Министерство образования и науки РФ
Северо-Кавказский горно-металлургический институт
(государственный технологический университет)
*
*
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Кафедра иностранных языков
АНГЛИЙСКИЙ ЯЗЫК
Методические указания к практическим занятиям для студентов
направления подготовки
150400.62 - «Металлургия»
Составители Калустьянц Ж.С., Сергеева И.В.
ВЛАДИКАВКАЗ 2015
УДК 811.111
ББК 81.2 Англ.
Рецензент: канд. филол. наук, проф. Делиева Л.М.
Методические указания по английскому языку / сост. Калустьянц Ж.С.,
Сергеева И.В.; Северо-Кавказский горно-металлургический институт
(государственный технологический университет).- Владикавказ: СевероКавказский
горно-металлургический
институт
(государственный
технологический университет). Изд-во «Терек», 2015. - 31 c.
Методические указания предназначены для работы со студентами,
обучающимися по направлению подготовки «Металлургия», и ставят своей
целью подготовить их к чтению и переводу соответствующей технической
литературы на английском языке, а также сформировать базовые навыки и
умения для устного общения на языке по данному направлению. Пособие
содержит адаптированные и оригинальные тексты из иностранных журналов
и научно-технической литературы, а также тексты, переведенные с русского
на английский язык. Тексты снабжены упражнениями, рассчитанными на
активизацию лексического и грамматического материала.
УДК 811.111
ББК 81.2 Англ.
Редактор:
Компьютерная верстка:
o Составление: Северо-Кавказский
горно-металлургический институт
(государственный технологический
университет), 2015
o Калустьянц Ж.С., Сергеева И.В., составление,
2015
Подписано в печать. Формат бумаги 60х84 1/16. Бумага офсетная. Гарнитура
«Таймс». Печать на ризографе. Усл. п. л. 1,2. Тираж. Заказ № .
Северо-Кавказский горно-металлургический институт (государственный
технологический университет). Изд-во «Терек».
Отпечатано в отделе оперативной полиграфии СКГМИ (ГТУ).
360021. Владикавказ, ул. Николаева, 44.
2
Contents
Unit 1. Metallurgy.
4
Unit 2. Metals and Alloys
5
Unit 3. Foundry
11
Unit 4. Molding
14
Unit 5. Types of Furnaces
20
Unit 6. Metals and Their Alloys
26
3
Unit 1.
METALLURGY
SOME WORDS ABOUT METALLURGY
Metallurgy is one of the oldest of arts but one of the youngest of sciences.
Many of our metals were known in ancient times, but it is only within the last
century or two that the knowledge of the properties of the metals has made it
possible to apply them in any extended way for industrial purposes.
With the development of physics of metals, metallography, theory of heat
treatment, and other phases of the science of metals, the field of metallurgy
has broadened.
Metallurgy in this broader sense falls into three divisions: chemical or
extractive, physical and mechanical. Chemical metallurgy includes the
metallurgical processes involving chemical change and the methods of
production and refining.
Physical metallurgy deals with the nature, structure, and physical
properties of metals and alloys.
Mechanical metallurgy includes the processes of working and shaping
metals — processes which do not involve chemical changes.
NOTES AND COMMENTARY
art - зд. ремесло
has made it possible – сделало возможным
in ancient times – в ранние времена, в старину
in this broader sense falls into – в этом
within the last century – за последнее
более широком значении делится на
столетие
deals with - рассматривает
EXERCISES
I.
Find in the text the English equivalents of these Russian word
combinations.
1) в промышленных целях
2) применять
3) метод производства
4) очищение от примесей, улучшение качества
5) свойства металлов
6) теория термической обработки
7) в широком смысле
8) химическое изменение
9) включать
10)
сплавы
11)
обработка
12)
извлекать
II.
Answer the questions.
1) What phases of the science of metals do you know?
2) What does physical metallurgy deal with?
3) What does mechanical metallurgy include?
4
Unit 2.
METALS AND ALLOYS
PHYSICAL PROPERTIES OF METALS AND ALLOYS
The word constitution used with reference to metallic substances does not
have the same meaning as composition. Constitution denotes the manner of
arrangement of the metal atoms as to geometric form in solid crystals, and the
regular or ordered arrangement of different kinds of metal atoms and their relation
to each other in such a crystal.
The pattern formed by this orderly arrangement of the atoms is known as the
space lattice.
Most metals crystallize with one of the three following lattice structures:
Close-packed cubic: copper, nickel, lead, aluminium, cobalt, silver, gold,
platinum.
Body-centred cubic: iron, molybdenum, tungsten, chromium.
Hexagonal close-packed: zink, cadmium, magnesium, beryllium, titanium.
This union of atoms into a geometric array is the physical difference
between liquid and solid metal.
The formation of metal crystals within a melt begins at each cooling surface
of the liquid mass and extends from the exterior to the interior as heat is lost from
the mass. Every change in the conditions of cooling, such as increasing or
decreasing the rate at which heat is conducted away from the freezing mass, will
have an influence on the size and shape of the crystals and, therefore, on the
constitution and properties of the solidified mass.
Melting and Boiling Points. - The temperature at which a metal melts, is
called the melting point, the metals of lower melting points are generally the soft
metals and those of high melting the hard metals.
The boiling point of a substance depends on the surrounding-pressure. The
term "boiling point" refers to the temperature at which the metal boils under
normal atmospheric pressure.
Electrical Conductivity. - The electrical conductivity of a substance is the
electrical conducting power of a unit length per unit of cross-sectional area. The
electrical resistance of metals or alloys is increased by decreasing the size of the
crystals and, therefore, increasing the number of crystal boundaries. In general, all
metals increase in resistivity with increase in impurities. The resistivity of metals is
also increased in most cases by an increase in temperature.
Heat Conductivity. - Heat conductivity is measured as the heatconducting
ability of a unit length or thickness of a substance per unit of cross-sectional area.
Magnetism. - Magnetism is measured as the magnetic force exerted by a
unit volume of a substance under standard magnetizing force. Iron, cobalt and
nickel are the only metals possessing considerable magnetism at room temperature,
and they become non-magnetic when heated to a certain temperature. Strong
permanent magnets have been made chiefly of one of several compositions of
5
steel, but in recent years a number of magnet alloys of much greater magnetism,
able to exert forces many times their own weights, have been developed.
Density and Porosity. - Porosity, the quality of containing pores is lack of
denseness. Density, on the other hand, denotes weight per unit of volume. The
distinction will be manifest from the fact that some heavy metals, like grey cast
ironware porous enough to leak under heavy hydraulic pressures, whereas some
lightweight metals, like aluminium, are dense and compact.
Most metals expand on heating and contract on cooling.
Colour. - Most of the metals are silvery white or grey in colour. Copper is
the only red metal, and gold the only yellow one, although a number of copperbase alloys are also yellow. All solid metals have metallic lustre, although the true
colour and lustre of many metals are often obscured by a coating of oxide — which
may be white, grey, red, brown, bluish, or black.
NOTES AND COMMENTARY
the number of crystal boundaries – число
границ кристаллов
in most cases – в большинстве случаев
the only - единственный
at room temperature – при комнатной
температуре
when heated to a certain temperature – при
нагревании до определенной температуры
able to exert forces many times their own
weights – могут обладать подъемной силой во
много раз большей своего собственного веса
is lack of – зд. лишена
on the other hand – с другой стороны
weight per unit of volume – вес на единицу
объема
like grey cast iron – подобно серому чугуну
under heavy hydraulic pressure – под большим
гидравлическим давлением
whereas – в то время, как
most metals expand on heating – большинство
металлов расширяются при нагревании
silvery white or grey in colour – серебристобелого или серого цвета
the only yellow one – единственный желтый
металл
copper-base alloys – сплавы с медной основой
the true colour and lustre – истинный цвет и
блеск
by a coating of oxide – покрытием окисла
with reference to – по отношению к
the same meaning – то же значение
the manner or arrangement – способ
расположения
as to – что касается
to each other – друг к другу
is known, as the space lattice - известен как
пространственная решетка
close-packed cubic – кубическая с плотно
упакованными атомами
body-centred cubic – кубическая объемноцентрированная структура
hexagonal close-packed – гексагональная с
плотно упакованными атомами
union of atoms into a geometric array –
объединение атомов в геометрическом порядке
within a melt – в расплавленном металле
as the heat is lost from the mass – по мере того,
как масса теряет тепло
every change – каждое изменение
the rate at which heat is conducted away from –
скорость, с какой тепло отдается из
an influence on – влияние на
melting point – точка плавления
depends on – зависит от
the metal boils under – металл кипит при
the electrical conducting power of a unit length
per unit of cross sectional area –
электрическая проводимость
6
EXERCISES
1)
2)
3)
4)
5)
I.
Answer the questions.
Name the main physical properties of metals and alloys.
What does the boiling point of a substance depend on?
When do most metals extend?
What is the difference between liquid and solid metal?
What metals possess considerable magnetism at room temperature?
II.
Match the term with its definition.
1) porosity
2) composition
3) melting point
4) boiling point
5) electrical conductivity
6) density
a) the temperature at which a metal
melts
b) the electrical conducting power of a
unit of cross sectional area
c) the quality of containing pores is lack
of denseness
d) the temperature at which the metal
boils under normal atmospheric pressure
e) the manner of arrangement of metal
atoms as to geometric form in solid
crystals
f) weight per unit of volume
III.
Find in the text sentences containing the following words and
translate them into Russian.
1) solid crystals
2) composition
3) surface
4) cooling
5) electrical resistance
6) lightweight metals
7) to leak
8) resistivity
9) the solidified mass
10)
denseness
7
IV.
Find 13 words on the topic in the crossword-puzzle and give
their Russian equivalents.
C
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S
S
MECHANICAL PROPERTIES OF METALS AND ALLOYS
Strength. - The strength of a material is the property of resistance to
external loads or stresses without incurring structural damage.
The strength of metals and alloys depends upon two factors, namely, the
strength of the crystals of which the metals are constructed and the tenacity of
adherence between these crystals.
Stress and Strain. - A stress is the force within a body which resists
deformation due to an externally applied load. If this load acts upon a surface of
unit area, it is called a unit force and the stress resisting it a unit stress.
When an external force acts upon an elastic material, the material is
deformed and the deformation is in proportion to the load. This distortion or
deformation is strain.
Elasticity. - Any material subjected to an external load is distorted or
strained. Elastically stressed materials return to their original dimensions when the
load is released if the load is not too great. The property of regaining the original
dimensions upon removal of the external load is known as elasticity.
The Nature of Elasticity. - The elasticity of a metallic substance is a
resistance of its atoms to separation or compression or rotation about one another,
and thus is a fundamental property of the material. So elasticity is demonstrated as
a function of atomic forces.
Yield Point. - This is a point on the stress - strain curve at which the stress
levels off or actually decreases while strain continues. The term is strictly
applicable only to mild steels.
8
Ultimate Strength. - The greatest load that the specimen has supported
divided by the original cross-sectional area is called the ultimate tensile strength or
the ultimate strength of the piece.
Ductility. - Ductility is the capacity of a metal to be permanently deformed
in tension without breaking.
Toughness. - Toughness has been defined as the property of absorbing
considerable energy before fracture. The toughness of a metal is indicated by the
amount of slip which may occur within the crystals without resulting in rupture of
the metal.
Malleability. - Malleability is the property of a metal which permits
permanent deformation by compression without rupture.
Brittleness. - Brittleness implies sudden failure. It is the property of
breaking without warning, i.e., without visible permanent deformation.
Failure of metals and alloys under repeated or alternating stresses, too small
to produce even a permanent deformation when applied statically, is called fatigue
failure.
Corrosion Fatigue. - Failure by corrosion fatigue is a fatigue failure in
which corrosion has lowered the endurance limit by the formation of pits that act
as centers for the development of fatigue cracks.
Hardness. - The quality of hardness is a combination of a number of
physical and mechanical properties.
NOTES AND COMMENTARY
depends upon - зависит
ultimate tensile strength – предел прочности
of which the metals are constructed – из
при растяжении, сопротивление разрыву
которых состоит металл
ultimate strength – предел прочности
tenacity of adherence – прочность сцепления
to be permanently deformed in tension –
force within a body – сила, действующая в теле
постоянно деформироваться в растяжении
due to – зд. в результате
is indicated by the amount of slip which may
a unit force – единичная сила
occur within the crystals – определяется
a unit stress - напряжение
величиной сдвига, который может произойти в
is in proportion to the load – пропорционален
кристаллах
нагрузке
breaking without warning – внезапный разрыв,
subjected to – подвергнутый
разрыв без предупреждения
original dimensions – первоначальные размеры
under repeated or alternating stresses – при
too great – слишком большой
повторяющихся или чередующихся
upon removal – после устранения
напряжениях
about one another – один вокруг другого
fatigue failure – излом усталости
yield point – предел текучести
number of physical and mechanical properties –
strain curve – кривая деформации
ряд физических и механических свойств
levels off – понижается (спадает)
mild steels – малоуглеродистые стали
9
EXERCISES
I.
Make words out of these letters and translate them into
Russian.
1) tacesinser
2) ibsivel
3) ranetexl
4) canytiet
5) thgenrst
6) rooornisc
7) recendanu
8) larufei
9) guhsensot
10)
lilelbaityma
1)
2)
3)
4)
5)
6)
7)
1)
2)
3)
4)
5)
1)
2)
3)
4)
5)
II.
Name the property according to its definition.
- the property of regaining the original dimensions upon removal of the
external load.
- the property of breaking without warning.
- a combination of a number of physical and mechanical properties.
- a point on the stress - strain curve at which the stress levels off or actually
decreases while strain continues.
- the capacity of a metal to be permanently deformed in tension without
breaking.
- the property of resistance to external loads or stresses without incurring
structural damage.
- the property of a metal which permits permanent deformation by
compression without rupture.
III. Make up definitions out of these words and name the property.
separation, another, atoms, a resistance, or, or, of, to, rotation, one, about
compression.
which, permanent, a metal, the property, of, deformation, without, by,
compression, rupture, permits.
mechanical, a number, a combination, properties, of, of, and, physical.
before, absorbing, the property, fracture, considerable, of, energy.
due to, within, load, deformation, a body, which, an, applied, the force,
externally, resists.
IV. Finish the sentences according to the text.
Ductility is the capacity of a metal to be permanently deformed …
Elasticity is demonstrated as …
When an external force acts upon an elastic material …
Elastically stressed materials return to their original dimensions when …
The strength of metals and alloys depends upon two factors: …
10
CASTING METALS
Cast Iron.— The term cast iron is applied to ferrous alloys. Among the
ferrous metals, cast iron occupies first place and is recognized as one of the
cheapest materials used in the manufacture of everyday life products. Cast iron is
not considered a very strong or tough structural material, but it is the most
economical. Its low melting point, low shrinkage, good fluidity, and machinability
are properties that recommend its use.
Pig Iron.— The chief raw material for cast iron is pig iron, which is
produced in a blast furnace by smelting iron ore with coke and a flux (substances
promoting fusion) such as limestone. The final analysis of the pig iron is
substantially determined by the kind of iron ore used in the smelting process.
Pig iron got its name from the shape of the molds in which metal from the
blast furnace was cast. Originally, the pigs were cast in sand molds.
Modern large-volume production of pig iron is carried out by casting blastfurnace metal by means of a large machine, which is in principle an endless
conveyer chain of pig molds.
Some pig irons are used in gray-iron foundries, and are called foundry pig
irons. Pig iron used for making steel by the acid Bessemer process or the acid
open-hearth process is known as Bessemer pig iron. Basic pig iron is used for the
basic open-hearth process.
Non-Ferrous Metals. — The non-ferrous metals used in the foundry are
usually alloys of two or more metals. Non-ferrous castings include those composed
of copper-base alloys (brass and bronze), aluminium-base alloys, zinc-base alloys,
tin-base alloys, lead-base alloys, bearing metals, and some special alloys composed
of magnesium or nickel and other metals.
NOTES AND COMMENTARY
cast iron - чугун
is applied to ferrous alloys – применяется к
железистым сплавам
everyday life products – предметы
повседневного обихода
pig iron – чушковый чугун
blast furnace – доменная печь
by smelting iron ore with coke and flux – путем
плавки железной руды с коксом и флюсом
got its name from the shape of the molds –
получил это название от формы изложения
1)
2)
3)
4)
5)
is carried out - осуществляется
by means of - посредством (при помощи)
endless conveyer chain – бесконечная
конвейерная цепь
gray-iron foundries – литейные заводы,
изготавливающие серый чугун
non-ferrous metals – цветные металлы
aluminium-base alloys – сплавы с алюминиевой
основой
EXERCISES
I.
Answer the questions.
What metal occupies the first place among the ferrous metals?
Where did pig iron get its name from?
What is pig iron used for?
What is the final analysis of iron determined by?
How is pig iron produced?
11
II.
1)
2)
3)
4)
5)
Find the sentences with these words in the text and translate
them into Russian.
open-hearth
blast furnace
smelting
shrinkage
bearing metals
12
Unit 3.
FOUNDRY
Foundry Equipment
1-12 melting plant – плавильная установка
1 cupola furnace (cupola), a melting furnace
– вагранка, плавильная печь
2 blast main (blast inlet, blast pipe) воздухопровод
3 tapping spout – выпускной желоб
4 spyhole – смотровое отверстие
5 tilting-type [hot-metal] receiver –
приемник расплавленного металла
6 mobile drum-type ladle – передаточный
ковш барабанного типа
7 melter - плавильщик
8 founder (caster)- заливщик
9 tap bar (tapping bar) – лом для
пробивания летки
10 bott stick (Am. hot stick) – глиняная
пробка на стержне летки
11 molten iron – расплавленный чугун
12 slag spout – выпускной желоб для шлака
13 casting team – бригада заливщиков
14 hand shank – ручной литейный ковш
15 double handle (crutch) – хомут с
ручками
16 carrying bar – хомут для переноски
ковша
24-29 continuous casting – непрерывная
разливка
24 sinking pouring floor – опускающийся
пол разливочного пролета
25 solidifying pig – затвердевший чугун
26 solid stage – твердое состояние
27 liquid stage – жидкое состояние
28 water-cooling system – система водяного
охлаждения
29 mould (Am. mold) wall – стенка
литейной формы
30-37 moulding (Am. molding) department
(moulding shop) – формовочное отделение
30 moulder (Am. molder) – формовщик
31 pneumatic rammer – пневматическая
тромбовка
32 hand rammer – ручная тромбовка
33 open moulding (Am. molding) box –
открытая формовочная опока
34 рattern - модель
35 moulding (Am. molding) sand –
формовочная смесь
36 сore – литейный стержень
37 core print – стержневой знак
38-45 cleaning shop (fettling shop) – очистное
отделение
13
17 skimmer rod – лопата для перекачивания
шлака
18 closed moulding (Am. molding) box –
закрытая опока
19 upper frame (cope) – верхняя опока
20 lower frame (drag) – нижняя опока
21 runner (runner gate, down-gate) –
литейная часть со стояком
22 riser (riser gate) - выпор
23 hand ladle – ручной литейный ковш
38 steel grit or sand delivery pipe –
распределительная труба для песка
39 rotary-table shot7blasting machine –
дробеструйная машина с
вращающимся столом
40 grit guard – ограждение от дроби
41 revolving table – вращающийся стол
42 casting - отливка
43 fettler - обрубщик
44 pneumatic grinder – пневматический
шлифовальный станок
45 pneumatic chisel – пневматическое
зубило
METAL CASTING
One of the basic processes of the metal-working industry is the production
of metal castings. Numerous methods have been developed through the ages for
producing metal castings, but the oldest method is that of making sand castings in
the foundry. Primarily, work consists of melting metal in a furnace and pouring it
into suitable sand molds, where it solidifies and assumes the shape of the mold.
However, the operation of making sand castings is not as simple as it seems
Metal-castings methods may be classified into three groups depending upon
the type of mold used and the manner in which the molten metal is introduced
into the mold.
The mold may be made from heat-resisting material, such as sand, some
suitable ceramic material, or plaster. The kind of material chosen to make the mold
is, of course, determined primarily by the melting temperature of the cast metal.
Molten metals may be poured into the mold by gravity or, on the other hand,
pressure may be applied to force the liquid metal into the mold. The latter method
is known as die casting. Die-casting pressure may be furnished by air, hydraulic
means, mechanical means, or centrifugally.
Among the mold materials, sand is used more than all others, since it can be
packed to any required shape with small effort.
This method of production is relatively simple, inexpensive, and is not
limited to any particular type of metal or to certain sizes and shapes of castings. Of
course, sand molds are used only once, and each casting requires a new mold.
Wider use of the permanent type of mold made from steel, iron or any other
suitable metal, depending upon the melting temperature of the cast metal, is
therefore greatly desired.
Bronze molds are employed at times for casting metals and alloys of very
low melting temperature such as zinc-base and lead-base alloys.
Modern casting techniques also permit that steel molds, coated inside with
refractory material, also be successfully used for production of iron and steel
castings.
14
The metal molds are usually made in two parts which are either clamped
together or closed by a screw or other suitable device. The molten metal may be
introduced into the mold either by gravity or pressure.
The inner surfaces of the metal mold are in most cases finished smooth.
They can be re-used. These qualities make them superior to sand castings.
NOTES AND COMMENTARY
through the ages – в течение веков
it can be packed to any required shape – ему
the oldest method is that of sand castings – можно придать любую нужную форму
древнейшим методом является метод литья в sand molds are used only once –
земляные формы
воспользоваться земляными изложницами
assumes the shape of the mold – принимает можно только один раз
форму изложницы
at times – иногда
depending upon the type of mold used – в coated inside – покрытые внутри
зависимости от типа используемой формы
refractory material – огнеупорный материал
introduced into – выливается в
made in two parts – изготовляется из двух
by gravity – силой тяжести
частей
on the other hand – с другой стороны
in most cases finished smooth – в большинстве
die casting – литье под давлением
случаев изготовляется гладкой
may be furnished – может осуществляться
1)
2)
3)
4)
5)
6)
7)
EXERCISES
I.
Learn the words and special terms on foundry.
II.
Answer the questions.
What is the oldest method of casting?
How may metal-casting methods be classified?
Put the steps in the right order according to the technology:
pouring the metal into suitable sand molds
solidifying
making sand molds
melting metal in a furnace
Why is sand used as mold material?
What other mold materials do you know?
What methods of pouring molten metals into a mold do you know?
What does the melting temperature of the cast metal determine?
III.
Write the English equivalents of these Russian words and
make up sentences of your own with them.
1) литье
2) печь
3) форма
4) жидкий металл
5) использовать вторично
6) выливать
7) производство
8) в зависимости от
9) требуемая форма
10)
подходящий
15
Unit 4.
MOLDING
SAND MOLDING EQUIPMENT AND MATERIALS
There are three principal methods of making sand molds. Green-sand or
damp-sand molds are formed by mixing silica, 8 per cent or 15 per cent clay, and
a small amount of water. Green-sand molds are recommended for cast iron.
Dry-sand molds are formed by mixing sand of somewhat coarse grain with
a clay-bonding material and water, and then baking the mixture dry. These molds
are used where heavy work is to be cast. Dry-sand molds are usually made up one
day, baked overnight, and assembled and cast the next day. Dry-sand molds are
recommended for steel castings.
A modified sand mold (also called a skin-dried mold) has been found
suitable for certain types of sand castings. Silica sand (silicon dioxide) is mixed
with a dry-sand bond. The mixture is packed around the pattern to a thickness of
1/2 inch thus forming a partial mold, which is permitted to dry out. When the
partial mold is dry the remaining portion of the mold is completed with green sand.
There are three classes of materials for molding that are kept in stock in the
foundry. Molding sands (light, medium and heavy), facings (graphite for blacking
or finely ground soft coal) and miscellaneous (fire clay, core binders and parting
compounds).
Light sand is used for the castings such as stove plate. The sand should be
very fine to bring out this detail; it must be strong; i.e., high in clay content, so that
the mold will retain every detail as the metal rushes in. Fine sand can be used for
such casting because the work will cool so quickly that after the initial escape of
the air and steam there will be very little gas to come off through the sand.
Medium sand is used in bench work and light floor work-such as making
machinery castings having from 1/1 to 2 sections. These castings are less fine than
those molded in light sand. Therefore, the molding sand for this type of casting is
coarser than in the case previously described.
Heavy sand is used for very large iron and steel castings. This sand is high in
silica, low in lime, and its grain is coarse in order to resist the heat of the molten
metal and enable the formed gases to pass through the molding sand for a long
time after the molten metal is poured. This type of molding sand must be held
firmly together by a large proportion of clay which makes a strong bond.
Foundry Facing Materials are either applied or mixed with the molding
sand that comes in contact with the melted metal. The object is to give a smooth
surface to the casting.
Different forms of carbon are used for facing purposes-because carbon will
glow and give off gases, but it will not melt. The principal carbon facing is
graphite.
16
NOTES AND COMMENTARY
green sand (damp sand) – сырой песок
should be very fine to bring out this detail –
должен быть очень мелким, чтобы
sand of somewhat coarse grain –
крупнозернистый песок
воспроизвести эту деталь
and then baking the mixture dry – а затем
come off through – выходить (удаляться) через
высушиванием смеси
песок
are usually made up one day – обычно
bench work – верстачная работа
заготавливаются днем
light floor work – негромоздкая работа
baked overnight – высушиваются за ночь
less fine – более крупный
assembled and cast the next day – сборка и
is high in silica – содержащий много кварца
литье происходит на следующий день
for a long time after – долгое время после
skin-dried mold – форма, высушенная с
which makes a strong bond – который
поверхности
действует как сильное связующее вещество
dry-sand bond – сухой песок в качестве
facing materials – припылы
связующего вещества
comes in contact – соприкасается
partial mold – частичная форма (неполная
the object is to give a smooth surface to – этот
форма)
элемент должен придавать поверхности
гладкость
the remaining portion of the mold is completed
with green-sand – остальная часть формы
заполняется сырым песком
are kept in stock – имеется в качестве сырья
2)
3)
4)
5)
6)
EXERCISES
I.
Read the sentences and say whether they are true or false.
There are four classes of materials for molding that are kept in stock in the
foundry.
Medium sand is used for the castings such as stove plate.
Heavy sand is used for very large iron and steel castings.
Dry-sand molds are usually made up two days.
Dry-sand molds are recommended for aluminium castings.
II.
Make up sentences out of these words.
1) carbon, facing, forms, are, different, purposes, used, of, for.
2) Sand, three, method, molds, making, are, principal, there, of.
3) With, portion, completed, green, when, the mold, mold, the, sand, the,
partial, of, is, dry, remaining, is.
4) Are, overnight, molds, dry-sand, usually, baked.
Stove, for, light, such, sand, the, plate, castings, used, is, as.
1)
2)
3)
4)
5)
6)
7)
8)
III. What is the Russian for these words and word combinations?
facing materials
clay-bonding material
silicon dioxide
to resist the heat
graphite for blacking
to give a smooth surface
the remaining portion
mixed with dry-sand bond
17
9) glow and give off gases
10)
small amount of water
TYPES OF MOLDING MACHINES
Modern molding machines successfully perform a considerable amount of
work that was done by hand.
Those molding machines that are used primarily for packing sand in flasks
can be classified as squeezer machines, jar (or jolt) machines, jolt squeezers, and
sand slingers. Other types of machines employed in molding are pattern-draw machines (stripping-plate machines and stripper machines) rollover machines,
combination machines, vibrators, and others.
The squeezer machine rams sand into the flask, which is placed between the
machine table and an overhead plate, thus obtaining uniform density of the sand
contained in the flask.
The jar or jolt machine consists of a rugged base cylinder and piston which
is attached to the machine table. The table is lifted by air pressure directed against
the piston from below, and is then permitted to drop. This action produces a jar
which rams the molding sand evenly in the flask. The operation is very rapid, and
some of the jolt machines used for small flasks give more than a hundred blows
per minute.
The jar-squeezer machine, also called the jolt-squeezer machine, combines
the operating principles of the jolt machine and the squeezer machine. A complete
mold, drag and cope, is produced by means of this machine.
Machines called sand slingers are sand-filling and ramming devices used in
the rapid molding of large castings. These machines can be used in combination
with other molding devices such as the roll-over machine and the pattern-draw machine.
Machines of various kinds have been developed for the purpose of drawing
pattern out of the mold. There are two types of pattern-drawing machines: the
stripping-plate machine and the stripper.
In the stripping-plate machine, the pattern is fitted through a plate that fits
accurately around the pattern. The patterns are drawn through the plate, either by
moving the pattern supports down with a lever or by raising the plate and the mold
half up, free from the pattern. The stripping-plate machine is best adapted to that
class of work which offers difficulties in drawing the pattern from the sand.
A stripper is a machine that either lifts the mold away from the pattern or
lifts the pattern away from the mold.
NOTES AND COMMENTARY
overhead plate – подвесная плита
modern molding machines – современные
directed against the piston from below –на
формовочные машины
поршень снизу
was done by hand – выполнялось вручную
can be classified as squeezer machines – можно and is then permitted to drop – а затем падает
rams … sand evenly in – набивает песок
классифицировать как формовочные машины
18
jar (jolt) machines, jolt squeezers –
встряхивающие машины, прессы
sand slingers – пескометы
pattern-draw machines – формовочная машина
с протяжкой модели, протяжная машина
stripping-plate machines – протяжная машина
roll-over machines – формовочная машина с
поворотной плитой
combination machines – комбинированная
машина
to ram sand into the flask – набивать песок в
опоку
-
равномерно
a hundred flows per minute – сто ударов в
минуту
drag and cope – нижняя и верхняя опоки
by means of – при помощи
pattern is fitted through a plate – образец
захватывается плитой
by moving the pattern supports down with a
lever – путем опускания вниз опор модели
рычагом
adapted to – приспособлена к
EXERCISES
I.
Say what type of machine does this or that operation.
rams sand into the flask
molds rapidly large castings
draws patterns out of the mold
lifts the mold away from the pattern
II.
Describe the work done by every machine.
19
Unit 5.
TYPES OF FURNACES.
Task:
- read the texts describing different types of furnaces
- make a plan to each text
- make up 5 questions to each of the texts
- retell any text you like
THE CUPOLA FURNACE
The cupola is the oldest type of furnace and the most economical. It may be
obtained in different sizes and can be operated for as long a time as may be
required to produce a given amount of melted metal. It is difficult to produce metal
of precisely uniform quality in the cupola as compared to furnaces in which
uniformity of the molten material can be controlled by frequent and periodic tests
and adjustment. Cupola capacities vary from 1 to 15 tons of metal per heat (the
amount of metal melted at one time).
The cupola is a cylindrical shell constructed from boiler plate and lined with
firebrick. The main furnace structure is usually supported on cast-iron legs, and the
opening at the bottom of the furnace may be closed by cast-iron doors, which
swing up into position and are held closed by an iron upright at the center.
Refractory sand protects these doors during the melting of the charge, which is
placed over the layer of sand. At the end of the melting operation, the doors swing
out of the way and materials remaining from the charge drop down through the
opening.
On one side of the cupola, level with the bottom, is the breast opening for
lighting the fire. This opening is also used as the tap hole. Opposite the tap hole,
and somewhat higher, is the slag hole. The charging door is located approximately
halfway up the vertical shell. The top of the cupola is open except for a metal
shield.
A single row of openings or tuyeres is arranged around the circumference of
the shell's interior at its base as a means of introducing air to the coke bed. A wind
box, externally circling the cupola at the level of the tuyeres, supplies the air.
Cupola Zones. — A foundry cupola is generally divided into a number of
zones: the crucible zone, tuyere zone, combustion zone, melting zone,
preheating zone, and the stack zone.
The crucible zone is located at the bottom of the cupola; it is situated in the
space between the sand bottom of the furnace and the bottom of the tuyere
openings. Molten iron and slag accumulate in this space between the burning
pieces of coke.
The tuyere openings are above the cruicible and take up a space from 3 to 6
inches in depth depending upon the size of furnace.
20
The combustion zone is that section of the cupola which extends from the
bottom of the tuyeres to the top of the coke bed.
The melting and preheating zones extend from the top of the combustion
zone to the charging door. The location of the charging door depends upon the size
of the cupola. High charging doors, however, are recommended for large cupolas
which are run all day, since greater fuel efficiency can be gained from the use of
such charging doors.
The purpose of the stack, which is another zone of the cupola, is to carry off
the waste gases. It is located above the charging door. A roof hood is usually
fastened to the stack to prevent leaks around the cupola.
Diagram of a Foundry Cupola for Melting Cast Iron
NOTES AND COMMENTARY
cupola furnace - вагранка
charging door – загрузочное отверстие
at one time - одновременно
except for a metal shield – кроме
lined with firebrick – облицованный
металлического щита
огнеупорным кирпичом
coke bed – коксовая колоша
is usually supported on cast-iron legs – обычно
wind box – воздушная коробка
поддерживается чугунными опорами
the crucible zone – тигельная зона
swing up into position - закрываются
tuyere zone – фурменная зона
held closed – держатся закрытыми
combustion zone – зона горения
iron upright – чугунной подпоркой
preheating – (предварительный) нагрев
refractory sand – огнеупорный песок
stack zone – шахта (печи), зона отвода газов
melting of the charge – плавка загрузки
take up a space – занимать пространство
swing out of the way - открываются
the top of the coke bеd – верхний слой коксовой
drop down – падать вниз
колоши
on one side – с одной стороны
to carry off the waste gases – выводить лишние
level with the bottom – на уровне с днищем
газы
breast opening – окно, летка
roof hood - покрышка, зонт
tap hole – выпускное отверстие
slag hole – шлаковая летка
21
THE BLAST FURNACE
The modern blast furnace is a tall circular structure about 100 ft. high built
of firebrick and reinforced by a steel shell on the outside. The interior form is
circular. A heavy concrete and brick foundation is built either on bedrock or upon
heavy pilings driven deep into the earth if bedrock is too far below the surface.
Iron is reduced from the ore in the furnace by means of coke charged with
ore, and the impurities are fluxed or slagged by means of limestone also charged
with the ore. The air blown through the furnace is heated by means of stoves that
constitute an important part of the apparatus of the blast furnace. These stoves heat
the brickwork in them to about 1150°C and the air pumped through the stoves is
thus heated to about 900°C before it is blown into the furnace.
The ore, coke, and limestone are conveyed from the ground to the top of the
furnace by means of two cars running on an inclined hoist. The cars dump the
charge into a hopper from which it is then dropped into the furnace by lowering
first the upper bell, then lowering the lower bell. The use of these two bells
prevents gases and flame from being blown into the air from the top of the furnace
every time it is charged. Hot air is blown into the furnace through the tuyeres in the
hearth of the furnace.
As the iron and slag are formed, they drop to the hearth at the bottom of the
furnace. Since the iron is heavier than the slag, it settles to the bottom while the
slag floats on the top of the molten iron. There are two holes in the hearth of the
blast furnace. The iron is tapped from the lower hole; the slag is tapped from the
upper hole. Many of the impurities in the ore are collected and removed with the
limestone in the form of molten slag.
The iron runs from the furnace into troughs which convey it to a ladle. The
iron in the ladle is then cast into pigs or else taken while molten to the steel making
furnaces.
NOTES AND COMMENTARY
blast furnace – доменная печь
cars running on an inclined hoist – тележки,
reinforded by a steel shell on the outside – движущиеся по наклонному подъемнику
укрепленная стальным кожухом извне
dump the charge into the hopper – сбрасывает
upon heavy pilings driven deep into the earth – загрузку в хоппер
на тяжелых сваях, вбитых глубоко в землю
upper bell – верхний конус
bedrock – скальная порода
lower bell – нижний конус
by means of coke charged with ore – при as the iron and slag are formed – по мере
помощи кокса, загружаемого с рудой
образования чугуна и шлака
is cast into pigs – отливается в чушки
constitute an important part – составляют
or else taken while molten to the steel making
важную часть
furnaces – или же отправляется в печи для
brickwork – кирпичная кладка
изготовления стали
to the top of the furnace – на колошник печи
22
THE BESSEMER CONVERTER
In the Bessemer process of making steel air is blown through the molten pig
iron, and the oxygen of the air combines with the carbon, manganese, and silicon
of the pig iron. This action generates heat and frees the iron from the major part of
its impurities thus converting the iron into steel.
The Bessemer converter, in which the process takes place, is a pear-shaped
tilting vessel made of steel plates and lined with heat-resisting bricks and clay. The
top of the converter is cut off to form a mouth through which molten metal is
charged and discharged. In the bottom of the vessel are a number of holes through
which air is blown.
When the air blast is turned on, a shower of sparks bursts from the mouth of
the converter. Immediately thereafter appear short ruddy flames and a dense cloud
of reddish-brown fumes caused by the burning of the silicon and manganese in the
iron. In about five minutes this part of the refining action is accomplished, and the
next stage, the removal of carbon, begins.
The ruddy flames become more luminous, changing to a yellowish white.
For about ten minutes the glare continues, and during that time the converter
emits a deep roar caused by the violent generation of gas within it.
Suddenly the flame drops, and the operator must diminish the blast of air
and remove the metal from the converter.
Bessemer steel is used because of the low cost of the process.
Today we have a new, more perfect technology of converting pig iron into
steel in which the blast of air is replaced by a jet of nearly pure oxygen.
NOTES AND COMMENTARY
generates heat – производит тепло
the top of the converter is cut off to form a
mouth – верх конвертера срезан, образуя
frees the iron from the major part of its
impurities – освобождает чугун от большей
горловину
части примесей
turned on - включен
thus converting the iron into steel – таким
a shower of sparks bursts from the mouth –
образом, превращая чугун в сталь
поток искр вырывается из горловины
pear-shaped tilting vessel – грушеобразный
the converter emits a deep roar caused by the
наклоняющийся сосуд
violent generation of gas within it – конвертер
made of steel – сделан из стали
издает сильный рев, вызванный бурным
lined with - облицован
образованием газа в нем
THE OPEN HEARTH FURNACE
The name open hearth is given to it because the hearth of the furnace is
exposed to the sweep of the flames which melt the steel.
The open-hearth process is one of the most important methods of making
steel. It is much slower than the Bessemer but it is easier to control, and for that
reason it is more frequently used.
The furnace is lined with firebrick to withstand the very high temperatures
used. The charge consists of molten pig iron, scrap iron and steel and some
hematite. Lime is added to the charge to take out the phosphorus and sulphur as
23
slag. Manganese, carbon, nickel, vanadium, or other materials are added to make
the kind of steel desired.
The fuel is blown into furnace through one of the two large openings, or
ports, located on each end of the furnace. To facilitate combustion, previously
heated air is blown through the port along with the fuel. Combustion occurs above
the hearth, and the smoke and other products of combustion escape through the
ports at the other end of the furnace.
Beneath the furnace are two large chambers through which air or gas flows
freely.
There are three stages in the operation of this furnace. The first is known as
the process of charging; the second — as the melting down process; the third —
the period of refining. The period of refining is especially important and requires
the constant supervision of the operator. The refining consists first in removing
objectionable impurities and then controlling the elements other than iron which
the final product must contain. Alloying elements are added to the steel before it is
tapped or when it is in the ladle.
NOTES AND COMMENTARY
open-hearth furnace – мартеновская печь
for that reason - по этой причине
the hearth is exposed to the sweep of the flames
– дно печи подвергается воздействию факела
пламени
the charge consists of molten pig iron, scrap iron
and steel and some hematite – загрузка состоит
из расплавленного чугуна, лома и стали и
небольшого количества красного железняка
to take out – чтобы перевести
to make the kind of steel desired – чтобы
получить нужный сорт стали
to facilitate combustion previously heated air is
blown – чтобы ускорить горение, вдувается
заранее нагретый воздух
combustion occurs above the hearth – горение
происходит над подиной (ванной)
melting down process – процесс плавления
the period of refining – период рафинирования
the constant supervision of the operator –
постоянное наблюдение оператора
the elements other than iron which the final
product must contain – элементы кроме чугуна,
которые должны содержаться в окончательном
продукте
THE ELECTRIC FURNACE
The finest grades of steel are produced by the electric furnace method.
Stainless and heat resistant steels are made almost exclusively by that process.
Electricity is used only for the production of heat and does not of itself
impart any superior quality of steel. Nevertheless, the electric furnace method
gives certain advantages impossible in other steel melting processes. The electric
furnace generates extremely high temperatures. The temperature is at all times
under precise control and is easily regulated.
The production of heat by electricity is unique, oxygen is not necessary to
support combustion and the atmosphere within an electric furnace may be
regulated at will.
The electric furnace is a circular steel shell resembling a huge tea-kettle in
general appearance. It is mounted on rockers so that the furnace can be tilted to
pour off molten metal and slag. The bottom of the furnace consists of a layer of
24
heat resistant materials below which it is lined with refractory bricks. The side
walls which are also lined with refractory bricks contain three or more openings.
The roof of the furnace is lined with 250 mm or more of refractory bricks
and is shaped like a flat dome. Through this dome great columns of carbon reach
into the furnace. These are the electrodes which carry the current to the steel
charge.
NOTES AND COMMENTARY
finest grades of steel – лучшие марки стали
Is mounted on rockers so that the furnace can
does not of itself impart any superior quality of be tilted to pour off molten metal – установлена
steel – само по себе не придает стали какого- на поворотных опорах так, что печь может
либо высшего качества
наклоняться для слива расплавленного металла
is lined with – облицована
is at all times under precise control and easily
regulated – все время находится под точным
is shaped like flat dome – имеет форму,
контролем и легко регулируется
похожую на плоский колпак
at will – по желанию
25
Unit 6.
METALS AND THEIR ALLOYS.
Task for self-study:
- read the texts
- write down all special terms to each of the texts
- answer the questions
- make a report on any metal you like
ALLOYS
Pure metals are comparatively seldom used; in engineering, application is
made chiefly of alloys which consist of two or more metals, or of metals and
metalloids.
Alloys are metallic solids, complex in composition, solution of two or more
metals, or metals and metalloids.
Each constituent of an alloy is called a component. Alloys may be binary
(two-component), ternary (three-component), etc.
The ability of various metals to form alloys differs greatly and, therefore, the
structure of various alloys after solidification may also be very diverse.
In the liquid state, alloys are entirely homogeneous and from the physical
point of view constitute a single phase. Nonhomogeneity may appear when an
alloy is transformed from the liquid to the solid state, i.e. several solid phases are
formed. After solidification, alloys may consist of one, two or more phases
depending upon the nature of their components. Certain metals are not mutually
soluble in the liquid stale; they form two layers with different specific weights
(e.g., lead and iron, lead and zinc, etc.). It is difficult to form an alloy in such cases
since it is necessary to mix the metals into each other.
ALUMINIUM AND ITS ALLOYS
Next to oxygen, aluminium is the most abundant element in nature: about
7.45 per cent of the earth's crust consists of aluminium.
Aluminium is extracted from rock with a high alumina content. The most
important sources are bauxite, kaolin, nepheline and alunile.
Bauxite is the principal source of aluminium. The less silica in a bauxite the
higher its quality as an aluminium ore. Kaolin clays are very abundant in nature
but the extraction of aluminium from these ores presents difficulties due to the
considerable amount of silica present.
26
The most important properties of aluminium are its low specific gravity
(2.7), high electrical and thermal conductivities, high ductility, and corrosion
resistance in various media.
Pure aluminium has only few applications; it is used for the manufacture of
electrical wire, chemical apparatus, household utensils and for coating other
metals.
Aluminium alloys are more widely used in industry. Wrought aluminium
alloys have a high mechanical strength which in some cases approaches the
strength of steel. Wrought aluminium alloys are further classified as non-heattreatable and heat-treatable alloys. .Wrought aluminium alloys also include
complex alloys of aluminium with copper, nickel, iron, silicon and other alloying
elements. Complex wrought aluminium alloys of the duralumin (dural) type and
certain others have found most extensive application in many industries.
Several grades of duralumin are available in the Russia. They are identified
by the Russian letter Д followed by a figure indicating the number of the alloy in
the series. Duralumin, grade Д-1 can be obtained in the form of sheets, bar stock
and tubing; grades Д-6 and Д-16 аre usually produced in the form of bars, and
grade Д-ЗП is made as wire for rivets.
1.
2.
3.
4.
5.
6.
7.
8.
9.
Answer the following questions:
What elements are the most abundant in nature?
What are the most important sources of aluminium?
What are the most important properties of aluminium?
Is pure aluminium widely used?
Do wrought aluminium alloys have a high mechanical strength?
How are wrought aluminium alloys further classified?
What complex alloys do wrought aluminium alloys also include?
What aluminium alloys have found most extensive application in many
industries?
How are various grades of duralumin identified?
MAGNESIUM AND ITS ALLOYS
Magnesium has a specific gravity of approximately 1.7; its alloys are the
lightest of all engineering metals employed.
The melting point of magnesium is 650° C; its boiling point is 1007° C.
Magnesium is very inflammable and burns with a dazzling flame, developing a
great deal of heat.
The mechanical properties of magnesium, especially the tensile strength, are
very low and therefore pure magnesium is not employed in engineering.
The alloys of magnesium possess much better mechanical properties which
ensure their wide application.
The principal alloying elements in magnesium alloys are aluminium, zinc
and manganese. Aluminium, added in amounts up to 11 per cent, increases the
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hardness, tensile strength and fluidity of the alloy. Up to 2 per cent zinc is added to
improve the ductility (relative elongation) and castability. The addition of 0.1-0.5
per cent manganese raises the corrosion resistance of magnesium alloys.
Small additions of cerium, zirconium and beryllium enable a fine-grained
structure to be obtained, they also increase the ductility and oxidation resistance of
the alloys at elevated temperatures.
Magnesium alloys are classified into two groups: wrought alloys, grades
MA1, MA2, casting alloys, grades MЛ4, MЛ5.
Wrought magnesium alloys MA1 and MA2 are chiefly used for hot smith
and closed-die forged machine pants. They are less frequently used as sheets,
tubing or bar stock.
Magnesium casting alloys MЛ4 and MЛ5 are widely used as foundry
material though their castability is inferior to that of aluminium-base alloys.
1.
2.
3.
4.
5.
6.
7.
8.
Answer the following questions:
What specific gravity has magnesium?
What is the melting point of magnesium?
Why is pure magnesium not employed in engineering?
What are the principal alloying elements in magnesium alloys?
How much aluminium is added to magnesium?
How much zinc is added to magnesium?
How much manganese is added to magnesium?
8. For what purpose are small additions of cerium, zirconium and
beryllium added to magnesium?
COPPER AND ITS ALLOYS
Copper is a valuable metal. Its wide application in many fields of
engineering is due to its exceptionally high electrical and thermal conductivity, low
oxidisability, good ductility and to the fact that it is the basis of the important
industrial alloys, brass and bronze.
The raw materials for the production of copper are sulphide or oxide copper
ores. Most of the copper is smelted from sulphide ores (about 80 per cent) while
oxide ores account for only 15 to 20 per cent. Sulphide ores are more wide-spread
in nature due to the higher affinity of copper for sulphur than for oxygen.
The most abundant copper sulphide ore is copper pyrite containing the
mineral chalcopyrite (Cu2Fe2S4). In some cases, the so-called copper glance is
used; it contains the mineral chalcocite (Cu2S). All copper ores are very lean as
they contain only from 1 to 5% Cu. Therefore, before smelting they must be
concentrated by flotation. Flotation converts lean copper sulphide ores into a concentrate containing from 15 to 20% Cu.
Before smelting, the copper concentrate and rich copper sulphide ores are
subjected to an oxidising roasting process at 600—900° C thereby part of the
sulphur is removed in the form of a gas. This gas is trapped and utilised in the
production of sulphuric acid.
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Various grades of copper are used for engineering purposes. It must be noted
that even a minute amount of impurities sharply alters the properties of pure
copper.
The mechanical strength of pure copper is not high and depends upon the
degree of deformation (reduction in working). Pure copper is used chiefly for
electrical engineering products such as cables, busbars and wire.
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 antifriction properties in others. Copper alloys comprise two
main groups — brasses and bronzes. Alloys of copper and zinc are called brasses.
The addition of appreciable amount of tin, nickel, manganese, aluminium and other
elements to copper-zinc alloys imparts higher hardness, strength and other
desirable qualities. Complex copper-zinc alloys comprising three, four or more
components are special brasses.
In Russia brasses are identified by means of the Russian letter Л (the first of
the Russian word for brass) followed by letters designating the chief elements and
numbers which indicate percentage content of these elements. Thus, grade ЛT 96
is the brass tombac (T) containing 96% Cu and Zn. The designation of gradе
ЛЖМЦ-59-l-l indicates that the brass contains 59% Cu, 1 % Fe, 1 % Mn, the
remainder is Zn.
Alloys of copper with a number of elements including tin, aluminium,
silicon, manganese, iron and beryllium are called bronzes. Tin bronzes are divided
into two groups: wrought bronzes, containing up to 6% Sn, and casting bronzes,
containing over 6% Sn. Special bronzd are copper-base alloys in which the
principal admixtures are Al, Ni, Mn, Si, Fe, Be and others. Special bronzes are
fully equivalent substitutes for the more expensive tin bronzes and, therefore, have
great economical value. These bronzes are designated on the same principle as
brasses. The designation begins with the Russian letters Бp (the first two letters of
the Russian for bronze) which are followed by letters indicating the main elements
and numbers showing the average percentage of these elements.
Certain grades of special bronzes deserve more detailed consideration.
Aluminium bronzes contain from 4 to 11% Al; their high mechanical properties
and corrosion resistance considerably surpass those of tin bronzes and brasses. The
castability of aluminium bronzes is good and they are frequently used in foundry
practice. Sheets, strips, bars and wire are made of grades БpA5 and БpA4 by the
rolling process. Aluminiur bronzes with admixtures of iron and manganese, grades
БpAЖ9-4, БpAЖMЦ10-3-1.5 and БpAMЦ9-2, are suitable for castings and for
working, especially for smith and closed-die forging.
1.
2.
3.
4.
Answer the following questions:
What are the raw materials for the production of copper?
Why must all copper ores be concentrated by flotation?
Whаt purpose is pure copper chiefly used for?
What properties does the alloying of copper with other elements
increase?
29
5.
6.
7.
8.
What main groups do copper alloys comprise?
What alloys of copper are called bronzes?
Into what groups are bronzes divided?
Why are aluminium bronzes frequently used in foundry practice?
TITANIUM AND ITS ALLOYS
As an engineering material titanium has been widely applied only in the last
years.
Titanium is a silvery-white metal which melts at approximately 1668°C and
has a specific gravity of 4.505. Commercially pure titanium possesses high
strength properties. The tensile strength of most titanium alloys ranges from 100 to
140 kg/mm2, in conjunction with high elongation.
The hardness, tensile strength and yield point of titanium are increased with
the degree of cold deformation. The elongation value drops rapidly when the
degree of cold deformation (reduction) exceeds 50 per cent and becomes equal to
10 per cent. Impurities found in commercial titanium can be divided into two
groups: elements which form interstitial solid solutions with titanium (O2, N, C and
H2) and elements which form substitution solid solutions (Fe and other metallic
elements). The first have a much greater effect on the mechanical properties than
those in the second group.
Even very small amounts of oxygen and nitrogen in titanium alloys sharply
reduce the ductility. A carbon content of more than 0.2 per cent reduces both the
ductility and impact strength of a titanium alloy. It is supposed that the brittleness
of titanium is a result of strain ageing and is connected with the presence of
dissolved hydrogen in the beta-phase.
Titanium and its alloys are hardened either by a surface heat treatment
followed by ageing at 400°—500° C or by producing a case which contains
nitrogen, carbon and boron Industrial titanium alloys contain vanadium,
molybdenum, chromium, manganese, aluminium, tin, iron or other elements,
singly or in various combinations.
A combination of high mechanical properties with low specific weight and
excellent corrosion resistance enables titanium to be used in building supersonic
air craft.
1.
2.
3.
4.
5.
Answer the following questions:
What is titanium?
What does the hardness, tensile strength and yield point of titanium depend
upon?
Do very small amounts of oxygen and nitrogen in titanium alloys reduce
the ductility?
How are titanium and its alloys hardened?
What constituents do industrial titanium alloys contain?
30
Литература
1. Алехина М.С. Английский для металлургов. М.: Русский язык, 2005.
2. Андреев Г.Я., Гураль Л.Л., Лев А.Л. Сборник технических текстов на
английском языке. М.: Издательство «Высшая школа», 1972.
3. Пивкин С.Д. Практикум по переводу для инженерных специальностей
вузов. Учебное пособие. - Нижнекамск: Нижнекамский химикотехнологический институт (филиал) КГТУ, 2010. 149 с.
4. Шевчук Д.А. Английский словарь технический для ускоренного изучения
английского языка. М.: Научная книга, 2014.
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