Exercises. I. Use the following words and phrases in sentences of your own:

I. Use the following words and phrases in sentences of your own:

to penetrate, hardness, cross-section, to determine, to evaluate, plasticity, elasticity, to influence, unit stress, engineering materials, property, to subject, load, external forces, to cause, impact loads, compression loads, torsional loads, specimen, shearing loads, unit, surface, clamp, bending loads, rupture machine, extension, dial

II. Answer the following questions:

1. Why is it necessary to know the properties of engineering materials? 2. To what forces are machine parts subjected in the process of work? 3. How are the loads distinguished according to their influence upon the metal? 4. What are the most important mechanical properties of metal? 5. What special devices are used for testing mechanical properties? 6. What is stress? 7. What is strain? 8. What is strength of metals? 9. What is elasticity of metals? 10. What is plasticity of metals?

III. State the forms and functions of infinitives and translate the following sentences:

1.Malleability of a metal is also known as its ability to be deformed permanently under compression without rupture. 2. To determine properties of a metal special machines are used. 3. Plasticity of a metal makes it safe to use in all types of structures. 4. The materials to be tested are clamped between two clamps on the rupture machine. 5. It is common practice to divide metallurgical materials into ferrous and non-ferrous ones. 6. Some metals possess special properties, one of which is power to conduct electric current. 7. The ability of a material to take deformation without breaking is known as plasticity. 8. Engineering materials have large industrial applications and their mechanical properties to be studied require much attention.

IV. Fill in the blanks with prepositions to, within, from, into, on, in, of, by means of, per, without, by:

1. The composition... metals and alloys is important... the effect it has... their mechanical, electrical, or magnetic properties. 2. Metals can be cast... various shapes weighing... a few ounces... many tons. 3. Their plasticity, or ability to deform... rupture allows their formation... a required shape. 4. The strength... a metal is generally measured... tensile tests. 5. Tensile strength is expressed... pounds... square inch. 6. When a metal is subjected... stresses exceeding its elastic limit, the crystals of the metal elongate by an action... shearing which takes place... the crystals and between the crystals. 7. One way... measuring the hardness is to

determine the depth... which a diamond cone or ball will penetrate... the metal under a given load.

V. Make up nouns and adjectives from the following verbs and translate them into Russian:

to subject, to differ, to compress, to develop, to determine, to extend, to remove, to evaluate, to break, to deform, to define, to penetrate, to resist, to indicate, to consider

VI. Supply synonyms for the following words:

force, to call, to treat, to apply, a specimen, hard, small

VII. Supply antonyms for the following words:

external, constant, tensile, hardness, compression

VIII. Make up questions to which the italicized words are the answers:

l. The deformation test of a metal property is performed in a laboratory. 2. By testing a metal one can define its me chemical properties. 3. In some materials, such as stone or iron, the possible elastic deformation may be very small. 4. In some materials, such as lead, plasticity may imply an almost total absence of elasticity. 5. Elasticity is the capacity of the material to resist produced deformations without permanent change of form.

IX. Giving answers to the following questions describe the principle of operation of the rupture machine shown in Fig. 1:

l. What is a rupture machine used for? 2. How do the clamps of the rupture machine operate when testing a specimen? 3. By what means is the load upon the specimen under test determined?

CHAPTER II

MECHANICAL TOOLS

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