Non-ferrous metals

Task 1. Make a list of the non-ferrous metals and compare it with your partner.

Task 2. You are going to read about non-ferrous metals. Seven sentences have been removed from the text. Choose from the sentences (A-H) the one which fits each gap (1-7). There is one extra sentence which you do not need to use. There is an example at the beginning (1).

A	These characteristics are: high electrical and thermal conductivity, high corrosion resistance, non-magnetic qualities, light weight, etc.
B	It has high corrosion-resistant qualities and is used for plating other metals such as iron or brass.
C	Aluminium is a soft, silvery white metal.
D	On account of its low electrical resistance, aluminium is used in certain cases in wires and cables as conductors.
E	It was replaced for these purposes by iron and steel.
F	Aluminium is the most abundant of the metals and the most widely distributed.
G	It is quite ductile and can be easily rolled, drawn, forged and welded.
H	Metallurgists propose copper to be used for making electrical contacts, wires, water heaters, etc.

Non-ferrous metals are more expensive than ferrous metals and are used only when some characteristic not possessed by iron or steel is essential or desirable in application. 1) A.

The metals most frequently used to make non-ferrous metal castings are copper, tin, zinc, nickel, gold, aluminium and lead. Some of the basic non-ferrous metals and their characteristics are described below.

Copper was used in prehistoric times for making weapons and tools and later was alloyed with tin to form bronze, which was the most important metal of the Greeks and Romans. 2) _______. Various grades of copper are used for engineering purposes. The great development of the electric industries has resulted in such extensive uses of the metal that it now ranks next to iron in importance.

We know copper to be a reddish-brown tough metal. Among non-ferrous metals copper is the most important. Because of its high electric conductivity about 60 % of all the copper produced is used in electrical work. It has high corrosion-resistant qualities. 3) _______.

The copper alloys are more widely employed. The alloying of copper with other elements increases the strength of the metal in some cases and improves the anticorrosive and anti-friction properties in others.

Aluminium is the typical metal in the third group in the periodic clas­sification of the elements. 4) _______. It is found in feldspars, micas, kaolin, clay, bauxite, cryolite, alunite, corundum and certain gems. Compounds of aluminium have been known for many years and they were recognised as being derived from a metal that had not been isolated. 5) _______. It is light in weight, has high corrosion-resistant qualities. Scientists suggest aluminium to be used for automobile and airplane parts. It can be used also for making different light-weight objects used in everyday life such as: frames, cooking utensils, chairs.

Aluminium has a very low density, 2.7; it is used in construction when a metal is required and weight is important. It is ductile, malleable, and can be rolled. Its tensile strength is low in comparison with that of iron; it cannot be machined and polished readily and does not yield good castings. These defects can be overcome by alloying it with other metals. The metals which alloy freely with aluminium are copper, zinc, and iron. Usually where aluminium alloys are made, aluminium predominates. 6) _______.

Zinc is a hard, brittle, bluish-white metal that is employed in the pure form as sheet zinc.

Lead is a very heavy bluish-grey metal which is very soft. We know lead to be supported by a core to strengthen it. Lead is used for lining pipes, acid tanks and coating electrical cables.

Tin is a silvery, corrosion-resistant metal. We suggest tin to be used as an alloying element. Tin is hardly used in pure form.

Nickel is a hard, tough, silvery metal. 7) _______.

There are many applications of non-ferrous metals in the unalloyed state, but in most cases, some alloying element is added.

Task 3. Find in the text equivalents to the following words and expressions:

електро- та термо-провідність, корозійностійкий, олово, свинець, зброя, польовий шпат, слюда, глина, м’який, вага, межа міцності на розтягнення, у порівнянні з золотом, легко сплавляється, дроти, провідник, чиста форма, труби, міцний.

Task 4. Translate into Ukrainian the following words and word combinations:

more expensive, desirable in application, non-magnetic qualities, light weight, most frequently used, metal castings, making weapons and tools, engineering purposes, extensive uses, the anticorrosive and anti-friction properties, the most abundant of the metals, the most widely distributed, automobile and airplane parts,ductile, malleable, unalloyed state.

Task 5. Match the words in column A with their meaning from column B.

	A		B
	feldspar	a)	свинець
	alloying element	b)	межа міцності на розрив
	expensive	c)	бак для кислоти
	mica	d)	жорсткий
	lead	e)	олово
	corrosion resistance	f)	слюда
	tin	g)	легуючий елемент
	tough	h)	польовий шпат
	acid tank	i)	стійкість до корозії
	tensile strength	j)	дорогий

Task 6. Fill in the gaps with the verbs given below used in the proper tense form:

to show, to possess, to give rise to, to beat

1. Copper _______ high corrosion-resistant qualities

2. These defects _______ by alloying it with other metals.

3. Some of the basic non-ferrous metals and their characteristics _______ below.

4. The great development of the electric industries _______ such extensive uses of the metal that it now ranks next to iron in importance.

Task 7. Translate next sentences into English:

1. Кольорові метали використовуються через їх фізичні властивості, такі як: стійкість до корозії, тепло та електропровідність та інші.

2. Люди сплавили мідь з оловом, щоб утворити бронзу.

3. Мідь використовується для дротів, електричних контактів, нагрівачів води, і т.п.

4. В автомобільній та повітряній промисловостях конструктори використовують алюміній через його легку вагу та антикорозійні властивості.

5. Олово найчастіше використовується як легуючий елемент.

6. Кольорові метали дуже рідко використовуються в чистому виді, дуже часто додається який-небудь легуючий елемент.

Task 8. Put the verbs in brackets into Passive Voice and translate the following sentences into Ukrainian:

1. Iron, like most metals, (to find) in the Earth's crust in an elemental state.

2. If a piece of copper (to heat) it becomes coated in black copper oxide.

3. Tensile strength (to measure) in units of force per unit area.

4. A malleable metal easily (to deform), especially by hammering or rolling, without cracking.

5. Hardness (to measure) on the Mohs scale or various other scales.

6. Blast furnaces (to use) for non-ferrous smelting processes, particularly in the production of lead.

Task 9. Fill in the table using the information from the texts:

metal	composition	usage

Task 10. Memorize the following words and word combinations:

1.	acid tank	бак для кислоти
2.	anti-friction properties	анти-зношувальні властивості
3.	coating electrical cables	покриття електрокабелів
4.	cooking utensil	кухонне начиння
5.	core	осердя, ядро
6.	corrosion resistance	стійкість до корозії
7.	corundum	корунд, наждак
8.	to derive	отримувати, добувати
9.	feldspar	польовий шпат
10.	frame	рама
11.	electrical contacts	електричні контакти
12.	to employ	використовувати, застосовувати
13.	expensive	коштовний, дорогий
14.	gem	дорогоцінне каміння
15.	grades of copper	сорт міді
16.	mica	слюда
17.	pipe	труба
18.	plating	покриття
19.	pure form	чиста форма
20.	sheet zinc	листовий цинк
21.	tensile strength	межа міцності на розрив
22.	thermal conductivity	термопровідність
23.	unalloyed state	несплавлений стан
24.	water heater	водневий нагрівач
25.	wire	дріт

Unit 9

PROPERTIES OF ENGINEERING MATERIALS

Task 1. What are the most important properties of engineering materials?

Task 2. Can we change the properties of engineering materials? How?

Task 3. Read and translate the text:

Properties of engineering materials are known to affect manufacture and application of them. While using engineering materials we must know their physical characteristics. All engineering materials have definite characteristics which determine their abilities to assume external loads because of which materials change their shape. Metals are known to be subjected to the influence of external forces when they are treated. These forces are called "loads" and may have different characteristics: according to their value they may be small or large; according to the duration and character of their action they may be constant and impact. According to the influence of the load upon the metal causing different changes of its shape, loads are distinguished as compression, tensile, torsion, shearing and bending ones. By testing a metal under a load one can define what mechanical properties it has. In order to have a clear conception of the metal properties it is subjected to tests on special devices and machines. The determination of these properties is made in the laboratory using a specimen of the metal to be tested.

In studying engineering processes an engineer who is to build a machine must select suitable materials for each machine member. One must know the characteristics of engineering materials. These are as follows: strength, stiffness, ductility, toughness, elasticity, plasticity, fatigue resistance, shock resistance, corrosion resistance, wear resistance, hardness, frictional qualities, machinability, casting and forging properties. They depend upon the chemical composition and the physical structure of the material.

Strength is the property of hard materials to be subjected to the influence of external forces without incurring damage, without changing their shape. The ultimate tensile strength of a material is that unit stress developed in the material by maximum slowly applied load that material can resist without rupturing in a tensile test.

Special machines, called "rupture machines", are used to test metals for strength. When testing a specimen, the upper clamp remains fixed and the lower one is being slowly lowered, thus causing the extension of the specimen. The load upon the specimen may be easily determined at any moment by means of pointer indications on the dial.

Elasticity is the ability of a material to change its shape under the influence of external loads and return to its original form upon removal of the loads. All materials are elastic but the range of elasticity varies for different materials. Elasticity is evaluated by means of the modulus of elasticity. The modulus of elasticity is considered to be the ratio of the unit stress to the unit deformation within the proportional limit of the material to be tested. A rupture machine may be used to determine the elasticity of metals.

Plasticity is the property of a material when under the influence of loads, specimens of different materials may elongate while their cross-section decreases. Plasticity is the opposite of elasticity. So, plasticity is the ability of material to change its form without breaking under the influence of load and preserve this changed form after removal of the load. For determining the plasticity of metals a rupture machine may be used too.

There are some processes changing and improving the properties of metals. Heat-treatment is the process of controlled heating and cooling of metals to change their structural arrangement and to ensure certain desirable properties. Annealing consists of heating the metal to a temperature slightly above the critical temperature and then cooling slowly to produce an even grain structure, reduce the hardness, and increase the ductility. Normalising is a form of annealing in which the material is cooled in the air. Quenching or rapid cooling from above the critical temperature by immersion in bold water or some other cooling medium is a hardening treatment. Tempering consists of reheating the quenched metal to restore ductility to some extent and reduce the brittleness.

Task 4. Find in the text equivalents to the following words and expressions:

певні характеристики, змінювати форму, зовнішні сили, обробляти, тривалість, пружність, згинання, прилад, примірник, показник ступеня гнучкості, властивість, зберігати, визначення пластичності металу, покращувати властивості металу, тепло обробка, охолодження.

Task 5. Make word combinations from the words in column A and column B, translate them into Ukrainian:

	A		B
	controlled	a)	machines
	special	b)	materials
	unit	c)	re­sistance
	engineering	d)	heating
	rupture	e)	loads
	wear	f)	strength
	external	g)	devices
	tensile	h)	stress

Task 6. Translate into Ukrainian the following words and word combinations:

strength, stiffness, ductility, toughness, elasticity, plasticity, fatigue resis­tance, shock resistance, corrosion resistance, wear re­sistance, hardness, frictional qualities, machinability, casting and forging properties, annealing, normalising, quenching, tempering.

Task 7. Fill in the gaps with the verbs given below. Put them in proper tense form. Translate the following sentences into Ukrainian:

to be, to calculate, to be identical, to determine, to keep, to undergo

1. Elasticity _______ by means of the modulus of elasticity.

2. Tempering consists of reheating the quenched metal _______ ductility to some extent and reduce the brittleness.

3. In order to have a clear conception of the metal properties it _______ to tests on special devices and machines.

4. Viscosity _______ a measure of the resistance of a fluid to deform under shear stress.

5. By testing a metal under a load one _______ what mechanical properties it has.

6. The average density of an object _______ to its total mass divided by its total volume.

Task 8. Complete the sentences using the given words:

Strength		… quality of being easily made into any shape, and of staying in that shape until something changes it.
Elasticity		…making metal hard by heating it and then slowly letting it get cold in the air.
Plasticity		…a way of treatment by immediate cooling in corresponding media.
Heat-treatment	is	…property of hard materials to resist external forces.
Annealing		…second heating for changing material properties.
Normalising		…making metal hard by heating it and then slowly letting it get cold.
Quenching		…the ability of the material to stretch and go back to its usual length or shape.
Tempering		…the processing of material with the help of controlled heat.

Task 9. Translate next sentences into English:

1. При обробці, метали піддаються впливу зовнішніх сил.

2. Щоб чітко визначити властивості матеріалу, його слід перевірити різними приладами та інструментами.

3. Будуючи машину, інженер має обрати правильний матеріал з потрібними властивостями та характеристиками.

4. Пластичність – це властивість матеріалу змінювати форму під дією зовнішніх сил та зберігати її (форму).

5. Тепло-обробка- це процес контрольованого охолоджування і нагрівання металів, з метою зміни їх структури і отримання певних властивостей.

6. Еластичність - це властивість матеріалу змінити свою форму під впливом зовнішніх сил і повернутися до його первинного виду.

Task 10. Find in the text synonyms to the following words:

form,distinct characteristics, steady, to choose, sample

Task 11. Memorize the following words and word combinations:

1.	annealing	відпал
2.	to assume	приймати, брати на себе
3.	bending	згинання
4.	clamp	затиск, клема
5.	corrosion resistance	стійкість до корозії
6.	device	прилад
7.	ductility	ковкість, тягучість
8.	duration	тривалість
9.	external forces	зовнішні сили
10.	fatigue resistance	втомна стійкість
11.	frictional qualities	якості тертя
12.	hardness	твердість
13.	heat-treatment	тепло обробка
14.	machinability	здатність до обробки
15.	physical characteristics	фізичні характеристики
16.	quenching	закалювання
17.	shearing	нарізання
18.	shock resistance	ударостійкість
19.	specimen	зразок, примірник
20.	stiffness	жорсткість
21.	tensile	розрив, розтягнення
22.	tempering	відпуск, пом’якшення
23.	torsion	кручення
24.	toughness	пружність, гнучкість
25.	wear resistance	зносостійкість

Unit 10

Дата добавления: 2015-11-14