Addition, tensile strength, percentage, ferrous, brittle, shock, furnace, engineering, strength, impurities, mould

1. Metals consisting of iron with some other elements are known as … metals.

2. Grey iron does not stand great ….

3. … metals are usually used in industry in the form of alloys.

4. Wrought iron contains a small …of carbon.

5. Iron ore is smelted in a blast furnace to separate iron from ….

6. Metals are usually tested for ….

7. Metals are usually melted and poured into a form which is called a ….

8. Very much carbon makes cast iron …which reduces its ….

9. The … of nickel and manganese increases the strength of cast iron.

10. Cupola is the name of the … for making grey cast iron.

1. Agree or disagree with the following statements. Prove your reason. Use the expression: As far as I know…

1. Cast iron tends to be brittle except for malleable iron.

2. The main alloying elements of iron are carbon and silicon.

3. Cast iron has become an engineering material with a wide range of application.

4. Cast iron can be cast into any shape and size.

5. Malleable iron castings are much stronger than grey iron castings.

6. The blast furnace is called so, because a blast of hot air is forced into it while producing pig iron.

7. Steel and cast iron contain equal quantity of carbon.

8. It is difficult to machine alloy grey iron castings.

1. Translate the sentences paying attention to the degrees of comparison of adjectives. Find the examples of the degrees of comparison in the text.

1. The properties of alloys are much better than those of pure elements.

2. Carbon is the most important alloying element for iron.

3. What are the most common metals used in industry?

4. Malleable iron is stronger than grey iron.

5. Non-ferrous metals are more expensive than ferrous metals.

6. Metallurgy is one of the oldest of arts but one of the youngest of sciences.

7. Gold is the least chemically active of all metals.

8. The metal with the highest melting point will melt first.

9. Steel has worse resistance to corrosion than non-ferrous metals such as copper, zinc, tin and aluminum.

10. Some materials are less elastic than others.

11. Gold is much softer than copper, so it is easier to hammer it into shape.

12. Copper is much harder than gold and it was much more difficult for early people to shape it.

1. Look through the text and find answers to the questions:

1. What is wrought iron?

2. What properties does wrought iron possess?

3. When was wrought iron widely used? What objects were made of it then?

4. Is wrought iron used now?

Wrought iron is an iron alloy with a very low carbon content, in comparison to steel, and has fibrous inclusions, known as slag. This is what gives it a "grain" resembling wood, which is visible when it is bent to the point of failure. Wrought iron is tough, malleable, ductile and easily welded. Before the development of effective methods of steelmaking and the availability of large quantities of steel, wrought iron was the most common form of malleable iron. A modest amount of wrought iron was used as a raw material for manufacturing steel, which was mainly used to produce swords, cutlery and other blades. Demand for wrought iron reached its peak in the 1860s with the adaptation of ironclad warships and railways, but then declined as mild steel became more available. Before they came to be made of mild steel, items produced from wrought iron included rivets, nails, chains, railway couplings, water and steam pipes, nuts, bolts, horseshoes, handrails, and ornamental ironwork.

Wrought iron is no longer produced on a commercial scale. Many products described as wrought iron, such as guard rails, garden furniture and gates, are made of mild steel. They retain that description because they were formerly made of wrought iron or have the appearance of wrought iron. True wrought iron is required for the authentic conservation of historic structures.

1. Translate the text in writing. Use a dictionary. Get ready to retell the text.

Furnaces

A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally iron. In a blast furnace fuel and ore are continuously supplied through the top of the furnace, while air (sometimes with oxygen enrichment) is blown into the bottom of the chamber, so that the chemical reactions take place throughout the furnace as the material moves downward. The end products are usually molten metal and slag phases tapped from the bottom, and flue gases exiting from the top of the furnace.

The blast furnace takes an important part in modern iron production. Modern furnaces are highly efficient, including Cowper stoves to pre-heat the blast air and employ recovery systems to extract the heat from the hot gases exiting the furnace. Competition in industry drives higher production rates. The largest blast furnaces have a volume around 5,580 m³ (190,000 cu ft) and can produce around 80,000 tonnes (88,000 short tons) of iron per week.

This is a great increase from the typical 18th-century furnaces, which averaged about 360 tonnes (400 short tons) per year. Variations of the blast furnace, such as the Swedish electric blast furnace, have been developed in countries which have no native coal resources.

Production of castings made from different metals requires different types of melting furnaces. The cupola furnace is usually used for melting grey iron. The air cupola and electric furnaces are used to melt the metal for making malleable iron castings. For melting steel, the open-hearth, crucible and electric furnaces are used. Non-ferrous metals are generally melted in crucibles or electric furnaces.

Unit 11

1. Memorize the following words and expressions:

die raise promote reduce intend disadvantage machineability harmful open-hearth furnace grade cold shortness harden quality content particular ordinary impact insufficient

пресс-форма повышать способствовать уменьшить предназначать недостаток обрабатываемость вредный мартеновская печь качество, сорт хладноломкость закаливать(ся), твердеть качество содержание особенный обычный ударная сила недостаточный

прес-форма підвищувати сприяти зменшувати призначати недолік, вада оброблюваність шкідливий мартенівська піч якість, сорт ламкість в холодному стані гартувати(ся), твердіти якість вміст особливий звичайний ударна сила недостатній

1. Practise the reading of the following words:

Quality, furnace, hearth, disadvantage, machineability, promote, oxygen, manganese, percent, fatigue, structural, exceptional, cementite, medium, type, converter.

1. Read and translate the text:

Steel

Steel is the most important material for machine-building. Unlike carbon irons steel contains lower amounts of carbon and harmful impurities. The process of steel production generally consists in reducing the amounts of the above ingredients. The main methods of steel making are the basic oxygen process, the open-hearth process and the electric steel making process.

There are two kinds of steel: carbon and alloy steel. Carbon steel is an iron-carbon alloy containing up to 2.14% carbon and impurities such as silicon, manganese, sulfur, and phosphorus. Carbon is the chief element that determines the properties of this steel. The mass percent of each of the elements contained in steel is the following: up to 99% Fe; to 2.14 C; 0.15% to 0.35% Si; 0.2% to 0.8% Mn; to 0.07% S; and to 0.07% P.

Carbon is found in steel as cementite which raises hardness, elasticity and strength, but reduces ductility and impact strength and lowers machineability. Small amounts of silicon and manganese do not have a particular effect on steel. Sulfur and phosphorus are harmful impurities. Sulfur promotes brittleness at red heat in forging and rolling and also reduces the fatigue strength and corrosion resistance. The phosphorus content of up to 0.07% makes steel highly brittle at ordinary temperatures, i.e. it promotes cold shortness. Phosphorus strongly affects the properties of high-carbon steels.

Carbon steel is divided into two groups: structural steel and tool steel. Structural steel contains not more than 0.6% carbon or up to 0.85% carbon in exceptional cases. Structural steel with the lowest carbon content from 0.05 to 0.15% is called machine steel. Machine steel is very soft and can be used for making machine-parts that do not need strength. Medium carbon steel with the carbon content from 0.15 to 0.6 % is a better grade; it is stronger than machine steel. This steel is suitable for parts with high strength and hardness which are intended to carry medium loads without friction. This steel usually needs surface hardening. It is used for nuts, connecting rods, piston pins, etc.

Tool carbon steel has an increased carbon content from 0.7% and over. The steel is very hard, strong and intended for the manufacture of tools and dies. It comes in two types: good-quality steel and high-quality steel. The hardness of both types of steel is the same, but high-quality steel is less brittle and more resistant to impact loads. High-quality steel is produced in electric furnaces, while good-quality steel is produced in open-hearth furnaces and oxygen converter furnaces.

Carbon steels have the following disadvantages:

1) They do not combine hardness and strength with ductility.

2) They have a high coefficient of thermal expansion.

3) They lose hardness and cutting abilities at a temperature of about 200° C and also strength when heated above 200° C.

4) They have poor resistance to corrosive atmosphere.

5) They show insufficient electrical properties.

Carbon steel is used in the cases where the above limitations do not affect the service properties of products. Where carbon steel cannot meet special requirements, the choice is made of alloy steel which has found extensive uses.

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

Вищевказаний, широке застосування, відповідати особливим вимогам, особливий вплив, поганий опір, менш крихкий, нести навантаження, недостатній, обмеження, втрачати ріжучу здатність,у виняткових випадках, для виробництва інструментів, підвищений вміст, в той час як, на відміну від, підходящий.

1. Answer the questions:

1. What are the main methods of steel making?

2. What steel is called carbon steel?

3. How does carbon affect the properties of steel?

4. Why is phosphorus a harmful impurity?

5. When is machine steel used?

6. What two types of tool steel do you know?

7. How do they differ?

8. What happens to carbon steel when it is heated?