Л.Ш. Атабаева - Английский язык. Технические факультеты и специальности (1254789), страница 13
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Many metals canbe melted and cast in moulds, but special conditions are required for metalsthat react with air.Vocabulary:1. arrangement – расположение2. coarse – грубый, крупный3. to draw – тянуть704. lead – свинец5. to hammer – ковать6. rolling – прокатка7. metal fatigue – усталость металла8. vessel – сосуд, котел9. to cast – отливать10. stress – давление, напряжение11. separation – интервал, расстояние12. dense – плотный13. treatment – обработка14.
ductile – эластичный, ковкийComprehension3.2. Complete the following sentences1. Metals are …2. Metallurgy is …3. Most metals are …4. The regular arrangement of atoms in metals …5. The properties of the metals depend on …6. Metals with small grains will be …7. … controls the nature of the grains in the metal.8. Alloying is …3.3 Translate into English1.
Металлы имеют кристаллическую структуру из-за правильногорасположения атомов.2. Чем меньше зерен, тем тверже металл.3. Легирование изменяет структуру зерен и свойства металлов.4. Металл деформируется и разрушается из-за усталости и ползучести.5. Металлы – плотные материалы потому, что между атомами в металлах малое расстояние.Unit 44.1. Read the text and find the English equivalents to the following Russian word-groups.1) могут легко деформироваться2) нужные формы3) температура перекристаллизации4) пластическая деформация сжатия715) самое обычное изделие проката6) зазор между плунжером и штампом7) протягивание металла через фильеру8) волочение проволоки9) уменьшение диаметра10) растягивать выше точки текучестиMETALWORKINGMetals are important in industry because they can be easily deformedinto useful shapes. A lot of metalworking processes have been developedfor certain applications.
They can be divided into five broad groups: rolling,extrusion, drawing, forging, sheet-metal forming.During the first four processes metal is subjected to large amounts ofstrain (deformation). But if deformation goes at a high temperature, themetal will recrystallize – that is, new strain-free grains will grow instead ofdeformed grains. For this reason metals are usually rolled, extruded, drawn,or forged above their recrystallization temperature. This is called hot working. Under these conditions there is no limit to the compressive plastic strainto which the metal can be subjected.Other processes are performed below the recrystallization temperature.These are called cold working. Cold working hardens metal and makes thepart stronger.
However, there is a limit to the strain before a cold part cracks.Rolling is the most common metalworking process. More than 90 percent of the aluminum, steel and copper produced are rolled at least once inthe course of production. The most common rolled product is sheet. Rollingcan be done either hot or cold. If the rolling is finished cold, the surface willbe smoother and the product stronger.Extrusion is pushing the billet to flow through the orifice of a die.
Products may have either a simple or a complex cross section. Aluminum window frames are the examples of complex extrusions.Tubes or other hollow parts can also be extruded. The initial piece is athick-walled tube, and the extruded part is shaped between a die on the outside of the tube and a mandrel held on the inside.In back-extrusion (штамповка выдавливанием) the workpiece isplaced in the bottom of a hole and a loosely fitting ram is pushed against it.The ram forces the metal to flow back around it, with the gap between theram and the die determining the wall thickness. The example of this processis the manufacturing of aluminum beer cans.72Drawing consists of pulling metal through a die. An example of drawingis wire drawing. The diameter reduction that can be achieved in one die islimited, but several dies in series can be used to get the desired reduction.Sheet metal forming is widely used when parts of certain shape and sizeare needed.
It includes forging, bending and shearing. One characteristic ofsheet metal forming is that the thickness of the sheet changes little inprocessing. The metal is stretched just beyond its yield point (2 to 4 %strain) in order to retain the new shape. Bending can be done by pressingbetween two dies. Shearing is a cutting operation similar to that used forcloth.Forging is the shaping of a piece of metal by pushing with open orclosed dies. It is usually done hot in order to reduce the required force andincrease the metal‟s plasticity.Vocabular:1. rolling – прокатка2. extrusion – экструзия, выдавливание3.
drawing – волочение4. forging – ковка5. sheet – лист6. cross section – поперечное сечение7.die – штамп, фильера8. to subject to – подвергать9. initial – первоначальный10 to harden – упрочнятьComprehension4.2. Answer the questions1) Why are metals so important in industry?2) What are the main metalworking processes?3) Why are metals worked mostly hot?4) What properties does cold working give to metals?5) How can the reduction of diameter in wire drawing be achieved?6) What is sheet metal forming and where it can be used?4.3. Match the following prefixes from the box with their definitions:interpostbipremultiexa) more than one; manyb) later than;afterc) before; in preparation73d) former and still livinge) between; among a groupf) two; twice; double4.4.Translate into English1) Перекристаллизация- это рост новых, свободных от деформациизерен.2) Во время горячей обработки металл может подвергаться оченьбольшой пластической деформации сжатия.3) Поверхность холоднокатанного листа более гладкая, и он прочнее.4) Поперечное сечение фильеры для экструзии может быть простым или сложным.5) При волочении проволоки диаметр отверстия волочильной доски каждый раз уменьшается.6) Штамповка листового металла включает в себя ковку, изгиб иобрезку.7)Небольшая деформация листа при растяжении помогает сохранить новую форму детали.8) При проковке деталь должна быть горячей для уменьшения необходимых усилий и увеличения пластичности металла.Unit 55.1.
Read the following web page and complete the missing headingsusing the words :a. Aluminium b. Copperc. Glass d. Plastic e. Rubberf. Steel g. Timber.RECYCLABLE MATERIALS1) … Scrap can be sorted easily using magnetism. If the metal is galvanized ( coated with zinc) the zinc is fully recyclable.
If it is stainless steel,other metals mixed with the iron, such as chromium and nickel, can also berecovered and recycled.2) … Sorting is critical, as there are key differences between the clearand coloured material used in bottles and jars, and the high-grade materialused in engineering applications, which contains traces of metals.743) … Scarcity makes recycling especially desirable, and justifies thecost of removing insulation from electric wires, which are a major source ofscrap.
Pure metal can also be recovered from alloys derived from it, notablybrass ( which also contains quantities of zinc, and often lead) and bronze (which contains tin).4) … The cost of melting down existing metal is significantly cheaperthan the energy-intensive process of electrolysis, which is required to extract new metal from ore.5) … Hardwood and softwood can be reused. However, the frequentneed to remove ironmongery and saw or plane off damaged edges, canmake the process costly.6) … Tyres are the primary source of recyclable material.
These can bereused whole in certain applications. They can also be ground into crumbswhich have varied uses.7) … An obstacle to recycling is the need to sort waste carefully. Whilesome types can be melted down for reuse, many cannot, or result in lowgrade material.5.2. Match the materials (1-8) to the definitions (a-h).1. stainless steela. a metal used to make brass, and in galvanizedcoatings on steel2. zincb. the predominant metal in steel3. ironc.
a type of steel not needing a protective coating, asit doesn‟t rust4. bronzed. a dense, poisonous metal5. leade. rocks from which metals can be extracted6. hardwoodf. an alloy made from copper and tin7. oreg. timber from pine trees8. softwoodh. timber from deciduous trees5.3. Complete the following sentences using from, with or of.1. Bronze contains significant amounts … copper.2. Galvanised steel is steel coated … zink.3. Steel is an alloy derived … iron.4.
Pure metals can usually be recovered … alloys.5. To produce stainless steel, iron is mixed … other metals.6. Stainless steel contains quantities … chromium and nickel.7. Glass tableware contains traces … metals, such as lead.8. When new metal is extracted … ore, the costs can be high.75Compiled by Atabaeva L.
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