2. Составьте словарь к тексту.

3. Прочитайте текст снова и письменно ответьте на вопросы:

1. What process improves the mechanical properties of metals?

2. What new properties do hot-worked products have?

3. How are the flow lines in the forged metal oriented and how does it affect the strength of the forged part?

4. What are the best strain-hardening alloys?

5. Where can we use strain-hardening alloys?

Вариант 5

1. Прочитайте и письменно переведите на русский язык текст:

METALWORKING

1. Metals are important in industry because they can be easily deformed into useful shapes. A lot of metal working processes have been developed for certain applications. They can be divided into five broad groups: rolling, extrusion, drawing, forging, sheet-metal forming.

2. During the first four processes metal is subjected to large amounts of strain (deformation). But if deformation goes at a high temperature, the metal will recrystallize – that is, new strain-free grains will grow instead of deformed grains. For this reason metals are usually rolled, extruded, drawn, or forged above their recrystallization temperature. This is called hot working. Under these conditions there is no limit to the compressive plastic strain to which the metal can be subjected.

3. Other processes are performed below the recrystallization temperature. These are called cold working. Cold working hardens metal and makes the part stronger. However, there is a limit to the strain before a cold part cracks.

4. Rolling is the most common metal working process. More than 90 percent of the aluminum, steel and copper produced are rolled at least once in the course of production. The most common rolled product is sheet. Rolling can be done either hot or cold. If the rolling is finished cold, the surface will be smoother and the product stronger.

5. Extrusion is pushing the billet to flow through the orifice of a die. Products may have either a simple or a complex cross section. Aluminium window frames are the examples of complex extrusions.

6. Tubes or other hollow parts can also be extruded. The initial piece is a thick-walled tube, and the extruded part is shaped between a die on the outside of the tube and a mandrel held on the inside.

7. In back-extrusion (штамповка выдавливанием) the workpiece is placed in the bottom of a hole and a loosely fitting ram is pushed against it. The ram forces the metal to flow back around it, with the gap between the ram and the die determining the wall thickness. The example of this process is the manufacturing of aluminium beer cans.

2. Составьте словарь к тексту.

3. Прочитайте текст снова и письменно ответьте на вопросы:

1. Why are metals so important in industry?

2. What are the main metalworking processes?

3. Why are metals worked mostly hot?

4. What properties does cold working give to metals?

5. What is rolling?

Тексты по направлению

190600.62 "Эксплуатация транспортно-технологических машин и комплексов" вариант 1

1. Прочитайте и письменно переведите на русский язык текст:

THE ENGINE

1. The word engine originally meant any ingenious device, and came from the Greek word ingenious, clever. Any kind of vehicle must be able to move. The ability to move demands power. A machine that produces mechanical power or energy is called an engine or a power plant. Engines present one of the most interesting groups of problems considered in the engineering field. One of the main problems is receiving the maximum possible power or thrust for minimum weight. The weight is included in the factor called the weight/power ratio, which may be defined as the weight in pounds per horse power output. Another important problem is that of fuel. Both in the past and today the designers work at the of getting lower specific fuel consumption. Specific fuel consumption is obtained by dividing the weight of the fuel burned per hour by the horse power developed.

2. Another possible problem considered in any engine is its flexibility. Flexibility is the ability of the engine to run smoothly and perform properly at all speeds and through all variations of atmospheric conditions.

3. One more important problem worked at by the designers is the engine reliability. The engine is to have a long life, with maximum of time between overhaul periods. In some cases the problem of balance is one of the main. Balance has several possible meanings but the principle factor is freedom from vibration. Besides any engine must be started easily and carry its full load in a few minutes. There are gasoline engines, diesel engines, gas turbines, steam engines, jet engines and rocket engines. Each of them has certain advantages and disadvantages over other forms of power plants.