Unit6Rawmaterialsofsteelmaking冶金专业英语

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2. Steel scrap and sponge iron Scrap and sponge iron can be used as iron supplier and cooling agent. Worldwide, scrap participates 40 percent in steel production input and must therefore be considered as an important raw material. Its use in steelmaking varies, depending on the production process applied. In BOF, scrap accounts for about 20 percent, while in electric arc furnace, it may be 100 percent.
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Raw Materials of Steelmaking
The hot metal tapped from the blast furnace is the principal raw materials used for steelmaking. Besides hot metal，further charge materials are: steel scrap, sponge iron, slag formers, alloying agents and oxidizing agents.
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Large quantities of tramp elements within the hot metal still have to be removed partly or completely. In fact, this is a most important task of steelmaking.
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ቤተ መጻሕፍቲ ባይዱ


Steel scrap may be classified according to its sources: Circulating scrap This arises during the steelmaking and rolling process in a given works. It consists of sheared ends and rejected materials which is normally returned immediately to the steelmaking vessel. Process scrap This arises at the customer’s works during the manufacture of finished articles. It is usually returned quickly to the steelmaking plants.
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1. Blast furnace iron (Hot metal) Blast furnace iron consists of the element iron combined with numerous other chemical elements, the most common of which are carbon, manganese, phosphorus, sulphur, and silicon. Pig iron may contain 3.0 to 4.5 per cent of carbon, 0.15 to 2.5 per cent or more of manganese, 0.02 to 0.06 per cent of sulphur, 0.3 per cent or more silicon and small amount of phosphorous.
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Capital scrap This arises from scrapping manufactured goods and equipment. In some cases it may be returned to the works after three or four years’ use, or with heavy capital equipment the life may be fifty years or more, but the average appears to be about twenty years. Circulating and process scrap usually return to the steelmaker without contamination from undesirable elements, and heavy capital scrap is generally of the same quality.
Unit 6
Raw materials of steelmaking
unit6
PartⅠ Reading and Comprehension text
background Language points Words & expressions
practice PartⅡ Translation Training 翻译技巧（六） 词类转译法（III）
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Much “short life” capital scrap, however, becomes contaminated with coatings of various kinds and is returned, without the complete separation of non-ferrous components in the form of pressed bundles. This gives a sharp increase in the residuals in the steel, which detracts from its properties for a number of applications.