II. READING (20 points). a) Put the following words into the certain gaps

a) Put the following words into the certain gaps. There are two extra words:

a) hammer; b) heat; c) energy; d) nitrogen; e) current; f) joining; g) frames; h) welding; i) chemical; j) oxygen; k) arc; l) types.

TYPES OF WELDING

Welding is a process of 1) … together metallic parts by heating the place of contact to the fusion state. Welding processes are classified according to the source of 2) … employed for heating, the metals and the state of the metal at a place of welding. There are different types of 3) … such as hammer welding, thermit welding, electric arc welding, gas welding etc.

Hammer welding is a process in which two heated metal parts are joined and fused together by force from power 4) ….

Thermit welding is a process consisting of a 5) … reaction. It is used in repairing large sections such as rails, 6) … etc.

Resistance welding process forms a whole group consisting of many types of welding such as spot welding, butt welding and others.

In arc welding the workpiece are not melted by the flame. They are melted by an electric 7) …. In order to create the arc, a powerful electric 8) … must be provided. The current must be at least 60 a, otherwise the arc will not create enough 9) ….

In gas welding, it is necessary to use a mixture of two gases. To create a hot flame, a combustible gas must be fixed with 10) …. Gas welding is normally used to join steel to steel.

b) Define whether these sentences are true (T) or false (F):

1. Hammer welding is a process consisting of chemical reaction.

2. In gas welding a mixture of more than two gases is used.

3. Arc welding is a process when two metal parts are melted by an electric arc.

4. Welding is a process when two plastic parts are joined together by melting.

5. Resistance welding process includes many types of welding.

6. When joining steels thermit welding is applied.

7. In arc welding the current must be not less than 60 a.

8. Thermit welding is used in repairing large sections.

9. To create a hot flame, a combustible gas must be fixed with nitrogen.

10. Welding processes are classified according to the origin of power employed for heating.

Total Score – 40 points