2018-02-14
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1. Let’s talk about expansion and contraction. This is extremely important and very easy. Understanding these principles can prevent you from having welding catastrophes.
2. When cast iron (and other metals) is heated, they expand. When cast iron (and other metals) cool, they contract.
3. The rails buckled under the intense heat of the fire.
4. The sidewalk was cracked and buckled from the earthquake.
5. To buckle means to become bent or curved because of heat or pressure.
6. This type of plastic allows for expansion and contraction during temperature changes.
7. Contraction is the process of becoming smaller.
8. Butt welding can be used to run a processing machine continuously, as opposed to having to restart such machine with a new supply of metals.
9. Make sure all the windows are securely fastened before you leave.
10. Most modern railways use continuous welded rail (CWR. In this form of track, the rails are welded together by utilizing flash butt welding to form one continuous rail that may be several kilometers long. Because there are few joints, this form of track is very strong, provides good riding qualities, and needs less maintenance; trains can travel on it at higher speeds and with less friction (трение).
11. Flash butt welding is the preferred process which involves an automated track-laying machine running a strong electrical current through the touching ends of two unjoined pieces of rail.
12. Butt-welding is an economical and reliable way of jointing without using additional components. A butt-welding joint is made by gradually heating up the two weld ends with a weld plate and then joining them under a specific pressure. This process is very suitable for prefabrication and producing special fittings.
Buckling of railroad track continues to be problematic for railway engineers and maintenance personnel across all railway networks.
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Ex. 12. Make sure you pronounce the following words and phrases correctly:
relatively, lengthening, evenly, figure 0.9 meters, cautiously, early in the 20th century, to some extent, due to temperature changes, longitudinal expansion and contraction.
Ex. 13. Read the text and translate it, using a dictionary, if necessary.
JOINTS
Because each joint is a relatively weak spot in a track, design engineers have reduced the number of joints by lengthening the rails. The customary (≈ usual) length when locomotives were introduced was 0.9 m (3 ft), but in the 1830s this was increased to 4.6 or 6.1 m (15 or 20 ft). Early in the 20th century the most common length for rails was 9.1 m (30 ft), and this figure soon became 10 m (33 ft) when 12.2-m (40-ft) freight cars came into general use. To some extent (≈ partly) the length of rails has been limited by difficulties in transporting them.
In the United States rails are often butt-welded together to form lengths as long as 0.4 km (0.25 mi). At first this was done cautiously for fear that expansion and contraction due to temperature changes would cause buckling. Experience showed, however, that longitudinal expansion and contraction are not excessive and need not lead to buckling. Techniques were developed for making butt welds as strong as the rails themselves. Where welding is not used, rails are joined by bars bolted to the sides so as to cover the joint. The first such joint bar was invented by Robert Stevens. On earlier railroads using metal rails, the individual sections were not fastened together in any way.
Advances in track construction in the 20th century included using longer and stronger joint bars and wider tie plates to spread the weight of trains more evenly on the ties.
Ex. 14. Translate the sentences into Russian paying attention to the words:
Ø technical - технический;
Ø technician - техник;
Ø technique - (технический)прием;
Ø technology - технология.
1. Many books on furniture making are too technical or require artistic skills.
2. No one here has the technical knowledge to fix the copier.
3. Avoid technical terms or phrases which, although familiar to you, may be unknown to your listener.
4. I have purposely avoided the use of technical terms.
5. Compaq Computer Corp. enjoys one of the best reputations for technical support in the computer business.
6. He started a new job as a computer technician after completing his course.
7. With the touch of a button, these highly trained technicians can change the picture being transmitted.
8. Technicians may be classified as either skilled workers or semi-skilled workers.
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9. There are various techniques for dealing with industrial pollution.
10. In mathematics, we use many techniques of problem-solving.
11. A scientific technique is any systematic way of obtaining information about a scientific nature or to obtain a desired material or product.
12. There have been major new developments in satellite technology.
13. Lower prices forced the industry to cut costs and develop more efficient technology.
14. The primary reason for introducing new technology such as robots is to reduce costs and improve product quality.
15. The smart phones will begin to use new technology to become wireless Internet devices.
UNIT FIFE CONTINUOUS WELDED TRACK
Ex. 1. To refresh your memory translate the following termsinto Russian.
| ü contraction ü expansion ü butt weld ü flash-butt welding | ü tie plate ü to butt weld ü to fasten (down) ü technique | ü buckling ü welding ü derailment ü wrought iron |
Ex. 2. Copy and memorize the following terms.
| Glossary |
| buckling - выпучивание железнодорожных рельсов contraction - сжатие expansion - расширение flash-butt welding - стыковая сварка оплавлением force - сила site welding - сварка при монтаже tie plate - рельсовая (путевая) подкладка to butt weld - сваривать соединением встык butt weld - стыковой сварной шов to fasten (down) - скреплять; закреплять to grease - смазывать |
