Методичка по английскому языку для ИТС (пр. С.С.Иванов)

on engine lathes. The vertical turret lathe is the fastest lathe for short and heavy work.

The more extensively used turret lathes with a horizontal axis of turret indexing do not have a cross-slide carriage. The horizontal turret lathe, commonly called the screw machine, is used in the production of duplicate parts.

Comprehension.

1. What does the turret serve for? 2. What parts can be economically machined on turret lathes? 3. Into what two main groups are turred lathes classified? 4. How many tool holes are there on hexagon turret? 5. How do turrets of all types of turret lathes travel?

Translate from Russian into English:

револьверная головка, удерживать режущий инструмент, большое количество режущих инструментов, без измерений, шестиугольная револьверная головка, степень точности, многоинструментальные держатели, одновременно, горизонтальная ось вращения, короткие и тяжѐлые заготовки, винторезный станок, запасные части.

Give the heading to each paragraph of the text, make up questions, answer the questions.

Complete the sentences with the proper words:

spindle holes, alignment, separately, a cut, dead centre, angle, measurements.

1. Each jaw has to be moved ... by turning the screw of the jaw. 2. Each point must have ... of 60 degrees and ... must be very clean. 3. ... of the centres can be best tested by taking ...4. Having got different ... the worker has to change the position of the ...

Translate into Russian. Pay attention to modal verbs and their equivalents.

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1. Steel has to be widely used in machine-building because of its high strength. 2. Tools made of high-speed steel will be able to do the work at much speeds than carbon tool steels. 3. Special alloy steels can be used for parts requiring great wear resistance, 4. Before turning a work in the Lathe the lathe centres are to be aligned. 5. A short work may be turned without using the dead centre.

State the forms and functions of infinitives and translate the following sentences into Russian.

1. To strengthen a drill the thickness of a web is increased. 2. The tailstock spindle is graduated in order to facilitate the measurements of travel of the spindle. 3. The end to be sharpened had to be placed in the horizontal plane.

4.In order to keep dead and live centres in good conditions they are to be oiled.

5.The aim was to develop a new method of cutting metals.

Dialogue.

Tell me of turret, will you?

The point is that the turret serves to hold cutting tools used in machining the

work.

To my mind, the machining possibilities of turret lathes are very extensive. Exactly so.

Can you remind me of the vertical turret lathe.

-Certainly, I can. The vertical turret lathe is the fastest lathe for short and

heavy work.

-And what about horizontal turret lathe?

It is called a screw-machine and used in the production of duplicate parts.

Unit 1. SUBMERGED ARC WELDING

Submerged arc welding (SAW) is a common arc welding process. It requires a continuously fed consumable solid or tubular (metal cored) electrode. The molten weld and the arc zone are protected from atmospheric contamination by being "submerged" under a blanket of granular fusible flux. When molten,

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the flux becomes conductive and provides a current path between the electrode and the work. SAW is normally operated in the automatic or mechanized mode, however, semi-automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are available. Deposition rates approaching 100 lb/h (45 kg/h) have been reported - this compares to 10 lb. /h (5kg/h) (max) for shielded metal arc welding. Currents ranging from 200 to 1500 A are commonly used; currents of up to 5000 A have been used (multiple arcs). Single or multiple (2 to 5) electrode wire variations of the process exist. DC or AC power can be utilized, and combinations of DC and AC are common in multiple electrode systems. Constant voltage welding power supplies are most commonly used, however constant current systems in combination with a voltage sensing wire feeder are available.

Material applications are carbon steels, low alloy steels, stainless steels, nickel-based alloys, surfacing applications are wear-facing, build-up, and corrosion resistant overlay of steels.

Advantages of SAW: 1) high deposition rates (over 100 lb. /h (45 kg/h) have been reported; 2) high operating factors in mechanized applications; 3) deepweld penetration: 4) sound welds are readily made (with good process design and control); 5) high speed welding of thin sheet steels at over 100 in/min (2,5 m/min) is possible; 6) minimal welding fume or arc light is emitted.

Limitations of SAW: 1) limited to ferrous (steel or stainless steels) and some nickel based alloys; 2) normally limited to long straight welds or rotated pipes or vessels: 3) it requires relatively troublesome flux handling systems; 4) flux and slag residue can present a health and safety issue; 5) requires interpass and post-weld slag removal.

Key SAW process variables: 1) wire-feed speed (main factor in welding current control); 2)arc voltage; 3) travel speed; 4) electrode stick-out (ESO) or contact tip to work (CTTW); 5) polarity and current type (AC or DC).

Other factors: 1) flux depth / width; 2) flux and electrode classification and type; 3) electrode wire diameter; 4) multiple electrode configuration.

VOCABULARY

сила тяжести; 14) шлак; 15) удаление шлака; 16) многоточечная сварка: 17) прочный шов; 18) переменная (величина); 19) плавкий, расходуемый; 20) вредное действие атмосферы.

II. Переведите на РЯ следующие слова и словосочетания:

1) carbon steel; 2) stainless steel; 3) build-up; 4) wearfacing; 5) molten weld; 6) granular flux; 7) to range; 8) wire-feeder; 9) constant current; 10) consumable electrode; 11) solid electrode; 12) application; 13) ferrous alloys; 14) residue; 15) design; 16) operating factors; 17) polarity; 18) to emit: 19) process control: 20) key variables.

Охарактеризуйте различия в семантике синонимов:

rate - speed - velocity, to feel - to sense, application - use - usage, coal - carbon, guard - shield - protect – defend

Вставьте нужное слово или словосочетание, используя содержание текста.

High deposition ... is one of SAW advantages.

This process requires continuously fed ... electrode.

SAW is normally ... in the automatic or semiautomatic mode.

Currents ... from 200 to 1500A are commonly used.

... current is current flowing in one direction only.

... current does not change its quantity.

Wearfacing and build-up are referred to surfacing ... of SAW.

One of SAW advantages is that minimal welding fume or arc light is ...

This process is normally limited ... long straight welds.

The molten weld and the arc zone are ... from atmospheric contamination.

Переведите на АЯ следующие предложения.

1. При дуговой сварке под флюсом требуется плавкий сплошной или трубчатый электрод. 2. Шов защищен от вредного действия атмосферы флюсом. 3. Расплавленный флюс становится электропроводным. 4. Чаще

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всего используются источники тока с постоянным напряжением. 5. Этот метод применим лишь для сварки сплавов железа. 6. К самым важным переменным процесса относятся полярность и ток - переменный или постоянный. 7. Дуговая сварка под флюсом применяется для сварки низколегированных и нержавеющих сталей. 8. При правильном расчете и контроле за процессом получают прочные швы. 9. Результаты сварки могут зависеть от типа используемых флюса и электрода.

Unit 2. PLASMA ARC WELDING

Plasma arc welding (PAW) is an arc welding process similar to gas tungsten arc welding (GTAW). The electric arc is formed between an electrode, which is usually but not always made of sintered tungsten and the work-piece. The key difference from GTAW is that in PAW, by positioning the electrode within the body of the torch, the plasma arc can be separated from the shielding gas envelope. The plasma is then forced through a fine-bore copper nozzle which connects the arc and the plasma exits the orifice at high velocities, approaching the speed of sound, and temperature approaching 20 000 °C.

Plasma arc welding is an advancement over the GTAW process. It can be used to join all metals that are weldable with GTAW, i.e. most commercial metals and alloys. Several basic PAW variations are possible by varying the current, plasma gas flow rate, and the orifice diameter, including: micro-plasma (< 15 Amperes); melt-in mode (15-400 Amperes); key-hole mode (100 Amperes). Plasma arc welding has a greater energy concentration as compared to GTAW. A deep narrow penetration is achievable, reducing distortion and allowing square-butt joints in material up to 12 mm thick. Greater arc stability allows a much longer arc length and much greater tolerance to arc length changes. Its limitation is that PAW requires relatively expensive and complex equipment as compared to GTAW.

At least two separate (and possibly three) gas flows are used in PAW: plasma gas which flows through the orifice and becomes ionized; shielding gas, which flows through the outer nozzle and shields the molten weld from the atmosphere; back-purge gas, required for certain materials and applications. These gases can be the same, or of differing composition.

Key process variables are: current type and polarity; usually DCEN from a CC source; AC square wave, common on aluminum and magnesium. Current can vary from 0,5 to 1200 A; current can be constant or pulsed at frequencies

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Exercises

Найдите в тексте английские эквиваленты следующих слов и словосочетаний:

1) основное различие; 2) корпус горелки; 3) газовый пузырь; 4) отверстие; 5) скорость; 6) скорость звука; 7) скорость потока плазмы; 8) металлы промышленного значения; 9) деформация; 10) квадратное стыковое соединение; II) допустимое отклонение (от заданных параметров); 12) газ, очищающий обратную сторону шва; 13) прямоугольный импульс; 14) магний; 15) конструкция электрода

Переведите на РЯ следующие слова и словосочетания:

1) sintered tungsten; 2) forced through; 3) fine-bore nozzle; 4) high velocity; 5) advancement; 6) orifice diameter; 7) to vary the current; 8) arc stability; 9) square butt; 10) outer nozzle; 11) pulsed current; 12) gouging; 13) surfacing; 14) arc spraying; 15) current levels.

Вставьте нужное слово или словосочетание.

1. Plasma arc welding is ... to gas tungsten arc welding. 2. In PAW the plasma arc is separated from the ... . 3. The plasma is ... through a fine-bore copper nozzle. 4. The plasma exits the orifice at . . . . 5. PAW has a greater ... as compared to GTAW. 6. PAW reduces distortion and allows ... in thick materials. 7. Greater arc stability allows much greater ... to arc length changes. 8. Paw requires relatively ... and ... equipment. 9. Plasma gas flows through the ... and becomes highly ionized. 10. Shielding gas protects the ... from the atmospheric contamination.

Переведите на АЯ следующие предложения.

1. Плазма - это поток сильно ионизированного газа. 2. Плазменная дуга может быть отделена от защитного газового пузыря. 3. При плазменной сварке электрод размещен в корпусе горелки. 4. Плазменная сварка представляет собой шаг вперед по сравнению с газовольфрамовой. 5. Варианты плазменной сварки различаются по силе тока, скорости потока плазмы и диаметра отверстия. 6. При плазменной сварке возможно

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проплавление большой глубины и малой ширины. 7. Защитный газ проходит через наружный мундштук. 8. Используемые при плазменной сварке газы могут быть как одинаковыми, так и разными по составу. 9. Обычно используют отрицательный электрод при источнике тока постоянной величины, не зависящей от напряжения дуги. 10. При сварке алюминия и магния обычно используется переменный ток с прямоугольным импульсом.

Unit 3. GAS METAL ARC WELDING

Gas metal arc welding (GMAW), sometimes referred to by its subtypes, metal inert gas (MIG) and metal active gas (MAG) welding, is a semiautomatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. A constant voltage, direct current power source is most commonly used with GMAW, but constant current systems, as well as alternating current, can be used.

Originally developed for welding aluminum and other non-ferrous metals in the 1940s, GMAW was soon applied to steels because it allowed for lower welding time compared to other welding processes. The cost of inert gas limited its use in steels until several years later, when the use of semi-inert gases such as carbon dioxide became common. Further developments during 1950s and 1960s gave the process more versatility and as a result, it became a highly used industrial process. Today, GMAW is commonly used in industries such as the automobile industry, where it is preferred for its versatility and speed. Unlike welding processes that do not employ a shielding gas, such as shielded metal arc welding, it is rarely used outdoors or in other areas of air volatility. A related cause a much greater heat input, which will make the wire electrode melt more quickly and thereby restore the original arc length. This helps operators keep the arc length consistent even when manually welding with hand-held welding guns. To achieve a similar effect, sometimes a constant current power source is used in combination with an arc voltage-controlled wire feed unit. In this case, a change in arc length makes the wire feed rate adjust in order to maintain a relatively constant arc length. In rare circumstances, a constant current power source and a constant wire feed rate unit might be coupled, especially tor the welding of metals with high thermal conductivity, such as aluminum. This grants the operator additional control over the heat input into the weld, but requires significant skill to perform successively.

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