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ІІ. Reading
Ex. 6 Read and translate the text.
Text A


Non – Ferrous Metals

Non-ferrous metals are more expensive than ferrous metals and are used only when some characteristics not possessed by iron or steel are essential or desirable in application. These characteristics are: high electrical and thermal conductivity, high corrosion resistance, non-magnetic qualities, light weight, etc. The metals most frequently used to make non-ferrous metal castings are copper, tin, zinc, lead, nickel, gold and aluminium. Some of the basic non-ferrous metals and their characteristics are described below.

Copper is a reddish – brown tough metal. It has very high electric conductivity and high corrosion – resistant qualities. Copper is used for making electrical contacts and wires, pipes, telephone cables, etc.
Aluminium is a soft, silvery white metal. It is light in weight has high corrosion – resistant qualities and is used for automobile and airplane parts as well as for making different light – weight objects used in everyday life.
There are many applications of non-ferrous metals in the unalloyed state, but in most cases, some alloying element is added.
The above-mentioned non-ferrous metals may be mixed in various proportions to form many alloys, chief among them being brasses, bronzes, and aluminium alloys. There is a wide range of use for non-ferrous alloys.
Brasses are yellowish or reddish alloys of copper and zinc in different proportions.
An addition of tin makes brasses stronger. Brasses are ductile and may be treated without heating them. They are corrosion – resistant and are used for making bearings, musical instruments, etc.
Bronze is an alloy containing primarily copper and tin, but other elements may be added to the alloy to increase its properties such as hardness and resistance to wear.
Aluminium alloys. Aluminium is used extensively for castings that are to be light in weight, light in colour, or that must not rust. Since aluminium is too soft for making castings it is necessary to mix some other metals with it. The metals that alloy freely with aluminium are copper, zinc and iron. Usually where aluminium alloys are made the aluminium predominates. All non–ferrous castings will take a high polish and will not rust so easily as the ferrous metals, a characteristic that makes them especially useful in wet or damp places. Non–ferrous metals are rather expensive and scientists try to replace them with some ferrous alloys of lower cost, possessing the same properties.