Упражнения

1. Найдите в тексте английские эквиваленты следующих слов и словосочетаний:

1. Неплавящийся электрод, 2. источник тока, 3. цветные металлы, 4. баллонный газ, 5. переменный ток, 6. постоянный ток, 7. сплав, 8. защитная среда при сварке, 9. (отрицательное) воздействие окружающей среды, 10. источник тока постоянной величины, 11. шов, загрязненный окалиной, 12. решить проблему, 13. двуокись углерода, 14. прогревание, 15. жаростойкий, 16. плотно прилегать, 17. зона расплава, сварочная ванна, 18. чугун, 19. размеры зазора, 20. заостренный, конусообразный.

П. Расшифруйте следующие аббревиатуры и дайте перевод их полных форм:

GTAW, TIG, MIG, DCEN, DCEP, DC, AC

Ш. Переведите на РЯ следующие слова и словосочетания:

1. Filler metal. 2. copper alloys, 3. shielded metal arc welding, 4. atmospheric contamination, 5. heliarc inert gas welding, 6. polarity of the electrode, 7. to produce high quality welds, 8. water-cooled torch, 9. to reduce weld quality, 10. carbon steel, 11. to prevent contamination, 12. tool steel, 13. root side of the weld, 14. dissimilar metals, 15. to form a bond, 16. compatible material, 17. weld pool, 18. dilution, 19. base material, 20. to utilize tungsten electrodes.

IV. Охарактеризуйте различия в семантике синонимов:

Contamination – pollution, to use – to utilize – to employ, seam – weld, respond – react, application – use.

Unit 3. GAS TUNGSTEN-ARC WELDING (GTAW) EQUIPMENT

In tungsten inert gas (TIG) welding, (also known as GTAW), an arc is struck between a virtually non-consumable tungsten electrode and the workpiece. The heat of the arc causes the edges of the work to melt and flow together. Filler rod is often required to fill the joint. During the welding operation, the weld area is shielded from the atmosphere by a blanket of inert argon gas. A steady stream of argon passes through the torch, which pushes the air away from the welding area and prevents oxidation of the electrode, weld puddle, and heat affected zone.

The basic equipment requirements for manual TIG welding are as follows.

The equipment consists of the welding torch plus additional apparatus to supply electrical power, shielding gas, and a water inlet and outlet. Also, personal protective equipment should be worn to protect the operator from the arc rays during welding operations.

Different types of TIG welding equipment are available through normal supply channels. Water-cooled torches and air-cooled torches are both available. Each type carries different amperage ratings. Consult the appropriate manual covering the type of the torch used.

Argon is supplied in steel cylinders containing approximately 330 cu ft at a pressure to 2000 psi (13,790 kPa). A single or two stage regulator may be used to control the gas flow. A specially designed regulator containing a flowmeter may be used. The flowmeter provides better adjustment via flow control than the single or two stage regulator and is calibrated in cubic feet per hour (cfh). The correct flow of argon to the torch is set by turning the adjusting screw on the regulator. The rate of flow depends on the kind and thickness of the metal to be welded.

Blanketing of the weld area is provided by a steady flow of argon gas, directed

through the welding torch. Since argon is slightly more than 1-1/3 times as heavy as air, it pushes the lighter air molecules aside, effectively preventing oxidation of the welding electrode, the molten weld puddle, and the heat affected zone adjacent to the weld bead.

The tremendous heat of the arc and the high current often used usually necessitate water cooling of the torch and power cable. The cooling water must be clean; otherwise, restricted or blocked passages may cause excessive overheating and damage to the equipment. It is advisable to use a suitable water strainer or filter at the water supply source. If a self-contained unit is used, such as the one used in the field (surge tank) where the cooling water is recirculated through a pump, antifreeze is required if the unit is to be used outdoors during the winter months or freezing weather. Some TIG welding torches require less than 55 psi (379 kPa) water pressure and will require a water regulator of some type. Check the operating manual for this information.

Nomenclature of a Torch:

1. A cap prevents the escape of gas from the top of the torch and locks the electrode in place.

2. A collet is made of copper; the electrode fits inside and when the cap is tightened, it squeezes against the electrode and keeps it in place.

3. A gas orifice nut allows the gas to escape.

4. A gas nozzle directs the flow of shielding gas onto the weld puddle. Two types of nozzles are used; the one for light duty welding is made of a ceramic material, and the one for heavy duty welding is a copper water-cooled nozzle.

5. There are three plastic hoses, connected inside the torch handle, carrying water, gas, and the electrode power cable.

VOCABULARY

Water inlet – подвод воды

Normal supply channels – обычная торговая сеть

Water-cooled torch – водоохлаждаемая горелка

Amperage rating – номинальная сила тока

Flowmeter – расходомер, газомер

Adjusting screw – регулировочный винт

Passage – канал, рукав для подачи воды

Water strainer - фильтр

Self-contained unit – автономная установка

Surge tank – уравнительный резервуар

To recirculate – циркулировать в замкнутом цикле

Antifreeze – антифриз, (вещество, предупреждающее замерзание жидкостей)

Collet – конусная втулка

Gas orifice nut – гайка на выходном отверстии для газа

Light duty welding – сварка с небольшой нагрузкой

Nomenclature – перечень (частей комплекта), комплектность

Gas nozzle – газовое сопло