3. Translate the following words into Russian:

A property, strong, a boundary, a conductivity, to reduce, a friction, useful, relatively, an expansion, to create, to apply, an expansion.

4. Find the nouns in the text, which can be characterized by the following adjectives and make your own sentences

Boiling, electrical, specific, thermal, melting, different, definite.

5. Fill in the blanks using the verbs in the brackets

1. Copper .... some of the characteristics of aluminum (to share).

b) Copper alloys ... also widely used for friction (to be).

c) Copper alloys ...properties that require special attention when welding (to possess).

d) Copper ... the highest electrical conductivity (to have).

e) Copper's high electrical conductivity ... it widely used in the electrical industries (to make).

6. Fill in a suitable word or word combination from the list below

1. Copper alloys are also widely used for friction or....

2. Copper shares some of the characteristics of....

3. All of the copper alloys derive their strength from....

4. Copper has the highest.... of any of the commercial metals.

5. Zinc has a relatively.... temperature.

(Bearing applications, cold working, aluminum, low boiling, electrical conductivity.)

7. Retell the text using the active vocabulary of the unit

Unit Three

1. Study and try to memorize the following words and word combinations:

1. A tool - инструмент

2. an absence - отсутствие

3. to braze - делать твердым

4. to forge - ковать

5. rate of oxidation - степень окисления

6. alloy - сплав

7. oxy-fuel gas welding - газопламенная кислородная сварка

8. friction - трение

2. Read and translate the text Welding Magnesium - Base Alloys

Magnesium is the lightest structural metal. It is approximately two-thirds as heavy as aluminum and one-fourth as heavy as steel. Magnesium alloys containing small amounts of aluminum, manganese, zinc, zirconium, etc., have strengths equaling that of mild steels. They can be rolled into plate, shapes, and strip.

Magnesium can be cast, forged, fabricated, and machined. As a structural metal it is used in aircraft. It is used by the materials-moving industry for parts of machinery and for hand-power tools due to its strength to weight ratio.

Magnesium can be welded by many of the arc and resistance welding processes, -as well as by the oxy-fuel gas welding process, and it can be brazed.

Magnesium possesses properties that make welding it different than the welding of steels. Many of these are the same as for aluminum. These are:

1.Magnesium oxide surface coating

2.High thermal conductivity

3.Relatively high thermal expansion coefficient

4.Relatively low melting temperature

The normal metallurgical factors that apply to other metals apply to magnesium as well. Magnesium is a very active metal and the rate of oxidation increases as the temperature is increased. The melting point of magnesium is very close to that of aluminum, but the melting point of the oxide is very high. In view of this, the oxide coating must be removed.

Magnesium has high thermal heat conductivity and a high coefficient of thermal expansion. The thermal conductivity is not as high as aluminum but the coefficient of thermal expansion is very nearly the same.

3. Make up nouns from the following verbs and translate them:

1. to possess

2. to apply

3. to process

4. to resist