The production, characteristics and use of aluminium and its
The production, characteristics and use of aluminium and itsAluminium is a strong, durable and lightweight metal. In today's energy-conscious society, these three basic properties combine to make the metal the preferred material of construction for transport applications, where weight saving to reduce fuel consumption and to increase load carrying capacity is vital. Products like motor cars, is an obvious example. It is not surprising therefore, that the use of aluminium in all its various forms - plate, sheet, extrusions, castings and forgings - is increasing across the whole range of transport applications. The use of aluminium for automobile engine blocks and cylinder heads, heat exchangers, transmission housings, engine parts and automobile wheels has risen steadily over the last decade.
The reasons for the extensive use of aluminium lies in the diverse range of properties (mechanical, physical etc.) exhibited by aluminium and its alloys:
�h A key property is low density. Aluminium is only one-third the weight of steel.
�h Aluminium and most of its alloys are highly resistant to most forms of corrosion. The metal's natural coating of aluminium oxide provides a highly effective barrier to the effects of air, temperature, moisture and chemical attack.
�h Aluminium is a superb conductor of electricity. This property allied with other intrinsic qualities has ensured the replacement of copper by aluminium in many situations.
�h Aluminium is non-magnetic and non-combustible, properties invaluable in advanced industries such as electronics or in offshore structures.
�h Aluminium is non-toxic and impervious, qualities that have established its use in the food and packaging industries since the earliest times.
Other valuable properties include high reflectivity, heat barrier properties and heat conduction. The metal is malleable and easily worked by the common manufacturing and shaping processes.
Another area that is becoming increasingly important is the economic disposal of used vehicles using materials recycling. Aluminium offers the best prospects from all of the materials currently used in vehicles, approximately 95% of the aluminium in old vehicles is regained. New technologies will continually increase this, the low energy requirement for processing scrap into new semi-finished products is an important contribution to solving ecological problems.
All the above properties can be found in an impressive array of commercially available alloys. The composition and logic of those alloys are regulated by an internationally agreed classifications system for wrought alloys and by various domestic nomenclature schemes for the casting alloys.
Aluminium alloys with great durability and high strength, some with a tensile strength greater than that of constructional steels, are available to the designer in the form of extruded profiles, rolled sheet and plate, castings and forgings. The majority of these alloys consist of aluminium with carefully controlled additions of magnesium, silicon, manganese or a combination of magnesium and silicon, although some high strength alloys with additions of copper and zinc and recently, lithium, have been developed for industry.
The following table shows the average use of aluminium castings and production methods in the...
To view the complete essay, you be registered.