Molten pig iron, gaseous oxygen and steel scrap are the main constituents for making steel in the converter. Pig iron contains carbon, manganese, phosphorus, sulphur and silicon in addition to iron. Steel contains similar constituents, but in different proportions. Steelmaking, therefore, consists in eliminating or adding certain constituents which control the properties of the ultimate product. All the elements discussed, including iron have a strong affinity for oxygen, which in the converter process may be obtained from air, oxygen-enriched air, pure oxygen, steam-oxygen mixtures, or additions of iron oxide. The reaction of all these elements with oxygen results in the production of heat.
The essential principle of the converter process consists in blowing air through a body of molten metal or introducing oxygen onto the surface of the molten metal, thus rapidly oxidizing the various elements which enter the slag, or in the case of carbon, leave the converter as a gas. The heat generated is sufficient to maintain the metal in a liquid state and melt, some scrap.
Molten blast furnace iron (scrap iron) of the proper composition is poured into the Bessemer converter, a pear-shaped steel vessel mounted on trunnions. The converter is tilted to receive the metal. The capacity varies from 5 to 100 tons. The lining of the converter is of acid refractory material. When the vessel is charged, air is admitted from the blowing engines to a blast box at the bottom of the converter. From this box the air passes through numerous holes or tuyeres, to the interior of the converter. After the blast is turned on, the vessel is slowly turned upright. The air blows through the charge and oxidizes the silicon, manganese, and carbon, in the order given. The combustion of these materials furnishes the heat to carry on the process. The progress of the operation is shown by the flame issuing from the mouth of the converter. At first this flame is short and dry with very little visibility; then a reddish-brown flame of low luminosity occurs during the period when silicon and manganese are oxidized. As the carbon burns, the flame changes in character and increases in size, becoming yellowish-white. When the flame drops at the end of blow, the vessel is again turned down on its side and the blast is shut off. The photocell is now being used in some plants to control the blow, to determine when to turn down the vessel, and also to aid in better control of temperature. This whole operation of "blow" usually takes from 12 to 18 min.
The material now known as "blown metal" contains traces of silicon and manganese and 0.06% of carbon or less. Substantially all the phosphorus and sulphur of the original pig iron are present in the blown metal, which also contains about 0.2% FeO (iron oxide). This last constituent makes the metal "red short", incapable of being successfully forged or rolled; consequently deoxidizing agent is added to the blown metal. In making soft or low-carbon steel, ferromanganese is usually added to the blown metal while it is being poured from the converter into the ladle. Then the ladle is carried over the ingot moulds and the ingots are poured.
Дополнительные слова и словосочетания:
1) pear-shaped – грушевидный
2) acid refractory material – кислый огнеупорный материал
3) a blast box – воздуходувная коробка
4) the mouth of the converter – горловина конвертора
5) "blown metal" – продутый металл
6) "red short" – красноломкий
VIII. Прочтите текст и дайте краткое содержание текста в 4-x предложениях.
IX. Определите, соответствуют ли содержанию текста данные утверждения.
1. Производительность варьируется от 5 до 100 тонн.
2. Металл деформируется и разрушается из-за усталости и ползучести.
3. Воздух вдувается через загрузку и по очереди окисляет кремний, марганец и углерод.
4. Перекристаллизация – рост новых, свободных от деформации зерен.
5. Материал, известный как «продутый металл» содержит незначительное количество кремния, марганца и около 0.06 % углерода или менее.
X. Вставьте нужные по смыслу слова, в соответствии с содержанием текста.
1. The reaction of … results in the production of heat.
a) the flaw of gases;
b) all these elements with oxygen;
c) clay brick.
2. The … is of acid refractory material.
a) the bottom of open-hearth furnace;
b) the hearth with openings;
c) lining of the converter.
3. The converter is tilted to … the metal.
a) charge;
b) receive;
c) deoxidize.
4. Steel contains …, but in different proportions.
a) finished product;
b) slag inclusions;
c) similar constituents.
5. This whole operation of … usually takes from 12 to 18 min.
a) segregation;
b) "blow";
c) elimination.
XI. Установите, какие из приведенных утверждений, соответствуют содержанию текста.
1. The ability of cast steel continuously offers several advantages.
2. The photocell is now being used in some plants to control the blow.
3. Consequently, intermediate reheating furnaces or soaking pits would no longer be needed.
4. Steelmaking, therefore, consists in eliminating or adding certain constituents which control the properties of the ultimate product.
5. The first blast furnaces were probably very similar to those that can be seen in some parts of India and Africa today.
XII. Выберите из текста предложения, в которых характеризуется Бессемеровский конвертер.
XIII. Переведите данный отрывок без словаря:
In the basic Bessemer or Thomas process iron containing as much as 2 per cent phosphorus can be used. Since the converter is lined with dolomite, lime additions can be made. The oxygen contained in the air blown through the metal combines with the phosphorus, and this product reacts with the lime to form a stable compound that can be removed with the slag. This technique serves two purposes: it removes the phosphorus from the iron; and it enables a slag to be produced that can be used as a fertilizer.
Дополнительный текст
I. Прочтите данный отрывок, подготовьте рассказ 10-ти предложений о Генри Бессемере.
Henry Bessemer, English inventor and engineer, was born at Charlton on January 19, 1813. He discovered the first process for making inexpensive and plentiful steel. The so-called Bessemer process of steelmaking was a great event in the world's economic history. Previously steel had been scarce and expensive, made chiefly by the crucible process. Bessemer's engineering education was self-acquired.
In 1830 he came to London. There he worked out a process for the manufacture of "gold" powder.
At the time of the Crimean War Bessemer designed a rotating artillery shell. Finding the cast-iron cannon of the day too weak for it he set out to discover a stronger material. He discovered a process in which air was blown through pig iron. Sufficient heat was generated by the reactions to keep the charge hot and liquid. Many difficulties were encountered, principally because of phosphorus in the pig iron which was used as the raw material. Bessemer did not understand that in a converter lined with acid refractories, harmful phosphorus was not removed. He, however, developed his own source of non-phosphoric pig iron and brought it to commercial success.
In 1859 he established steel works at Sheffield producing guns and steel rails.
The application of this process to pig iron high in phosphorus was developed by Sidney Thomas (1878), who discovered the proper basic refractories. His method, the basic Bessemer or Thomas process, is of great importance in Europe.
The Bessemer process, both acid and basic, produced enormous quantities of steel used in bridges, railway construction and shipbuilding.
In his later years Bessemer, while still interested in steel, devoted his energies to other matters: a solar furnace, a large telescope etc.
Bessemer was one of the founders, and president of Iron and Steel Institute. He was made a fellow of the Royal Society and received many other honours. He died at Denmark Hill, London, on March 15, 1898.
XIV. Используя рис.1 (см. приложение), опишите Бессемеровский конвертер.