Topic 6. Engineering materials

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Topic 6. Engineering materials

Vocabulary:

Property- свойство

Ferrous- железосодержащий

Steel- сталь

Alloy- сплав

Proportion- соотношение, пропорция

Improve- улучшать

Tungsten- вольфрам

Brass- латунь

Plastic- пластмасса, пластик

Pressure- давление

Undergo- подвергаться

Engineers have to know the best and most economical materials to use. Engineers must also understand the properties of these materials and how they can be worked. There are two kinds of materials used in engineering — metals and non-metals. We can divide metals into ferrous and non-ferrous. The former contain iron and the latter do not contain iron. Cast iron and steel, which are both alloys, or mixtures of iron and carbon, are the two most important ferrous metals. Steel contains a smaller proportion of carbon than cast iron. Certain elements can improve the properties of steel and are therefore added to it. For example, chromium may be included to resist corrosion and tungsten to increase hardness. Aluminium, copper, and the alloys (bronze and brass) are common non-ferrous metals.

Plastics and ceramics are non-metals; however, plastics may be machined like metals. Plastics are classified into two types — thermoplastics and thermosets. Thermoplastics can be shaped and reshaped by heat and pressure but thermosets cannot be reshaped because they undergo chemical changes as they harden. Ceramics are often employed by engineers when materials which can withstand high temperatures are needed.

TASKS:

1. Find English equivalents in the text:

1. Смесь железа с углеродом

2. Некоторые элементы

3. подвергаться химическим изменениям

4. улучшать свойства стали

5. противостоять коррозии.

2. Are these statements true or false?

1. Engineers must know the properties of engineering materials.

2. All materials can be classified as metals and non-metals.

3. Non-ferrous metals can contain iron.

4. Steels have to contain more carbon than cast iron.

5. Ceramics can resist high temperatures.

6. Thermosets may be machined.

7. Thermoplastics can be shaped and reshaped.

3. Complete the sentences:

1. Plastics are classified into two types _____.

2. Chromium may be included ____

3. Plastics and ceramics are ____.

4. Steel contains ____.

5. Thermoplastics can be shaped ____.

4. Answer the questions:

1. What kinds of materials do you know?

2. What can be shaped by heat and pressure?

3. Are there any elements which improve the properties of steel?

4. What are non-ferrous metals?

5. How many kinds of materials are there in engineering?

6. Fill in the scheme:

Classification of Engineering Materials

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