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Інженерна мех. 4 курс Гусаренко.doc
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Welding

Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence This is often done by melting the work pieces and adding a tiller 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.

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 outer space.

Until the end of the 19th century, the only welding process was forge welding, which blacksmiths had used tor centuries to join metals by heating and pounding them. Following the wars, several modem welding techniques were developed, including manual methods like shielded metal arc welding, now one of the most popular welding methods, as well as semi-automatic and automatic processes such as gas metal arc welding, submerged arc welding, flux-cored arc welding and electro slag 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.

3. True or false statements:

1. The welded metal is heated to a melting temperature.

2. At present, the basic types of welding are gas welding electric resistance welding and electric arc welding.

3. Welding can not be done in many different environments.

4. Welding can be a dangerous and unhealthy practice.

5. Some welding processes are commonly used in a wide variety of conditions.

4. Listen to the text once again and answer the following questions:

1. What is welding?

2. What are the basic types of welding?

3. Until the end of 19th century, the only welding process was forge welding, wasn’t it?

4. When were several modern welding techniques developed?

5. Is robot welding becoming more commonplace industrial settings today?

V. Communicative skills.

Topic for discussion: How do machines help people do work by changing the amount of force?

Unit 11 Topic: The Main Joints of Machine Elements

1. Pre – reading tasks.

a) You will read a text about the main joints of Machine elements. Do you know the advantages of welding?

b) Read and memorise the following words and word-combinations in their specialized meanings.

1. detach – роз’єднувальний, змінний

2. permanent – постійний

3. fluid – рідина

4. strap – обхват, стягувати

5. curvilinear – криволінійний

6. tightness – герметичність, компактність

7. electrode wire – електродна проводка

8. butt – стик, торець

9. fillet – закругление, валик

10. joint – з’єднання