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.
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
сопротивляться утончению и разрушению
6. проявлять большее деформационное упрочнение
7. разрушение детали при штамповке
8. внутренние дефекты в металле
9. неметаллические включения
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.
There were lot of guests on my farm this summer.They spoke different languages. But we understood and got along with each other well. The weather was fine. My guests walked,swam and played. Tomorrow they will ride horses. In the mornning a girl from Italy often sings nice songs for us. A boy from Canada paints wonderful pictures every afternoon. Yesterday he drew my portrait. Three days ago we visited Hobbit. He was hospitable and polite. He made jokes and told us about his new magazine. Hobbit will send you this magazine in a week. When will you come to see me?
Як на мене, то я дуже люблю театр, особливо Театр української драми імені Івана Франка.
Я надзвичайно ціную трупу цього театру. Мені подобаються традиційні театральні декорації, майстерно зроблені костюми. І, звичайно, це дуже важливо, які п'єси знаходяться в репертуарі. Київський театр української драми завжди ретельно добирає п'єси для його репертуару.
Іноді дуже важко дістати квитки на спектакль.
Недавно я відвідав Театр української драми, де я бачив п'єсу «Благочестива Марта» іспанського драматурга Лопе де Вега.
Головні ролі в спектаклі були зіграні відомими акторами. У цілому, цей спектакль має чудовий склад.
Цього разу наші місця були в другому ряду партеру. Перед початком ми купили програму.
У цьому спектаклі багато музики. Але чим я особливо насолодився в цій виставі було почуття гумору, яке пройшло крізь увесь спектакль.
Я вважаю, це була одна з найкращих робіт, яку я побачив у цьому сезоні.
Объяснение:
As for me I like theatre very much, especially, The Ivan Franko Ukrainian Drama Theatre.
I highly appreciate the cast of this theatre. I like the traditional scenery, skill-made costumes. And, of course, it's very important what plays are in the repertoire. The Kyiv Ukrainian Drama Theatre always chooses the plays for its repertoire very thoroughly.
Sometimes it is very difficult to get tickets to the performance.
Not long ago I visited The Ukrainian Drama Theatre, where I saw the play "The Pious Martha" by the Spanish playwright Lope de Vega.
The leading parts in the performance were played by the well-known actors. Generally speaking this production has an excellent cast.
This time our seats were in the second row of the pit. Before the beginning of the performance we bought a bill.
There is a lot of music in this production. But what I especially enjoyed in this performance was the sense of humour which permeated the whole performance.
I consider it was one of the best performances I have seen this season.