II. READING (30 points). a) Read the text and answer the questions given below (give full answers):
a) Read the text and answer the questions given below (give full answers): STEEL Steel is an alloy consisting mostly of iron, with a carbon content between 0.2% and 2.14% by weight (C:110–10Fe), depending on grade. Carbon is the most cost-effective alloying material for iron, but various other alloying elements are used such as manganese, chromium, vanadium, and tungsten. Carbon and other elements act as a hardening agent, preventing dislocations in the iron atom crystal lattice from sliding past one another. Varying the amount of alloying elements and form of their presence in the steel (solute elements, precipitated phase) controls qualities such as the hardness, ductility, and tensile strength of the resulting steel. Steel with increased carbon content can be made harder and stronger than iron, but is also more brittle. The maximum solubility of carbon in iron (as austenite) is 2.14% by weight, occurring at 1149 °C; higher concentrations of carbon or lower temperatures will produce cementite. Alloys with higher carbon content than this are known as cast iron because of their lower melting point and castability. Steel is also to be distinguished from wrought iron containing only a very small amount of other elements, but containing 1–3% by weight of slag in the form of particles elongated in one direction, giving the iron a characteristic grain. It is more rust-resistant than steel and welds more easily. It is common today to talk about 'the iron and steel industry' as if it were a single entity, but historically they were separate products. Though steel had been produced by various inefficient methods long before the Renaissance, its use became more common after more efficient production methods were devised in the 17th century. With the invention of the Bessemer process in the mid-19th century, steel became a relatively inexpensive mass-produced material. Further refinements in the process, such as basic oxygen steelmaking, further lowered the cost of production while increasing the quality of the metal. Today, steel is one of the most common materials in the world and is a major component in buildings, infrastructure, tools, ships, automobiles, machines, and appliances. Modern steel is generally identified by various grades of steel defined by various standards organizations.
1. When steel is distinguished from wrought iron what properties does it get? 2. How is cementite produced? 3. What is the role of carbon and other elements in iron? 4. What is the carbon content in steel? 5. Is steel with increased carbon content more brittle? 6. What is the role of steel today? 7. When did steel become relatively inexpensive mass-produced material? 8. Historically iron and steel were not separate products, were they? 9. How are hardness, ductility and tensile strength defined of the resulting steel? 10. What is cast iron? 20 points b) Translate these sentences from Russian into English: 1. Легирование изменяет структуру зёрен и свойства металлов. 2. Холодная обработка делает металл твёрже и прочнее, но некоторые металлы имеют предел деформации. 3. Толщина стенки алюминиевой банки определяется зазором между пуансоном и штампом. 4. Прокатка является самым обычным процессом обработки металла, а лист – самый распространённый продукт прокатки. 5. Горячая обработка металла улучшает его механические свойства и устраняет пористость и внутренние дефекты. 10 points Total Score – 50 points
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