1. Answer the following questions:

1. Give the definition of electron beam welding.

2. What are three basic components in an electron beam-welding machine?

3. What do recent advances in equipment allow?

4. What is on of the major advantages of electron beam welding?

5. How is the heat input of electron beam welding is controlled?

6. Why is the heat-affected zone much smaller than that of any arc welding process?

7. Is filler metal used in electron beam welding?

8. What kind of metals can be welded with the electron beam welding process?

9. What are the disadvantages of the electron beam process?

2. Give the summary of the text.

3. Fill in prepositions if necessary. Translate these sentences into Russian.

1. The original work was done_______a high vacuum.

2. _______electron beam welding, X-rays may be produced if the electrical potential is sufficiently high.

3. There are three basic components______an electron beam-welding machine.

4. Mechanical pumps can produce vacuums______the medium pressure level.

5. The succession_______electrons striking the same place causes melting and then evaporation______the base metal.

6. The depth-to-width can exceed a ratio of 20______1.

7. The weld joint details_______electron beam welding must be selected _______care.

8. The cooling rate is much higher and_______many metals this is advantageous.

9. Almost all metals can be welded_______the electron beam welding process.

4. Translate the following word combinations into Russian. Use them in the sentences of your own.

High-velocity electrons; transformed into heat; because of their affinity; the target becomes extremely hot, three basic components; pressure level; a substantial temperature increase; beam spot size; extremely accurate; to produce dense welds; high capital cost.

5. Find in the dictionary all derivatives of the following words. Translate them into Russian.

Minimize, advantageous, preparation, accurate, use, to operate, addition, precise, to absorb, development, substantial, vapors.

6. Point out which of these sentences do not contain information from the text. Translate these sentences into Russian.

1. The process utilized an electron gun similar to that used in an X-ray tube.

2. The addition of the heat brings about a substantial temperature increase at the point of impact.

3. The laser can operate at considerable distance from the work piece.

4. The succession of electrons striking the same place causes melting and then evaporation of the base metal.

5. The beam penetrates through the metal vapor and melts the metal below.

6. The electron beam gun emits electrons, accelerates the beam of electrons, and focuses it on the work piece.

7. The welding characteristics of the laser and of the electron beam are similar.

8. Recent advances in equipment allow the work chamber to operate at a medium vacuum or pressure.

9. Laser welds made in these materials are similar in quality to welds made in the same materials by electron beam process.

10. In welding, the target is the base metal which absorbs the heat to bring it to the molten stage.