Read the text and decide if the statements are true (T) or false (F). 1. The metal is shaped by pressure in mechanical working processes.

1. The metal is shaped by pressure in mechanical working processes.

2. Mechanical working includes machining or grinding, and the casting of molten metal into a mould.

3. The initial materials for the mechanical working of metals are ingots and billets.

4. Mechanical working involves the plastic deformation of cold metal by the external action of special tools.

5. Mechanical working doesn’t change the shape and dimensions of the billet but the volume of a metal shaped changes throughout the process.

6. The ductility of a metal increases with temperature, and its resistance to deformation is reduced.

7. The rate of deformation in mechanical working affects the plasticity of the metal.

8. The degree of deformation must be maintained within known limits.

9. The type of stressed state and the type of deformation affect the ductility of the metal being shaped in the course of mechanical working operation.

The shaping of metal by mechanical means in either the hot or cold state is called mechanical working. In mechanical working processes the metal is shaped by pressure. This excludes machining or grinding, and the casting of molten metal into a mould. Mechanical working processes include rolling, drawing, extrusion, smith forging, die forging and press working.

The initial materials for the mechanical working of metals are ingots and billets of various cross sections and weights.

Mechanical working involves the plastic deformation of either cold or heated metal by the external action of special tools such as mill rolls, forging dies, flat hammer dies or extruding dies. Mechanical working changes the shape and dimensions of the billet but the volume of a metal shaped remains substantially constant throughout the process.

The plasticity of a cast metal having coarse-grained dendritic structure proves to be less than that of a metal, which had undergone deformation and has, therefore, a more fine-grained structure. As a rule, the ductility of a metal increases with temperature, and its resistance to deformation is reduced.

The rate of deformation in mechanical working affects the plasticity of the metal in various ways. An increase in the deformation rate within a definite limit is accompanied by a decrease in plasticity. A further increase in this rate, after a certain point, improves the plasticity.

The degree of deformation, both in hot and, especially, in cold working, must be maintained within known limits. Rates exceeding the upper limit lead to the formation of cracks, tears and other discontinuities in the metal.

The type of stressed state and the type of deformation also affect the ductility of the metal being shaped in the course of mechanical working operation.

2. Find the following words and word-combinations in English in the text: шліфування; відливання розплавленого металу у (ливарну) форму; вільне кування; штамповане кування; зовнішня дія; прокатний стан; кувальні штампи; пласкі молотові штампи; штампи для видавлювання металу; розміри; об’єм; пластичність; виливаний метал; грубозерниста структура; дрібнозерниста структура; рівень деформації; визначена межа; певна точка; верхня межа; тріщини; дірки; ковкість.

3.Answer the following questions to the text.

1. What is mechanical working?

2. What do mechanical working processes include?

3. What are the initial materials for the mechanical working of metals?

4. What does mechanical working involve?

5. Does mechanical working change the shape and dimensions of the billet? What about the volume of a metal shaped?

6. The ductility of a metal increases with temperature, doesn’t it?

7. What does the rate of deformation in mechanical working affect?

8. Must the degree of deformation be maintained within known limits?

9. What do the type of stressed state and the type of deformation affect?

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