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There are different types of forging: open die forging ( is usually done by hammering a part between two flat faces), closed die forging (shaping of hot metal within the walls of two dies that come together to enclose workpiece on all sides), and two closed-die forging operations ( an example of this process is the pushing of a short length of a rod through a hole, clamping the rod, and then hitting the exposed length with a die to form the head of a nail or bolt).

Assignments:

I.General understanding. Answer the questions:

1.What are the main metalworking processes?

2.Why are metals worked mostly hot?

3.What properties does cold working give to metals?

4.What is rolling? Where is it used?

5.What is extrusion? What shapes can be obtained after extrusion?

6.What is sheet-metal forming? Where can it be used?

7.What is forging? What types of forging do you know?

II. Translate into English:

Зазор между плунжером и штампом; температура перекристаллизации; нужные формы; толщина листа; края схватываются; самый обычный процесс обработки металла; сложное сечение; верхний штамп; головка болта; свободно входящий плунжер; полые части; горячая обработка; каждый из этих процессов; металл подвергается; процессы обработки металлов подразделяются на пять типов; примером этого процесса является; уменьшить необходимое усилие.

III. According to the key words try to guess the metal process:

1.metal’s plasticity;

2.the most common process;

3.production of aluminium beer cans;

4.metal is subjected to large amounts of strain;

5.cold working;

6.diameter reduction;

7.forming the head of a nail or bolt;

8.making the roof of an automobile;

9.complex or simple cross section.

IV. What questions could you ask to get these answers:

1.aluminium window frames are the examples of complex extrusions.

2.cold working hardens metal and makes the part stronger.

3.forging is the shaping of piece of metal by pushing with open or closed dies.

V. 1) Fill in the table according to the text and using additional information. These sites may help you :

•http://www.custompartnet.com/wu/sheet-metal-forming

•http://www.forging.org

•http://www.popularmechanics.com/home_journal/workshop/1274426.htmll

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2) Be ready to present one of the processes using the table.

VI. Render the text in English:

Тормоза прогресса: технологичные металлы

В современном мобильном телефоне содержится сорок различных металлов. 20 лет назад в телефонном аппарате их могло быть всего два — медь и железо. Арифмометры и пишущие машинки в прошлом веке делали целиком из ванадиевой стали, а в современном домашнем компьютере содержится уже 60 различных металлов. Некоторые эксперты считают, что дефицит так называемых технологичных металлов наступит раньше, чем последняя капля нефти сгорит в двигателе автомобиля.

Термин «технологичные металлы» ввел в обиход знаменитый американский аналитик рынка металлов Джек Лифтон. К этой группе относятся несколько десятков элементов периодической системы Менделеева: родий, марганец, кобальт, индий, ниобий, галлий, медь, тантал, палладий, платина, ванадий, титан, литий, теллур, селен, гафний, цирконий, рений, германий и 17 так называемых редкоземельных металлов во главе с лантаном. Все они обладают выдающимися свойствами и критически важны для наиболее наукоемких отраслей экономики. Понятие «критически важный» означает невозможность полноценной замены данного материала каким-либо другим без серьезных ухудшений свойств конечного продукта. Для каждой отдельной отрасли имеется свой перечень ключевых элементов. Так, например, для автоиндустрии это родий, палладий, платина, ванадий, неодим и лантан. Без германия, галлия, индия и европия невозможно представить производство полупроводников, волоконной оптики и электроники. Литий становится критически важным для индустрии компактных источников тока. Ниобий, молибден, вольфрам, тантал и рений применяются для создания специальных сталей и сверхтвердых сплавов. Изготовление высокоточной оптики немыслимо без лантана и полировального компаунда на основе оксида церия. Теллур, индий, галлий и селен незаменимы в солнечной энергетике. Без титана и рения ни один реактивный самолет не поднимется в небо. Список можно продолжать бесконечно долго, и с каждым годом он становится все длиннее.

«Популярная механика»

Use the words and phrases given below:

Технологичный металл — manufacturable metal; арифмометр — adding machine; пишущая машинка — typewriter; дефицит — deficit, lack; ввести в обиход — put into practice; аналитик рынка металлов — metals market analyst; периодическая система элементов Менделеева — Mendeleev periodic table; родий — rhodium; индий — indium; ниобий — niobium; галлий — gallium; тантал — tantalum; теллур — tellurium; гафний — hafnium; цирконий — zirconium рений — rhenium; германий — germanium; редкоземельный — rare-earth; выдающиеся свойства — outstanding properties; полноценная замена — full substitute; конечный продукт — finished product; полупроводник

— semiconductor; волоконной оптика — fiber optics; источник тока — current source; сверхтвердый сплав — extra-hard alloy; реактивный самолет — jet.

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Unit 3

Read the text:

Metalworking and Metal Properties

An important feature of hot working is that it provides the improvement of mechanical properties of metals. Hot-working (hot-rolling or hot-forging) eliminates porosity, directionality, and segregation that are usually present and toughness than the unworked casting. During the forging of a bar, the grains of the metal become greatly elongated in the direction of flow. As a result, the toughness of the metal is greatly improved in this direction and weakened in directions transverse to the flow. Good forging makes the flow lines in the finished part oriented so as to lie in the direction of maximum stress when the part is placed in service.

The ability of a metal to resist thinning and fracture during cold-working operations plays an important role in alloy selection. In operations that involve stretching, the best alloys are those which grow stronger with strain (strain hardening) — for example, the copper-zinc alloy, brass, used for cartridges and the aluminium-magnesium alloys in beverage cans, which exhibit greater strain hardening.

Fracture of the workpiece during forming can result from inner flaws in the metal. These flaws often consist of nonmetallic inclusions such as oxides or sulfides that are trapped in the metal during refining. Such inclusions can be avoided by proper manufacturing procedures.

The ability of different metals to undergo strain varies. The change of the shape after one forming operation is often limited by the tensile ductility of the metal. Metals such as copper and aluminium are more ductile in such operations than other metals.

Assignments:

I.General understanding. Answer the questions:

1.What process improves the mechanical properties of metals?

2.What properties do hot-working products have?

3.How does the forging of a bar affect the grains of the metal? What is the result of this?

4.How are the flow lines in the forged metal oriented and how does it affect the strength of the forged part? What are the best strain-hardening alloys? Where can we use them?

5.What are the inner flaws in the metal?

6.Can a metal fracture because of the inner flaw?

7.What limits the change of the shape during forming operations?

II. Find the following phrases in the text:

Важная особенность горячей обработки; улучшение механических свойств металла; необработанная отливка; направление максимального напряжения; способность сопротивляться утончению и разрушению; проявлять большее деформационное упрочнение; разрушение детали при штамповке; внутренние дефекты в металле; неметаллические включение; способность металлов подвергаться деформации; ограничивается пластичностью металла при растяжении.

III. Find the terms in the text that mean the same as the following definitions:

1.A distinctive attribute or aspect of something (para 1);

2.The state or condition of being porous (para 1);

3.A small hard particle of a substance (para 1);

4.The action or state of setting someone or something apart from others (para 1);

5.A metal made by combining two or more metallic elements (para 2);

6.A force tending to pull or stretch something to an extreme or damaging degree (para 2);

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7.A piece of metal or other material that is in the process of being worked on or made or has actually been cut or shaped by a hand tool or machine (para 3);

8.A mistake or shortcoming in a plan, theory, etc. which causes it to fail or reduces its effectiveness (para 3).

IV. Put the words in the correct order to make up sentences. Then translate them:

1.Of, metal, elongated, grains, direction, of, the, become, the, greatly, in, the, flow.

2.Selection, important, fracture, metal, ability, of, a, to, resist, and, an, role, in, plays, alloy, the, thinning.

3.Other, and, in, more, aluminium, metals, forming, copper, are, operations, ductile, than.

V. Translate these sentences into English:

1.Горячая обработка металла улучшает его механические свойства и устраняет пористость и внутренние дефекты.

2.Удлинение зерен в направлении текучести при ковке значительно улучшает прочность металла в этом направлении и уменьшает его прочность в поперечном.

3.Хорошая проковка ориентирует линии текучести в направлении максимального напряжения.

4.Деформационное упрочнение металла при холодной обработке очень важно для получения металлов с улучшенными свойствами.

5.Внутренние дефекты металла — это неметаллические включения типа окислов или сульфидов.

6.Изменение формы при штамповании неметаллических деталей ограничивается пластичностью металла при растяжении.

VI. Read the text carefully and fill in the table given after the text. Ask five questions to it:

ZA Alloys

Pure aluminium has good corrosion resistance and working and forming properties but poor machining characteristics and low mechanical strength. By adding other elements to aluminium, its strength and machining characteristics can be improved. Such a combination of two or more elements, at least one of which is metallic, is called an alloy and the predominant metal in the system is referred to as the base metal.

Silicon, copper, zinc and magnesium are common alloying elements and are often added to aluminium in substantial proportions. Iron, manganese, nickel, chromium, titanium, antimony, cadmium, cerium, lithium, beryllium and molybdenum are also added in smaller proportions with various beneficial effects.

Titanium, tungsten, cerium and molybdenum all contribute to grain refinement of cast aluminium. Manganese and antimony are often added to improve corrosion resistance. Cobalt and nickel affect strength and workability while cadmium and tin increase hardness in heat treatable alloys.

The market penetration of ZA alloys has been added by the fact that traditional high volume foundry metals have significant shortcomings that detract from their inherent advantages:

-cast iron has high energy and machining costs, protective finishes are nearly always required and there are industry environmental problems;

-bronze has high material and energy costs and the environmental problem of lead for many important alloys;

-aluminium has limitations in strength, bearing properties and finishing along with moderately high energy costs. Of course, each of these classic materials does have distinct advantages in given applications.

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In contrast, the zinc casting alloys have advantages that are highly attractive to foundries:

–excellent casting properties;

–low energy consumption;

–pollution free melting and casting;

–excellent machinability;

–lower material cost and density than bronze.

VII. Render the text in English:

Алюминий

«Крылатый металл», любимец авиаконструкторов. Чистый алюминий втрое легче стали, очень пластичен, но не очень прочен.

Чтобы он стал хорошим конструкционным материалом, из него приходится делать сплавы. Исторически первым был дуралюмин (дюралюминий, дюраль, как мы его чаще всего зовем) — такое имя дала сплаву немецкая фирма, впервые его предложившая в 1909 году (от названия города Дюрен). Этот сплав, кроме алюминия, содержит небольшие количества меди и марганца, резко повышающие его прочность и жесткость. Но есть у дюраля и недостатки: его нельзя сваривать и сложно штамповать (нужна термообработка). Полную прочность он набирает со временем, этот процесс назвали «старением», а после термообработки состаривать сплав нужно заново. Поэтому детали из него соединяют клепкой и болтами.

В последней четверти XX века прогресс в металлургии привел к появлению алюми- ний-литиевых сплавов. Если до этого добавки в алюминий были направлены только на увеличение прочности, то литий позволял сделать сплав заметно легким. Из алюминийлитиевого сплава был сделан бак для водорода ракеты «Энергия», из него же делают сейчас и баки «Шаттлов».

Выбор конструктора за прошедшие 50 лет стал намного богаче. Тем не менее, как тогда, так и сейчас алюминий — металл №1 в ракете. Но, конечно же, есть и целый ряд других металлов, без которых ракета не сможет полететь.

«Популярная механика»

Use the words and phrases given below:

Втрое легче — three times lighter; конструкционный материал — constructional material; дюралюмин / дюраль — duralumin / dural; термообработка — heat treatment; старение — age-hardening, aging; клепка — rivet; добавка — additive; сделать сплав заметно легким — make an alloy substantially lighter; бак — tank.

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Unit 4

Read the text:

Steel

The most important metal in industry is iron and its alloy — steel. Steel is an alloy of iron and carbon. It is strong and stiff, but corrodes easily through rusting, although stainless and other special steels resist corrosion. The amount of carbon in steel influences its properties considerably. Steels of low carbon content (mild steels) are quite ductile and are used in the manufacture of sheet iron, wire and pipes. Medium-carbon steels containing from 0. 2 to 0. 4 per cent carbon are tougher and stronger and are used in structural steels. Both mild and me- dium-carbon steels are suitable for forging and welding. High-carbon steels contain 0. 4 to 1. 5 per cent carbon, are hard and brittle and are used in cutting tools, surgical instruments, razor blades and springs. Tool steel, also called silver steel, contains about 1 per cent carbon and is strengthened and toughened by quenching and tempering.

The inclusion of other elements affects the properties of the steel. Manganese gives extra strength and toughness. Steel containing 4 per cent silicon is used for transformer cores or electromagnets because it has large grains acting like small magnets. The addition of chromium gives extra strength and corrosion resistance, so we can get rust-proof steels. Heating in the presence of carbon or nitrogen-rich materials is used to form a hard surface on steel. High speed steels, which are extremely important in machine tools, contain chromium and tungsten plus smaller amounts of vanadium, molybdenum and other metals.

Quenching is a heat treatment when metal at a high temperature is rapidly cooled by immersion in water or oil. Quenching makes steel harder and more brittle and more liable to fracture than normal steel, with small grain structure.

Tempering is heat treatment applied to steel and certain alloys. Hardened steel after quenching from a high temperature is too hard and brittle for many applications and is also brittle. Tempering, that is re-heating to an intermediate temperature and cooling slowly, reduces this hardens and brittleness. Tempering temperatures depend on the composition of the steel but are frequently between 100 and 650 C. Higher temperatures usually give a softer, tougher product. The color of the oxide film produced on the surface of the heated metal often serves as the indicator of its temperatures.

Annealing is a heat treatment in which a material at high temperature is cooled slowly. After cooling the metal again becomes malleable and ductile (capable of being bent many times without cracking).

All these methods of steel heat treatment are used to obtain steels with certain mechanical properties for certain needs.

Assignments:

I.General understanding. Answer the questions:

1.What are the main properties of steel?

2.What are the drawbacks of steel?

3.How can we get rust-proof (stainless) steel?

4.What can be done to obtain harder steel?

5.What makes steel softer and tougher?

6.What makes steel more malleable and ductile?

7.What temperature range is used for tempering?

II. Translate into English:

Сплав железа и углерода; прочный и жесткий; легко коррозирует; нержавеющая сталь; низкое содержание углерода; ковкость; листовое железо; проволока; трубы; конструкционные стали; пригодны для ковки и сварки; твердый и хрупкий; режущие ин-

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струменты; хирургические инструменты; инструментальная сталь; упрочнять; добавление марганца (кремния, хрома, вольфрама, молибдена, ванадия); температура нормализации; мелкозернистая структура; быстрое охлаждение; закаленная сталь; состав стали; оксидная пленка; индикатор температуры; медленное охлаждение.

III. Summarize the information from the text and fill in the table:

IV. Scan the table which follows to find a metal which is:

Soft; ductile; malleable; tough; easily machined; low cost; corrosion-resistant; highly conductive.

A research engineer is talking about the application of a new type of metal alloy. The table below shows three applications and should show the sequence of actions and reactions.

Words and word combinations to be remembered:

2) As you listen, complete the table:

* SMA is an abbreviation for Shape Memory Alloys

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Unit 5

I.Scan the following text to identify the paragraphs which contain:

a)Conditions in which corrosion occurs;

b)Need to consider corrosion in design;

c)A definition of corrosion;

d)Factors which limit the corrosion;

e)Effects of rust.

Read the text:

Corrosion

A major consideration in engineering design is maintenance. One of the most common causes of failure in the long term is corrosion. This is any deterioration in the component’s appearance or physical properties.

Corrosion covers a number of processes whereby a metal changes state as a result of some form of interaction with its environment. It often occurs where water, either as liquid or vapor in air of high humidity, is present.

In general, corrosion becomes worse when impurities are present in damp conditions. It never starts inside a material, and there will always be surface evidence that indicates corrosion exists, although close examination may be needed.

A common example of corrosion is the rusting of steel where a conversion of metallic iron to a mixture of oxides and other compounds occurs. This not only changes the appearance of the metal but also results in a decrease in its cross section.

It is imperative that a design takes into account whether a material will be affected in a particular environment and, if corrosion is likely, at what rate.

Many factors can intervene in a way to restrain its progress. An example is aluminium and its alloys which perform satisfactorily in many engineering and domestic applications when exposed to air and water. This is due to the rapid production of a tough adherent film of oxide which protects the metal from further attack so that corrosion halts.

Assignments:

II. General understanding. Answer the questions:

1.In corrosion, why do metals change state?

2.Name two factors which encourage corrosion.

3.Where can signs of corrosion always be found?

4.What is rust?

5.Why may rust be dangerous to a structure?

6.What must designers consider regarding corrosion?

7.Why does aluminium perform well when exposed to air and water?

III. Match terms and their definitions:

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IV. Say whether these sentences are true (T) or false (F):

1.Corrosion often appears where liquid or vapor is present.

2.The rusting of steel and aluminium is a typical example of corrosion.

3.Corrosion is considered to be one of the most common reasons of failure.

4.Corrosion always starts inside the material.

5.Maintenance doesn’t demand a very important consideration in engineering design.

6.Aluminium alloys do satisfactorily when subjected to air and water.

V. 1) Match English and Russian equivalents:

Common forms of corrosion

2) Work in pairs, A and B. Your partner has some information about one of the types of corrosion on the list above. Find out what it is and obtain information from him or her to

complete as much as you can of the table below.

Type

Where does it occur?

What happens?

What is the result?

Student A. It describes the form of corrosion where localized grains of metal are consumed, leaving small, irregular, but possibly deep holes.

Although the amount of material removed may be small, the metal may be perforated.

Intergranular cor-

Surface corrosion

Fretting corrosion

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