Metals and alloys

Date: 2015-10-07; view: 507.

II. Answer the following questions.

I. Copy the underlined words and word-combinations, translate them into Ukrainian and learn them.

1. What were the first metals which were used by primitive man?

2. What was a material which was so important in the ancient world that its name is given to one of the cultural stages in human development?

3. What metal ceased to be classed as a precious material and began its career as the world's most valuable metal from the standpoint of actual use?

4. What metals were known as “The Seven Metals”?

5. How do metals vary in considering their chemical properties?

6. How are alloys usually prepared?

7. What is the enormous importance of alloys?

All metals are divided into ferrous metals and non-ferrous metals. Ferrous metals include iron, steel and its alloys. Non-ferrous metals are metals and alloys the main component of which is not iron but some other element. Metals, in general, and especially ferrous metals are of good importance in variations.

Metals possess the following properties: 1) All metals have specific metallic luster. 2) They can be forged. 3) Metals can be pulled. 4) All metals, except mercury, are hard substances. 5) They can be melted. 6) In general, metals are good conductors of electricity.

These characteristics are possessed by all metals but the metals themselves differ from one another. Steel and cast iron are referred to the group of ferrous metals. Cast iron is the cheapest of the ferrous metals. It is chiefly used in building for compressed members of construction, as the supporting members.

When an engineer designs a steelwork he must carefully consider that the steel frame and every part of it should safely carry all the loads imposed upon it. The steel framework must be carefully hidden in walls, floors and panitions. It is steel and metal that is employed as reinforcement in modern ferroconcrete structures. In the curriculum of the university there is a special course on metal structures.

Aluminium. This is the oldest and best known light metal. It is used in aircraft, automobile, chemical and some other industries.

Copper. Copper is the best conductor of electricity. There are different alloys with copper. An alloy of copper and tin is called bronze. This metal is often used for making various ornaments.