Урок 2.2

Упражнение № 1. Прочитайте слова.

[J] yield, creep, steam, lead, fatigue;

[Ç] toughness, phenomenon, phase, atmosphere, factor, fire.

Упражнение №2. Сопоставьте слово с его переводом и соответствующей ему транскрипцией.

duration	[ Çq'Ë°Ñ]	усталость материала
ductility	[dju¶ 'Ïe IS(q)Í]	продолжительность
creep	[ 'ÄÏÂIÐI» ]	пластичность
breakage	[ÐÏJÃ]	ползучесть
fatigue	[ÌAÐ'ËIÎqËI]	повреждение

Text A

Material selection

A boiler is classified as a fired pressure vessel. Parts of the boiler that are subjected to high internal pressure of steam or water are referred to as pressure parts. Tubes, drum, and headers are examples of pressure parts. Other component like burner is not subjected to such internal pressure, it is classified as nonpressure part. Selection of materials for pressure parts of a boiler and their mechanical design and construction are the important aspects of a boiler design. There are several factors that should be taken into account for material selection. They are: mechanical properties. Mechanical properties such as ultimate tensile strength, yield strength, creep strength, creep rupture strength, ductility, and toughness are required to be considered for boiler construction. High temperature properties: a) creep becomes important in boilers at operating of 450 – 650 C; creep can take place and lead to fracture as an extended static load much lower than that will cause yielding or breakage when the load is of short duration; b) creep and fatigue interaction. When materials are exposed to cyclic loadings while operating at temperatures within their creep range, the creep reduces their fatigue life.

Notes:

pressure part элемент, работающий под давлением;

yielding деформация;

C градус по Цельсию.

Ответьте на вопросы к тексту:

1. How is boiler classified?

2. What parts are classified as pressure parts?

3. What are the important aspects of a boiler design?

4. What factors should be taken into account for material selection?

5. What mechanical properties are mentioned in the text?

6. What high temperature properties are mentioned in the text?

7. In what case does the creep reduce fatigue life of the materials?

Упражнение №3. Переведите слова и словосочетания на русский язык.

Fired pressure vessel; subject to (v.); high internal pressure; steam (n.); refer to (v.); drum (n.); header (n.); burner (n.); selection (n.); mechanical design; construction (n.); aspect (n.); mechanical property; ultimate tensile strength; yield strength; creep strength; ductility (n.); toughness (n.); require (v.); high temperature property; lead (v.); fracture (n.); an extended static load; cause (v.); breakage (n.); short duration; fatigue (n.); interaction (n.); expose (v.); creep range; reduce (v.); fatigue life.

As; etc.; and; or; for; when; while; within; that; at; such as; than.

Упражнение №4. Переведите слова и словосочетания на английский язык.

Резервуар под давлением с огневым подводом тепла; поломка; предел ползучести; периодические нагрузки; пластичность; увеличенная постоянная нагрузка; срок службы при нагрузках; разлом (растрескивание); элемент, работающий под давлением; подвергать; жесткость; максимальный предел прочности при растяжении; деформация; малая продолжительность; механическое свойство; коллектор; горелка; подвергать (воздействовать); взаимодействие; требовать; принять во внимание;

Когда; при; для; как; и так далее; такой как; чем.

Упражнение №5. Сопоставьте слово (А) с его определением (В).

А

1. metal fatigue;

2. fracture;

3. breakage;

4. tensile strength;

5. drum.

В

1. the ability of steel or concrete etc. to bear (выдерживать) pressure or weight without breaking;

2. the cracking or breaking of a hard object or material;

3. a large round container for storing liquids such as oil, chemicals etc.;

4. the action of breaking something, or the fact of being broken;

5. weakness in metal that makes it likely to break, caused for example by frequent shaking over a long period.

Упражнение №6. Дайте производные от перечисленных ниже слов. Укажите часть речи которой является данное слово и его производные. Переведите на русский язык.

Select, construct, operate, turn, break, burn, consider, classify, interact, boil, design.

Упражнение №7. Переведите следующие предложения, обращая внимание на функцию причастия II (Participle II).

1. The tubes placed in order to redirect the shell fluid past the tubes are attached on front and rear ends in tube sheets.

2. Heat transferred from the warmer fluid to the colder fluid encounters resistances that will create several losses.

3. A heat-transferring surface can be calculated for a desired heat rate.

4. The required cooling down or heat up of the pipe fluid must be known to perform a global calculation of the dimensions of a double-pipe heat exchanger with parallel flow.

5. The inner tube bent into a U-shape is very long.

6. The shell or outer tube bolted to a connector at the end completely encloses the inner tube.

7. Double-pipe heat exchangers well adapted to high temperature and high pressure are inexpensive and easily maintained.

8. Parts of the boiler that are subjected to high internal pressure of steam or water are referred to here as pressure parts.

9. When high heat-transfer rates are required, an alternative apparatus, known as a shell-and-tube heat exchanger can be used.

10. Various manufacturers dealt with fouling introduced new cleaning techniques.

11. A boiler is classified as a fired pressure vessel.

Упражнение №8. Переведите следующие словосочетания (группы существительных).

Water circulation; fire tube boiler; water tube boiler; heat transfer process; shell boiler; water flow; water tube; temperature difference; material selection; pressure part; fatigue life; energy source; steam pressure; surface temperature; heat-transfer rate; pipe fluid.

Упражнение №9. Переведите следующие предложения, обращая внимание на причастие I (Participle I).

1. The brush moving back and forth through the tubes removes all kinds of foulants.

2. We take into account only devices exchanging heat between two fluids.

3. Double-pipe heat exchangers having the small amount of heat-transfer surface per section are generally found in small total-surface requirement applications.

4. Estimates must always be done with great care according to the parameters influencing on the size of a heat exchanger.

5. The diameter of the pipe and the length of the heat exchanger giving a rough idea of the dimensions can be calculated with the help of equation.

6. The designer using lower fluid velocities maintains the pressure drop limitations.

Текст B

Manufacturing methods

Welding, cold forming, hot forming, and expanding are some of the modern manufacturing methods. They are used to fabricate a particular material into required shapes. A consideration of these requiring methods used in manufacture is important, as the least expensive fabricated product with adequate properties rather than the cheapest steel should dictate the choice. Weldability of material is important manufacturing consideration. Welding problems that have to be overcome include: a) solidification cracking, b) heat affected zone liquefaction cracking, c) hydrogen induced cracking, d) lamellar cracking; e) reheat cracking. For example, the tubes and headers from which power station boilers are assembled must be strong enough to resist internal pressure and system forces (системные нагрузки), and corrosion both from the water side and the heat transfer medium, which may be water, steam, flue gas, carbon dioxide, helium or sodium. Carbon steel has neither the strength nor the corrosion resistance required to operate at the high temperature and its resistance is improved by alloying. Materials selection in most of the methods is standardised.

Ответьте на вопросы к тексту:

1. What modern manufacturing methods are used to fabricate a particular material into required shapes?

2. What welding problems are mentioned in the text?

3. Why must the tubes and headers from which power station boilers are assembled be strong?

4. Has carbon steel the strength or the corrosion resistance required to operate at the high temperature?

Упражнение №1. Переведите слова и словосочетания на русский язык.

Manufacturing method; welding; cold forming; hot forming; modern manufacturing method; fabricate (v.); particular (adj.); shape (n.); expensive (adj); adequate (adj.); cheap (adj.); dictate (v.); choice (n.); weldability (n.); manufacturing consideration; overcome (v.); include (v.); solidification cracking; hydrogen (n.); induce (v.); cracking (n.); lamellar cracking; reheat cracking; scaling resistance; maximum surface temperature; header (n.); power station; assemble (v.); strong (adj.); resist (v.); internal pressure; force (v.); corrosion (n.); heat transfer medium; steam (n.); flue gas; carbon dioxide; helium (n.); sodium (n.); carbon steel; strength (n.); the corrosion resistance; alloying; material selection; standardise (v.).

Some; with; into; which; neither….nor; both….and; than; in; and; that.

Упражнение №2. Переведите слова и словосочетания на английский язык.

Изменение формы в холодном состоянии; изменение формы в горячем состоянии; образование усадочных трещин; водород; слоистое растрескивание; водородное растрескивание; растрескивание при повторном нагреве; окалиностойкость; собирать, монтировать; углекислый газ; гелий; натрий; уголь, сажа, слой нагара; углеродистая сталь; легирование, получение сплава; развальцовка; вызывать, побуждать; электрическая станция, энергоустановка.

С; в; некоторые; ни….ни; как….так и; который; чем; что.

Упражнение №3. Найдите в тексте причастия I и II (Participle I & II). Определите их функцию и переведите на русский язык.