6. Find in the text the English equivalents of the following word combinations.

Зварювання тиском, розвиток нових технологій, фізичні властивості металів, джерело тепла та тиску, дугове зварювання в інертному газі вольфрамовим електродом, покривати електрод флюсом, дугове зварювання під флюсом, автоматичні та полуавтоматичні прилади, використання електронних променів та лазерів, аерокосмічна промисловість.

7. Chose the correct definition to the word:

alloy

1. chemical element

2. mixture of metals

3. product of ignition

strength

1. property of hard materials

2. property of liquids

3. property of gases

torch

1. tool for gas welding

2. tool for spot welding

3. tool for hammer welding

8. Fill in the gaps with proper prepositions.

1. Brazing and soldering are other means ..... joining metals.

2. The welding process best suited .... joining two pieces .... metal depends .... the physical properties .... the metals, the specific use .... which they are applied, and the production facilities available.

3. Forge welding was practiced .... centuries.... blacksmiths and other artisans.

4. .... gas-metal welding, a bare electrode is shielded .... the air.... surrounding it .... argon or carbon dioxide gas or .... coating the electrode .... flux.

5. Resistance welding is extensively employed....many fields .... sheet metal or wire manufacturing and is particularly adaptable .... repetitive welds made .... automatic or semiautomatic machines.

9. Put the questions to the underline words or word combinations.

1. The welding process best suited to joining two pieces of metal depends on the physical properties of the metals, the specific use to which they are applied, and the production facilities available.

2. With the development of new techniques during the first half of the 20th century, welding replaced bolting and riveting in the construction of many types of structures, including bridges, buildings, and ships.

3. Forge welding is used rarely in modern manufacturing.

4. The electrode is fed into the electric arc, and melts off in droplets to enter the liquid metal that forms the weld.

5. The point where the two metals meet creates resistance to the flow of current.

10. Communicative situations:

1. Make up a dialogue on the topic “ Most common welding processes and their division”

2. Make a report on the topic “The principles of welding processes classification”

11. Make up a summary of the text and use it to retell the text. Text c bending, projection, shearing, staking

Bending is a process by which metal can be deformed by plastically deforming the material and changing its shape. The material is stressed beyond the yield strength but below the ultimate tensile strength. The surface area of the material does not change much. Bending usually refers to deformation about one axis.

Bending is a flexible process by which many different shapes can be produced. Standard die sets are used to produce a wide variety of shapes. The material is placed on the die, and positioned in place with stops or gages. It is held in place with hold-downs. The upper part of the press, the ram with the appropriately shaped punch descends and forms the v-shaped bend.

Bending is done using Press Brakes. Large and small presses are used for specialized applications. Programmable back gages, and multiple die sets available currently can make for a very economical process.

Air Bending is done with the punch touching the work piece and the work piece, not bottoming in the lower cavity. This is called air bending. As the punch is released, the work piece ends up with less bend than that on the punch (greater included angle). This is called spring-back. The amount of spring back depends on the material, thickness, grain and temper. The spring back usually ranges from 5 to 10 degrees. Usually the same angle is used in both the punch and the die to minimize setup time. The inner radius of the bend is the same as the radius on the punch.

Bottoming or coining is the bending process where the punch and the work piece bottom on the die. This makes for a controlled angle with very little spring back. The tonnage required on this type of press is more than in air bending. The inner radius of the work piece should be a minimum of 1 material thickness in the case of bottoming; and up to 0.75 material thickness, in the case of coining.

Projection welding is a variation of spot welding. Projections are designed in one part. These act as current concentrators for the welding process. When the two parts are mated together, these projections are the high points that first make contact. As the power is cycled, the projections simultaneously carry the current and are welded. This process is known as Resistance Projection Welding, RPW.

Due to the efficiency of power transfer, thicker materials can be successfully welded. Materials as thick as 3 mm (0.125 in) can be successfully welded. For thin stock, the traditional spot welding is a preferred method.

Low carbon steels, low alloy steels, stainless steels, as well as aluminum can be welded using this process.

Projections are usually semi-spherical or blunt conical type.

Projection welding requires that the height of projections be controlled to within a range of 0.075 mm (0.003 in).

Shearing is a process for cutting sheet metal to size out of a larger stock such as roll stock. Shears are used as the preliminary step in preparing stock for stamping processes.

Material thickness ranges from 0.125 mm to 6.35 mm.

The shearing process produces a shear edge burr, which can be minimized to less than 10% of the material thickness. The burr is a function of clearance between the punch and the die (which is nominally designed to be the material thickness), and the sharpness of the punch and the die.

Staking is a method of fastening (usually sheet metal) by squeezing protrusion formed in one part inside a hole in the second part, and then deforming the protrusion. The act of deformation causes radial expansion of the inner part and locks it in the hole.