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.
ІІІ. Language
Ex.7. Match word and word combinations in column A with those in column B:
| A 1.вологий 2. олово 3. свинець 4. латунь 5. в’язкий 6. легіруючий елемент 7. іржа 8. обробляти 9. невід’ємний 10. м’який 11. ковкий 12. твердість | B 1. tough 2. lead 3. alloying element 4. rust 5. brass 6. ductile 7. soft 8. essential 9. hardness 10. to treat 11. damp 12. tin |
Ex.8. Match words and their definitions:
| 1. to mix 2. to treat 3. rust 4. pipe 5. wire 6. to describe 7. aluminium 8. to predominate 9. casting 10. application | 1.a reddish – brown substance that forms the surface of iron 2. metal in the form of thin thread 3. to say what sth is like, or what happened 4. the practical use 5. to combine two or more substances 6.to be most important or greatest in number 7. the process of metals’ melting or pouring into a form 8. to put a chemical substance into smth in order to protect it from damage 9. a light silver-coloured metal that is used for making cooking equipment 10. a tube that carries gas or liquid |
Ex.9. Find the right ending of the sentences and translate these sentences:
1. Non ferrous metals are rather … ……………………………………….
a) cheap
b) expensive
c) essential
d) inexpensive
2. Aluminium is used extensively for casting that are………………………..
a) to be light in weight, to be easily machined, or that must rust
b) to be light in weight, light in colour, or that must not rust
c) to be light in colour, light in weight, or that must be brittle
3. All non-ferrous castings will take a high polish and ………………………..
a) will not rust so easily as the ferrous metals
b) will rust so easily as the ferrous metals
c) will alloy freely with carbon.
4. Brasses are very ductile and………………………………………………...
a) may be combined with carbon and silicon
b) may be so hard that ordinary tool steel will not cut them.
5. It is necessary to mix aluminium with some other metals………………….
a) because it is too hard for making castings.
b) because it is too brittle for making castings.
c) because it is too soft for making castings.
Ex. 10. Fill in the blanks using words in brackets:
a) are described; b) copper; c) light weight; d) tin; e) a soft
1. Brasses are yellowish or reddish alloys of … and zinc in different proportions.
2. Characteristics of non-ferrous metals are thermal conductivity, high corrosion resistance, … etc.
3. The metals most frequently used to make non – ferrous castings are: copper, …, zinc, lead, etc.
4. Some of the basic non – ferrous metals …below.
5. Alluminium is …silvery white metal.
Ex.11 Put questions to get the following answers:
1. The metals most frequently used to make non-ferrous metal castings are copper, tin, zinc, lead, nickel, gold and aluminium
2. Copper is used for making electrical contacts and wires, pipes, telephone cables, etc.
3. Aluminium is a soft, silvery white metal.
4. An addition of tin makes brasses stronger.
5. 5. Bronze is an alloy containing primarily copper and tin, but other elements may be added to the alloy.
6. The metals that alloy freely with aluminium are copper, zinc and iron.
IV. Comprehension
Ex.12. Agree or disagree with the following statements:
1. Copper is a reddish – brown tough metal.
2. Non-ferrous metals are very cheap.
3. An addition of alluminium makes brasses stronger.
4. All – ferrous castings will take a high polish and will not rust so easily as the ferrous metals.
5. The metal most frequently used to make non-ferrous metal castings is copper.
6. Usually where aluminium alloys are made the aluminium predominates.
7. Aluminium is a strong, yellow metal.
Ex.13. Answer the following questions:
1. What are the main characteristics of non – ferrous metals?
2. What are the properties of copper and what is it used for?
3. What purposes is aluminium used for?
4. What metals are used for producing non – ferrous castings?
5. What do you know about brasses?
6. What do you know about bronzes?
7. What are the main properties of non – ferrous castings?
8. Why are attempts made to replace non – ferrous metals by ferrous ones?
