Unit 2 Text 1 Basic Metallurgy of Cast Iron

The term ‘cast iron’, like the term ‘steel’, identifies a large family of ferrous alloys. Cast irons primarily are alloys of iron that contain more than 2% carbon and form from 1 to 3% silicon. Wide variations in properties can be achieved by varying the balance between carbon and silicon, by alloying with various metallic or nonmetallic elements, and by varying melting, casting and heat treating practices.

Cast irons, as the name implies, are intended to be cast to shape rather than formed in the solid state. Cast irons have low melting temperatures, are very fluid when molten, do not form undesirable surface films when poured, and undergo slight to moderate shrinkage during solidification and cooling. However, cast irons have relatively low impact resistance and ductility, which may limit their use.

Mechanical properties of cast irons - especially strength, ductility, and modulus of elasticity - depend strongly on structure and distribution of microstructural constituents. Physical properties such as thermal conductivity and damping capacity are also strongly influenced by microstructure.

The four basic types of cast iron are white iron, gray iron, ductile iron and malleable iron. White iron and gray iron derive their names from the appearances of their respective fracture surfaces: white iron exhibits a white, crystalline fracture surface, and gray iron exhibits a gray fracture surface with exceedingly tiny facets. Ductile iron derives its name from the fact that, in the as-cast form, it exhibits measurable ductility. By contrast, neither white nor gray iron exhibits significant ductility in a standard tensile test. Malleable iron is cast as white iron, then “malleablized” - that is, heat treated to impart ductility to an otherwise exceedingly brittle material.

Besides the four basic types, there are other specific forms of cast iron to which special names have been applied. Chilled iron is white iron that has been produced by cooling very rapidly through the solidification temperature range. An area of the casting that solidifies at a rate intermediate between those of chilled iron and gray iron, and which exhibits microstructural and fracture-surface features of both types, is known as mottled iron. Compacted graphite cast iron (also known as vermicular iron) has a structure intermediate between those of gray iron and ductile iron.

Task 1.

Phonetic Exercise

Practise after the speaker and learn to pronounce the words given below.

identify /ai’dentifai/; constituents /kn’stitjunts/; appearance /‘pirns/; surface

/’s:fis/; exhibit /ig’zibit/; tensile /’tensail/; malleablized / mli‘blaizd/; intermediate / int‘mi:djt/; graphite /’grж fait/; vermicular /v:’mikjul/.

Task 2.

Lexical Exercises

Exercise 1. Find the English equivalents for the words and word

combinations given below and use them in the

sentences of your own.

большое разнообразие свойств; равновесие; литье; в твердом состоянии; отвердение; охлаждение; теплопроводимость; амортизация; белый чугун; серый литейный чугун; растяжение; наделять свойствами; температура отвердения.

Exercise 2. Match the English words and word combinations given

below with their Russian equivalents. Use them in the

sentences of your own.

1. cast iron 1. закаленный (отбеленный) чугун

2. fluid when molten 2. половинчатый (о чугуне)

3. ductile iron 3. их имя происходит от

4. malleable iron 4. чугун (продукт вторичной плавки)

5. chilled iron 5. жидкий (текучий) в расплавленном

состоянии

6. the solidification temperature 6. их название происходит

7. mottled iron 7. ковкий (тягучий) чугун

8. they derive their names from 8. температура отвердевания

Exercise 3. Answer the following questions.

1. How can the properties of cast irons be changed? 2. What are the characteristics of cast irons? 3. What do mechanical properties of cast irons depend on? 4. Name the four basic types of cast iron. 5. Are there any other specific forms of cast iron?

Exercise 4. More about word-building: Prefixes.

In the text given above find the words with prefixes: un-; under-; inter-; im-. Define their meanings if:

un- = not; lack of; do opposite of; release from:

do – undo = не делать

under- = beneath; lower; insufficiently:

developed – underdeveloped = плохо развитый, недоразвитый

inter- = between:

related – interrelated = взаимосвязанный

im- = in, into, against, over:

impregnate = насыщать

Here are the meanings of some words. Fill each blank with the most appropriate word.

undersell - to sell at a lower price

intervene - to come between

underpayment - bad, insufficient payment

immigrate - to move to a foreign country as a permanent resident

interval - a period between two events

1. A lot of Protestants . . . to America, because the Catholic Church was severely following them. 2. Because they buy in larger quantities at lower prices, chain stores are usually able to . . . goods to small shop-owners. 3. During the … the students had their lunch in the university canteen. 4. Because of permanent .. . . she decided to quit the job. 5. The summer vacation . . . between the close of one school year and the beginning of the next.

Exercise 5. Translate at sight

Uranium. The heaviest of all elements, a radio-active metal used for nuclear power production.

Cadmium. Used to electro-plate iron for rust protection. Also used for control rods in the atomic reactors of nuclear power stations.

Chromium. Used to give a shiny plating to other metals, and used in alloys of steel to produce stainless steel.

Cobalt. Used in the manufacture of steel cutting-tools. It also produces the blue used in pottery such as the famous ‘Sevres’ products.

Magnesium. Mainly used in the production of strong, light alloys such as duralumin. Also used for photographers flash bulbs. It burns in air with a brilliant, white flame.

Task 3.

Listening Comprehension

Listen to the lecture and answer the following questions

1. How many metals are used now?

2. What are the eight most widely used metals?

3. Why can’t other metals be regarded as very important engineering materials?

Task 4.

Focus on Grammar

Participle

Present Participle (I) - ing

Active Passive

Simple giving being given

Perfect having given having been given

Past Participle (II) -ed (III form of irregular verbs)

open - opened give - given

Past Participle always has a passive meaning.

1. Present Participles can be used as adjectives to describe an action which is still happening.

They watched the burning forest. Они наблюдали за горящим лесом.

На русский язык переводится причастием, деепричастием, определительным или обстоятельственным придаточным предложением.

2. Past Participles can be used as adjectives to describe the result of an action that has happened.

Тhe completed work was given to the teacher. Завершенная работа была передана преподавателю.

Обычно переводится причастием прошедшего времени или страдательным причастием.

3. Participles are often used in participle clauses to describe two actions that happen

a) at the same time: She sat by the fire reading a book.

He went to the party very well dressed.

b) one after another: Opening the bag she took out a purse.

Caught by the boy, the bird tried to fly away.

c) two actions that happen one because of another:

Not knowing what to do I just waited.

4. The subject of a participle need not be the same as the subject of the following verb, but in this case the participle must follow its noun/pronoun. This construction is not connected with the subject of a sentence and has the function of an adverbial modifier:

The day being fine, we decided to go swimming.

Так как день был прекрасным, мы решили искупаться.

Pure iron ranks ninth among the metals in degree of malleability, gold being the most malleable metal known.

По степени ковкости железо занимает девятое место среди металлов, причем золото является самым ковким из известных металлов.

Эти обороты называются независимыми причастными оборотами и переводятся на русский язык придаточными предложениями времени, причины, уступительными, условными с соответствующими союзами. Иногда могут переводиться самостоятельными предложениями с сочинительными союзами причем, а, и и т.д. При этом всегда необходимо помнить о контексте и общем смысле высказывания.

Exercise 1. Use simple or perfect forms of Present Participle.

1. She was sitting in the arm-chair, (to look) through a newspaper. 2. (To get) a letter from an unknown lady, I decided to invite her for a lunch. 3. (To enter) the room he suddenly saw that there were several unknown people in it. 4. Mother stood (to wave) her hand until we drove away. 5. Every day I see them (to pass) the house. 6. Romeo (to believe) that Julia was dead, decided to kill himself. 7. (To be) there twice, she decided to spend her vacation somewhere else. 8. She entered the hall (to accompany) by her mother. 9. (To warn) she decided not to take the risk and stayed at home. 10. Sam ,(to feel) that the interview was over, stood up.

Exercise 2. Use the present or past participle.

1. They watched the (to burn) forest helplessly. 2. The (to complete) letter was in front of him, but he was (to hesitate) to post it. 3. (To have) a shower, she got dressed. 4. He went to visit his aunt (to dress) as a real gentleman. 5. She gave me a drink (to make) of five different fruits. 6. (To advise) to give up work for a while, he undertook a trip to Europe. 7. During the flight I was (to read) a book. 8. He was (to dress) in a blue cotton shirt and a pair of grey trousers, (to spot) with vegetable oil.

Exercise 3. In the following pairs of sentences, the same verb is missing

twice, once used as a present participle and once as a past

participle. Insert the verbs in their correct forms.

1. I fell on ice, . . . my arm. Three people, . . . in an accident, were taken to hospital. (to hurt)

2. The film, . . . by Stephen Spielberg, is expected to be a great hit. They . . . beautiful silverware in Sheffield. (to make)

3. I looked at her, . . . her youth and beauty. This actress, though . . . by everybody, is very shy and modest. (to admire)

4. He walked down the road, . . . a song. This song is usually . . . by him at the beginning of a concert. (to sing)

5. Books . . . out of the library must be returned within 10 days. . . . a book from the shelf she didn’t notice that it missed several pages. (to take).

Exercise 4. Participle clauses can express the following ideas:

at the same time; because; after; if; with the result that

Which of the above ideas do the following participle clauses express?

1. Kissing her mother goodbye, she went off to the station. 2. Knowing how much I liked this book, she presented me with it. 3. Awakened early, he had enough time to pack. 4. Having read the book, I went to bed. 5. Having read the book, I knew all about the subject. 6. He left the house saying he would be back by dinner. 7. Taken in three times a day, this medicine will help you in a week. 8. Having spent all our money in the restaurant, we went home.

Exercice 5. Translate into Russian, paying attention to the use of the participles.

1. Alloy is a material consisting of two or more elements. 2. A series of alloys known as aluminium bronzes posess high strength. 3. If worked beyond certain limits, the metal will become very brittle. 4. Depending upon the kind of metal and the final shape desired, one or more rolling operations may be possible. 5. The speed-range depends on the kind of speed-change mechanism used. 6. Engineers of the company designed a press line, believed to be the first of its kind in Britain. 7. Machines and machine products have made possible a standard of living unsurpassed in history. 8. Owing to these methods it has become possible to obtain new mechanical properties of the alloy. 9. The tin strengthens and hardens copper, making it hard and resistant to wear. 10. Iron oxide is the major problem when forging steel. 11. When broken, the material has a black, silken fracture. 12. A piece of steel heated to a bright cherry red and suddenly chilled becomes extremely hard. 13. Manganese, phosphorus, sulphur and silicon are the elements separately and distinctly acting on physical properties of steel. 14. Having found out how to separate the mixture into its components, we understood that we could finish our experiment successfully. 15. Iron and sulphur being ground together, a greenish-black powder is obtained. 16. The atoms in diamond being closer to each other than in graphite, this substance is very hard.