Read and translate the text.

3. Answer the following questions:

1. What is Friction Stir Welding?

2. Where is the FSW used?

3. Where is the Mig welding used?

4. When was the FSW technique developed?

5. Why is the usage of aluminium increasing?

6. At what stage is the knowledge of friction stir welds?

4. Find the antonyms to the words:

High, frequently, strength, productive, disadvantages, to decrease, to join, to heat, different, often, to understand.

5. Complete the following sentences:

1. Aluminium alloys are used in...

2. The two most frequently used alloys are...

3. Mig welding is....

4. The technique was developed...

5. The unique characteristic of aluminium....

6. Although the practical application of the FSW has been successful...

6. Chose the correct definition to the word:

shipbuilding

a. brunch of industry

b. brunch of economy

c. brunch of medicine

friction

a. physical process

b. chemical process

c. biological process

tungsten

a. metal

b. gas

c. plant

Select the correct form.

1. He has worked in that field (for, since) many years.

2. Nick said that he (saw, had seen) the result of friction stir welding.

3. This tool is mine and that one is (your, yours).

4. Rita wants (me to go, that I go) to the exhibition of welding equipment with her.

8. Give the three forms of the verbs:

To flow, to join, to use, to form, to leave, to have, to be, to make, to know, to produce.

Fill in the gaps with a proper article.

1. It is also of interest in many other applications, such as... topside structures of offshore platforms, railway wagons and in....brewing industry.

2. However, two disadvantages with MIG welding are... deformation of... base material and... decrease in... strength of... heat affected zone.

3.... components that are going to be joined are placed on... backing plate and clamped using... powerful fixture.

4. Because of... increased use of aluminium as... manufacturing material,... conversion from steel to aluminium within... welding fabrication industry is becoming increasingly common.

5. Most unprotected aluminium base alloy or filler alloy combinations are quite satisfactory for general exposure to... atmosphere.

6. Although... practical application of... FSW technique has been successful, there is still... lack of design data and understanding of... failure mechanisms.

Complete the questions on the text.

1. Did/Was ______?

2. ___or____?

3. _________didn’t/wasn’t?

4. When/Why/Where?

5. Who/What______?

11. Communicative situations:

1. Make a report on the topic “ What is the usage of FSW ”

2. Speak with your friend about advantages and disadvantages of FSW

Retell the text.

TEXT B

PLASMA

Plasma welding. Plasma welding provides the highest effect when used for joining metals with a high thermal conductivity, such as copper, aluminium and other alloys. This method allows avoidance of preheating and performance of single-pass welding on a wide range of thickness of materials. Thus, the straight polarity plasma arc can weld copper up to 50 mm thick in a single pass without groove preparations. Plasma welding of aluminium and its alloys at a DCRP provides a high quality of welded structures up to 20 mm thick. Strength characteristics of the weld metal containing no tungsten inclusions and no oxide films are at a level of 95% of those of the base metal.

A range of the plasma welding machines has been developed. Machines operating at currents of 50, 100, 300, 500 and 800 A are available. The technology and optimal layout of the microplasma equipment have been devised for all types of welding of parts of thin-sheet metals (bellows, casings of instruments, magnetic cores, transformers and many others).

An important property of microplasma welding is a high degree of constriction of the arc and low sensitivity of sizes of the weld being formed (its width and depth) to variations in the arc length.

The use of this welding method instead of argon-arc welding leads to a substantial increase in productivity and quality of welding of thin metals (0.1 – 2.0 mm) and improves vendibility of products.

Modern electronics allows a contactless ignition of the arc, regulation of the current drop at the end of welding and fast precise setting of the process parameters.

Plasma surfacing. Surfacing can be used to make the most diverse items with the desirable surface properties, i.e. corrosion-, heat-, wear-resistant, antifriction, etc., as well as to repair worn-out pieces.

Plasma surfacing can be performed at a direct current of reverse or straight polarity, using wire or powder consumables.

Owing to minimum penetration of the base metal and its minimum dilution with the deposited metal, the process of plasma surfacing at a DCRP provides the preset properties of the metal even in the first of the deposited layers, as compared with the third or fourth layers in the case of arc surfacing. This leads to metal saving and raises labour productivity. Powder materials, such as Co-based alloys and Ni-based alloys, Fe-based powders, stainless steel and bronze wire can be used as the coating materials.

Plasma surfacing gains wide acceptance in manufacture and repair of valves of various-application internal combustion engines, rolling mill shafts and other parts.

Exercises

1. Remember the following words and word-combinations:

layout -устаткування;

bellows -ковальські міхи;

vendibility -здатність до продажу;

constriction -скорочення;

reverse polarity -протилежна полярність;

straight polarity -пряма полярність.

Дата добавления: 2015-11-16