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
	superior	шар, прошарок
	lower	циліндричний
	inferior	камера
	circular	знижувати, нижчий
	proper	легше
	layer	рамка печі, що гойдається
	chamber	кращий
	rocker	гірший
	easier	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.	combustion	згоряння
7.	composition and quality	склад та якість
8.	to convert	перетворювати
9.	dioxidation	диоксидація
10.	flat dome	плоский верх
11.	hearth	горн, метало приймач
12.	heat resistant steel	теплостійка сталь
13.	kind	сорт, вид
14.	objectionable impurities	небажані домішки
15.	open-hearth furnace	мартенівська піч
16.	opening	канал
17.	precise control	точний контроль
18.	rectangular	прямокутний
19.	refractory brick	вогнетривка цегла
20.	scrap iron	металевий лом
21.	shallow pool	дрібна ванна
22.	stainless steel	нержавіюча сталь
23.	to tilt	нахиляти
24.	tool steel	інструментальна сталь
25.	to withstand	протистояти, витримувати

Lesson 7.