Continuous casting as at present applied to the production of steel may be defined as a process in which liquid metal is poured into an open-ended mould, from the lower end of which a partially solidified ingot is continuously withdrawn. The continuously cast ingot is, when completely solidified, cut into lengths having the dimensions of semi-finished blooms, billets or slabs.
The most important respect in which continuous casting simplifies conventional steelworks practice is in the elimination of the blooming or slabbing mill and its attendant processes.
In addition to simplifying manufacture, by eliminating several operations and much costly equipment, continuous casting avoids many of the losses which are incurred in the various stages of conventional production and delivers to the finishing mills a very high proportion of the metal cast. In conventional practice, every ingot must be cropped top and bottom, and some 12 to 25 per cent, according to the quality of the steel, is discarded for re-melting. In continuous casting, yields of 95 per cent, and more are attainable on plants of quite small capacity.
The quality of continuous cast material appears to be slightly superior to that produced by normal methods. The surface is markedly better than that of a conventional ingot of the same size, and surface conditioning is not normally required, even on highly alloyed steels.
Local conditions must to some extent determine the relative usefulness of continuous casting to each steelworks, but, in most cases, the reduction of operating costs should be about 10 per cent of the present cost of semi-finished billets or slabs. Savings of this magnitude are likely to have a profound effect on the economics of production. Similarly, the capital cost of installing a continuous casting plant will depend on individual requirements, but will usually be no more than a small fraction of the cost of the equipment which it will replace.
Дополнительные слова и словосочетания:
1) continuous casting of steel – непрерывная разливка стали
2) an open-ended mould – кристаллизатор
3) attendant processes – вспомогательные механизмы
4) must be cropped top and bottom – должны обрезаться сверху и снизу
5) yields of 95 per cent – выход годной продукции
составляет 95%
6) surface conditioning – обработка поверхности
7) capital cost – капитальные расходы
8) a continuous casting plant – установка для непрерывной разливки
стали
VII. Прочтите текст и передайте кратко его содержание на русском языке.
VIII. Установите, какие из приведенных утверждений, соответствуют содержанию текста.
1. The capital cost of installing a continuous casting plant will depend on individual requirements.
2. We can’t do without railroads, steel bridges, automobiles, ships, tools of all kinds, electric motors and generators, airplanes and money.
3. In conventional practice, every ingot must be cropped top and bottom, and some 12 to 25 per cent.
4. In most electric furnaces the heat is produced by means of an arc above the bath, or arcs between the slag and electrodes, suspended above the bath.
5. The quality of continuous cast material appears to be slightly superior to that produced by normal methods.
IX. Вставьте подходящие по смыслу слова.
1. The … ingot is cut into lengths having the dimensions of semi-finished blooms, billets or slabs.
a) high quality;
b) grey cast iron;
c) continuously cast.
2. The most important respect is in the … of the blooming or slabbing mill and its attendant processes.
a) elimination;
b) alloying;
c) removing.
3. Continuous casting avoids … which are incurred in the various stages of conventional production and delivers to the finishing mills a very high proportion of the metal cast.
a) rapid oxidation;
b) many of the losses;
c) internal porosity.
4. The surface … than that of a conventional ingot of the same size, and surface conditioning is not normally required, even on highly alloyed steels.
a) have a dendritic grain structure;
b) may be bright and crystalline in character;
c) is markedly better.
5. Similarly, the capital cost of installing … will depend on individual requirements.
a) a continuous casting plant;
b) tensile strength;
c) molten steel.
X. В первом и последнем абзацах определите предложения, выражающие главную мысль абзаца.
Дополнительный текст:
XI. Прочитайте данный текст и переведите его без использования словаря.
The ability of cast steel continuously offers several advantages. The continuity of pouring ensures that the cropping of billet ends is almost eliminated; this is of particular importance in casting expensive alloy steels. Billets can be cut from a continuously cast billet and the cut-off can be made to whatever length is convenient. This means that cut-off billets can be very much longer than normal ingots, such long billets can be fed directly into rolling mills for final shaping.
Another possibility is the direct feeding of billets from the casting machine into a mill, in which case the loss of heat from the billet during transit between the casting machine and mill is eliminated. Consequently, intermediate re-heating furnaces or soaking pits would no longer be needed.