Metalworking processes

Metals are shaped by processes such as casting, forging, flow forming, rolling, extrusion, sintering, metalworking, machining and fabrication. With casting, molten metal is poured into a shaped mould. With forging, a red-hot billet is hammered into shape. With rolling, a billet is passed through successively narrower rollers to create a sheet. With extrusion, a hot and malleable metal is forced under pressure through a die, which shapes it before it cools. With sintering, a powdered metal is heated in a non-oxidizing environment after being compressed into a die. With machining, lathes, milling machines, and drills cut the cold metal to shape. With fabrication, sheets of metal are cut with guillotines or gas cutters and bent into shape.

Cold working processes, where the product’s shape is altered by rolling, fabrication or other processes while the product is cold, can increase the strength of the product by a process called work hardening. Work hardening creates microscopic defects in the metal, which resist further changes of shape.

Various forms of casting exist in industry and academia. These include sand casting, investment casting (also called the “lost wax process”), die casting and continuous casting.

Unit 6

1. Memorize the following words:

determine decompose result in protect cause slow down reduce ability moisture acid medium brass film spot treatment rust corrodent coupling alloying crack dissimilar gasolene petroleum alkali inhibition inhibitor value

определять распадаться, разлагаться приводить к (чему-либо) защищать, предохранять вызывать, быть причиной замедлять уменьшать, ослаблять способность влага, влажность кислота окружающая среда латунь пленка, тонкий слой пятно обработка ржавчина коррозирующее вещество связь, соединение легирующий трещина неодинаковый, непохожий бензин нефть щелочь торможение, задержка замедлитель значение, величина

визначати розпадатися, розкладатися закінчуватися (чимсь) захищати, запобігати спричиняти, породжувати сповільнювати зменшувати, послаблювати здатність волога, вологість кислота навколишнє середовище латунь плівка, тонкий шар пляма обробка іржа кородуюча речовина зв’язок, з'єднання легуючий тріщина неоднаковий, несхожий бензин нафта луг гальмування, затримка уповільнювач значення, величина

1. Practise the reading of the following words:

Determine, moisture, air, acid, chemical, electrochemical, corrosion, corrodent, exhaust, medium, media, electrolyte, coupling, cathode, anode, decompose, intercrystalline, enamel, require, corrosive, alloying, treatment, inhibiton, inhibitor, solution, destructive.

1. Read and translate the text: