aluminum than raw metal from the mines.
Since aluminum is infinitely recyclable and loses none of its properties during the process, manufacturers want to use as much recycled material as possible.
Aluminum is also excellent in cold temperatures. Not only does the strength increase at low temperatures, but also the tensile, flow and impact measurements. The corrosion resistance of aluminum increases under these conditions, making it suitable for use in areas with cold and ice.
Aluminum can be produced through the traditional ore-based method, but also with recycled aluminum from process waste and used aluminum products.
Production starts with the raw material bauxite, which is a clay-like soil type found in a belt around the equator. The bauxite is extracted from mines located a few meters underground. During the production process, the bauxite is processed into pure aluminum oxide, before it can be converted into aluminum by electrolysis. The result is now liquid aluminum, which can be cast and transformed into various products.
Aluminum requires large amounts of energy when first produced. Recycling, the remelting of existing aluminum, uses only 5% of the original energy input. Recycling aluminum is therefore very important from an environmental perspective.
Welding aluminum is actually quite difficult, especially if you don't know how to do it. There are several reasons for this.
One important reason is the oxide layer that surrounds aluminum. The oxide layer first melts at about 2015°C - but the aluminum itself melts at about 660°C, depending on the alloy. If the oxide layer melts in the conventional way, the aluminum runs away and welding becomes impossible. Therefore, the oxide layer must be removed both before and during welding.
In gas welding, a flux is used to dissolve the oxide. When welding with covered electrodes, there is a substance in the electrode cover that dissolves the oxide layer. When the electrode is made positive, it causes the oxide coating to break up.
Whichever welding method is used, the oxide layer must be removed mechanically by grinding and brushing just before welding.
Another reason that makes welding aluminum difficult is that aluminum conducts heat many times better than steel. Heat must therefore be applied much faster when welding aluminum than steel to melt the base material. Aluminum has a low melting point, but it needs a much higher amount of heat than steel. TIG or MIG welding are welding methods that provide a more constant heat input.
Aluminum and steel need approximately the same amount of heat to weld the same volume. Even though aluminum weighs 1/3 of steel, it dissipates heat four times as fast, so extra heat must be added.
Aluminum expands about twice as much as steel when heated. When cooled, it shrinks accordingly. When welding, large shrinkage forces can easily occur, which can lead to deformation and cracks. We prevent this by welding with concentrated heat input, and as fast and cold as possible.
