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The Past and the Future of the Laser 1 глава
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АНГЛИЙСКИЙ ЯЗЫК
для студентов технических вузов
Основной курс
В 2 частях
Часть 2
Под общей редакцией
кандидата филологических наук доцента С. А. Хоменко
кандидата педагогических наук доцента В. Ф. Сколобан
Допущено Министерством образования
Республики Беларусь
в качестве учебного пособия для студентов
технических специальностей учреждений,
обеспечивающих получение
высшего образования
Минск
"Вышэйшая школа"
Рецензенты: доцент кафедры методики преподавания иностранных языков "МГЛУ, кандидат педагогических наук А. П. Пониматко; доцент, кандидат филологических наук, заведующий кафедрой английского языка естественных факультетов БГУ Т. Г. Лукша
Все права на данное издание защищены. Воспроизведение всей книги или любой ее части не может быть осуществлено без разрешения издательства.
ПРЕДИСЛОВИЕ
Данное пособие является продолжением первой части учебного пособия для студентов технических специальностей вузов (Английский язык для студентов технических вузов: Основной курс. В 2 ч. Мн.: Выш. шк., 2004). Оно включает в себя 6 разделов (Units 13—18), материал для дополнительного чтения и перевода. По аналогии с первой частью в конце пособия имеется раздел "Grammar", словарь активной лексики, ключи к кроссвордам.
Структура второй части пособия однотипна структуре первой части. Текстовой материал пособия заимствован из зарубежных источников, его тематика определена программой подготовки специалистов технического профиля.
Авторы
Английский язык для студентов технических вузов:
А64 Основной курс. В 2 ч. Ч. 2: Учеб. пособие / С. А. Хоменко,
В. Ф. Скалабан, А. Г. Крупеникова, Е. В. Ушакова;
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Под общ. ред. С. А. Хоменко, В. Ф. Скалабан. - Мн.: Выш.
шк., 2004.-207 с.
ISBN 985-06-0919-2.
Представляет собой вторую часть базового учебного пособия для студентов технических вузов. Рассчитано на 70 часов учебного времени. Содержит 6 учебных разделов, раздел для повторения, материал для дополнительного чтения и перевода, грамматический справочник, активный лексический словарь. Каждый раздел включает введение в тему, упражнения для формирования языковых навыков, задания по обучению чтению и говорению, для активизации речи и по обучению письменной речи. Текстовой материал заимствован из зарубежных источников и его тематика определена программой подготовки специалистов технического профиля.
Для студентов технических специальностей вузов.
УДК 811.111 (075.8) БВК 81.2 Англ-923
ISBN 985-06-0919-2
© Хоменко С. А., Скалабан В. Ф.,
Крупеникова А. Г., Ушакова Е. В., 2004 © Издательство "Вышэйшая школа", 2004
Unit Thirteen
MECHANICAL TECHNOLOGY
Section A. Welding
Lead-in
I. Discuss the following questions.
a) In what branches of engineering is welding used?
b) Have you ever seen the process of welding?
c) What safety rules should be observed during this process?
II. Listen to the students' conversation and learn how to weld workpieces
correctly.
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Denis: Will you tell me how to join these two
workpieces, Peter? Peter: No problem. It is not very difficult. I
think you should use an electric arc
to weld the pieces. Are they of the same
metal?
Denis: Oh, yes. Why do you ask? Peter: Well, it is desirable to join the workpieces of the same material,
for example, steel to steel, in order to make a very strong joint. Denis: Oh, I see. How do I weld them? Peter: Look at these pictures. Everything is shown and explained
here. It is essential to follow all these instructions. Denis: OK, I get it. By the way, I hear that electric arc welding is
dangerous. Is that right?
Peter: Yes. However, if you follow safety rules nothing will happen to you. Denis: What safety rules? Peter: Don't you know? First of all, it is necessary to put on special
protective clothing, you know, an apron, gloves, rubber
boots and a cap. Everything must be dry and clean. Then you
should always wear a mask or a helmet to protect your face... Denis: Fine. Shall we start welding now?
Peter: Well, let's try.
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III. Complete the dialogues.
1. - Is it easy to...?
- No, it is rather difficult to do that job. To my mind, you should
use an electric arc to...
2. - Should the workpieces be made... metal?
- Yes, it is desirable to...
3. - Electric arc welding is quite dangerous,...?
-..., that is why it is important to...
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- Will you tell me what they are?
- Well, it is necessary to...
IV. Match a line in A with a line in B.
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A
1. Electric arc welding is widely a) No problem.
used in industry. b) Actually, no. Why do you
2. Peter, could you help me, ask?
please? c) An apron, gloves, rubber
3. Are the workpieces of the same boots and a cap, a mask or
metal? a helmet.
4. I hear that electric arc welding d) Well, let's try.
is dangerous. e) Oh, I see.
5. What does special protective f) That's true.
clothing include?
6. Shall we start welding now?
Language Practice
Vocabulary
| 1. Find the Englisr | equivalents | in В to the Russian words in | A. | |
| A | В | |||
| 1. луч | a) beam | b) bead | c) sunshine | d)laser |
| 2. сварной шов | a) bead | b)cut | c) weld | d) beam |
| 3. свойство | a) property | b) substance | c) quantity | d) trait |
| 4. соединение | a) unit | b) joint | c) particle | d) meeting |
| 5. трещина | a)crack | b)cracker | c)canyon | d) web |
| 6.влиять | a) to effect | b) to avoid | c) to affect | d) to impress |
| 7. сваривать | a) to cook | b) to weld | c) to meet | d) to damage |
II. Match the words with the simitar meaning.
| piece | goal |
| must | to make up |
| the same | workpiece |
| to hold | essential |
| flame | similar |
| to create | to keep |
| aim | fire |
| important | should |
III. Divide the words into four columns according to their part of speech.
workpiece, electric, powerful, transformer, melt, dangerous, continuously, join, safety, quickly, soften, fusion, essential, dry, investment, currently, property, investigate
Grammar: Infinitive
IV. Give advice to your friend how to do things in column A. Choose in column B the right variant.
EXAMPLE: To mark a hole on the plate you should use a pencil.
| B use this new method of welding use these two gases use a transformer use a hammer use gas welding use an electric drill |
to drive in the nail
to get a strong joint
to cut holes in metal
to create a suitable flame
to provide the necessary electric
current to join two steel plates
V. Say what device you will use to do the following things.
EXAMPLE: - to drill a hole in a plate
In order to drill a hole I will use a drill.
If you want: - to find the necessary information quickly
- to join two workpieces
- to assemble cars
- to cut metals
- to perform difficult tasks
- to measure the speed of the car
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VI. Explain why people do the following things. Give as many reasons as
you can.
EXAMPLE: Why do you use calculators?
We use calculators fin order) to count quicker, to avoid mistakes, to save time, etc.
1. Why do people need computers?
2. Why does everybody want a car?
3. Why did you practise in the lab yesterday?
4. Why are we using solar energy nowadays?
5. Why have engineers created robots?
6. Why...?
Change the structure of the sentences below so as to keep their meaning
unchanged.
EXAMPLE: It is very important to make a strong joint. To make a strong joint is very important.
1. It is impossible to store gas in an open tank.
2. It is quite necessary to make metal electrodes.
3. It is very essential to provide a hot enough flame.
4. It is not difficult to adjust the welding flame.
5. It is unnecessary to mix these substances.
6. It is easy to follow these instructions.
VIII. How do you find doing these things? Use the adjectives: important,
essential, valuable, easy, difficult, necessary.
EXAMPLE: to put on protective clothing
It is absolutely necessary to put on protective clothing.
to weld metal joints
to follow the safety rules
to use an electric arc
to join two workpieces of the same material
to provide a powerful electric current
not to use a transformer when welding
IX. Translate the following pairs of sentences into Russian. Pay attention
to the difference between the sentences of each pair.
1. a) To check the ammeter is necessary.
b) To check the ammeter it is necessary to connect it to the circuit.
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2. a) To improve the quality of welding is very important.
b) To improve the quality of welding we use lasers.
3. a) To make strong joints you should weld two pieces of the same
metal.
b) To make strong joints is essential in automobile industry.
4. a) To follow these instructions is really difficult.
b) To follow these instructions you should read them attentively first.
X. Restore the original sentences.
1. is, gas welding, to join, used, steel to steel
2. these metal plates, to join, is, rather, difficult
3. must be supplied, in order to, a current, an arc, create
4. to provide, is, current, at a low voltage, it, necessary
5. to make, a strong joint, to weld, is, the same metal surfaces, it,
desirable
6. the operator, protective clothing, himself, should have, to protect
XI. Correct mistakes.
1. It is difficult do this job.
2. 
You should to put on special clothing to protect yourself.
3. You have to wear uniform be safe.
4. The overalls should to be dry and clean.
5. Take workpieces of the same metal in order make a strong joint.
6. It is essential not provide a weak flame.
7. Important not to move the electrode too quickly.
8. To join these plates it is rather difficult.
XII. Translate the sentences into English using your active vocabulary.
1. Необходимо использовать электрическую сварку, чтобы со
единить эти детали.
2. Обычно используют трансформатор, чтобы подать необходи
мый ток.
3. Сварить эти две металлические пластины совсем нетрудно.
4. Ток должен быть достаточно высоким, чтобы создать необ
ходимую дугу.
5. Чтобы получить прочное соединение, нужно сваривать дета
ли из одинакового материала.
6. Очень важно правильно держать электрод при электричес
кой дуговой сварке.
7. Чтобы получить сварочное пламя, необходимо смешать эти
два газа.
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8. Лазерная сварка в настоящее время используется для сварки
сталей, сплавов и различных материалов, не так ли?
9. Важно упомянуть, что лазерная сварка имеет уникальные
преимущества: низкая стоимость, глубокое проникновение и уз
кий шов, а также скорость и прочность,
10. Чтобы определить свойства лазерных сварных швов, нуж
но провести много экспериментов.
Reading and Speaking
I. Look at the pictures and guess what the text is about. Skim the text to
see if you were right.
II. How is welding connected to electricity? Find in the text sentences
with words of the same root and translate them into Russian.
III. Read the text attentively and find out how to weld plates correctly.
Welding is one of the most important operations that are used in industry. Many parts of machines, automobiles, airplanes, ships, bridges and buildings are welded.
In order to join two metal pieces it is necessary to soften them with heat and then to press, hammer or fuse them together. The most widely used method of welding is electric arc welding where the workpieces are joined by means of electricity at the temperature of about 7,232 °F. This is the hottest heat that can be obtained for engineering purposes.
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In electric arc welding two workpieces are welded by an electric arc. In order to create the arc a powerful electric current should be provided. The current must be at least 60A and for thicker workpieces it may be 250A or more.
To supply the current it is necessary to use a transformer. The latter must be switched on to strike the arc. To join the workpieces the electrode
holder should contain an electrode rod. When the arc is struck the electrode must brush against the workpiece at 80° to its surface. As the current flows between the electrode and the workpiece the tip of the electrode melts and falls onto the workpiece. Thus a joint is created.
It is essential to hold the electrode approximately 4 mm from the surface of the workpiece. One should not leave the electrode too long in the same position because it will become attached to the workpiece. The electrode must be moved across the joint continuously backwards in a straight line. However, if it is moved too quickly neither the electrode nor the workpiece will melt.
And it is important to remember that to weld plates by an electric arc is quite dangerous. In order to protect yourself you should always follow certain safety rules. For example, it is absolutely necessary to wear overalls with long sleeves, gloves, an apron, a cap, and rubber boots. A mask or helmet is used to protect the face and especially eyes from sparks.
IV. What do letters a-f in the pictures refer to?
V. Answer the questions below.
1. What is welding? What processes does it involve?
2. What method of welding is the most widely used today?
3. What device is used to supply the current?
4. How is a joint created?
5. How far should the electrode be held from the workpiece?
6. Why is it dangerous to leave the electrode in the same position?
7. In what way is it necessary to move the electrode across the joint?
8. What safety rules should you follow in the process of welding?
VI. Complete the following sentences with suitable words.
1.... two workpieces an electric... is used.
2. It is necessary... a powerful electric... for arc welding.
3.... the workpieces the electrode holder must contain an elect
rode....
4. The electrode should be... some millimeters from the... of the
workpiece.
5.... a strong joint the workpieces must be of the same....
6. The electrode can become... the workpiece.
7. The electrode must be... across the... continuously.
VII. Give a title to the text.
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VIII. Make a dialogue according to the instructions below. Use the words necessary, useful, essential, etc. and expressions of request and opinion.
Student A. You have missed your class and you don't know how to weld plates. Prepare your questions and ask your friend for instructions.
Student B. Help your friend to understand the welding process. Get ready to answer his questions.
Further Reading
I. Modern life is much facilitated by the use of lasers. This equipment has
some advantages. Can you name any?
II. Laser is an international word today. Skim the text and find all the
international words in it.
III. Give Russian equivalents to these compound nouns.
| laser welded joints joint performance conventional weld joint |
laser beam welding
high power density welding process
cost effectiveness
IV. Read the text carefully and say what you have learnt about laser welding.
Laser Beam Welding
The unique properties of lasers account for their widespread application in manufacturing industry. Laser beam welding is currently used in order to weld steels, aluminum alloys and dissimilar materials. This high power density welding process has unique advantages of cost effectiveness, deep penetration and narrow bead in comparison with conventional welding processes. As the thermal cycles of laser beam welding are generally much faster than those of arc welding it is possible to form a rather small weld zone that exhibits locally high hardness.
However, it is important to point out that the metallurgical and mechanical properties of laser welds and the response of conventional materials to this new process have not been fully established yet. It is currently difficult to determine the tensile properties of the laser welded joint area owing to the small size (-2-3 mm) of the fusion zone. Therefore an experimental investigation of the mechanical properties of laser-welded joints was carried out. To determine the hardness profile of the welded metal three similar joints were
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produced by a CO2 laser and microhardness measurements were conducted at three locations. It is important to mention that the microhardness test results, however, exhibited no significant difference between these three locations for all the welded joints.
The welding process may lead to drastic changes in the micro-structure with accompanying effects on the mechanical properties and, hence, on the performance of the joint. Laser welded joints, like all other welded joints, may contain defects in the form of cracks in the narrow weld area. The size and location of such cracks directly affect the joint performance and the lifetime of a structure. Nevertheless, it is essential to remember that laser beam welding has a number of advantages over conventional processes. Despite the high investment cost of laser welding equipment, it is expected that laser beam welding will have a great impact on fabrication and manufacturing industries within the next decade.
V. Say if the following statements are true or false. Correct the false
statements.
1. Laser beam welding is widely used at present.
2. Arc welding is less advantageous than laser beam welding.
3. Laser beam welding is very hard.
4. The research on laser welding has been carried out recently.
5. It is currently difficult to establish the properties of the laser
welded joint area because the workpiece is very thin.
6. Laser beam welding may lead to dramatic changes in the
microstructure and the performance of the joint.
7. Laser welded joints may contain defects in the form of crackers.
8. Laser beam welding is rather expensive, that is why it will not be
widely used in indusry in the near future.
VI. Discuss these questions in groups:
a) What are the advantages and disadvantages of laser beam welding? Fill in the table.
| Laser Beam Welding | |
| Advantages | Disadvantages |
| 1. cost effectiveness 2.... … | 1. unestablished properties 2.... … |
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b) How does laser beam welding differ from arc welding? Compare the two. Use the logical patterns of comparison and contrast.
comparison: in comparison with, similarly, in the like fashion, as does X, so does X
contrast: in contrast to, on the one hand, on the other hand, however, nevertheless
c) Can you suggest any other ways of welding?
VII. You are an engineer and you want to introduce laser beam welding at the Automobile plant you work at. Persuade the chief engineer that laser beam welding is better than arc welding.
Activity
I. Ask your friend for his opinion.
EXAMPLE: (good) to complete this work today / to put it off till tomorrow A: Which is better: to complete this work today or
put it off till tomorrow? B: Well, to my mind, it's better to complete this work
today so tomorrow you will be free.
(easy) to collect the data / to process it
(useful) to check welding equipment regularly / to check it
occasionally
(difficult) to follow safety instructions / to neglect them
(valuable) to invent new things / to improve existing things
(important) to learn theory / to practise
(good) to attend classes / to study independently
II. Study these Safety Rules. Discuss with your partner why it is necessary
to follow them. Consult the dictionary if necessary.
CAUTION
Welding can be dangerous. Any of these accidents may happen to you:
(a) you could be blinded by sparks;
(b) you could get an electric shock;
(c) your face, body, arms, legs or feet could be burnt;
(d) there could be a fire in the workshop.
PROTECTIVE CLOTHING
1. A mask or helmet must be worn in electric arc welding. (In gas
welding, goggles can be used.)
2. Clothes must be kept dry and clean.
3. Thick, heavy boots must be worn. These must be made of some
insulating material such as rubber.
4. Gloves, an apron and a cap must be worn.
5. Overalls must have long sleeves and no pockets or cuffs.
WORKSHOP
1. The floor must be made of concrete.
2. There must be a metal container on the floor for the sparks.
You can begin as follows:
- Peter, why is it necessary to wear a mask or goggles in electric arc
welding?
- Well, it is important to wear a mask and goggles because otherwise
you can....
III. Solve the crossword. Down:
1. 
a flat, thin, usually large piece of
something hard
2. something imperfect, a fault
3. to produce something new
4. to change the usual shape of some
thing so as to spoil its appearance
or usefulness
5. a place where things are joined
together
6. a stated quality, power or effect
that belongs naturally to some
thing
7. a line of light shining out from
some bright objects
8. laser beam welding produces a very narrow weld...
9. not easily broken, changed or destroyed
10. a very thin mark caused by breaking, but not into separate parts
11. to join by pressure or melting together
Across:
1....?
Writing
I. You are a materials engineer and specialize in welding. Recommend your client to introduce LBW in his plant. Point out the advantages of laser beam welding. The linking words and connectors in the box can help you.
first, next, also, besides, furthermore, finally, so, as, because, thus, however, etc.
Complete the memo given below.
MEMORANDUM
To: Mr. A. Kiselev From: Mr {your name)
Welding processes
Although this is a preliminary* report, and further detailed study is necessary, I can safely say that the introduction of laser beam welding is an advantageous alternative to arc welding for a number of reasons.
First of all, it is necessary to...
Thus I strongly recommend that you immediately consider replacing arc welding by laser beam welding. As a first step I suggest you contact the following companies for advice...
Предварительный
II. Choose one of the following passages and translate it into Russian. Use the dictionary if necessary.
a) Oxy-Acetylene welding relies on the heat of a flame (approximately 3000cC) to melt the material that is welded. Fusion can either be autogenous or with the addition of a filler material. To obtain the high flame temperature that is required for oxy-fuel welding processes it is necessary to combine oxygen with a fuel gas (acetylene or propane). Certain precautions should be taken when you handle these gases. Two techniques are used to weld flat joints: the leftward welding and the rightward welding. The advantages of rightward welding over the leftward technique are higher speed, less distortion1 and more economical use of gas and filler rod2.
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