2Курс 4 семестр

Донецьк: 7010104010 Професійне навчання. Технологія та обладнання зварювального виробництва.

Unit 1 Gas Welding and Arc Welding

Gas welding is a non-pressure process using heat from a gas flame. The flame is applied directly to the metal edges to be joined and simultaneously to a filler metal in the form of wire or rod, called the welding rod, which is melted to the joint. Gas welding has the advantage of using equipment that is portable and does not require an electric power source. The surfaces to be welded and the welding rod are coated with flux, a fusible material that shields the material from air, which would result in a defective weld.

Arc Welding

Arc-welding is the most important welding process for joining steels. It requires a continuous supply of either direct or alternating electrical current. This current is used to create an electric arc, which generates enough heat to melt metal and create a weld.

Arc welding has several advantages over other weld­ing methods. Arc welding is faster because the concen­tration of heat is high. Also, fluxes are not necessary in certain methods of arc welding. The most widely used arc-welding processes are shielded metal arc, gas-tungsten arc, gas-metal arc, and submerged arc.

Shielded Metal Arc

In shielded metal-arc welding, a metallic electrode, which conducts electricity, is coated with flux arid con­nected to a source of electric current. The metal to be welded is connected to the other end of the same source of current. An electric arc is formed by touching the tip of the electrode to the metal and then drawing it away.

The intense heat of the arc melts both parts to be welded and the point of the metal electrode, which supplies filler metal for the weld.

This process is used mainly for weld­ing steels.

Vocabulary notes:

1. gas welding – газове зварювання

2. arc welding – електродугове зварювання

3. resistance welding – контактне зварювання

4. laser welding – лазерне зварювання

5. electron-beam welding – електронно променеве зварювання

6. flame – полум'я

7. edge - край

8. simultaneously - одночасне

9. filler - наповнювач

10. wire - дріт

11. rod – стрижень

12. to melt- плавити

13. joint – з'єднання

14. advantage - перевага

15. to require – вимагати

16. surface - поверхня

17. flux -флюс

18. fusible - плавкий

19. to shield – захищати

20. touching - дотик

21. tip – кінчик

Завдання № 1: Дайте відповіді на запитання.

1. Give the definition of gas welding.

2. What kinds of welding can be used for joining steels?

3. What does arc welding require?

4. Is an electric arc formed by touching the tip of the electrode to the metal?

Завдання №2: Доповніть речення згідно зі змістом текста.

1. This current is used to create an electric arc, which generates enough heat _____.

2. Arc-welding has several advantages over other welding _________.

3. The flame is applied directly to the metal edges ________.

4. The surfaces to be welded and the welding rod are coated with flux fusible material that shields the material _________.

5. Arc-welding is faster because the concentration of heat is _______.

Завдання №3: Знайдіть а) синоніми, b) антоніми до наступних слів у тексті.

а) stream, identical, blaze, joined, to cover.

b) to separate, disadvantage, indirect, low, different.

Завдання №4: Виберіть речення, які відповідають змісту тексту.

1. Gas-welding is a pressure process using heat from a gas flame.

2. Arc-welding requires an electric power source.

3. Fluxes are not necessary in certain methods of arc-welding.

4. The intense heat of the arc cools doth parts to be welded.

5. In shielded metal-arc welding, a metallic electrode is coated with flux and connected to a source of electric current.

Завдання №5: Складіть речення з поданих слів.

1. welding, is, flame, gas, process, using, a non-pressure, heat, from, a gas.

2. is, steels, important, arc-welding, welding, the most, process, for, joining.

3. over, has, weld­ing, several, advantages, arc welding, other, methods.

4. Also, methods are, not, necessary, in arc welding, certain, fluxes, of.

5. weld­ing, this, is, used, steels, mainly, process, for.