Metalworking ProcessesMetals are im

Metalworking Processes

Metals are important in industry because they can be easily deformed into useful shapes. A lot of metalworking processes have been developed for certain applica¬tions. They can be divided into five broad groups:
1. rolling,
2. extrusion,
3. drawing,
4. forging,
5. sheet-metal forming.
During the first four processes metal is subjected 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 are performed below the recrystallization temperature. These are called cold working. Cold working hardens 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 metal working process. More than 90 percent of the aluminum, steel and copper produced is rolled at least once in the course of produc¬tion. The most common rolled product is sheet. 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. Aluminium window frames are the examples of complex extrusions.
Tubes or other hollow parts can also be extruded. The initial piece is a thick-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 a loosely fitting ram is pushed against it. The ram forces the metal to flow back around it, with the gap between the ram and the die determining the wall thickness. The example of this process is the manufacturing of aluminium beer cans.

Exercises

Exercise 1.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. Find the following in the text:

1. могут легко деформироваться 2. нужные формы 3. подвергать большим деформациям 3. зерна свободные от деформации 4. температура перекристаллизации 5. пластическая деформация сжатия 6. самый обычный процесс обработки металла 7. самое обычное изделие проката 8. отверстие фильеры 9. первоначальный 10. сложное сечение 11. пустотелые детали 12. свободно входящий плунжер 13. зазор между плунжером (пуансоном) и штампом 14. толщина стенки

Exercise 3. 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.

Результаты (английский) 1:

Metalworking ProcessesMetals are important in industry because they can be easily deformed into useful shapes. A lot of metalworking processes have been developed for certain ¬ applica tions. They can be divided into five broad groups:1. rolling,2. extrusion,3. drawing4. forging,5. sheet-metal forming.During the first four processes metal is subjected to large amounts of strain has been carried out (deformation). But if deformation goes at a high temperature, the metal will recrystallize — that is, the new strain has been carried out-free grains will grow instead of deformed grains. For this reason metals are usually rolled, extruded, drawn, forged or above their recrystallization temperature. This is the so-called hot working. Under these conditions there is no limit to the compressive plastic strain has been carried out to which the metal can be subjected.Other processes are performed below the recrystallization temperature. These are the so-called cold working. Cold working metal hardens and makes the part stronger. However, there is a limit to the strain has been carried out before a cold part cracks.RollingRolling is the most common metal working process. More than 90 percent of the aluminum, steel and copper mass-produced is rolled at least once in the course of the produc ... ¬ tion. The most common product is rolled sheet. Rolling can be done either hot or cold. If the rolling is finished cold, the surface will be smoother and the product stronger.ExtrusionExtrusion is pushing the billet to flow through the orifice of a die. Products may have either a simple or a complex cross section. Aluminium window frames are the examples of complex extrusions.Tubes or other hollow parts can also be extruded. The initial piece is a thick-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) (extrusions), the workpiece is placed 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 the ram and the die determining the wall thickness. The example of this process is the manufacturing of aluminium beer cans.ExercisesExercise 1. 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 does cold working properties 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. Find the following in the text:1. can easily deform 2. the desired form 3. expose large deformation 3. grain strain-free 4. recrystallization temperature 5. plastic deformation of the compression of 6. the most common metal processing 7. most usual product 8 rental. spinneret hole 9. the original 10. complex section 11. hollow parts 12. free incoming plug 13. the gap between the plunger (punch) and the stamp 14. wall thicknessExercise 3. Translate into English:1. The ability to perekristallizovyvat′sâ metal at high temperature is used in hot processing. 2. Recrystallization is the growth of new strain-free grains. 3. During hot metal processing may be very large plastic deformation of the compression. 4. Cold treatment makes the metal harder and firmer, but some metals have a limit of deformation. 5. Plates can be made hot or cold. 6. the surface of cold-rolled sheet smoother and stronger. 7. cross-section of dies for extrusion can be simple or complex. 8. Aluminum and copper alloys for extrusion are the best because of their plasticity deformation. 9. Aluminum cans, tubes for toothpaste are examples of the use of stamping extruding. 10. Wall thickness aluminium banks determined by the clearance between the marker and the stamp.