Wiredrawing Dies

In the manufacture of wire, a drawplate (волочильная доска) is usually employed. This tool is a metal plate con­taining a number of holes, successively less in diameter and known as wire dies. A piece of metal is pulled through the largest die to make a coarse wire. This wire is then drawn through the smaller hole, and then the next, un­til the wire is reduced to the desired measurement. Wiredrawing dies are made from extremely hard mate­rials, such as tungsten carbide or diamonds.

Thread-Cutting Dies

For cutting threads on bolts or on the outside of pipes, a thread-cutting die (резьбонарезная плашка) is used. It is usually made of hardened steel in the form of a round plate with a hole in the centre. The hole has a thread. To cut an outside thread, the die is lubricated with oil and simply screwed onto an unthreaded bolt or piece of pipe, the same way a nut is screwed onto a bolt. The correspond­ing tool for cutting an inside thread, such as that inside a nut, is called a tap (метчик).

Vocabulary

chip [t∫ip] стружка

sharp [∫a:p] острый

friction ['frik∫эn] трение

content ['kontэnt] содержание

range [reind₃] диапазон

inexpensive [inik'spensiv] недорогой

to permit [pэ'mit] позволять, разрешать

common ['komэn] обычный

tungsten ['tAŋstэn] вольфрам

ingredient [in'gri:diэnt] ингредиент

diamond ['daiэmэnd] алмаз

tips наконечники

ceramic [si'ræmik] керамический

truing ['truiŋ] правка, наводка, заточка

die [dai] матрица, штамп

matrix ['meitriks] матрица

to employ [im'ploi] применять

to pierce ['piэs] протыкать, прокалывать

to punch [pAnt∫] пробивать отверстие

matching ['mæt∫iŋ] сочетающийся, парный

coarse [ko:s] грубый

wire ['waiэ] проволока

to draw [dro:] тащить, волочить

thread [θred] резьба

hardened ['ha:dnd] закаленный

to lubricate ['lu:brikeit] смазывать

to screw [skru:] привинчивать

nut [nAt] гайка

outside [,aut'said] наружный, внешний

inside [,in'said] внутри, внутренний

8. Welding

Welding is a process when metal parts are joined to­gether by the application of heat, pressure, or a combi­nation of both. The processes of welding can be divided into two main groups:

• pressure welding, when the weld is achieved by pressure and

• heat welding, when the weld is achieved by heat. Heat welding is the most common welding process used today.

Nowadays welding is used instead of bolting and riv­eting in the construction of many types of structures, including bridges, buildings, and ships. It is also a basic process in the manufacture of machinery and in the mo­tor and aircraft industries. It is necessary almost in all productions where metals are used.

The welding process depends greatly on the proper­ties of the metals, the purpose of their application and the available equipment. Welding processes are clas­sified according to the sources of heat and pressure used.

The welding processes widely employed today include gas welding, arc welding, and resistance welding. Other joining processes are laser welding, and electron-beam welding.