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III. Can you read these chemical elements? If not, find their names in the text.

C, S, P, Se, W, Mo, V, Cr, Co, Ni, Ті, Al, Cu, N, Nb.

IV. Are these statements true or false? Correct the false statements.

1. There are many kinds of steels.

2. Three major classes are carbide steels, low-alloy steels, and high-alloy steels.

3. Carbon steel was used in building the Golden Gate Bridge.

4. Great strength, hardness and other valuable mechanical properties are obtained by the addition of a great amount of carbon.

5. Low-alloy steels are the most popular kind of steel.

6. Tool steel is used for producing automobile bodies, ships and spoons.

7. Tool steel is not cost-efficient.

8. Tungsten, molybdenum, vanadium, and chromium in different combinations may improve high-temperature performance of stain­less steel.

9. A remarkable resistance of stainless steel to corrosion and heat is achieved with the help of chromium and high carbon content.

V. Your friend studied the properties of different steels in the practical class. Ask him what he has found out. These are the possible questions.

What types of steel did you study?

What is the carbon content of carbon steels? How does it influence their properties?

Where may carbon steels be used?

VI. Annotate the text.

20.

Composite Materials

Modal Verbs

Plastics

Lead-in

I. Discuss the following questions.

a) Are plastics widely used today? Make a list of possible applications of plastics. Compare it with that of your groupmates.

b) What properties do plastics have?

II. Alice meets her friend Andrew in the University library. Listen to their dialogue and say what you have learnt about plastics.

Alice: Hi, Andrew, are you busy now?

Andrew: Yes, I am. I have to draw up a laboratory report. Can you help me do it properly?

Alice: Well, as far as I know, a laboratory report must contain the object of the experiment, the results that were obtained and the conclusions.

Andrew: And what about the procedure and the equipment? Must they be included into the report, too?

Alice: In my view, both of them must be included if you need a detailed report. By the way, Andrew, what did you have to determine during your experiment?

Andrew: We had to compare the properties of different plastics.

Alice: And what results did you get?

Andrew: Well, you know that plastics may be divided into thermo­plastics and thermosetting plastics. So we have come to the conclusion that thermoplastics may be heated several times, while thermosetting plastics may be heated only once.

Alice: Oh, this is very interesting. And as far as I understand, this peculiarity of plastics must be taken into account when dif­ferent engineering products are produced.

Andrew: Certainly. And I will have to prove it in my report.

III. Complete the dialogue.

A: ….

B: Yes, I'm very busy. I have to draw up … . Do you know how to do it properly?

A:

B: What do I have to do to draw up a laboratory report?

A:

B: And must the procedure and the equipment be included into the report, too?

A:

B: I had to determine the basic properties of thermoplastics.

A:

B: Certainly. It was very interesting.

A:

B: Oh, we will have to carry out another tensile test in a week.

A: Well, good luck to you.

B:

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