Open hearth furnace. The electric furnace

Task 1. What is the difference between open hearth and electric furnaces?

Task 2. Read and translate the following text:

The open-hearth furnace is rectangular and rather low, holding from 15 to 200 tons of metal in a shallow pool. The purpose of this furnace is to convert various types of ferrous material into finished steel of proper composition and quality. The open-hearth process is a very versatile one, for it involves melting, refining and dioxidation.

The name open hearth is given to it because the hearth of the furnace is exposed to the sweep of the flames which melt the steel.

The open-hearth process is one of the most important me­thods of making steel. It is much slower than the Bessemer but it is easier to control, and for that reason it is more frequently used.

The furnace is lined with firebrick, to withstand the very high temperatures used. The charge consists of molten pig iron, scrap iron and steel and some hematite. Lime is added to the charge to take out the phosphorus and sulphur as slag. Manganese, carbon, nickel, vanadium, or other materials are added to make the kind of steel desired.

The fuel is blown into furnace through one of the two large openings, or ports, located on each end of the furnace. To fa­cilitate combustion, previously heated air is blown through the port along with the fuel. Combustion occurs above the hearth, and the smoke and other products of combustion escape through the ports at the other end of the furnace. Beneath the furnace are two large chambers through which air or gas flows freely.

There are three stages in the operation of this furnace. The first is known as the process of charging; the second - as the melting down process; the third - the period of refining. The period of refining is especially important and requires the constant supervision of the operator. The refining consists first in removing objectionable impurities and then controlling the elements other than iron which the final product must contain. Alloying elements are added to the steel before it is tapped or when it is in the ladle.

The electric furnace. The finest grades of steel are produced by the electric furnace method. Stainless and heat resistant steels are made almost exclusively by that process.

Electricity is used only for the production of heat and does not of itself impart any superior quality of steel. Nevertheless, the electric furnace method gives certain advantages impossible in other steel melting processes. The electric furnace generates extremely high temperatures. The temperature is at all times under precise control and is easily regulated.

The production of heat by electricity is unique, oxygen is not necessary to support combustion and the atmosphere within an electric furnace may be regulated at will.

The electric furnace is a circular steel shell resembling a huge tea-kettle in general appearance. It is mounted on rockers so that the furnace can be tilted to pour off molten metal and slag. The bottom of the furnace consists of a layer of heat resistant materials below which it is lined with refractory bricks. The side walls which are also lined with refractory bricks contain three or more openings.

The roof of the furnace is lined with 250 mm or more of refractory bricks and is shaped like a flat dome. Through this dome great columns of carbon reach into the furnace. These are the electrodes which carry the current to the steel charge.

Electrical furnaces are used in making high-grade steels from cold material; they are also used in additional refining of steel produced by the Bessemer and open-hearth processes. The electric furnace is now capable of making high-grade tool steels equal in quality to the steels produced by crucible process.

Task 3. Find in the text equivalents to the following words and expressions:

прямокутна й досить низька, мілка ванна, склад, плавлення, очищення, обкладений вогнетривкою цеглою, складатися з, червоний залізняк, додаватись, попередньо нагріте повітря, легуючі елементи, завантаження, вимагати постійного нагляду, шкідливі домішки, випускати (сталь), нержавіюча й жаростійка сталь, переваги, плаский купол, додаткове очищення, тигельний процес, правильний склад, плавлення, розкислення, очистка, витримувати високі температури, чавун у чушках, металолом, легуючі елементи, шар, бокові стіни.

Task 4. Translate into Ukrainian the following words and word combinations:

open-hearth furnace, to convert, ferrous material, quality, to involve, the hearth of the furnace, flames, to melt the steel, to control, to withstand, charge, scrap, lime, steel desired, to locate, along with, occur, large, freely, ladle, to impart, generate, precise control, be regulated at will, resembling a huge tea-kettle, side walls, roof, to be shaped, to carry the current, high-grade steels, a strong blast of air, to form a slag, the specified percentage, rolling or forging, tilting vessel, heat-resisting bricks and clay, a shower of sparks, reddish-brown fumes, the refining action, proper composition and quality, the hearth of the furnace, to fa­cilitate combustion, the process of charging, the melting down process, the period of refining, a circular steel shell, to be tilted to pour off molten metal and slag, refractory bricks, crucible process.

Task 5. Match the words in column A with their meanings from column B.

A	B
1. superior	a) a) шар, прошарок
2. lower	b) b) циліндричний
3. inferior	c) c) камера
4. circular	d) d) знижувати, нижчий
5. proper	e) e) легше
6. layer	f) f) рамка печі, що гойдається
7. chamber	g) g) кращий
8. rocker	h) h) гірший
9. easier	i) i) належний

Task 6. Translate next sentences into English:

1. При виготовленні сталі Бесемерівським процесом паливо не застосовується.

2. Спочатку йде обробка, а потім готова сталь виливається в ківш.

3. Перетворювач обкладено вогнетривкою цеглою та глиною.

4. Після закінчення треба зменшити потік повітря та вийняти готову сталь.

5. Мартенівська піч використовується для перетворення чорних метал на сталь.

6. Піч працює при високих температурах, тому вона обкладена вогнетривкою цеглою.

7. Один з етапів роботи печі це процес очищення.

8. Сьогоднішні технології дозволяють підтримувати процес згоряння без використання кисню.

Task 7. Make up the sentences from the given words. Start with the underlined word. Translate the sentences.

1. production, used, heat, The electric, is, stainless, for, and, resistant, of, furnace, steels.

2. is, because, The open-hearth, more, is, it, frequently, used, control, easier, process, to.

Task 8. Fill in the gaps with the verbs given below used in the proper tense form:

to include, to involve, to hold, to occur,

to consist of, to line with, to add, to blow

1. The open-hearth furnace _____ from 15 to 200 tons of metal in a shallow pool.

2. The open-hearth process _____ melting, refining and dioxidation.

3. The furnace _____ firebrick, to withstand the very high temperatures used.

4. The charge _____ molten pig iron, scrap iron and steel and some hematite.

5. Some materials like manganese, carbon, nickel, vanadium, or others _____ to make the kind of steel desired.

6. The fuel _____ into furnace through one of the two large openings, or ports.

7. Combustion _____ above the hearth.

8. The operation of this furnace _____ three stages in.

Task 9. Fill in the gaps with the words given below. Pay attention that some words are odd.

precise control, heat, heat resistant, ladle, method,

atmosphere, furnace, advantages, temperatures, steels

1. The finest grades of steel are produced by the electric furnace _______.

2. Stainless and _______ steels are made almost exclusively by that process.

3. Electricity is used only for the production of ______.

4. The electric furnace method gives certain _______ impossible in other melting processes.

5. The electric furnace generates extremely high _______.

6. The temperature is at all times under _______ and is easily regulated.

7. Electrical furnaces are used in making high-grade _______ from cold material.

8. The _______ within an electric furnace may be regulated at will.

Task 10. Answer the following questions:

1. What is the open-hearth furnace?

2. What is the purpose of the open-hearth furnace?

3. What were the reasons for the name “open-hearth”?

4. List the features of the open-hearth process?

5. Give the description of the open-hearth furnace and list the components of its charge.

6. Describe the stages of the open-hearth process.

7. What is the purpose of the electric furnace?

8. List the features of the electric furnace.

9. Give a description of the electric furnace.

10. Where is the electric furnace used?

Task 11. Fill in the table using the information from the texts:

Melting unit	Design of the unit	Charge	Purpose
Open-hearth furnace
Electric furnace

Task 12. Memorize the following words and word combinations:

1.	alloying elements	легуючі елементи
2.	chamber	камера
3.	additional refining	додаткове очищення
4.	advantage	перевага
5.	circular steel shell	круглий стальний каркас
6.	composition	склад
7.	quality	якість
8.	to convert	перетворювати
9.	dioxidation	диоксидація
10.	flat dome	плоский верх
11.	hearth	под печі, горн, металоприймач
12.	heat resistant steel	теплостійка сталь
13.	kind	сорт, вид
14.	objectionable impurities	небажані домішки
15.	open-hearth furnace	мартенівська піч
16.	opening	отвір, канал
17.	precise control	точний контроль
18.	rectangular	прямокутний
19.	refractory brick	вогнетривка цегла
20.	scrap iron	металевий лом
21.	shallow pool	мілка ванна
22.	stainless steel	нержавіюча сталь
23.	to tilt	нахиляти
24.	tool steel	інструментальна сталь
25.	to withstand	протистояти, витримувати

Unit 7

FERROUS METALS

Task 1. Make a list of the ferrous metals and compare it with your partner.

Task 2. You are going to read about ferrous metals. Seven sentences have been removed from the text. Choose from the sentences (A-H) the one which fits each gap (1-7). There is one extra sentence which you do not need to use. There is an example at the beginning (1).

A	It is very cheap, in fact, it is the cheapest of all the engineering metals used in machine-building.
B	But very much carbon makes steel brittle, which reduces its strength.
C	Various grades of copper are used for engineering purposes.
D	Carbon is the most important of all elements to be presented in ferrous alloys.
E	Cast iron is a general term applied to iron-carbon alloys containing more than 1.7 per cent of carbon.
F	However, in comparison with other metals grey iron is weak.
G	This process is known as casting.
H	It has high resistance to corrosion.

To produce ferrous metals one must combine iron with carbon, silicon, other elements. 1) ___D___ Ferrous metals are used in industry in two general forms: steel and cast iron, which differ in the quantity of carbon content. These two ferrous alloys are derived from pig iron which is produced in a blast furnace in form of pigs. Metals are usually melted and poured into a form which is called a "mould". 2) _______ The cast metal is shaped in the mould where it cools and solidifies. Thus one can cast different objects known as castings. The shop where metals are cast is called a "foundry". Castings are used to produce different types of machinery.

Steel is a ferrous material with a carbon content from 0.1% to 1.0%, which makes it much stronger than iron and is therefore widely used in machine building. 3) _______ Therefore the carbon content in steel is confined to certain limits. Semisteel is a name to a metal made by melting 20 to 40% of steel scrap with cast iron in the cupola. Steel castings are more expensive but stronger and tougher.

Cast steel normally contains about 0.5% of carbon, and is used to replace cast iron when castings of considerable strength are required.

Forged steel is steel that has been hammered, drawn, pressed or rolled in the process of manufacturing of a particular part.

Alloy steels are those in which some alloying element in addition to the carbon is present in some appreciable quantity. The principal alloying elements used in steel are nickel, chromium, vanadium, molybdenum, manga­nese, and to lesser extent, copper, tungsten, cobalt, beryl­lium and boron.

Cast iron contains a higher percentage of carbon than steel does (more than 2.0 %). 4) _______. Cast iron without the addition of alloying elements is weak in tension and shear, strong in compression and has low resistance to impact. It is obtained from the cupola furnace where pig iron is remelted in contact with coke.

Grey cast iron has the carbon present in the free or graphite state and is soft, easily machined, and only moderately brittle.

White cast iron has most of the carbon in the combined state and is therefore hard and brittle.

Malleable cast iron is made by heating white iron castings for a period of several days in airtight pots filled with an oxide of iron. 5) _______.

Grey iron foundries are the most numerous because grey iron can be cast into almost any conceivable shape and size. Grey iron is also adapted to a great variety of castings, such as automobile, gas, steam, and hydraulic engine cylinders, bed plates for machines, car wheels, agricultural machinery parts, furnace and stove parts, water pipes, gears, etc. 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 readily-machined. 6) _______. The alloy of grey castings is composed of iron, carbon, silicon, phosphorus, manganese, and sulphur. These elements are used in different proportions depending on the grade of castings.

There is one more kind of ferrous materials - wrought iron. It is quite ductile and can be easily rolled, drawn, forged and welded. 7) _______. The carbon content is generally less than 0.1% and the material must contain not less than 1% slag.

Task 3. Find in the text equivalents to the following words and expressions:

кількість, вміст вуглецю, чушки, мульда, затвердівати, цех, крихкий, ливарний цех, обмежувати, вагранка, межа міцності, легована сталь, кокс, сплав, колізія, сірий чавун, дешевий, необхідні форма та розмір, опорні плити, труба, шестерня.

Task 4. Translate into Ukrainian the following words and word combinations:

ferrous alloys, the quantity of carbon content, a blast furnace, melted and poured into, to cool and solidify, casting, brittle, weak in tension and shear, easily machined, airtight pots, stove parts, water pipes, soft, grade of castings, to be rolled, drawn, forged and welded.

Task 5. Match the words in column A with their meaning from column B.

	A		B
	casting	a)	вуглець
	gear	b)	вагранка
	cast iron	c)	машинне обладнання
	cupola	d)	шестерня
	semisteel	e)	ливарна форма
	stove	f)	ливарний цех
	mould	g)	виливок
	machinery	h)	піч
	carbon	i)	чавун
	foundry	j)	напівсталь

Task 6. Fill in the gaps with the verbs given below used in the proper tense form:

to consist, to form, to have, to restrict

1. The cast metal _______ in the mould where it cools and solidifies.

2. The carbon content in steel _______ to certain limits.

3. Cast steel normally ______ about 0.5% of carbon.

4. The alloy of grey castings ________ of iron, carbon, silicon, phosphorus, manganese, and sulphur.

Task 7. Translate next sentences into English:

1. Вміст вуглецю допомагає визначити чорний метал.

2. Сталь та чавун виготовляються в доменних печах.

3. Метал плавиться та заливається в мульду, де він охолоджується та затвердіває.

4. Виливки виготовляються в ливарному цеху, а потім використовуються в різних видах машинного обладнання.

5. Сталь широко використовується в машинобудування оскільки вона міцніша за залізо.

6. Легована сталь містить в собі, окрім вуглецю, ще деякі легуючі елементи.

7. Чавун виготовляється в мартенівських печах з заліза в чушках.

8. Автомобільні колеса, газові та парові двигуни, труби та шестерні виготовляються з сірого чавуну.

Task 8. Find in the text antonyms to the following words:

brittle, to heat, weaker, cooling, scanty

Task 9. Fill in the table using the information from the texts:

metal	composition	usage

Task 10. Memorize the following words and word combinations:

1.	alloy steel	легована сталь
2.	airtight pots	герметичні резервуари
3.	bed plate	базова плита, станина
4.	brittle	крихкий
5.	casting	лиття; виливок
6.	cast steel	лита сталь
7.	coke	кокс
8.	ductile	пластичний, ковкий
9.	to draw	витягувати
10.	ferrous metals	чорні метали
11.	forged steel	кована сталь
12.	foundry	ливарний цех, ливарне виробництво
13.	machinery	обладнання
14.	malleable cast iron	ковкий чавун
15.	mould	мульда, ливарна форма
16.	pigs	чушки
17.	resistance to impact	ударна міцність
18.	semisteel	напівсталь
19.	shop	цех
20.	to solidify	затвердівати
21.	steam engine	паровий двигун
22.	strength	міцність
23.	tough	тугий, пружний, гнучкий
24.	wheel	колесо
25.	wrought iron	коване залізо

Unit 8

Дата добавления: 2015-11-14