Text b.

During the last few years an increasing amount of attention has been devoted to the development of mills having working rolls of very small diameter, each of these rolls being supported by more than one backing roll. Such units may be described as multi-roll mills.

The advantages associated with the use of small-diameter working rolls are:

(1) The forces to which the various mill components are subjected, and especially the working rolls themselves, become smaller as the diameter of these rolls is reduced.

(2) The smaller the working rolls the greater is the overall reduction.

(3) Mills in which such rolls are installed are particularly suitable for the rolling of materials characterized by a high resistance to deformation, as, for example, stainless and other highly alloyed steels, nickel and titanium alloys.

(4) Since small rolls mean a reduction in the sizes of the mill itself, and in the floor space occupied, savings in capital outlay (капитальные вложения) might be expected.

(5) It might be noted that the multi-roll mill will occupy an important place at plants concerned with the rolling of strip materials, especially if these materials are required in thin gauges, i.e. less than 0.005 in. thick, and if they are characterized by having a high resistance to deformation.

IX. Составьте план к данному тексту.

Lesson 4.

Preliminary Exercises

I. Переведите предложения, помня о том, что глаголы “to appear” и “to prove” могут выполнять различные функции и поэтому по-разному переводиться.

1. Bodmer in 1842 appears to have been the first designer of a ring-rolling mill.

2. First hand-driven mills appeared towards the end of the sixteen century.

3. Automatic devices prove to be very useful during rolling operations.

4. Great progress made in the manufacture of sheet and strip proves the importance of this branch of metal fabrication.

II. Прочитайте и переведите следующие термины.

Ring rolling; rolling process; railway tyres; production time; material costs; input weight; large-scale production; four-mandrel mill; ring wall thickness; metal-formers, bar ends; two-stage rolling.

III. Переведите следующие предложения, учитывая, что окончание –ing могут иметь три различные грамматические формы:

1. Причастие I

2. Герундий

3. Отглагольное существительное

1. At the beginning of this century metal rolling mills were simple and imperfect.

2. Slabs can be only reduced after reaching the desired temperature in the furnace.

3. Different types of ring-rolling mills were developed according to the size of the ring being produced.

4. The first machine for making rings produced shaped bars by bending flat strip into a circular form.

5. When designing a mill the engineer concerned should decide on the dimensions of housings, rolls, bearings, etc.

6. The rolling of metals was known as far back as in the sixteen century.

Text A.

Rolling of rings

Ring rolling is a specialized form of rolling process and its value and virtues do not appear to be as widely appreciated as they should by metal formers. It is not a new method because railway tyres have long been made by this technique.

The first machine for making rings was constructed in England in 1827; it produced shaped bars by bending flat strip into a circular form with the bar ends being welded to form the ring.

Bodmer in 1842 appears to have been the first designer of a ring-rolling mill to produce seamless rings.

The first attempt in Germany was made by Alfred Krupp in 1849 for the purpose of producing railway tyres; he constructed the first ring-rolling mill in 1858-54 and by 1855-56 he had modified it for two-stage rolling.

Different types of ring-rolling mills have been developed according to the size of the ring being produced. For the large-scale production of small rings, a mechanical four-mandrel mill is used. It consists of a driven roll and four mandrels mounted on a rotating table whose centre is eccentric to the driven roll.

Rings of medium or large sizes are produced in a small series or as singles parts on hydraulic single-mandrel mills. In the case considered, reduction in ring wall thickness and, consequently, an increase in its diameter is achieved by moving the mandrel hydraulically towards the main roll.

During recent years the process has been increasingly applied in a number of fields owing to its technological advantages when compared with other techniques used for the production of rings, e.g. casting, the bending of profiles and the welding of the ends, and forging.

The advantages of ring rolling are a much shorter production time, uniform quality, close tolerances, and especially the considerable saving in material costs – about 90% of the input weight turns into finished product.

Terms to be remembered:

casting – литье

forging – ковка

mandrel – оправка

mandrel mill – стан для прокатки бесшовных труб (на оправке)

railway tyre – бандаж железнодорожного колеса

seamless – бесшовный

shaped bar – сортовой прокат фасонного сечения

to weld – сваривать

Exercises

IV. Переведите и запомните слова:

value, virtue, appreciate, flat, circular, eccentric, to bend, saving, costs, input profile, ring.

V. Найдите в тексте все слова с окончанием –ing, еще раз их переведите, определяя их грамматическую функцию.

VI. Ответьте на следующие вопросы.

1. What information does the text carry?

2. What proves that ring rolling is not a new method of rolling?

3. What types of ring-rolling mills are described in the text?

4. Why is the process increasingly applied in a number of fields?

5. What are the advantages of ring rolling?

VII. Перескажите текст.

VIII. a) Просмотрите тест. Какой тип стана описывается здесь? (время – 2 мин)

b) Переведите текст без словаря (время – 5мин).

Plate mills are widely used in rolling practice. These mills continue to be modernized often with the purpose of enlarging the size of the product: 5330 mm wide aluminum alloy plate can be produced on one mill; 5000 mm wide plate is produced on another mill; and several produce plate in the range or 3560-4220 mm. Large plates are in demand for welding, for example, to form large-diameter pipe in plant where facilities for spiral welding or narrower strip are not provided and, of course, for shipbuilding and boiler making. Roll bending is frequently incorporated.

A number of steelworks use a dual-purpose plate mill. Controlled rapid cooling of plates to improve plate strength and to give a finer grain size has received considerable attention.