ЗМІСТ:

1	What is Welding?............................................................	4
2	The History of Welding………………………………...	7
3	Forge or Blacksmith Welding. Thermit Welding…….	11
4	Welding Processes. Arc Welding (Part I)……………..	13
5	Arc Welding (Part II)…………………………………..	16
6	Gas Welding…………………………………………….	21
7	Electric Welding………………………………………..	24
8	Energy Beam Welding. Solid State Welding………….	29
9	Soldering. Brazing……………………………………...	32
10	Geometry of Welding……….………………………….	35
11	Texts for Additional Reading………………………….	37
1.1	Arc Welding Hazards…………………………………..	37
1.2	Quality of Welding……………………………………..	45
1.3	Distortion and Cracking……………………………….	46
1.4	Weldability……………………………………………...	47
1.5	Difficulties………………………………………………	48
1.6	Unusual Conditions of Welding……………………….	50
1.7	Safety Issues…………………………………………….	51
1.8	Costs and Trends……………………………………….	53
	Welding Glossary………………………………………	55

UNIT 1

exercise 1 Read and translate the text into Ukrainian paying special attention to the words given in bold type:

What is Welding?

W elding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material (the weld puddle) that cools to become a strong joint, with pressure sometimes used in conjunction with heat, or by itself, to produce the weld. This is in contrast with soldering and brazing, which involve melting a lower-melting-point material between the workpieces to form a bond between them, without melting the workpieces. Many different energy sources can be used for welding, including a gas flame, an electric arc, a laser, an electron beam, friction, and ultrasound. While often an industrial process, welding can be done in many different environments, including open air, underwater and in space. Regardless of location, however, welding remains dangerous, and precautions must be taken to avoid burns, electric shock, poisonous fumes, and overexposure to ultraviolet light. Fuses of two masses of metal may be brought about four different processes, namely: 1) Forge or blacksmith welding, 2) Thermit welding, 3) Electric welding, 4) Gas welding. Until the end of the 19th century, the only welding process was forge welding, which blacksmiths had used for centuries to join metals by heating and pounding them. Arc welding and oxyfuel welding were among the first processes to develop late in the century, and resistance welding followed soon after. Welding technology advanced quickly during the early 20th century as World War I and World War II drove the demand for reliable and inexpensive joining methods. Following the wars, several modern welding techniques were developed, including manual methods like shielded metal arc welding, now one of the most popular welding methods, as well as semi­automatic and automatic processes such as gas metal arc welding, submerged arc welding, flux-cored arc welding and electroslag welding. Developments continued with the invention of laser beam welding and electron beam welding in the latter half of the century. Today, the science continues to advance. Robot welding is becoming more commonplace in industrial settings, and researchers continue to develop new welding methods and gain greater understanding of weld quality and properties.

Exercise 2 Answer the following questions:

1. What is welding?

2. What is the difference between soldering and welding?

3. What energy sources are used for welding?

4. In what environments can welding be done?

5. What were the earliest methods of welding?

6. What new welding methods do you know?

Exercise 3 Give Ukrainian equivalents to the following words and explain their meanings:

Soldering, brazing, electric arc, energy sources, ultraviolet light, forge welding, arc welding, oxyfuel welding, resistance welding, friction.

Exercise 4 Find in the text five sentences used in Passive Voice.

Exercise 5 Tell which of the following statements are true and which are false. Correct the false statements to make them true:

1. Welding is a fabrication process of connecting wires, by causing friction.

2. Welding is often done by cooling the workpieces and adding a filler material.

3. Many different natural resources are used for welding.

4. Blacksmith welding had been used for centuries to join metals by heating and pounding them.

5. The new methods of welding continue to advance.

Exercise 6 Put five questions to the text.

UNIT 2

exercise 1 Read and translate the text: