Dmitry Ivanovich Mendeleyev

Dmitry Ivanovich Mendeleyev is a famous Russian chemist. He is best known for his development of the periodic table of the properties of the chemical elements. This table displays that elements' properties are changed periodically when they are arranged according to atomic weight.

Mendeleyev was born in 1834 in Tobolsk, Siberia. He studied chemistry at the University of St. Petersburg, and in 1859 he was sent to study at the University of Heidelberg. Mendeleyev returned to St. Petersburg and became Professor of Chemistry at the Technical Insti­tute in 1863. He became Professor of General Chemistry at the University of St. Petersburg in 1866. Mendeleyev was a well-known teacher, and, because there was no good textbook in chemistry at that time, he wrote the two-vol­ume «Principles of Chemistry» which became a classic textbook in chemistry.

In this book Mendeleyev tried to classify the elements according to their chemical properties. In 1869 he pub­lished his first version of his periodic table of elements. In 1871 he published an improved version of the peri­odic table, in which he left gaps for elements that were not known at that time. His table and theories were proved later when three predicted elements: gallium, germanium, and scandium were discovered.

Mendeleyev investigated the chemical theory of solu­tion. He found that the best proportion of alcohol and water in vodka is 40%. He also investigated the thermal expansion of liquids and the nature of petroleum.

In 1893 he became director of the Bureau of Weights and Measures in St. Petersburg and held this position until his death in 1907.

UNIT 2

METALWORKING

I. Text A: Metalworking processes: Rolling. Extrusion,

Text B: Drawing. Forging. Sheet metal forming,

Text C: Metalworking and Metal Properties.

II. Famous scientists. Mikhail Vasilyevich Lomonosov.

Text A: «METALWORKING PROCESSES»

Metals are important in industry because they can be easily deformed intouseful shapes. A lot of metalworking processes have been developed for certain applica­tions. They can be divided into five broad groups:

Rolling,

Extrusion,

Drawing,

Forging,

Sheet-metal forming.

During the first four processes metal issubjected to large amounts of strain (deformation). But if deformation goes at a high temperature, the metal will recrystallize — that is, new strain-free grains will grow instead of deformed 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 strain to which the metal can be subjected.

Other processes areperformed below the recrystalli­zation temperature. These are called cold working. Cold workinghardens metal and makes the part stronger. However, there is a limit to the strain before a cold part cracks.

Rolling

Rolling is the most common metalworking process. More than 90 percent of the aluminum, steel and copper produced is rolledat least once in the course of produc­tion. The mostcommon rolled product issheet. Rolling can be done either hot or cold. If the rolling is finished cold, the surface will be smoother and the product stronger.

Extrusion

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 otherhollow 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 impact extrusion (also called back-extrusion) (штамповка выдавливанием), the workpiece is placed in the bottom of a hole and aloosely fitting ram is pushed against it. The ramforces the metal to flow back around it, with thegap between the ram and the diedetermin­ing the wall thickness. The example of this process is the manufacturing of aluminum beer cans.

Vocabulary:

useful— полезный

shape — форма, формировать

rolling — прокатка

extrusion — экструзия, выдавливание

drawing — волочение

forging— ковка

sheet — лист

to subject — подвергать

amount — количество

condition — состояние, условие

perform — выполнять, проводить

to harden — делаться твердым, упрочняться

at least — по крайней мере

common — общий

billet — заготовка, болванка

orifice — отверстие

die — штамп, пуансон, матрица, фильера, во­лочильная доска

cross section — поперечное сечение

window frame — рама окна

tube — труба

hollow — полый

initial — первоначальный, начальный

thick-walled — толстостенный

mandrel — оправка, сердечник

impact— удар

loosely — свободно, с зазором

fitting — зд. посадка

ram — пуансон, плунжер

force — сила

gap — промежуток, зазор

to determine — устанавливать, опреде­лять

General understanding:

1. 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. What is rolling? Where is it used?

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

7. What are the types of extrusion?

Exercise 2.1. Find the following in the text:

1. могут легко деформироваться

2. нужные формы

3. подвергать большим деформациям

4. зерна свободные от деформации

5. температура перекристаллизации

6. пластическая деформация сжатия

7. самый обычный процесс обработки металла

8. самое обычное изделие проката

9. отверстие фильеры

10. первоначальный

11. сложное сечение

12. пустотелые детали

13. свободно входящий плунжер

14. зазор между плунжером (пуансоном) и штампом

15. толщина стенки

Exercise 2.2. Translate into English:

1. Способность металла перекристаллизовываться при высокой температуре используется при горячей

обработке.

2. Перекристаллизация — это рост новых, свобод­ных от деформации зерен.

3. Во время горячей обработки металл может под­вергаться очень большой пластической деформации сжатия.

4. Холодная обработка делает металл тверже и прочнее, но некоторые металлы имеют предел дефор­мации.

5. Листовой прокат может производиться горячим или холодным.

6. Поверхность холоднокатаного листа более глад­кая и он прочнее.

7. Поперечное сечение фильеры для экструзии мо­жет быть простым или сложным.

8. Алюминиевые и медные сплавы являются наи­лучшими для экструзии из-за их пластичности при деформации.

9. Алюминиевые банки, тюбики для зубной пасты являются примерами использования штамповки вы­давливанием.

10. Толщина стенки алюминиевой банки определя­ется зазором между пунсоном и штампом.

Text В: «DRAWING»

Drawing consists of pulling metal through a die. One type is wire drawing. The diameter reduction that can be achieved in one die is limited, but several dies in se­ries can be used to get the desired reduction.

Sheet metal forming

Sheet metal forming (штамповка листового металла) is widely used when parts of certain shape and size are needed. It includes forging, bending and shearing. One characteristic of sheet metal forming is that the thick­ness of the sheet changes little in processing. The metal is stretched justbeyond itsyield point (2 to 4 percent strain) in order toretain the new shape.Bending can be done by pressing between two dies.Shearing isa cutting operation similar to that used for cloth.

Each of these processes may be used alone, but often all three are used on one part. For example, to make the roof of an automobile from a flat sheet, the edges are gripped and the piece pulled in tension over alower die.Next anupper die is pressed over the top, finishing the forming operation (штамповку), and finally the edges are sheared off to give the finaldimensions.

Forging

Forging is the shaping of a piece of metal by pushing with open or closed dies. It is usually done hot in order to reduce therequired force andincrease the metal's plas­ticity.

Open-die forging is usually done byhammering a part between two flat faces. It is used to make parts that are too big to be formed in a closed die or in cases where only a few parts are to be made. The earliest forging machines lifted a large hammer that was then dropped on the workpiece, but now air or steam hammers are used, since they allow greater control over the force and the rate of forming. The part is shaped by moving or turning it be­tween blows.

Closed-die forging is the shaping of hot metalwithinthe walls of two dies that come together toenclose the workpiece on all sides. The process starts with arod or bar cut to the length needed to fill the die. Since large, complex shapes and large strains areinvolved, several dies may be used to go from the initial bar to the final shape. With closed dies, parts can be made to closetoler­ances so that little finish machining is required.

Two closed-die forging operations are given special names. They areupsetting andcoining. Coining takes its name from the final stage of forming metal coins, where the desiredimprint is formed on a metal disk that is pressed in a closed die. Coining involves small strains and is done cold. Upsetting involves a flow of the metal back upon itself. An example of this process is the push­ing of a short length of a rod through a hole,clampingthe rod, and thenhitting the exposed length with a die to form the head of anail or bolt.

Vocabulary:

to pull— тянуть

reduction — сокращение

to achieve — достигать

in series — серия, последовательно

beyond — выше, свыше

yield point — точка текучести металла

to retain — сохранять, удерживать

to bend — гнуть

shearing — обрезка, отрезание

edge — край

to grip — схватывать

lower die — нижний штамп

upper die — верхний штамп

forming operation — операция штампования

dimension — измерение, размеры

required — необходимый

increase — увеличение

open-die forging — ковкав открытом штампе (под­кладном)

hammering — ковка, колотить

within — внутри, в пределах

to enclose — заключать

rod — прут, стержень

bar — прут, брусок

involved — включенный

tolerance — допуск

upsetting — высадка, выдавливание

blow — удар

coining — чеканка

imprint — отпечаток

clamp — зажим

to hit — ударять

General understanding:

1. How can the reduction of diameter in wire drawing be achieved?

2. What is sheet metal forming and where it can be used?

3. What is close-die forging?

4. What is forging?

5. What are the types of forging?

6. What types of hammers are used now?

7. Where are coining and upsetting used?

8. What process is used in wire production?

9. Describe the process of making the roof of a car.

Exercise 2.3. Find the following word combina­tions in the text:

1. протягивание металла через фильеру

2. волочение проволоки

3. уменьшение диаметра

4. толщина листа

5. растягивать выше точки текучести

6. сохранить новую форму

7. края отрезаются

8. конечные размеры

9. уменьшить необходимое усилие

10. увеличить пластичность металла

11. воздушные или паровые молоты

12. сила и скорость штампования

13. внутри стенок двух штампов

14. отделочная обработка

15. малые допуски

Exercise 2.4. Translate into English:

1. При волочении проволоки диаметр отверстия во­лочильной доски каждый раз уменьшается.

2. Штамповка листового металла включает в себя ковку, изгиб и обрезку.

3. Небольшая деформация листа при растяжении помогает сохранить новую форму детали.

4. Изменение формы при штамповке производится путем сжатия между двумя штампами.

5. Края листа при штамповке отрезаются для по­лучения конечных размеров.

6. При проковке деталь должна быть горячей для уменьшения необходимых усилий и увеличения пла­стичности металла.

7. После ковки в закрытых штампах детали не тре­буют большой механической обработки.

8. При чеканке деформация металла невелика и отпечаток формируется на поверхности металла.

9. Высадка используется для изготовления головок гвоздей и болтов.

Text C: «METALWORKING AND METAL PROPETIES»

An importantfeature of hot working is that itpro­vides theimprovement of mechanicalproperties of met­als . Hot-working (hot-rolling or hot-forging)eliminates porosity, directionality, andsegregation that are usu­ally present in metals. Hot-worked products have better ductility and toughness than the unworkedcasting. Dur­ing the forging of a bar, the grains of the metal become greatlyelongated in the direction of flow. As a result, the toughness of the metal is greatly improved in this direction andweakened in directionstransverse to the flow. Good forging makes the flow lines in thefinishedpart 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 (are strain hardening) — for example, the copper-zinc alloy, brass, used for cartridges and the aluminum-mag­nesium alloys in beverage cans, which exhibit greater strain hardening.

Fracture of the workpiece during forming can result frominner flaws in the metal. These flaws often con­sist of nonmetallicinclusions such as oxides or sulfides that aretrapped in the metal duringrefining. Such in­clusions can beavoided by proper manufacturing pro­cedures.

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

Vocabulary

feature — черта, особенность

to provide — обеспечивать

improvement — улучшение

property — свойство

eliminate — ликвидировать, исключать

porosity — пористость

directional — направленный

to segregate — разделять

casting — отливка

elongated — удлиненный

to weaken — ослабевать, ослаблять

transverse — поперечный

flow — течение, поток

finished — отделанный

thinning — утончение

fracture — разрушение

strain hardening — деформационное упрочнение

brass — латунь

beverage — напиток

can — консервная банка

to exhibit — проявлять

inner — внутренний

flaws — недостатки, дефекты кристалличес­кой решетки

inclusion — включение

trapped — зд. заключенный

refining — очищать, очистка

to avoid — избегать

to undergo — подвергаться

tensile ductility — пластичность при растяжении

General understanding:

1. What process improves the mechanical properties of metals?

2. What new properties have hot-worked products?

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?

5. What are the best strain-hardening alloys? Where can we use them?

6. What are the inner flaws in the metal?

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

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

Exercise 2.5. Find the following in the text:

1. важная особенность горячей обработки

2. улучшение механических свойств металла

3. необработанная отливка

4. направление максимального напряжения

5. способность сопротивляться утончению и разру­шению

6. проявлять большее деформационное упрочнение

7. разрушение детали при штамповке

8. внутренние дефекты в металле

9. неметаллические включения

10. способность металлов подвергаться деформации

11. ограничивается пластичностью металла при ра­стяжении

Exercise 2.6. Translate 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 металли­ческих деталей ограничивается пластичностью метал­ла при растяжении.

FAMOUS SCIENTISTS

Mikhail Vasilyevich Lomonosov was a famous Rus­sian writer, chemist, and astronomer who made a lot in literature and science.

Lomonosov was born on November 19, 1711, in Denisovka (now Lomonosov), near Archangelsk, and studied at the University of the Imperial Academy of Sciences in St. Petersburg. After studying in Germany at the Universities of Marburg and Freiberg, Lomonosov returned to St. Petersburg in 1745 to teach chemistry and built a teaching and research laboratory there four years later.

Lomonosov is often called the founder of Russian sci­ence. He was an innovator in many fields. As a scientist he rejected the phlogiston theory of matter commonly accepted at the time and he anticipated the kinetic theory of gases. He regarded heat as a form of motion, suggested the wave theory of light, and stated the idea of conserva­tion of matter. Lomonosov was the first person to record the freezing of mercury and to observe the atmosphere of Venus during a solar transit.

Interested in the development of Russian education, Lomonosov helped to found Moscow State University in 1755, and in the same year wrote a grammar that re­formed the Russian literary language by combining Old Church Slavonic with modern language. In 1760 he pub­lished the first history of Russia. He also revived the art of Russian mosaic and built a mosaic and colored-glass factory. Most of his achievements, however, were un­known outside Russia.

UNIT3