In principle, steelmaking involves only a relatively, outwardly simple steps. Principal iron ores consist of combinations of iron with oxygen (iron oxides), mixed with varying percentages of useless earthy materials. In order to remove the oxygen and useless materials, the iron ore along with coke and limestone are charged into the blast furnace. Hot air blown into the blast furnace burns the coke to generate heat. The hot carbon of the coke, and the carbon-bearing gases generated by its burning, combine with the oxygen of the iron oxide leaving the iron in metallic form. The iron, in the molten state, collects in the hearth at the bottom of the blast furnace. The limestone combines with the useless part of the ore to form molten slag that floats on the top of the pool of molten iron. In this process the iron becomes contaminated with some of the carbon from the coke used as fuel. The product of the blast furnace, pig iron, may contain somewhat over 4 per cent carbon. To make steel from pig iron, some of the carbon must be removed, because most steels contain considerably less than 1 per cent carbon. The unwanted excess of carbon is removed in the steelmaking processes, principally the Bessemer converter and the open hearth furnace processes, using controlled amounts of oxygen for its removal. The resulting final product, steel, is first poured into moulds to form ingots, which then are formed into useful shapes by rolling or other forming processes. However formed, the final products, in a great many cases, are subjected to heat treatment to develop special properties.
The procedures simply outlined above become complex in practice because of a vast array of complicating circumstances. Actually, the problems in each step of manufacture are very complex. Their solution requires considerable technical knowledge and ability. Some previous knowledge of the fundamental sciences of chemistry and physics is essential to a study of these problems.
The science of metallurgy is based on the two fundamental sciences, physics and chemistry, and is commonly subdivided into two major fields: namely, physical metallurgy which deals with the structure, fabrication and behaviour of metals, and chemical metallurgy which deals with the smelting of ores and minerals and with the refining and furnace reaction of molten metals.
Дополнительные слова и словосочетания:
1) in order to – для того, чтобы
2) carbon-bearing gases – газы, содержащие углерод
3) heat treatment – термообработка
4) unwanted, a – нежелательный, ненужный, лишний
5) complicating circumstances – сложные обстоятельства
6) smelting, n – выплавка, плавка
XI.Установите, какие из приведенных утверждений соответствуют содержанию текста.
1. Водород широко используется, так как он содержит большое количество химической энергии.
2. Металлургические искусство и наука чрезвычайно важны, так как они производят большинство ценных материалов для нашей промышленности.
3. Для того чтобы извлечь кислород и бесполезные материалы (примеси), железная руда вместе с коксом и известняком загружается в доменную печь.
4. В целом, предмет металлургии обычно делится на две части: черная и цветная металлургия.
5. Конечный продукт, сталь, вначале разливается в изложницы для формирования болванок, которые затем преобразовываются в необходимые формы.
XII. Вставьте подходящие по смыслу слова.
1. Principle iron ores consists of ... of iron with … (iron oxides), mixed with varying percentages of useless ... materials.
a) structures, hydrogen, ground;
b) compounds, carbon, clean;
c) combinations, oxygen, earthy;
2. The iron, in the . . . state, collects in the ... at the ... of the … furnace.
a) solid, mouth, top, open- hearth;
b) molten, hearth, bottom, blast;
c) liquid, tuyere, door, electric.
3. In this process the ... becomes contaminated with some of the ... from the coke used as ...
a) steel, oxygen, gas;
b) scrap, oxide, charge;
c) iron, carbon, fuel.
XIII. Укажите, какие из данных предложений соответствуют содержанию текста.
1. The product of the blast furnace, pig iron, may contain somewhat over 4 per cent carbon.
2. The modern blast furnace plant constitutes the largest and most complicated type of metallurgical apparatus in the world.
3. From the top of the furnace, the shaft constantly increases in diameter until the zone of fusion is reached.
4. To make steel from pig iron, some of the carbon must be removed, because most steels contain considerable less than 1 per cent carbon.
5. The furnace has a cylindrical crucible at its base, for the purpose of collecting the molten products of the smelting operation.
XIV. Закончите следующие предложения в соответствии с содержанием текста.
1. The science of metallurgy is based on two fundamental sciences, . . .
a) sociology and higher mathematics;
b) physics and chemistry;
c) mathematics and history.
2. The iron ore along with coke and limestone are charged into . . .
a) the open-hearth furnace;
b) high-frequency induction furnace;
c) the blast furnace.
3. However formed, the final products, in a great many cases, are subjected to heat treatment . . .
a) to remove the oxygen;
b) to develop special properties;
c) to achieve a higher temperature.
XV. Составьте план к тексту на русском языке.