Exercises

Міністерство освіти і науки України

Херсонський національний технічний університет

Рег. № 7/252 – 26.02.07

МЕТОДИЧНІ ВКАЗІВКИ

ДО САМОСТІЙНОЇ РОБОТИ

З ДИСЦИПЛІНИ „АНГЛІЙСЬКА МОВА”

ДЛЯ СТУДЕНТІВ ІІ – ІІІ ЕТАПІВ НАВЧАННЯ

СПЕЦІАЛЬНОСТЕЙ 090202, 090215, 090222

НАПРЯМУ „ІНЖЕНЕРНА МЕХАНІКА”

ФАКУЛЬТЕТУ МАШИНОБУДУВАННЯ

Херсон 2007

Методичні вказівки для самостійної роботи з дисципліни „Англійська мова” для студентів ІІ – ІІІ етапу навчання спеціальностей 090202, 090215, 090222 напряму „Інженерна механіка” факультету машинобудування / Укладач Статкевич О.К. – Херсон, ХНТУ 2007. 21ст.

Затверджено

На засіданні кафедри

Іноземних мов

Протокол № 8 від 17.05.06

Зав.кафедри _______доц.Фоменко Н.С.

Відповідальний за випуск Н.С.Фоменко к.філол.н., доц., завідувач кафедри іноземних мов

Unit 1

Metals and alloys

Text 1.

Metals

Metals are materials most widely used in industry because of their properties. The study of the productions and properties of metals is known as metallurgy.

The separation between the atoms in metals is small, so must metals are dense. The atoms are arranged regularly and can slide over each other. That is why metals are malleable (can be deformed and bent without fracture) and ductile (can be drawn into wire). Metals vary greatly in their properties. For example, lead is soft and can be bent by hand, while iron can only be worked by hammering at red heat.

The regular arrangement of atoms in metals gives them a crystalline structure. Irregular crystals are called grains. The properties of the metals depend on the size, shape, orientation, and composition of these grains. In general, a metal with small grains will be harder and stronger than one with coarse grains.

Heat treatment controls the nature of the grains and their size in the metal. Small amounts of other metals (less than 1per cent) are often added to a pure metal. This is called alloying (легирование) and it changes the grain structure and properties of metals.

All metals can be formed by drawing, rolling, hammering and extrusion, but some require hot-working. Metals are subject to metal fatigue and to creep (the slow increase in length under stress) causing deformation and failure. Both effects are taken into account by engineers when designing, for example, airplanes, gas-turbines, and pressure vessels for high-temperature chemical processes. Metals can be worked using machine-tools.

The ways of working a metal depend on its properties. Many metals can be melted and cast in moulds, but special conditions are required for metals that react with air.

Exercises