ABSTRACT
Aluminium’s unique properties have set the metal apart as a special building material exhibiting outstanding properties: strength, lightness, durability and versatility. Aluminium and its alloys are divided into two broad classes, cast and wrought. The latter class is subdivided into non heat-treatable and heat-treatable alloys. In the non heat-treatable group, properties are altered by the degree of cold-working that is performed, such as rolling. Casting alloys for general engineering applications are specified in BS 1490, aluminium alloy ingots and castings. The aluminium oxide ‘skin’ that is always present on the surface of aluminium exposed to oxygen provides both excellent atmospheric durability and resistance to a large number of chemicals. Young’s modulus of elasticity for aluminium is about one-third that of steel. This means that an aluminium structural member under load, and having the same section properties as a steel member will deflect to a greater extent than the steel one.
