Part II

In drawing seamless tubing the metal is forced between the die and the mandrel, and in this way the wall thickness, the outside diameter, and the inside diameter may be controlled. As in any cold-working operation, the metal should be free from scale and other defects before it is cold-drawn.

Cold-working operations may be divided into two large classes:

1. Where the cold working is carried out for the purpose of shaping the articles only; and where the hardening effect is not desired and must be removed at various stages of plastic shaping as well as from the finished article by annealing.

2. Where the object of cold working is not only to obtain the required shape but to harden and strengthen the metal, and where the final annealing operation is not carried out.

In order to shape metals by cold working they must be annealed at proper intervals. Otherwise deformation must be carried out at temperatures where annealing is simultaneous with hardening, as in the hot working of metals. The selected method will depend on the individual metal as well as on the desired product. Metals vary greatly in the ease with which they deform. Copper, for example, may be worked readily at room temperatures, whereas some steels can only be worked at a red heat. Practically all metals and alloys become brittle very near their melting points and hence must not be worked at too high temperatures. There are metals that can be worked only in certain temperature ranges without cracking. Thus zinc must be worked at 200 to 300 degrees of Fahrenheit; nearly pure iron must not be worked in the blue heat range. Brass must not be heated too near its melting point in annealing, also, or it becomes «burnt».

Topic: «geographical position of great britain» Part I

The United Kingdom of Great Britain and Northern Ireland is situated on 2 large islands and 5000 smaller ones. These are the British Isles. Great Britain, the largest island in Europe, includes England, Scotland and Wales. It is separated from Ireland by the Irish Sea, from the European Continent-by the North Sea, the English Channel and the Strait of Dover. On the west coasts Great Britain is bound by the Atlantic Ocean.

The southern part of Ireland is an independent republic.

The greater part of the surface of England and Ireland is flat. The northern part of Scotland and Wales is mountainous and rocky. The highest mountain of the country is Ben Navis in Scotland. The main rivers are short but can be used by ships. There is a number of lakes in the country. The coastline of the country has excellent harbours.

As a rule, the climate depends on the geographical position of the country. The British Isles are washed by the warm current of the Gulf Stream. So the weather is mild, wet, cloudy, windy and changeable.

The total area of the country is about 21600 square miles or 245000 square kilometers. The population of Great Britain is about 55 million, 44 being Englishmen. Nearly all people speak English, but some speak Celtic languages.

The main cities are London, Birmingham, Liverpool, Manchester.

Unknown words:

to separate – отделять(ся);

to include – включать в себя;

to wash – омывать;

to depend on – зависеть от;

to be situated – быть расположенным;

to be bound – быть ограниченным;

island – остров;

coast – берег, побережье;

surface – поверхность;

harbour – гавань;

current – течение;

independent – независимый;

flat – плоский, равнинный;

mountainous – гористый;

rocky – скалистый;

changeable – изменчивый;

moderate – умеренный;

mild – мягкий;

wet – влажный;

cloudy – облачный;

total – полный, весь;

as a rule – как правило;

the English Channel – пролив Ла Манш;

the Strait of Dover – пролив Па-де-Кале;

Ben Navis – гора Бен Невис;

The Gulf Stream – Гольфстрим;

Celtic – кельтский.