1. Remember the following words:

assembly – узел, механизм

anvil – шабот, наковальня

air clutch – пневматическая муфта

bottom dead centre – нижняя мёртвая точка

drive- shaft – ведущий вал, приводной вал

exert a force – оказывать давление

gravity drop hammer/power drop hammer– штамповочный молот

single acting hammer – штамповочный молот простого действия

fasten – прикреплять к чему-либо

incorporate – включать в себя

impart a stroke –сообщать ход

impose – налагать, спускать

derive from – происходить от

low profile forging – простая поковка

piston rod – шток

rated size – номинальный размер

stroke – ход

trimming – обрезка

squeeze – сдавливать

weighted rams – падающие части

2. Read and translate the text. Forging equipment

The type of machinery to be used depends on the shape, size, material, and the number of pieces to be made. Heavy forgings are produced in different types of presses and lighter ones by hammers.

Conventional drop forging hammers incorporate a weighted ram that, when it moves vertically in a downward stroke, exerts a striking force against a stationary component of the anvil near the base of the hammer. Forging dies being fastened to the weighted ram and the anvil assembly, and a workpiece being placed between them, the striking force is imposed on the workpiece, causing it to deform plastically with each successive blow, thus providing a forged configuration.

Power drop hammers are equipped at the top with a cylinder, a piston and a piston rod that is attached to the ram and that is powered by steam or compressed air. The piston is used to raise the ram and movable die to the desired height and to add force to the force of gravity on the down-stroke. These hammers range in rated size from 500 to 35,000 lb. In general, they are used to produce medium-size to large open-die and closed-die forgings. Gravity drop hammers derive their downward force entirely from the force of gravity, mechanical means raising the ram for the succeeding stroke or blow. Gravity drop hammers typically have a falling weight, or rated size, of 400 to 10,000 lb. and are used in the production of smaller and lighter open-die or closed-die forgings.

Conventional presses incorporate a ram that moves in a vertical direction to exert a squeezing action on the work metal. Such presses develop far less noise and vibration than hammers. Depending on their actuation, forging presses are classified as mechanical or hydraulic. Maximum capacities, exceeding those of the largest steam hammers, are developed by hydraulic presses. In general, presses can produce all of the types of forgings produced by hammers. Mechanical presses are driven by a motor and controlled by an air clutch; they have a full eccentric type of drive shaft that imparts a constant stroke to a vertically operating ram. Because of the short stroke, mechanical presses are best suited for low-profile forgings. Presses are rated on the maximum force they will exert at 3/8 or ¼ in. from the bottom dead centre. Capacities typically range from about 300 to 8000 tons. In smaller sizes (50 to 250 tons) they are widely used for trimming forgings produced on other types of equipment. As for hydraulic presses they produce high tolerance forgings. Capacities of hydraulic presses are known to range from 300 to 50000 tons.

3. Answer the following questions:

1. What exerts a striking force against a stationary component of the anvil near the base of the hammer? 2. What is the piston used for? 3. What hammers are used in the production of smaller and lighter open-die or closed-die forgings? 4. What are the advantages of forging presses as compared with power drop hammers?

4. Find the following phrases in the text:

С каждым последующим ударом; нужная (необходимая) высота; вообще; в зависимости от; лучше всего подходят; широко используются; что касается; мощность гидравлического пресса.

5. Fill in the gaps with the verbs from the text.

1. Conventional drop forging hammers…….a weighted ram that, when it moves vertically in a downward stroke…….a striking force against a stationary component.

2. When forging dies are……to the weighted ram and the anvil assembly, the striking force is…….on the workpiece.

3. Gravity drop hammers…….their downward force entirely from the force of gravity.

4. The ram moves in a vertical direction and…….a squeezing action on the work metal.

5. Mechanical presses are drive by a motor and have a full eccentric type of shaft that…….a constant stroke to a vertically operating ram.

5. Translate the following sentences paying a special attention to the word “force”.

1. In pneumatic hammers the rams fall not only under their own weight but are also forced to fall by the action of compressed air above the piston.

2. The force of the blow is controlled by a handle which adjusts the opening of the valve through a system of levers.

3. During the upward stroke the piston of the working cylinder compresses the air in the upper part of the cylinder and forces it through the upper channel into the working cylinder.

7. Read and translate the text without a dictionary.

Counterblow hammers develop striking by the movement of two rams that approach simultaneously from opposite directions and meet at a midway point. The rams are capable of striking from 100 to 200 blows per minute; they develop combined velocities equivalent to about 1.5 times the normal hammer velocities. Capacities of six large power drop and counterblow hammers, ranging in rated size from 25,000 lb. to 125,000 lb., are related to the production of blocker-type forgings in titanium alloys and low-alloy steel.

Text 3