Primary, constituent, possess, enhance, consist, withstand, contain, multiphase

1. Alloys usually have different properties from those of … elements.

2. It is possible to … the properties of a metal by alloying it with other metals.

3. Alloys may … of two, three or four components.

4. Parts which must … vibration can be made of single-phase alloys (solid solutions).

5. Iron is a … element for steel.

6. A mechanical mixture can … alloying elements in any proportions.

7. Mechanical mixtures are … alloys.

8. Solid solutions … high ductility.

1. Agree or disagree with the following statements. Prove your reason. Use the expression: I’m sure that is right(wrong) because …

1. Chemical compounds are widely used due to their plasticity.

2. The properties of alloys and their components are always the same.

3. Solid solutions are very ductile.

4. Pure metals are more often used than their alloys.

5. Sometimes the name of the base metal is used as the name of its alloy.

6. Bronze was the first alloy known to people.

7. Alloys can consist of only two constituent elements.

8. Alloys of the highest purity are rarely used.

1. Translate the text in writing. Use a dictionary. Find answers to the questions:

1. How do alloys solidify?

2. Why isn’t it necessary to study the solidification temperature of each of the alloys?

Phase Transformations

The structure of alloys is more complex than that of pure metals. The crystallization processes are also more complex and different. The main difference is that while pure metals crystallize at one strictly definite temperature, alloys solidify at two temperatures, the initial and the final temperature. In the interval between these temperature points there appear two phases, i.e. uniform fractions of the system: the liquid alloy and solidified crystals. The process of crystallization determines the choice of a metal for casting, forging and other processes, and also the conditions of heat treatment. The solidification temperatures of pure metals are well known and tabulated, while those of alloys greatly differ with the contents of components. Therefore, it is impossible and inexpedient to study the solidification temperature of each of the alloys. For this, there are constitution diagrams which graphically show the solidification temperatures of alloys and the character and state of alloys with changes in their composition. The diagrams afford a correct approach to the choice of an alloy and its treatment. They characterize the physical and mechanical properties of alloys.

Unit 10

1. Memorize the following words:

ferrous metal non-ferrous fluid pig iron blast furnace cupola coke limestone annealing quantity mould wrought-iron smelting casting engineering combine remove machine slag sulfure reduction therefore engine affect treat

чёрный металл цветной (металл) жидкий чугун в болванках доменная печь вагранка кокс известняк отжиг количество литейная форма сварочное железо плавка отливка технический соединяться устранять обрабатывать шлак сера восстановление следовательно двигатель влиять, действовать (на что-то) обрабатывать

чорний метал кольоровий рідкий чавун у болванках доменна піч вагранка кокс вапняк відпал кількість ливарна форма зварювальне залізо плавка відливка технічний поєднуватися усувати обробляти шлак сірка відновлювання отже двигун впливати, діяти (на щось) обробляти

1. Practise the reading of the following words:

Purpose, quantity, pure, impurities, remove, blast, furnace, oxygen, constituents, limestone, liquid, through, higher, percentage, possess, cast iron, cupola, manufacture, fluid, variety, hydraulic, automobile, fracture, wrought, sulfure, manganese, tensile, malleable, annealing.

1. Read and translate the text:

Ferrous metals

Different metals are widely used in the machine-building industry. Metals applied for industrial purposes are called “engineering metals”. There are two groups of metals: ferrous metals and non-ferrous metals.

Ferrous metals consist of iron combined with carbon, silicon, phosphorus and other elements. Carbon is the most important of all elements present in ferrous alloys. Ferrous metals are used in industry in two general forms: steel and cast iron, which differ in the quantity of carbon content.

The iron ore which we find in the ground is not pure. It contains some impurities that must be removed by means of smelting. The process of smelting consists of heating the ore in a blast furnace from the bottom and providing the oxygen which is necessary for the reduction of the ore. The ore becomes molten and its oxides combine with carbon from the coke. The non-metallic constituents of the ore combine with the limestone and form a liquid slag. This slag floats on the top of the molten iron and passes out of the furnace through a tap. The metal which remains is pig-iron.

Both steel and cast iron can be produced of pig iron. Cast iron contains a higher percentage of carbon than steel does (more than two percent). Pig iron can be melted again in another furnace — a cupola — with more coke and limestone. This is cast-iron. It possesses a number of properties which make it very useful in manufacture of machinery. It is very cheap; in fact, it is the cheapest of all engineering metals used in machine-building. In the molten state cast iron is vеrу fluid, and therefore it is easy to cast it into complex shapes. Grey cast iron is adapted to a great variety of castings, such as automobile, gas, steam, and hydraulic engine cylinders, bed plates of machines, car wheels, agricultural machinery parts, water pipes, and general machine parts. The nature of the metal used for grey iron castings is such that castings can be made so hard that ordinary tool steel will not cut them or, on the other hand, so soft that they can be easily machined.

Cast iron doesn’t have the strength of steel. It is brittle and may fracture under tension. It doesn’t stand great shock. Iron, which contains a smaller quantity of carbon, for example, wrought-iron, behaves differently from the iron which contains a lot of carbon.

Cast-iron may contain small proportions of other substances, such as silicon, phosphorus, sulfure, and manganese which are used in different proportions. The presence of these substances affects the behaviour of the metal. Thus, where greater strength is required, the alloy known as alloy grey iron can be used. Alloy grey iron has a high tensile strength when it comes from the mould, and when it is heat-treated, a much greater strength is produced. It is easy to machine because most of the carbon present is in free or uncombined state. But the most easily machined of all ferrous alloys used at present is malleable iron. Malleable iron is much stronger than grey iron, particularly in the matter of resisting shock. It acquires such properties due to the process of annealing.

1. Find in the text the English equivalents for the words and word-combinations given below:

Для промислових цілей, процентний вміст вуглецю, впливають на поведінку, завдяки процесу, особливо, окис, отже, вільний стан, складається з, повинні бути усунені, розплавлене залізо, розрізняються за кількістю, складні форми, з іншого боку, присутність цих речовин, набагато міцніше, виходить з печі.

5. Answer the questions:

1. What metals are called ferrous?

2. What process is necessary to obtain iron from iron ore?

3. In what furnace does this process take place?

4. How is the liquid slag formed?

5. What is the main difference between cast iron and steel?

6. Why is cast iron so useful for industry?

7. Is cast iron very strong?

8. What do you know about the properties of alloy grey iron?

9. What can you say about malleable cast iron?