Engineering Materials

1. Materials used in mechanical engineering consist chiefly of metals, alloys and plastics, which have almost completely replaced timber, largely used in the past. Rubber is employed for some purposes — mainly for fittings, packings, and washers. Leather is also used for washers, pump-plungers and driving belts.

2. Metals of various types and their alloys are by far the most widely used materials. One of the oldest is cast iron, which is made from iron-ore by smelting it in a kiln or chamber, called a "blast furnace". Run off into sand moulds and cooled, the cast iron forms blocks called pigs.

3. Cast iron is strong in compression but weak in tension. It is therefore used for making bases for machinery, stands, engine bed-plates, framework for machines, brackets, pedestal bodies, bearing-housings, gear-wheels, pulleys, intricate casings for machinery, engine cylinders, domestic utensils, fire-grades and architectural fittings of an ornamental nature, or, anything in which tensile stress is not involved.

4. Steel is produced by melting cast iron (pigs) and refining it to remove some of the carbon and other impurities.

Special kinds of steel comprise mild or structural steel, alloy steel, stainless steel, carbon (or tool) steel, self-(or air-) hardening tool steel, heat-resisting steel, and many others.

5. One method of preventing a nut from loosening is to fit what is termed a spring washer. There are several forms of these, and each claims its particular merit. When placed in position on a bolt, and the nut screwed on, the reaction of the spring, as it is compressed, exerts pressure against the nut and prevents the latter from turning and working loose.

6. When two shafts have their axes set at right angles to each other, the shafts may be driven, or rotated by the use of bevel gears. If it is desired to rotate one shaft at a different speed from the other, a bevel gear-wheel and bevel pinion would be used.

7. A screw-cutting lathe differs from a plain, or surfacing sliding lathe, for it must be arranged to provide uniform travel for the saddle along the bed carrying the slide-rest at various speeds to suit the pitch of screw-thread to be formed.

2. Найдите в тексте и переведите словосочетания:

1. Машиностроение, части машин пружинная шайба, быть в зацеплении, предотвращать самоотвинчивание гаек, шплинт, заклепка, муфта, роликовый подшипник, привод, токарный станок, червячная передача, фрезерный станок, демонтировать, деталь, стержень, нарезной, механический привод, заготовка, обработка, обдирный резец, строгальный станок, прокладка.

2. Outer race, ball cage, gearing, pivot, riveting, universal coupling, friction clutch, to operate a tool, to machine a workpiece, gear wheel, screw-threaded, to reduce the velocity of driven shafts, shank, milling machine, lathe, safety, clutch. Worm gearing, mesh, roller-race bearing, split pin.

3. Переведите устно и письменно (может использоваться для последовательного перевода):

Дата добавления: 2015-11-16