ALUMINIUM SHEET AND COIL

Aluminium is the world’s most abundant metal and is the third most common element, comprising 8% of the earth’s crust. The versatility of aluminium makes it the most widely used metal after steel. Although aluminium compounds have been used for thousands of years, aluminium metal was first produced around 170 years ago. In the 100 years since the first industrial quantities of aluminium were produced, worldwide demand for aluminium has grown to around 29 million tons per year. About 22 million tons is new aluminium and 7 million tons is recycled aluminium scrap. The use of recycled aluminium is economically and environmentally compelling. It takes 14,000 kWh to produce 1 tonne of new aluminium. Conversely it takes only 5% of this to remelt and recycle one tonne of aluminium. There is no difference in quality between virgin and recycled aluminium alloys. Pure aluminium is soft, ductile corrosion resistant and has a high electrical conductivity. It is widely used for foil and conductor cables, but alloying with
other elements is necessary to provide the higher strengths needed for other applications. Aluminium is one of the lightest engineering metals, having strength to weight ratio superior to steel. By utilising various combinations of its advantageous properties such as strength, lightness, corrosion resistance, recyclability and formability, aluminium is being employed in an ever-increasing number of applications. This array of products ranges from structural materials through to thin packaging foils.

PROPERTIES

The major advantages of using aluminium are tied directly to its’ remarkable properties. Some of these properties are outlined in the following sections.

(1) STRENGTH TO WEIGHT RATIO

Aluminium has a density around one third that of steel and is used advantageously in applications where high strength and low weight are required. This includes vehicles where low mass results in greater load capacity and reduced fuel consumption.

(2) CORROSION RESISTANCE

When the surface of aluminium metal is exposed to air, a protective oxide coating forms almost instantaneously. This oxide layer is corrosion resistant and can be further enhanced with surface treatments such as anodising.

(3) ELECTRICAL AND THERMAL CONDUCTIVITY

Aluminium is an excellent conductor of both heat and electricity. The great advantage of aluminium is that by weight, the conductivity of aluminium is around twice that of copper. This means that aluminium is now the most commonly used material in large power transmission lines. The best alternatives to copper are aluminium alloys in the 1000 or 6000 series. These can be used for all electrical conduction applications including domestic wiring. Weight considerations mean that a large proportion of overhead, high voltage power lines now use aluminium rather than copper. They do however, have a low strength and need to be reinforced with a galvanised or aluminium coated high tensile steel wire in each strand.

(4) LIGHT AND HEAT REFLECTIVITY

Aluminium is a good reflector of both visible light and heat making it an ideal material for light fittings, thermal rescue blankets and architectural insulation.

(5) TOXICITY

Aluminium is not only non-toxic but also does not release any odours or taint products with which it is in contact. This makes aluminium suitable for use in packaging for sensitive products such as food or pharmaceuticals where aluminium foil is used

(6) RECYCLING

The recyclability of aluminium is unparalleled. When recycled there is no degradation in properties when recycled aluminium is compared to virgin aluminium. Furthermore, recycling of aluminium only requires around 5 percent of the input energy required to produce virgin aluminium metal.

The combination of two remarkable properties of aluminium makes the need to recycle the metal obvious. These first of these factors is that there is no difference between virgin and recycled aluminium. The second factor is that recycled aluminium only uses 5% of the energy required to produce virgin material. Currently around 60% of aluminium metal is recycled at the end of its lifecycle but this percentage can still be vastly improved.

Aluminium is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery white, soft, ductile metal. Aluminium is the third most abundant element and the most abundant metal in the Earth’s crust. It makes up about 8% by weight of the Earth’s solid surface.