КАФЕДРА ТЕОРІЇ І ПРАКТИКИ ПЕРЕКЛАДУ
ГЕРМАНСЬКИХ І РОМАНСЬКИХ МОВ
МЕТОДИЧНІ ВКАЗІВКИ
до практичних заннять з дисципліни
«Практика перекладу з першої іноземної мови (англійська)»
для студентів спеціальності «Переклад»
4-го курсу денної та заочної форм навчання
Рекомендовано
на засіданні кафедри ТіППГіРМ
Протокол № 12 від 27/02/2012
Затверджено
на засіданні методради ДонДТУ
Протокол № 5 від 16/03/2012
Алчевськ
ДонДТУ
2012
УДК Ш 143.21
Методичні вказівки до практичних заннять з дисципліни
«Практика перекладу з першої іноземної мови (англ.)» (для студ. спец.
«Переклад» IV курсу
денної та заоч. форм навч.)/Укл.:
О.А. Калиновська. – Алчевськ: ДонДТУ, 2012 – 57 c.
Призначені для розвитку навичок перекладу технічних текстів
студентами IV курсу денної та заочної форм навчання . Призначені
для
допомоги студентам спеціальності «Переклад» самостійно
оволодіти навичками перекладу термінів та граматичних структур в
технічних текстах з різних галузей промисловості .
Укладач
Відповідальний за випуск
Відповідальний редактор
О. А. Калиновська, ст. викл
Т.В. Баркова, ст. викл.
М. М. Барков, доц.
ПЕРЕДМОВА
Методичні вказівки призначені для розвитку навичок
перекладу технічних текстів студентами IV курсу денної та заочної
форм навчання
Завданням методичних вказівок є забезпечення знань,
необхідних перекладачеві для роботи у різних галузях промисловості,
вивчення відповідної термінології та розвиток перекладацьких вмінь
та навичок.
Дані методичні вказівки складаються з тьох розділів, у яких
надано тексти з гірництва, автоматизації та металургії.
Тексти
запозичені з урахуванням їх інформативності та актуальності з
англійських та американських джерел. Вони відображають стиль
науково-технічної літератури з різних галузей промисловості.
Методичні вказівки також містять довідковий матеріал,
поданий у списках скорочень, тематичних термінів з перекладом,
іншомовних слів і висловів. Для перекладу текстів рекомендується
звертатися до великого англо-українського політехничого словника і
до галузевих перекладних словників.
Зміст
Chapter 1 ‘Mining” ……………………………………………….5
Chapter 2 “Metallurgy ……………………………………………18
Chapter 3 “Automatization” ……………………………………...34
Appendix 1 ……………………………………………………….53
Appendix 2 ……………………………………………………….55
List of literature …………………………………………………..57
I. Mining
Text 1
Coal: Research and Development
Coal is a readily combustible rock containing more than 50 percent
by weight of carbonaceous material, formed from compaction and
indurations of variously altered plant remains similar to those in peat. Most
coal is fossil peat. Peat is an unconsolidated deposit of plant remains from a
water-saturated environment such as a bog or mire; structures of the vegetal
matter can be seen, and, when dried, peat burns freely.
At one time coal was predominantly used to heat homes, as well as
power railroad locomotives and factories. Today, however, coal serves
different purposes for society. The chief use of coal is now electricity
generation. Other uses include coking coal for steel manufacturing and
industrial process heating.
When coal is heated in the absence of air, a porous, carbon-rich
material called "coke" is formed. Bituminous coal (also called metallurgical
coal or coking coal) is baked without air in an oven until most of its volatile
matter is released. During this process, it softens, then liquefies and
resolidifies into hard porous lumps. Coking coals are more expensive than
coals used for heating or electricity. When iron and steel are made, coke is
one of the constituents needed to properly heat the furnace (limestone and
iron ore are two other constituents used). Gaseous by-products from coke
ovens are also used. These include crude coal tar, light oils, and ammonia.
Seventy percent of steel production comes from iron made in blast furnaces
using coal and coke. In industrial process heating, coal is used to heat
boilers and ovens. The cement (which represents the biggest worldwide
industrial use of coal), glass, ceramic, and paper industries all use coal for
this purpose.
Methods of Coal Mining
Strip mining, open-pit (or open-cut) mining, and quarrying are the
most common mining methods that start from the earth's surface and
maintain exposure to the surface throughout the extraction period. The
excavation usually has stepped, or benched, side slopes and can reach
depths as low as 1,500 ft (460 m). In strip mining, the soft overburden, or
waste soil, overlying the ore or coal is easily removed. In open-pit mining
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the barren rock material over the ore body normally requires drilling and
blasting to break it up for removal. A typical mining cycle consists of
drilling holes into the rock in a pattern, loading the holes with explosives, or
blasting agents, and blasting the rock in order to break it into a size suitable
for loading and hauling to the mill, concentrator. There the metals or other
desired substances are extracted from the rocks.
Underground coal mining is the extraction of coal from below the
surface of the earth. The coal is worked through tunnels, passages, and
openings that are connected to the surface for the purpose of the removal of
the coal. Mechanical equipment breaks the coal to a size suitable for
haulage. Alternatively, the coal is drilled, explosives are loaded and blasted
to break the coal to the desired size. In order to protect the miners and
equipment in an underground coal mine, much attention is paid to
maintaining and supporting a safe roof for the extraction openings. Longwall mining is a method of underground mining believed to have been
developed in England near the end of the 17th cent. A long face of coal,
some 600 ft (180 m) in length, is operated at one time. The miners and
machinery at the working face are usually protected by mechanical props
which are advanced as the coal is extracted. The excavated area is either
allowed to cave in, or is filled in by waste material called stowing. The
Anderton shearer is a widely used coal cutter and loader for long-wall
mining. It shears coal from the face as it moves in one direction and loads
coal onto an armored conveyor as it travels back in the opposite direction.
Underground Mining Methods
Under certain circumstances surface mining can become
prohibitively expensive and underground mining may be considered. A
major factor in the decision to operate by underground mining rather than
surface mining is the strip ratio, or the number of units of waste material in
a surface mine that must be removed in order to extract one unit of ore.
Once this ratio becomes large, surface mining is no longer attractive. The
objective of underground mining is to extract the ore below the surface of
the earth safely, economically, and with as little waste as possible. The
entry from the surface to an underground mine may be through an adit, a
shaft, or a declined shaft. As is known, shafts are considered to be the
principal openings into mines. Shafts may be vertical and inclined. Vertical
shafts are preferred to inclined shafts because of generally lower sinking,
maintenance and hoisting costs. Shafts, which are generally vertical, are
usually distinguished from tunnels, which are horizontal. Shafts are usually
6
circular or rectangular and are generally lined with wood, masonry,
concrete, steel, or cast iron. Shafts sunk in loose water-bearing soils, where
there is great external pressure on the shaft sides, are nearly always circular;
rectangular shafts with wood lining are often used in mining work, as the
shafts are frequently of a temporary nature. Shaft sinking through rock is
generally accomplished by blasting.
A typical underground mine has a number of roughly horizontal
levels at various depths below the surface and these spread out from the
access to the surface. Ore is mined in stops, or rooms. Material left in place
to support the ceiling is called a pillar and can sometimes be recovered
afterward. Rubber-tired vehicles, rail haulage, and multiple drill units are
commonplace. In order to protect miners and their equipment much
attention is paid to mine safety. Mine ventilation provides fresh air
underground and at the same time removes noxious gases as well as
dangerous dusts that might cause lung disease.
Bituminous Coal and Anthracite
Bituminous coal is a soft coal containing a tar-like substance called
bitumen It is of better quality than lignite coal but of poorer quality than
anthracite coal. The carbon content of bituminous coal is around 60-80%,
the rest being comprised of water, as well as oxygen, hydrogen and sulphur.
Bituminous coals are graded according to moisture content, volatile content,
plasticity and ash content. Generally, the highest value bituminous coals are
those which have a specific grade of plasticity, volatility and low ash
content, especially with low carbonate, phosphorus and sulphur.
Plasticity is vital for coking and steel making, where the coal has to
behave in a manner which allows it to mix with the iron oxides during
smelting. Low phosphorus content is vital for these coals, as phosphorus is a
highly deleterious element in steel making.
When used for many industrial processes, bituminous coal must first be
"coked" to remove volatile components. Coking is achieved by heating the
coal in the absence of oxygen, which drives off volatile hydrocarbons and
some sulfur gases. This also drives off a considerable amount of the
contained water of the bituminous coal.
Anthracite is a hard, compact variety of mineral coal that has a high luster.
It has the highest carbon count between 92% and 98% and contains the
fewest impurities of all coals, despite its lower caloric content. Anthracite
ignites with difficulty and burns with a short blue flame, without smoke.
7
Physically, anthracite differs from ordinary bituminous coal by its
greater hardness, higher density and luster, the latter being often semimetallic with a somewhat brownish reflection. It contains a high percentage
of fixed carbon and a low percentage of volatile matter. It is also free from
included soft or fibrous notches and does not soil the fingers when rubbed.
Anthracitization is the transformation of bituminous coal into anthracite
coal.
Prospecting
The search for economically useful mineral deposits is called
prospecting. To establish the quality and quantity of a mineral deposit, the
type of country rock. This process is called proving. Prospecting and
proving are only two different stages of mining geological exploration; the
latter includes drilling and driving of openings.
Prior to the 20th century mineral deposits were found by
prospectors who looked for visible evidence of mineralization. To recognize
valuable minerals it was necessary to know their various distinctive physical
properties. For example, gold occurs in nature as a heavy malleable yellow
metal. The most important mineral of lead, galena, is dark gray, heavy. The
first ores of iron to be mined were deposits of magnetite, a black heavy
mineral capable of attracting a piece of iron.
The aim of prospecting is to provide information on a preliminary
estimation of the deposit and the costs of the geological investigations to be
made.
Prospecting work includes three stages: 1) finding signs of the
mineral; 2) finding the deposit; 3) exploring the deposit.
General indications of the possibility of exposing this or that mineral in a
locality can be obtained by studying its general topographical relief, the
type of ground and its general natural conditions. Thus, in mountains
regions where fissures were formed during the process of mountain
formation, ore minerals could be expected in the fissure fillings.
Certain deposits are only found in a particular type of ground. Coal
seams, for example, are found in sedimentary formations mainly consisting
of sandstones and shales. Veins, on the other hand, are found in crystalline
(igneous) rocks, and the type of country rock usually determines the type of
minerals.
At present, prospecting methods to be used are as follows:
1. Surface geological and mineralogical – river and glacial float tracing and
panning.
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2. Geochemical – metallometric, hydro chemical, emanation, gas,
biogeochemical and geobotanical surveys.
3. Aerial – visual aerial observations and aerial photography, with
geological interpretation of the data to be obtained; aerial magnetic, aerogamma, aeroelectric and combined geophysical aerial surveys.
Highly effective aerial methods of prospecting from aircraft and helicopter
have come into wide use. Besides, successful development of space
research has made it possible to explore the Earth’s resources from space by
satellites.
Some more facts about prospecting and exploration
The theory of prospecting is an applied geological science studying
the occurrence of commercial deposits of industrial minerals and the most
effective methods of discovering them.
The search for mineral deposits that can be worked is prospecting.
A prospecting is an occurrence of minerals of potential value, before its
value has been determined by exploration and development.
Mineral deposits include those containing metallic elements, such
as copper, lead, zinc, or iron; non-metallic materials, such as asbestos, clay,
phosphates, or sulphur; and mineral fuels, such as coal or petroleum.
Deposits such as sand, gravel or stone are usually considered the deposits of
the rock itself.
Mineral prospecting proceeds from the general to the specific, from
consideration of large regions to smaller areas within the region, and finally
to individual prospects.
Following a preliminary investigation, including a study of
available maps and reports, prospecting may often be concentrated on
smaller areas immediately. Prospecting methods may be subdivided into
direct and indirect methods. Direct methods include geologic and
photography mapping; the study of guides to ore; and the field examination
of the surface, supplemented by panning, trenching, drilling or sampling.
Indirect methods are of two kinds: 1) geophysical methods, which include
magnetic, electromagnetic and radioactivity surveys, both from air and on
the surface; electrical resistivity, gravimetric, and seismic surveys on the
surface; and electric, radioactivity, and temperature surveys, in boreholes;
2) geochemical and botanical surveys.
Where there is surface evidence of minerals, examination and
sampling may be all that is necessary to determine if further exploration is
warranted.
9
Air photographs are of growing importance to mineral exploration.
As is known, the use of air photographs is not new in geological studies but
much of the development has been achieved lately.
The detailed application of air photographs to mineral exploration is
generally indirect, their use allows the geologists to determine conditions
favorable for economic mineralization. Such conditions may include the
presence of faults or fracture zones, major igneous intrusions, dykes and
pegmatite. Geomorphologic information from air photographs may also be
of use in mineral exploration.
Advances in the development of color films are likely to increase
the importance of this method in mineral exploration.
Research into the applications of color photography and into the
use of airborne infrared sensors may help in the problem of rock
identification, and thus also in mineral exploration from air. Studies of the
spectral zone suggest that rocks and minerals may have characteristic
absorption, reflection, and emission spectra in this range.
Besides, it was found that the combination of survey methods for
example, photo geology and airborne geophysics, the integration of photo
geology with geochemical prospecting provided information that exceeded
the sum of data obtainable from air photography or geophysics when used
separately. Some types of deposits were discovered by using combined data
from air photographs and aeromagnetic survey.
Recent developments deal with the application of more
complicated remote sensing systems to material exploration. Certain types
of mineral deposits show strong and unique fluorescent properties, which
may be used in mineral exploration. The possibility of using maser devices
to excite spectral response in specific materials, e.g. fluorescent mineral has
been suggested.
Radar, having the capacity to penetrate and to record the metallic
content of surface and to some extent, of subsurface materials, may also
prove useful in combination with other forms of airborne mineral survey.
Scientists also suggest that thermal mapping from air should be used in
mineral exploration. Changes in infrared radiation, related to surface
temperature characteristics and the emissivity of surfaces, may be translated
into a strip thermal map. Long range detection of hot springs and gaseous
emanations will be among the practical applications of this system.
Fluorescent methods enable geochemists to analyze large numbers
of samples for major elements and for tracing elements. In this way, there is
much information, which gradually discovers the secrets associated with the
Earth’s interior. One of these secrets is the ways in which the chemical
10
elements are incorporated in igneous rocks and how interesting
replacements of one element by another occur within the mineral groups.
The value of tiny fossils is that they are not easily destructible and
that they occur in large numbers and is thus very good basis for rock
zonation.
Looking further ahead, there is the geological side of space
exploration. A new field of investigations is opening for geology. The
exploration of the Moon, Mars, Venus and other planets has already begun.
Unit Operations of Mining
During the development and exploitation stages of all mining when
natural materials - rock or soil, ore or waste - are excavated from the earth,
remarkably similar unit operations are employed. The unit operations are
the basic steps employed to produce mineral from the deposit.
The production cycle employs unit operations which are normally
grouped in two functions: rock breakage and materials handling. In most
mines breakage is accomplished by drilling (rock penetration) and blasting
(rock fragmentation).
Mineral handling is usually performed in two steps, loading
(excavation) and haulage. If considerable vertical lift is involved, then
hoisting may be required as well.
Production cycle = drill + load + haul
The cycle of operations in surface and underground mining is
distinguished mainly by the scale of the equipment. Mining today is almost
totally mechanized. Specialized machines used in both regimes are
remarkably similar in principle and function and are to meet the unique
needs and conditions.
In modern surface mining, blast holes several inches (mm) in
diameters are bored by mobile rotary or percussion drills for the placement
of explosives, when consolidated rock must be excavated. The charge is
then inserted and detonated to reduce the ore or waste to fragments. The
broken material is loaded
by power excavators or shovels, draglines or
wheel type into haulage units - railroad cars, belt conveyors, or trucks. Soil
and coal are mined in a similar way, although blasting is often unnecessary.
In quarrying dimension stone, the blocks are feed without blasting by
channeling machines or saws.
In underground mining, the cycle differs little, although equipment
on a reduced scale is usually employed. Smaller drill-holes are bored for
11
blasting, and down-sized trains, trucks, shuttle cars, or conveyors are used
to haul the ore or coal from the mine.
To addition to the productive phases of the actual mining cycle,
certain auxiliary operations must be performed. Underground these
auxiliary operations consist of providing and maintaining adequate roof
support, ventilation and air conditioning, power supply, pumping,
maintenance, lighting, communications, and delivery of supplies. In surface
mining, the first two are not necessary.
Rock breakage – the freeing detaching of large masses of rock
from its parent deposit.
Text 2
Mining and minerals in South Africa
South Africa, known throughout the world as a treasure trove, an
abundance of mineral resources, producing and owning a significant
proportion of the world’s minerals.
South Africa’s wealth has been built on the country’s vast
resources – nearly 90% of the platinum metals on Earth, 80% of the
manganese, 73% of the chrome, 45% of the vanadium and 41% of the gold.
Only crude oil and bauxite are not found here.
For many years, the country has been a leading producer of
precious metals such as gold and platinum, as well as of base metals and
coal. It is the world’s fourth-largest producer of diamonds.
And experts believe there is still considerable potential for the
discovery of other world-class deposits in areas that have yet to be fully
exploited.
Place in the economy
South Africa’s position as the world’s largest gold producer – a
position it held for over a century – was usurped by China in 2007.
China’s gold production for the year was estimated at 276 metric
tons, and at 270 tons by the China Gold Association. South Africa,
according to the Chamber of Mines of SA, produced 254 tons of the metal
in 2007.
Gold, once a keystone to the South African economy, has
diminished in importance as the country’s economy has diversified. In the
1970s and 1980s, gold exports were the predominant source of foreign
12
exchange earnings, with mining contributing around 14% of total value
added in the economy. This has shifted over time and, in 2007, mining and
quarrying contributed about 5.8% to the country’s gross domestic product
(GDP).
However, mining as an industry is still crucial to South Africa,
with precious metals contributing 65% to the country’s mineral export
earnings and 21% of total exports of goods in 2006. The country supplies
about 80% of the world are platinum. The mining industry is also South
Africa’s biggest employer, with around 460000 employees and another
400000 employed by the suppliers of goods and services to the industry.
Transformation
Ownership, access and opportunity in regards to the country’s
mineral resources are regulated by the Minerals and Petroleum Resources
Development Act of 2002, which recognizes the state’s sovereignty and
custodianship over the country’s mineral resources.
Transformation is a key issue facing South Africa’s mining sector.
Equitable access to mineral resources and opportunities has been legislated.
The charter aims to change the profile of the industry by advancing
the empowerment of South Africans. Currently, more than 70% of the
mining industry’s labor force is black, while less than 5% of managerial
positions are held by black people. Targets have been set by the government
and, by 2009; all mining companies will be expected to have 40% of
managerial positions held by previously disadvantaged South Africans.
Other key targets over the next 10 years include the transfer of
26% of all mining assets to black-owned companies as well as determining
that 51% of future mining projects have to be in the hands of black-owned
companies.
Strengths
With such a strong background as a major mining country, South
Africa’s strengths include a high level of technical and production expertise
as well as comprehensive research and development activities.
The country has world-scale primary processing facilities covering
carbon steel, stainless steel and aluminum industries, in addition to gold and
platinum. It is also a world leader of new technologies, such as a groundbreaking process that converts low-grade superfine iron ore into highquality iron units.
13
This kind of beneficiation, or adding of value to raw mineral
materials before export, has been identified by the government as a major
growth area. There are lucrative opportunities for downstream processing
and adding value locally to iron, carbon steel, stainless steel, aluminum,
platinum group metals and gold.
Industry leaders
The mining industry in South African is constantly changing and
adapting in response to global demands and market conditions. Over the
past few years, mining houses have transformed into large, focused mining
companies, marking a change in strategy to make the industry more
competitive.
Two of the world’s biggest mining companies originated in South
Africa. BHP Billiton, the world’s largest mining company, came after a
merger between South African mining company Billiton and Australian
company BHP.
Anglo American Plc, which has its primary listing in London and
its secondary listing in Johannesburg, owns many major subsidiaries, such
as Anglo Platinum, Anglo Coal, Impala Platinum and Kumba Iron Ore.
Diamond mining company De Beers, also a South African
company, is owned by Anglo American and a consortium led by the
Botswanan government. The world’s top diamond producer churned out
about 51.1-million carats in 2007.
New developments
There are many new developments in the pipeline for South
African mining. These include: Anglo-Australian miner Rio Tinto plans to
build a US$2.7-billion aluminum smelter at the Coega industrial
development zone near Port Elizabeth in the Eastern Cape. It would produce
around 720а000 tons of aluminum a year, and would be the largest
reenfield investment in South Africa to date.
Russian billionaire Viktor Vekselberg has said he would be
investing 1-billion in manganese production in South Africa. In September
2006, he announced plans to build manganese and ferroalloys plant at
Coega.
Mining giant De Beers is building two new mines in South Africa.
The first, at Voorspoed in the Free State, is expected to start production
14
towards the end of 2008, and will produce about 700а000 carats a year. The
second is already in production.
Indian steel giant Tata Steel is constructing a R650-million highcarbon ferrochrome plant in Richards Bay on the KwaZulu-Natal coast.
Text 3
Coal mining in Great Britain
Great Britain is rich in natural resources. The only exception is coal. Coal
is one of the chief sources of England’s wealth. As to coal resources Great
Britain takes the second place among the European capitalist countries.
Coal is the main, and practically, the only power basis of Great industry.
Some 76 % of Britain’s electricity is generated from coal.
The British coal-fields constitute four groups: South group, Central
group, North group and Scotland group.
The discovery of “black diamonds” turned England from an agricultural
country into one of the richest manufacturing countries in the world. The
oldest and still one of the most important coal-mining areas of England is
Northumberland and Durham coalfields.
As early as the thirteenth century the cottagers and farmers there
discovered that this black mineral burnt. The people burnt “black
diamonds” in the open fires in their houses.
At the beginning of the nineteenth century coal-mining was a small but
rapidly expanding industry, with an output of about 10 million tons per
annum. By the middle of that century the output had increased to about 50
million tons per annum.
The increasing demand for coal led to still further rapid growth of the
industry during the early years of the present century. In 1914-1918
production reached its zenith at 292 million tons and 1.107.000 persons
were employed at 3270 mines.
Due to various reasons production declined, but employment in the
industry continued to increase and in 1921 the number of persons employed
reached 1. 227. 000 for an output of 230 millions tons.
In 1981 there were 200 mines (600 faces), 56 % of existing ones were
constructed about 70 years ago, but they produced a half of the total output.
Coal production in Britain has halved (to only 100 mt) in the past 30
years while the number of operating mines has also halved (to 73) since
1981. Towards the end of 1985, 429 faces produced 88.4 mt of coal. Within
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a year the number of faces had been reduced to 334 with production
remaining virtually unchanged.
The tendency to reduce the number of faces operated has continued, and
face productivities of 500.000 t/y are now not uncommon. Shield-support
system and retreat mining have been adding 80 % and 25 % respectively to
productivity.
Now Britain still produces the cheapest coal in Europe. About 50 per
cent of the total production of West European coal is got from coal –fields
of Great Britain. 78 % of the total output is thermal coal, 2 % - anthracite
and 20 % - coking coal.
Coal constitutes an important item of British export too.
As far back as 1269 little ships began carrying coal from Newcastle,
Sunderland and Hartlepool to London and later to all parts of the world.
The greatest exporting coalfield of England is the South Wales one. The
coal from here is hard, black and does not dirty the fingers. It is anthracite
coal, and though it does not burn easily in open fires it is the best steam
coal, as it contains 90 to 95 per cent of carbon (ordinary “soft” coal has 85
to 90 per cent carbon). In a furnace it gives off great heat with practically no
smoke.
The production of coal in New South Wales comes from six
underground mines and major open-cut operation. All the mines are located
within an approximate radius of 100 km from Newcastle. The principal
export markets of these coal-fields are in Japan, Hong Kong, South Korea,
Taiwan, Pakistan, Germany, Israel and Netherlands, Domestic markets
include the Electricity Commission of New South Wales, with coal supplies
to the Wales Point Power Station.
Methods of working coal seams in South Wales
Mines of the South Wales coal-fields suffer from the difficult geological
conditions which makes the use of modern mining equipment difficult. The
coal-field has a workforce of 7.400 in II pits.
Liddell colliery is located approximately 25 km north-west of the town
of Singleton. Its coal mined underground, is conveyed to surface and
washed in the Liddell Coal Preparation Plant, then taken by train to the part
of Newcastle for shipment.
The coal seams generally dip gently from North West to south east over
the lease, the original workings having been in the Liddell Seam near
outcrop. Down dip, some 3.200 m from the portal along the main trunk
haulage route, the Liddell Seam splits, and present and future operation will
16
be in the portion of the lease where the seam is split into upper and Middle
Seams, which typically have a seam interval of 40 m thickness.
Both Upper and Middle seams are affected by geological discontinuities
in the form of faults and dykes, which are major factors in delineating long
wall panels.
In the Upper Liddell gate and tall road development formerly left some
0.3 m to 0.5 of coal in the roof to assist in roof supports using roof bolts and
straps, but longwall extraction mines virtually the full seam thickness.
In the Middle Liddell, the floor conditions are variable and may prove to
be weak and boggy unless the correct working section is maintained.
The initial longwall development, comprising two panels is in the Upper
Liddell Seam. In this location, the Liddell Seam has a cover of between 150
and 180 m. Seam thickness in the Upper Liddell over the longwall mining
area vary from 2.7 to 2.9 m. In the Middle Liddell, the seam thickness
varies from 2.5 m in the west to 1.8 m in the south east.
Geology and explorations
Historically, the presence of coal in Iran has been known since the
beginning of the last century. Geological mapping was carried out
systematically in some parts of the country by German experts shortly after
World War II. The Swiss geologist Stocklen, who lived in Iran for about 30
years, also made valuable studies of specific coal bearing zones.
Nevertheless, intensive geological studies and exploration work to
investigate Iran’s coal resources really began in 1966, when the decision
was takes to build a steel plant based on blast furnace iron making.
There are three major coal areas in Iran: 1. Kerman basin; 2. Elbers
Range; 3. Tabas Deposit.
Output from the mines in the Kerman basin comprise about 60 % of
NISCO’ s total production, the remaining 40 % coming from mines in the
Elbors Range. The Tabas deposit is still in the exploration stage.
Exploration methods include geological mapping, core drilling,
geophysical investigation.
Most of the coal seams outcrop at surface and, because of the
mountainous topography; a good proportion is suitable for mining through
adits, at shallow depths of cover. The thickness of the seams is, however,
generally less than 1 m. In the Karmozd mine, in the Central Elborz field,
for example, a seam of 0.4 m thickness is being mined. The dip of the seams
is usually more than 20°.
17
II. Metallurgy
Text 1
National steel puts its “Detroit’ strategy in gear
With its $1 billion capital spending plan and five facilities in the
Detroit area, National Steel is sending the auto Industry a signal that it is
‘In the automotive steel market to stay’.
National Steel is invading the Detroit metropolitan area with a $1
billion capital spending program from 1983 to 1992.
The company already has spent $120 million on the electro
galvanizing line that started up at National’s Great Lakes Division in
Ecorse, Mich., in December 1985; and $ 240 million on the continuous
caster and ladle metallurgy station that Great Lakes began operating last
November.
Nation will spend another $400 million on capital improvements at
Great Lakes, its flagship mill, over the next four years. Much of Great
Lakes’ flat – rolled production goes to Detroit’s automakers.
The automotive industry is also the primary customer of three other
new National facilities in the Detroit area:
The Product Application Center in Livonia, Mich., which since
1983 has been working closely with the automakers to help them
specify the best steel for automotive designs;
The Automotive Marketing and Sales Dept. in Novi, Mich., and
ProCoil Corp., a joint venture with Marubeni Corp. in Canton,
Mich., that will slit and blank National’s steel for automotive
customers starting next moth. National’sfifth Detroit – area
facility, the Howard M. Love Technical Research Center, which
opened in May, also aids the automakers, indirectly: It solves
monroutine problems in National’s steel mills.
“Our $1 billion in capital spending is targeted at the auto industry”,
explained James N. Howell, the National Steel vice president who is general
manager of Great Lakes Division. The spending, plus the five National
Steel facilities in the Detroit area, “is a clear signal to the automakers that
National is in the steel business, and specifically the automotive steel
business, to stay,” Mr.Howell told Iron Age in a recent interview.
A driving force behind National’s aggressive targeting of the auto
business has been Nippon Kokan, which bought 50 pct in equity interest of
National in 1984; since 1986 Kekichi Hagiwara, formerly of NKK, has
served as National’s request, NKK has assigned experts and given training
and technology to many different parts of the National Steel organization.
18
Sixty NKK engineers presently work at National, 16 in Pittsburgh, the
location of National’s headquarters and also its Product / Process
Technology Group; and the rest elsewhere, mainly in the Detroit area but
also at at National’s Granite City Div. and Midwest Div. in Portage, Ind.
The Technical Research Center in Trenton, Mich., has assigned several
NKK engineers to some of its most urgent projects in electrogalvanizing,
continuous casting, hot rolling, and process – control modeling.
NKK’s close business ties in Japan with Marubeni helped pave the
way for Marubeni to enter into the joint venture with National at ProCoil.
Six ProCoil employees were in Japan for training last month at a similar
processing center affiliated with Marubeni. A Marubeni expert will help
ProCoil “set up the same close, family – type relationship between the
steelmaker, the processor and the automaker as exists in Japan”, said Glenn
G.Pullianas. ProCoil’s vice president – administration.
Technical Assistance
Great Lakes Division has benefited from NKK’s technical
assistance in a number of ways. The steelmaker uses NKK’s technology in
its electtogalvanizing line. NKK’s most crucial contribution to Great Lakes,
however, has been the aid of its experts in writing standard operating
procedures (SOPs) and then insisting that they be adhered to. Throughout
National Steel, “we are changing from breakdown maintenance to
scheduled, preventive maintenance,” national President Hagiwara told Iron
Age.
So far about 75 pct of National’s units have written clear SOPs,
explained Ronald H. Doerr, National’s executive vice president and chief
financial officer. Mr. Howell, Great Lakes manager, was so impressed by
the NKK engineers’ help in developing inspection standards and scheduled
maintenance procedures that he requested an – other 11 maintenance
experts from NKK in addition to the team originally assigned him; they
arrived earlier this years and will aid the Ecorse mil for two years.
“The NKK experts are working with our hourly employees so that
in two years we will have our own experts, after the NKK engineers go
home”, said Mr. Howell. A number of hourly and salaried employees at
Great Lakes, most notably those on the electrpgalvanizing line and the new
continuous caster, received training in Japan at NKK’s Fukuyama mill,
which, with an annual capacity of 16 million tons, is the world’s largest
steel mill.
19
Before Great Lakes began its current campaign to improve its
yield, the steelmaker’s employees “tuned the equipment by hit – ormiss”,
explained Mr. Howell. “We didn’t have rigid standard procedures. We had
some scheduled downtime for maintenance, but the maintenance wasn’t
done consistently across the boards”.
“In the past, we didn’t always know the exact temperatures that
were best at each stage of producing each type of steel”, explained
Masaharu Ito, National’s executive vice president. But now the NKK
experts are collecting data and adjusting operations to help Great lakes
define the optimum parameters for each stage of production.
Great Lakes is using statistical process control throughout the mill.
“Now we run this place by SOPs and SRC”, said Mr. Howell. “That’s the
only way to do it. Too often steelmakers look for magical ways to get good
steel, but there is no such magic. Instead, we need to design out equipment
properly and then pay attention to the basics”.
The National /NKK campaign to raise steelmaking yield already is
paying off. The number of “offchenistry misses” has declined several fold
since NKK began assisting Great Lakes, said Mr. Howell.
The Great Lakes operators now know precisely what metallurgical
chemistry is required for specific steels and use that the first time, rather
than using trial and error to come up with the right chemistry. The clear
guidelines for process parameters have reduced the number of reflows of
oxygen required to get the chemistry right. The amount of steel used for its
originally designated application, or the “master slab”, has risen by 30 pct in
the past two years.
Overall, the proportion of liquid steel to shipped steel at Great
Lakes has risen from 75,0 pct in 1986 to 77,7 pct in 1987 and is projected to
jump to 84 pct for all of 1988. The proportion of hot – band steel to shipped
steel at Great Lakes likewise rose from 88 pct in 1986 to 90 pct in 1987 and
is projected to reach 92 pct this year. For all of National Steel, the
proportion of liquid steel to steel shipped for the “prime” application, that
is, the product for which it was originally intended, rose from 73-74 pct in
1983 – 84 to 76 pct in 1987. The target for 1988 is 77 pct, explained Mr.
Hagiwara, and 83 – 84 pct in 1990 – 91. These figures do not include steel
that is scrapped or used for secondary applications.
Great Lakes Typically takes two or three turns, or shifts, every
week or two to do scheduled maintenance on each area of the mill; for the
blast furnace, employees devote 1 ⅓ turns, or 12 hours, to maintenance
every week. “Each area must do the scheduled maintenance even if it’s
20
behind in production”, said Mr. Howell. “In the past, some areas would skip
the scheduled maintenance if they lagged their production targets”.
Text 2
The purpose of the 3000 roll mill
A 3000 two-stand tandem hot plate mill is designed for rolling steel
plates from slabs.
Assortment on sizes is: thickness – from 6 up to 25 mm, width –
from 1219 up to 2650 mm, length – up to 24000 mm (finish plate’s length).
Shape, sizes and admissible deviations on them must conform to
requirement of normative documents.
Technological process of plate making in 3000 mill
The initial material for producing plates in 3000 roll mill are slabs
after blooming-slabbing mill, after continuous casting machine or from
other plants. Sizes of the slabs are the next: thickness – 140 up to 320 mm,
width – 1000 up to 1400 mm, length – 1500 up to 2500 mm. The maximal
weight of the slab is 7,5 tons.
It is more efficient to produce plate, sheet and strip from slabs
since the final product will be of a higher quality and the losses for rejects
are reduced.
In up-to-date metallurgical plants, only plates over 50 mm thick
and weighing over 10 tons are rolled directly from ingots. Thinner and
lighter plates are rolled of ingots only in old metallurgical plants which do
not have mills for the rolling of slabs.
The weight of the required ingot is determined on the basis of the
size of the finished product and the metal consumption.
Ingots for flat products are usually flat in cross-section and are
characterised by the ratio of the width B to the thickness H, of the height L
to the thickness H or width B and the taper. Lately flat slabs obtained by
continuous casting techniques have been applied for this purpose.
The less the thickness and the greater the height of the ingot, the
less passes will be required, the less the temperature will fall at the end of
rolling and the higher the mill output. However, in selecting the ingot
thickness, the total draught assigned must ensure sheet or plate of the
specified quality.
The size and weight of slabs are selected to suit the size of the flat
product to be rolled. However, slabs of maximum width will prove most ef-
21
ficient. The greater the slab width, the simpler it is to obtain the required
finished width by broadside rolling in open-train mills. Wider slabs facilitate the operation of the broadside stand in a continuous mill or exclude the
necessity of its installation (when the slab width equals the width of the
finished plate).
The length of slabs which are to be rolled in open-train mills is
limited by the barrel length since longer slabs cannot be rolled broadside to
obtain the required width.
The slabs are stocking and treating in the north part of adjusting,
treatment of slabs making in first and second bays with oxygen-cutting
torch. The slabs, which ready to heating, stocking in third bay at north. The
treatment of slabs in some cases can making in third bay of adjusting. After
fire-cleaning slabs are marking by paint and packing in stack by size and
grade of steel.
The slabs given in tilting-table for heating from second part of
adjustag by crane with help of catcher, in case given from third part – by
magnet at one ore two. Tables stand at one in second and third part of
adjustag and purposed to taking slabs and to its lift up for single pushing.
Cargo capacity of each table – 588 kN, maximal speed of lifting – 52 mm/s,
driven by motor 185 kW, 450 r/m.
From tilting-table slabs pushing by pusher in roll table. The
pushers set at two in second and third part of stock. Its characteristics : type
– lath, maximal exertion at one pusher – 39,2 kN, work length of stroke of
pusher – 3020 mm, speed of work stroke – 0,4 m/s; speed of back stroke –
0,8 м/s; motor – 22 kW, 65 r/m.
From loading (transport) roll table slabs transports to furnaces.
Number of sections – 9. Length of the roll table – 97,5 m, diameter of rolls
– 450 mm, the length of roll’s barrel – 1700 mm, step of rolls – 700 mm.
Speed of roll table – 1,72 m/s. Drive of each section from motor – 45 kW,
565 r/m.
Before loading in furnace the slabs are weighed by tenzometrical
scales, which are set in section of roll table 6G. Maximal weight of the slab
– 10 t, minimal – 1 t.
From loading roll table slabs by pusher load in furnace. The
purpose of pusher is loading the slab in furnace, pushing across furnace and
drop it. Type of pusher – double lath. Number of pusher in each furnace – 2.
Exertion of pushing – 117,2 kN at one pusher. Maximal work length of
stroke of pusher – 2700 mm. Work stroke speed - 78 mm/s, back stroke
speed – 208 mm/s. Drive from motor – 100 kW, 475 r/m over reducing
gear.
22
Before rolling the slabs are reheated in 4 continuous furnaces,
charged and drawn at the end. Type of furnace – two-sequence four-zone
furnace. Furnaces stock up by mix of blast and natural gas or blast gas.
Torch is two-bar-guide of low pressure type “tube-in-tube”. Number of
torch in furnace – 24, at 6 torches in each zone of furnace. Each furnace
have control-measuring devices and heat automatic. The temperature of the
slabs may be room temperature or ranged from 700 to 900 ºC. After heating
the temperature of the slabs must ranged from 1150 to 1200 ºC.
Heated up to necessary temperature slabs drawn from furnace by
order of charger with permission of heater of metal. Slabs, which drowned
from furnace, transmit to stand by approach table. Roll table divide on two
sections, each have 7 rolls. Diameter of rolls – 400 mm. Length of roll
barrel – 1700 mm. Step of rolls – 700 mm. Speed of roll table – 2 m/s, drive
of each section from motor – 45 kW, 565 r/m over reducing gear.
Then slabs are entered in device for removing the scale from the surface of
the slab by means of water under high pressure. Maximal water pressure –
500 A, number of the hydro-scale-breaker is 2 – before and after the
roughing roll stand. Next the slab enters to roughing roll stand.
Drowned from furnace but not rolled or in some reasons not rolling
finished slabs at approach table transporting back to furnace № 4, there are
stopping by disappearing stopper and charge in furnace with safe it’s
marking. If returning by approach table is impossible then with help of
overhead traveling crane with taker slab take down straight away.
The purposes of roughing roll stand are: making about 75 percent
of common draught, for obtained the necessary thickness and width of the
plate and for removing scale. In roughing roll stand occurs width forming
and preparing it to finishing rolling. In mill can used lengthwise and
broadside rolling, but more preference is lengthwise rolling.
In 3000 mill about 80 per cent of the draught is obtained in the
roughing and only about 20 per cent in the finishing stand. In theory with
this correspondence the time of rolling in roughing and finishing stand is
equal or close. But practice shows that this correspondence in some cases is
wrong. The draught in roughing stand can be from 60 to 90 per cent. And in
finishing stand draught can be from 40 to 10 per cent.
For the turning the slabs at 900 in horizontal plane between passes
is used screw table, which has such descriptions: number of rolls – 12;
diameter of conical rolls – 380/260 mm; length of barrel– 3600 mm; speed
– 1…3 m/s.; langth of screw table – 3850 mm; driven by motor – 17,5 kW
with speed of rotation – 165 r/m. For centrized the slab during rolling and
measuring of him width is used guides (number of guides – two right and
23
two left; distance between the guides – maximal 4200 and minimal – 1500
mm; maximal sizes of roll stock at the turn on roll table are 2800x2800 mm;
speed of movement of rulers – 0,4…0,8 m/s; hydraulic drive with presser 10
mPa).
Description of four-high roughing roll stand.
The housing closed type, steel casting. Speed of rolling – 3 m/s.
Sizes of work roll: nominal diameter – 1000 mm; minimal
diameter – 940 mm; barrel length – 3000 mm; material - alloyed flake
graphite austenitic iron. Sizes of back-up roll: nominal barrel diameter of
roll – 1650 mm; minimal diameter – 1500 mm; roll barrel length – 2800
mm. Material of back-up rolls – hammered steel 60ХН
Maximal height of top rolls lift up – work 350 mm. Drive of
working rolls over universal spindles and pinion stand from constant current
motor with power 2171,2 kW (2950 h.p) and speed 0-25-60 r/m. Nominal
moment of two motors – 1656,2 kN*m. Moment of idling – 29,4 kN*m.
Maximal moment of two motors bearing in mind coefficient of overloading
2,5 and KUA of mill 0,9 – 372,4 kN*m; roll accelerating, roll slowing down
– 2.5 r/s2. Screw speed of lift up and lift down – 27 mm/s. Screw accelerate
– 21.8 mm/s2. Screw step – 24 mm. Diameter of screws – 480 mm. Drive
from motor – 100 kW, 730 r/m. Cylinders of pressure device: diameter of
piston– 1100 mm, most motion – 40 mm, working pressure – 31,5 MPa.
Balancing of top working and buck-up rolls is produced by
hydrocylinders under pressure. Balancing of top back-up roll: 1
hydrocylinder, with diameter 450 mm, most motion – 485 mm, maximal
working pressure – 10 MPa. Balancing of top working roll: 2
hydrocylinders, with diameter of 320 mm, most motion – 350 mm, maximal
working pressure – 10 MPa.
According to the initial width of the slab and final width of the
plate are used several methods of the rolling plates in roughing roll stand.
When the width of the slab is equal the width of final plate before
the edges are sheared, we make rolling lengthwise until the necessary
thickness and length will be obtained.
But in majority of cases the width of the slab is less then the width
of final plate.
When the length of the slab is equal the width of the plate, we turn
over the slab in 90º in horizontal plane and make rolling broadside until the
necessary thickness and length will be obtained.
24
When the length of the slab is less then the width of the plate, we
make some passes lengthwise, until the length of the slab will be equal the
width of the plate, the turn over the slab in 90º in horizontal plane and make
rolling broadside until the necessary thickness and length will be obtained.
Classification of the roll stands used on the 3000 roll mill
According to the number and arrangement of the rolls, mill stands
can be classified into five groups: two-high stands;
three-high stands;
four-high stands;
multiple-high roll stands / six-high stands, twelve-high stands,
twenty-high stands ./;
universal roll stands.
Two-high nonreversing stands
A two-high nonreversing stand has two rolls with a constant direction of
rotation around horizontal axis.
A two-high nonreversing roll stand, in which both rolls are driven, is widely
used in continuous and cross-country mills. Each roll-stand of these rolling
mills is employed for only one pass
Two-high reversing stands
In the two-high reversing stand the rolls rotate first in one direction and then
in the other so that the rolled metal may pass back and forth through the
rolls several times. These stands are employed in blooming and slabbing
mills, and as roughing stands of plate, universal, rail and structural, and
other mills.
Double two-high roll stands
The double two-high roll stand has four rolls arranged in pairs. These stands
are used in open-train section mills and have rolls 300 to 350 mm in
diameter. They may be found in old metallurgical plants, where the rate of
production is relatively low. Due to the complexity in setting up such stands
and their low production capacity, new mills of this type are no longer being
built.
25
Three-high roll stands
A three-high roll stand has three rolls with a constant direction of
rotation, arranged in a single vertical plane. Tilting tables are provided on
one or both sides of the stand to raise the bar and to enter it between the top
and middle rolls. Stands of this type find extensive application in open-train
section mills.
Three-High roll stands are also used in single-and double-stand
plate mills.
The middle idle roll is of smaller diameter than the other two.
During rolling, the middle roll is held against and rotated by either the top
or bottom roll: The application of a small-diameter middle roll increases the
amount of elongation and decreases the required lift of the rolled bar for
passing through the middle and top rolls. This type of stand is now rarely
employed in new mills where four-high reversing stands are preferable.
Four-high roll stand
The four-high roll stand has four rolls arranged in a vertical plane.
The two rolls smaller in diameter are the working rolls while the larger are
back-up rolls. The back-up rolls support the working rolls in operation and
redace their elastic deflections. These stands find widespread application in
reversing mills for the hot rolling of heavy steel plate. They are more
extensively employed in continuous mills for the hot and cold rolling of
sheet and strip.
Six-high roll stands
The six-high roll stand has two working and four back-up rolls .
The rigidity of the roll stands themselves and the lesser deflection of the
back-up rolls enable these mills to be used in the rolling of thinner strip in
coils to narrower thickness tolerances. These stands have only a slight
advantage over four-high stands but they are much more complex in design
and, therefore, are not widely employed.
Twelve and twenty-high roll stands
Twelve and twenty-high roll stands have two working rolls and (10
and 18) back-up rolls. The very small diameter of the working rolls (10 and
30 mm) and the rigidity of the roll stand as a whole enable the thinnest strip
26
and sheet to be rolled of high-carbon steel (thickness 5 to 50 microns and
width 100 to 1.000 mm with minimum thickness tolerances of 1 to 5
microns).
Universal roll stands
Universal roll stands are applied in rolling wide-strip steel, sheet,
plate and slabs. Here the metal is reduced by both horizontal and vertical
rolls. The latter roll the edges of the sheet stock straight and smooth. The
vertical rolls are mounted either on one side or on both sides of the stands
holding the horizontal rolls. The horizontal rolls may be of either two-threeor four-high arrangement.
Universal stands are also used for rolling wide - flange beams up to
1000 mm in depth in universal structural mills. The vertical rolls of
universal structural mills are idle running and are arranged between the
bearing chocks of the horizontal rolls in the same vertical plane.
Stands with vertical rolls
Stand with vertical rolls are widely used in continuous mills where
they alternate with ordinary stands. In this case any turning of the bar is
eliminated between stands.
Special stands
Special stands are used for rolling special shapes such as tyres, wheels,
tubes etc. These stands may differ from those mentioned above in the
number and arrangement of their rolls.
Text 3
Steel making process
A comparison of the chemical compositions of pig iron and steel
shows that the former contains more carbon, silicon, manganese,
phosphorus and sulphur. Consequently, steelmaking involved process which
reduces the concentration of a number of elements contained in pig iron.
Three types of smelting equipment are employed for steelmaking
in modern industry, namely: converters, open-hearth furnaces and electric
furnaces.
Steel may be made of:
27
1. Only molten pig iron – in the Bessemer and Thomas processes;
2. A combination of molten or solid pig iron and steel scrap – in openhearth and electric furnace.
3. Only steel Scrap – in electric furnace
Making Steel in Converters
Principle of a converter plant. A converter for making steel by
blowing air through molten pig iron is a pear-shaped vessel. The converter
has a shell, welded or riveted of steel plates, and lined with a refractory
material. On the outside the lined shell is embraced by the steel trunnion
ring. The converter is supported by trunnions and in uprights. The
hydraulic tipping device serves to tilt the converter into its horizontal and
vertical positions. The device is linked through a rack with a pinion
mounted on trunnion .
The converter bottom is pierced with tuyeres through which the air
blast passes into the metal bath. The wind box, secured to the bottom, receives the compressed air and distributes it to the tuyeres. The blast enters
wind box through the gooseneck, or elbow pipe, and hollow trunnion which
is linked through a revolving joint with connection.
Before pouring in the molten pig iron, the converter is turned on its
trunnions to the horizontal position. In this position the molten metal is contained in the belly of the converter and does not reach the tuyeres in the bottom. The pig iron is poured through the mouth (nose opening) of the vessel
which is then slowly raised to the vertical position, bottom downwards,
after starting the blast, to prevent the molten metal from running through the
tuyeres into the wind box. The amount of pig iron poured into the converter
must not exceed in volume one-fifth of the cylindrical part of the vessel.
The rest of the converter volume is required for metal circulation during the
blowing period.
The type of refractory lining used in the converter depends upon
the character of the steel-making process. In the Bessemer (acid) process the
lining is of dinas brick or quartzite; a basic material (burnt dolomite) is
employed for the Thomas (basic Bessemer) process. The lining of acid
converters can withstand from 1000 to 2000 runs; those of basic converters
– from 350 to 400 runs. The bottoms of both types deteriorate more rapidly
and are therefore more frequently changed.
Acid converters usually have a capacity of from 10 to 30 tons; the
capacity of basic converters ranges from 25 to 40 tons and higher.
Converters with a capacity of 60 to 80 tons and even higher are to be
installed in new plants.
28
Air blast pressures in converters range from 2 to 2.5 atm; about 350
cum of air is required per ton of pig iron. The number of tuyeres in the
bottom depends upon the size of the latter; each tuyere hole is from 10 to 20
mm in diameter.
The Bessemer Process.
Pig iron used in Bessemer process (in an acid line converter) must
have a high amount of silicon and manganese (up to 2 % and up to 1.5%
Mn) and the minimum possible amounts of sulphur and phosphorus. When
the air blast is blown through the molten metal the iron, silicon and
manganese burn to their oxides. In this process the temperature of the metal
bath is raised from 1250° to 1650°C.
The slag forming period (blow) in converter operation begins after
the blast is turned on and continues for four or five minutes.
The second period of the Bessemer process – carbon blow-begins
after almost all the silicon and manganese are burned out of the pig iron and
the metal reaches a sufficiently high temperature. This creates favorable
conditions for intensive burning of carbon from the molten metal.
In the third period the impurities of the metal are turned out and only iron is
oxidized. This period continues one or two minutes. Bessemer steel made
by this process contains very little carbon since it was burned out in the
second period.
Bessemer steel with a higher carbon content is obtained by two methods:
1. The blow is terminated at the moment when the molten metal still
contains the given amount of carbon;
2. The metal is decarbonized to the end and then the pig iron is
added to the converter to raise the carbon content to the required
value.
The Thomas Process.
In the Thomas process, or basic Bessemer, process steel is made in
a converter with a basic lining (of dolomite brick). First a definite amount of
freshly burned lime is charged into the converter, and then a highphosphorus pig iron (1.6 to 2% P) with the least possible silicon and sulphur
content.
In the first period of the blow, iron, silicon, and manganese are
oxidized and a basic slag is formed. This raises the bath temperature but
phosphorus is not yet removed from the metal. Carbon is burned out in the
29
second period in which the temperature of the metal falls to some extent.
When the carbon content in the metal is reduced to 0,1 – 0,2 per cent and
the temperature drops to 1400° – 1420° C, the run enters the third
phosphorus is intensively oxidized and slagged.
After the finishing the third period of the blow, i.e. before adding
deoxidishing to the finished steel, it is necessary to remove the phosphorus
slag by tilting the vessel. If this is not done the carbon, silicon and
manganese contained in the deoxidizers reduce the phosphorus in the slag
and transfer a part of it back into the metal.
Open-Hearth Furnace.
Modern open-hearth furnaces are built for various capacities and
can accommodate a metal charge up to 500 tons or more. The hearth of the
furnace may be either acid or basic. This fact determines the character of the
metallurgical processes in the furnace and the quality of the finished metal.
In acid open-hearth furnaces the refractory lining of the hearth, wools and
roofs is of dinas brick. The parts of the furnace subject to the severest
conditions – the upper layer, or bottom and banks of the hearth on which the
molten metal and slag rest – are rammed of silica sand and then fritted.
In a basic open-hearth furnace the hearth and walls are lined with
magnesite brick while the roof is of dinas burned or chrome magnesite. The
bottom and banks are burned in with grain magnesite or dolomite, and are
repaired after each heat. In the basic furnace steel is smelted under a basic
slag.
Both basic and acid open-hearth processes are characterized by a
number of distinct modifications, depending upon the choice of initial
materials which constitute the charge. In some plants, usually of the
mechanical engineering type, a solid charge is used. This procedure is
called the scrap-and-pig process and consists in charging solid pig iron,
scrap and a small quantity of iron ore into furnace at the beginning of the
process.
In metallurgical plants with operating blast furnace, open-hearth
furnace are charged with liquid pig iron (60 per cent), waste metal and scrap
(40 per cent), iron ore and fluxes. This method is called the scrap-and-ore
process.
Steelmaking in the open-hearth furnace comprises the following
periods:
1.Charging and melting down the charge;
2. Boiling of the bath of molten metal
30
3. Refining and deoxidizing.
Most open-hearth furnaces are filed with a mixture of blast furnace
and coke-oven gases.
The charging material (scrap, pig iron and flaxes are placed on the
hearth of the furnace through the charging doors. The charge is heated, and
the the metal and slag are melted and further heated by the heat of
combustion of the fuel in the melting chamber upon contact of the materials
with the hot gases. The finished metal is tapped through a taphone and spout
located in the lowest part of the hearth. During a smelting the taphone is
plugged with refractory clay.
Electric Furnace Steel Making
The most highly perfected steel-making units are electric furnaces
in which electric energy in converted by various methods into thermal
energy for heating and melting the metal.
Electric furnace steel used in making steel are of two types - arс
and induction (high frequency) furnaces. This first are more widely
employed in metallurgical.
Electric furnace steel making processes many advantages in
comparison with open-hearth and other steel-making processes. It is
possible in electric furnaces to obtain very high temperature (up to 2000°)
so as to melt metals with a high concentrations of components with high
melting points (chromium, molybdenum and other admixtures), operate
with highly basic slag (up to 55 – 60% CaO) and to remove a large part of
the phosphorus and sulphur from the metal, i.e., to effectively free the metal
of harmful impurities, and set up a reducing atmosphere or a vacuum (in
induction furnaces) thereby achieving better deoxidation and degasification
of the metal.
In the electric – arc furnace for steel making the charge is heated
and the melted by heat radiated from three arcs – according to the number
of phases of alternating The electric arcs are struck in the melting chamber
of the furnace between the vertically mounted electrodes and the furnace
between the vertically mounted electrodes and the metallic charge.
An electric-arc steel making furnace comprises a cylindrical
welded or riveted shell with a spherical bottom; refractory lining of the
hearth and walls; removable dome roof assembled of shaped refractory
brick in a roof ring (holes are left in the roof lining for the electrodes);
mechanism for supporting and feeding down the electrodes; two supporting
toothed rockers on which the furnace is held and titled on the toothed rails
31
of the foundation; and the tilting mechanism which enables the furnace to
be titled towards the tapping door and spout for pouring.
Power supply of the furnace is from the step-down transformer
located in separate premises. Copper bus bars are flexible cable are used as
power leads to the electrodes.
The roof of the electric-arc furnace is most frequently made of
dines brick but sometimes chrome-magnetite blocks are used for this
purpose.
Carbon or graphitized electrodes are employed in electric arc
furnaces. Graphitized electrodes offer less resistance to current and are
considered be more durable at high temperature. It is more expedient to us
graphitized electrodes for steel making but they are more expensive than the
carbon type.
In the course of the heat the lower ends of the electrodes are
consumed and the electrodes become shorter, therefore they are gradually
fed down into the furnace and, wherever necessary, a new electrode is built
up on top of the old one. Each of the three electrodes is held tightly in the
contact cheeks of the spring clamp to which power is supplied from the
secondary winding of the furnace transformer. The primary of this
transformer is supplied with high-tension current from 6000 to 300000V –
this current being transformer to a lower voltage from 90 to 280 V
depending upon the selected voltage stage. The power raiting of the
transformer depends upon the capacity of the furnace and the particular
steel-making technique being employed. The electric energy consumption
of arc furnaces operating on a solid charge may be taken as 6000 to 950
kWh per ton of finished steel.
Tapping and pouring the steel
The finished steel is tapped from the furnace into a well heated
steel ladle of the required capacity.
The size of the ladle is usually selected so that it accommodates the
whole heat from the furnace and part of the slag which is required as
thermal insulation of the metal surface.
From the ladle the steel is poured into metal moulds to produce
ingots or into sand moulds to obtain steel castings. Depending upon the king
of ingots to be produced, the moulds may have a square, round, rectangular
or other cross section (fluted moulds). A definite height-to-cross section
ratio has been established in practice for ingot moulds; the height should be
32
5 or 6 times more than the diameter or size of the cross section. The mould
walls are tapered to facilitate stripping from the solidified ingots.
Ingots are produced in a wide size range-from 100 kg to 100 tons.
Ingots weighing from 6 to 8 tons are the most common size; they are used
in rolling departments. Heavier ingots, designed for special purposes, are
seldom poured. In the top pouring of steel each mould is filled with liquid
steel separately.
Bottom pouring consists in teeming the steel from the ladle into the
funnel of a vertical runner from which the steel enters several moulds
through narrower runners.
The advantages of top pouring over bottom pouring lie in the
greater opportunities for nonmetallic inclusions to become separated from
the metal and that the hotter metal is in the top of the ingot. Bottom pouring
provides better surface quality on the ingot and hotter metal at the bottom.
As the liquid metal poured into the mould cools, its volume is
reduced thereby leading to shrinkage of the ingot. First to solidify is the
outside on the ingot adjacent to the mould walls; the interior part of the
ingot remains in a liquid state for some time after the mould is teemed. A
shrinkage cavity, or pipe, is formed in the upper central portion of the ingot
where the metal continues to be in the molten state for a long time.
The extent of the pipe in the ingots can be reduced somewhat if
solidification in the upper part of the mould is retarded. His is done by
applying a hot top. Hot tops are extensions of the moulds and are lined with
a refractory material. Due to the poor heat conductivity of the hot top walls
the metal in this part of the mould is retained in the liquid state for a
comparatively long time and a considerable part of the pipe is transferred to
the ingot top which is subsequently cut off together with the pipe.
In some cases the metal in the hot top is additionally heated with a
gas torch or by introducing a thermal mixture. Such measures the volume of
the pipe.
A large economy is achieved in the continuous casting of steel, a
new method that is being applied at a number of Soviet plants. A diagram
showing this method is given in Fig. Liquid metal runs in a continuous
stream from the ladle into the-intermediate device and then further, into the
water-cooled solidifiers. A steel seeder is placed in the bottom of the each
solidifier. This seeder prevents the first portion of the molten metal from
dropping straight through the solidifier. Upon contact with the seeders and
water-cooled walls the liquid metal begins to solidify on the ingot surface. It
welds to the seeders with which it is pulled downwards, out of the solidifier,
33
by rollers. Solidification of the continuous ingot produced in the solidifier is
intensified when it passes through the zone of secondary cooling by water.
The completely solidified ingot next passes to the gas-cutting
trucks continuing to travel downwards together with the trucks the ingots
are cut into billets of definite length which are carried by conveyers over the
inspection table and are delivered to the store house. The billets are
subsequently rolled into section of the required shape and size.
Vacuum casting steel has proved to be a very affective and
efficient method. In this proсedure steel, made in any unit, is held in a
closed chamber from which air and gases are continuously evacuated. As
result of this treatment the steel has a minimum content of gases and
nonmetallic inclusion.
Vacuum treatment is usually carried out in the ladle before pouring
the moulds.
The method of producing high-quality metal is not as widely
applied as it deserves.
III. Automatization
Text 1
Computer
A computer is a machine that manipulates data according to a list
of instructions. The first devices that resemble modern computers date to
the mid-20th century (around 1940 - 1945), although the computer concept
and various machines similar to computers existed earlier. Early electronic
computers were the size of a large room, consuming as much power as
several hundred modern personal computers. Modern computers are based
on tiny integrated circuits and are millions to billions of times more capable
while occupying a fraction of the space. Today, simple computers may be
made small enough to fit into a wristwatch and be powered from a watch
battery. Personal computers in various forms are icons of the Information
Age and are what most people think of as "a computer"; however, the most
common form of computer in use today is the embedded computer.
Embedded computers are small, simple devices that are used to control
other devices — for example; they may be found in machines ranging from
fighter aircraft to industrial robots, digital cameras, and children's toys.
The ability to store and execute lists of instructions called
programs makes computers extremely versatile and distinguishes them from
calculators. The Church–Turing thesis is a mathematical statement of this
versatility: any computer with a certain minimum capability is, in principle,
34
capable of performing the same tasks that any other computer can perform.
It is difficult to identify any one device as the earliest computer, partly
because the term "computer" has been subject to varying interpretations
over time. Originally, the term "computer" referred to a person who
performed numerical calculations (a human computer), often with the aid of
a mechanical calculating device.
The history of the modern computer begins with two separate
technologies - that of automated calculation and that of programmability.
Examples of early mechanical calculating devices included the abacus, the
slide rule and arguably the Antikythera mechanism (which dates from about
150-100 BC). The end of the Middle Ages saw a re-invigoration of
European mathematics and engineering, and Wilhelm Schickard's 1623
device was the first of a number of mechanical calculators constructed by
European engineers. However, none of those devices fit the modern
definition of a computer because they could not be programmed. It was the
fusion of automatic calculation with programmability that produced the first
computers. In 1837, Charles Babbage was the first to conceptualize and
design a fully programmable mechanical computer that he called "The
Analytical Engine". Due to limited finances, and an inability to resist
tinkering with the design, Babbage never actually built his Analytical
Engine. During the first half of the 20th century, many scientific computing
needs were met by increasingly sophisticated analog computers, which used
a direct mechanical or electrical model of the problem as a basis for
computation. However, these were not programmable and generally lacked
the versatility and accuracy of modern digital computers. A succession of
steadily more powerful and flexible computing devices were constructed in
the 1930s and 1940s, gradually adding the key features that are seen in
modern computers. The use of digital electronics (largely invented by
Claude Shannon in 1937) and more flexible programmability were vitally
important steps, but defining one point along this road as "the first digital
electronic computer" is difficult (Shannon 1940). A number of projects to
develop computers based on the stored program architecture commenced
around this time, the first of these being completed in Great Britain. Nearly
all modern computers implement some form of the stored program
architecture, making it the single trait by which the word "computer" is now
defined. While the technologies used in computers have changed
dramatically since the first electronic, general-purpose computers of the
1940s, most still use the Neumann architecture. The design made the
universal computer a practical reality.
35
Vacuum tube-based computers were in use throughout the 1950s,
but were largely replaced in the 1960s by transistor-based devices, which
were smaller, faster, cheaper, used less power and were more reliable.
These factors allowed computers to be produced on an unprecedented
commercial scale. By the 1970s, the adoption of integrated circuit
technology and the subsequent creation of microprocessors such as the Intel
4004 caused another leap in size, speed, cost and reliability. By the 1980s,
computers had become sufficiently small and cheap to replace simple
mechanical controls in domestic appliances such as washing machines.
Around the same time, computers became widely accessible for personal
use by individuals in the form of home computers and the now ubiquitous
personal computer. In conjunction with the widespread growth of the
Internet since the 1990s, personal computers are becoming as common as
the television and the telephone and almost all modern electronic devices
contain a computer of some kind.
The defining feature of modern computers which distinguishes
them from all other machines is that they can be programmed. That is to say
that a list of instructions (the program) can be given to the computer and it
will store them and carry them out at some time in the future. In most cases,
computer instructions are simple: add one number to another, move some
data from one location to another, send a message to some external device,
etc. These instructions are read from the computer's memory and are
generally carried out (executed) in the order they were given.
However, there are usually specialized instructions to tell the computer to
jump ahead or backwards to some other place in the program and to carry
on executing from there. Many computers directly support subroutines by
providing a type of jump that "remembers" the location it jumped from and
another instruction to return to the instruction following that jump
instruction.
Program execution might be likened to reading a book. While a
person will normally read each word and line in sequence, they may at
times jump back to an earlier place in the text or skip sections that are not of
interest. This is called the flow of control within the program and it is what
allows the computer to perform tasks repeatedly without human
intervention.
Comparatively, a person using a pocket calculator can perform a
basic arithmetic operation such as adding two numbers with just a few
button presses. But to add together all of the numbers from 1 to 1,000 would
take thousands of button presses and a lot of time—with a near certainty of
making a mistake. On the other hand, a computer may be programmed to do
36
this with just a few simple instructions. Once told to run this program, the
computer will perform the repetitive addition task without further human
intervention. It will almost never make a mistake and a modern PC can
complete the task in about a millionth of a second.
However, computers cannot "think" for themselves in the sense
that they only solve problems in exactly the way they are programmed to.
Large computer programs may take teams of computer programmers. In
most computers, individual instructions are stored as machine code with
each instruction being given a unique number (its operation code or opcode
for short). The command to add two numbers together would have one
opcode, the command to multiply them would have a different opcode and
so on. The simplest computers are able to perform any of a handful of
different instructions; the more complex computers have several hundred to
choose from—each with a unique numerical code. Since the computer's
memory is able to store numbers, it can also store the instruction codes.
This leads to the important fact that entire programs (which are just lists of
instructions) can be represented as lists of numbers and can themselves be
manipulated inside the computer just as if they were numeric data. The
fundamental concept of storing programs in the computer's memory
alongside the data they operate on is the crux of the Neumann. In some
cases, a computer might store some or its entire program in memory that is
kept separate from the data it operates on. While it is possible to write
computer programs as long lists of numbers (machine language) and this
technique was used with many early computers, it is extremely tedious to do
so in practice, especially for complicated programs. Instead, each basic
instruction can be given a short name that is indicative of its function and
easy to remember. These mnemonics are collectively known as a
computer’s language. Converting programs written in assembly language
into something the computer can actually understand (machine language) is
usually done by a computer program called an assembler. Machine
languages and the assembly languages tend to be unique to a particular type
of computer.
Though considerably easier than in machine language, writing a
long program in assembly language is often difficult and error prone.
Therefore, most complicated programs are written in more abstract highlevel programming languages that are able to express the needs of the
computer programmer more conveniently (and thereby help reduce
programmer error). High level languages are usually "compiled" into
machine language (or sometimes into assembly language and then into
machine language) using another computer program called a compiler.
37
Since high level languages are more abstract than assembly language, it is
possible to use different compilers to translate the same high level language
program into the machine language of many different types of computer.
This is part of the means by which software like video games may be made
available for different computer architectures such as personal computers
and various video game consoles. A computer system is a collection of
components that work together to process do. The purpose of a computer
system is to make it as easy as possible for you to use computer to solve
problems. A functioning computer system combines hardware elements
with software elements.
The task of developing large software systems is an immense
intellectual effort. Producing software with an acceptably high reliability on
a predictable schedule and budget has proved historically to be a great
challenge; the academic and professional discipline of software engineering
concentrates specifically on this problem. A computer's memory can be
viewed as a list of cells into which numbers can be placed or read. Each cell
has a numbered "address" and can store a single number. The computer can
be instructed to "put the number 123 into the cell numbered 1357" or to
"add the number that is in cell 1357 to the number that is in cell 2468 and
put the answer into cell 1595". The information stored in memory may
represent practically anything. Letters, numbers, even computer instructions
can be placed into memory with equal ease. Since the CPU does not
differentiate between different types of information, it is up to the software
to give significance to what the memory sees as nothing but a series of
numbers.
In almost all modern computers, each memory cell is set up to store
binary numbers in groups of eight bits (called a byte). Each byte is able to
represent 256 different numbers; either from 0 to 255 or -128 to +127. To
store larger numbers, several consecutive bytes may be used (typically, two,
four or eight). When negative numbers are required, they are usually stored
in two's complement notation. Other arrangements are possible, but are
usually not seen outside of specialized applications or historical contexts. A
computer can store any kind of information in memory as long as it can be
somehow represented in numerical form. Modern computers have billions
or even trillions of bytes of memory. While a computer may be viewed as
running one gigantic program stored in its main memory, in some systems it
is necessary to give the appearance of running several programs
simultaneously. This is achieved by having the computer switch rapidly
between running each program in turn. By remembering where it was
executing prior to the interrupt, the computer can return to that task later. If
38
several programs are running "at the same time", then the interrupt
generator might be causing several hundred interrupts per second, causing a
program switch each time. Since modern computers typically execute
instructions several orders of magnitude faster than human perception, it
may appear that many programs are running at the same time even though
only one is ever executing in any given instant. This method of multitasking
is sometimes termed "time-sharing" since each program is allocated a
"slice" of time in turn.
Before the era of cheap computers, the principle use for
multitasking was to allow many people to share the same computer.
Supercomputers in particular often have highly unique architectures that
differ significantly from the basic stored-program architecture and from
general purpose computers.
In the 1970s, computer engineers at research institutions
throughout the United States began to link their computers together using
telecommunications technology. This effort was funded by ARPA (now
DARPA), and the computer network that it produced was called the
ARPANET. The technologies that made the Arpanet possible spread and
evolved. In time, the network spread beyond academic and military
institutions and became known as the Internet. The emergence of
networking involved a redefinition of the nature and boundaries of the
computer. Computer operating systems and applications were modified to
include the ability to define and access the resources of other computers on
the network, such as peripheral devices, stored information. Initially these
facilities were available primarily to people working in high-tech
environments, but in the 1990s the spread of applications like e-mail and the
World Wide Web, combined with the development of cheap, fast
networking technologies like Internet and ADSL saw computer networking
become almost ubiquitous. A very large proportion of personal computers
regularly connect to the Internet to communicate and receive information.
"Wireless" networking, often utilizing mobile phone networks, has meant
networking is becoming increasingly ubiquitous even in mobile computing
environments.
Usually, a computer system requires three basic hardware items:
the central processor unit, which performs all data processing; a terminal
device, which helps users to communicate with their computer system and a
memory storing programs and data. These three devices are the required
hardware components of any computer system. Computer system includes
many other devices: printer, scanner and a modem. These computer devices
called hardware.
39
The term hardware covers all of those parts of a computer that are
tangible objects. Circuits, displays, power supplies, cables, keyboards,
printers and mice are all hardware. The need for computers to work well
together and to be able to exchange information has spawned the need for
many standards organizations, clubs and societies. The control unit's rule in
interpreting instructions has varied somewhat in the past. While the control
unit is solely responsible for instruction interpretation in most modern
computers, this is not always the case. Many computers include some
instructions that may only be partially interpreted by the control system and
partially interpreted by another device. This is especially the case with
specialized computing hardware that may be partially self-contained. For
example, EDVAC, the first modern stored program computer to be
designed, used a central control unit that only interpreted four instructions.
All of the arithmetic-related instructions were passed on to its arithmetic
unit and further decoded there. Instructions often occupy more than one
memory address, so the program counters usually increases by the number
of memory locations required to store one instruction. Programs are usually
written in a Programming languages like Pascal, C++, etc, they (programs)
deal with are organized into files. Applications are programs for specific
tasks.
Applications include: database soft, spreadsheets calculations,
word- processing on a word processor. To function hardware and software,
a computer needs an operation system program. Some operation systems
require users to type in commands to tell the computer to do. Many
computers use a graphical interface or point-and-click interface such as
Windows. Some interfaces allow plug-and-play, the possibility of
connecting new hardware the computer without having to adjust or
configure the system to take the new hardware into account: the interface
program recognizes the hardware automatically.
Text 2
What is voltage?
Of several electricity concepts, the idea of "voltage" or "electrical
potential" is probably the hardest to understand. It's also really tough to
explain. It's a headache for both the student and the teacher.
To
understand voltage we should first understand a little about its nearest
relative, magnetism.
40
Most of us are familiar with magnetic fields. Magnets are
surrounded with an invisible "field" which pulls upon iron, and which can
attract or repel other magnets. The magnetic field forces oblong magnetic
objects (such as iron rods, or iron powder) to twist and align to follow
particular directions. Put a bar magnet under a piece of paper, sprinkle on
some iron filings, and the filings all line up and show the general shape of
the invisible field. Obtain a small compass, and you'll see the compass
pointer twist and align with the magnetic field of the earth. That's
magnetism.
There is another type of invisible field besides magnetism. It is
called the "electric field" or "electrostatic field" or "e-field." This second
kind of field is much like magnetism. It's invisible, it has lines of flux, and it
can attract and repel objects. However, it is not magnetism, it is something
separate. It is voltage.
Most people know about magnetic fields but not about e-fields or
"voltage fields." In part, this is because magnetism is explained in school,
but for some reason voltage fields are hidden away under the name "static
electricity." E-fields are never mentioned in beginner's science textbooks.
This is odd, since voltage and "static electricity" go together. Whenever a
negative charge attracts a positive charge, invisible fields of voltage must
exist between the charges. Voltage causes the attraction between opposite
charges; the voltage fields reach across space. In reality, "static" electricity
has nothing to do with motion (or with being static.) The static electricity
involves high voltage. When you remove a wool thing from your clothes
dryer, all the fibers stand outwards, they are following the invisible lines of
voltage in the air. Fibers are the "iron filings" that make the voltage field
pattern visible. And whenever the charges within a conductor are forced to
flow, they only move because they're being driven along by a voltage-field
which runs through the length of the wire. Voltage causes current. Another
way to say it: electric currents are caused by "static electricity," and "static
electricity" is not necessarily static. The connection between voltage and
"static" electricity is not explained in the books, and that's one reason why
voltage phenomena seem so complicated and mysterious.
The Simple Math behind "Voltage"
To be a bit more specific, Voltage is a way of using numbers to
describe an electric field. Electric fields or "E-fields" are measured in volts
over a certain distance; volts per centimeter for example. A stronger e-field
has more volts per centimeter than a weaker field. Voltage and e-fields are
41
basically the same thing: they are two terms to describe the same basic
concept.
When you have e-fields, you have voltage. E-fields can exist in the
air, and so can voltage. Whenever you have a high voltage across a short
distance, then you have strong e-fields. Whenever an e-field is attracting or
repelling an object, instead we could say that the object is being driven by
the voltage in the space around the object.
Can an object have a certain voltage? No.
Voltage is a bit like length; it is a measurement made between two
things. My distance is 300ft above sea level, but simultaneously my
distance is also 1cm from the floor (since I'm not barefoot,) and it's also 93
million miles from the sun. My voltage might be -250 Volts in relation to
the earth, but it also might be billions of volts when compared to the moon.
Volts are always measured along the flux lines of electric field; therefore
voltage is always measured between two charged objects. If I start
measurement at the negative end of my flashlight battery, I can call that end
"zero volts", and so the other end must be positive 1.5 volts. However, if I
start measurement at the positive end instead, then the positive battery
terminal is zero volts, and the other terminal is negative 1.5 volts. Or, if I
start half way between the battery terminals, then one terminal is -.75 volts,
and the other terminal is +.75 volts. What is the real voltage of the positive
battery terminal? Nobody can say. The terminal can have several voltages
at the same time. But this is no big deal, because neither can anyone tell you
the battery's distance! We can easily imagine the distance between two
points, and we can also imagine the voltage between two points. But single
objects don't "have distance", and single objects also don't "have voltage."
Un - twisting the Terminology
You've probably heard of electromagnetism. In the word
"Electromagnetism," the term "electro" does not refer to electricity. Instead
it refers... to voltage! Electromagnetism is the study of e-fields and
magnetic fields: electro/magnetism. Charge flow (electric current) is
intimately associated with magnetism, and separate opposite charges are
intimately associated with voltage. A flow of electromagnetic energy along
a cable is composed half of electric current, and half of voltage. it's electromagnetism. Electromagnetism is a two-sided coin, so what is voltage? It's
one side of EM (the other side being magnetism.)
Voltage is also missing from our everyday language. If we have no common
words to describe something, we tend to never talk about it. For example,
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we have the word "magnetism", and most people have heard of magnetic
fields. Electric fields exist too, but unfortunately "electri-cism" is not an
English word. Everyone can discuss magnetism, but nobody ever talks
about "electricism." Without the word "electricism," we have a tough time
talking about electric fields, or about electric attraction/repulsion forces, and
we never realize that they are important in electric circuits. Yet there's a
word we could use instead of "Electricizm." If magnetism is "that which
involves magnetic fields", then what is "that which involves electric fields?"
Voltage! Pick up some nails with a magnet, and that's an example of
magnetism, then pick up some bits of paper with a fur-rubbed balloon, and
that's an example of voltage. There are three types of invisible fields:
gravity, magnetism and voltage
Electromagnetic Duality
Voltage and magnetism form a pair of twins; they are two halves of
a duality. Physicists and engineers even use the word "dual" to describe
them: voltage is the "dual" of magnetism, and magnetism is the "dual" of
voltage. This duality raises its head in many places in the physical sciences.
One small analogy: A spinning flywheel can store energy. So can a
compressed spring. In electrical physics, a superconductor ring can store
energy in the form of magnetism, and a capacitor can store energy in the
form of voltage. A coil of wire and a capacitor are the "duals" of each other.
Voltage Energy
Voltage is intimately connected with electrical energy. So is
magnetism. We can even say that electrical energy is the fundamental object
of our study, while voltage and magnetism are the two faces it displays to
the outside world. Another analogy: in mechanical physics, both the Kinetic
energy (KE) and the Potential energy (PE) are part of matter: relative
motion of an object has Kinetic Energy, and stretched or compressed
objects (e.g. springs) have Potential Energy. In a similar way, electrical
kinetic energy appears whenever positive charges flow through negative
charges. We call this "electric current," and it causes magnetism. On the
other hand, electrical potential energy appears whenever positive charges
are yanked away to a distance from their corresponding negative charges.
We call this "net electrostatic charge," and it causes voltage. Electrical KE
is associated with current, and electrical PE is associated with voltage.
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Potential Energy vs. "Potential"
Voltage is also called "electrical potential."
So... is voltage a type of potential energy? Close, but not totally accurate.
Confusion between voltage and potential energy is a common mistake. See
the following example: if you roll a big boulder to the top of a hill, you have
stored some potential energy. But after the boulder has rolled back down,
the hill is still there. The hill is like voltage: the height of the hill has
"Gravitational Potential." But the hill is not "made" of Potential Energy,
since we need both the hill and the boulder before we can create potential
energy. The situation with voltage is similar. Before we can store any
electrical potential energy, we need some charges, but we also need some
voltage-field through which to push our charges. The charges are like the
boulder, while the voltage is like the hill. You can push an electron up a
voltage-hill, and if you let it go it will race back down again.
Currents don't have Voltage
Voltage is not a characteristic of electric current. It's a common
mistake to believe that a current "has a voltage". But they are closely
connected. Voltage and current are two independent things. It is easy to
create a current which lacks a voltage: just short out an electromagnet coil.
It is also easy to create a voltage without a current: flashlight batteries
maintain their voltage even when they are sitting on the shelf in the store.
Water analogy: Think of water pressure without a flow. That's like voltage
alone. Now think of water that's coasting along; a water flow without a
pressure. That's like electric current alone.
Measuring Voltage
To measure voltage, we allow the "electricism" between a pair of
delicately suspended metal plates to deflect one of those plates. The
simplest voltmeter is called a "foil-leaf electroscope." Electroscopes are
simple versions of zero-current voltmeters. Find such things in books about
"static electricity", when they really should be in all electronics books. A
more complicated version of the foil-leaf electroscope is called a "quadrant
electrometer." These two devices can measure voltage directly, without
creating any electric current at all.
The Voltage of Light
44
Electromagnetic energy always has voltage. For example, if you
touch the antenna of a powerful radio transmitter, you can receive an
electric shock because of the high voltage at the antenna. Radio waves are
electromagnetic, and the intense waves surrounding a radio transmitter's
antenna have a high voltage-field. Radio waves can be measured in terms of
voltage. Even the brightness of the light from the sun can be measured in
terms of volts per meter. So can the energy which comes from the electric
generators and flows along wires to a 120v table lamp, so do light beams
and optical fibers, which are also have voltage.
Voltage and atoms.
The bonds between atoms are often associated with a constant
voltage. Voltage is the stuff that connects the protons and electrons of atoms
to each other, and it connects atoms together to form objects. Without
voltage, there would be no solids or liquids in the universe, just gas. When
you break a solid object, you are defeating the attractive microscopic
voltage which was binding it's atoms together. For example, A battery is a
couple of metal plates immersed in liquid. At the surface of the liquid where
it touches each plate, all the atoms line up in parallel and a voltage appears
between the liquid and the metal. The voltage of any battery is caused by
the micro-thin layer of atoms at the surface of the metal plates inside the
battery. Everything else in the battery is just there to provide the electrical
connections and the chemical fuel supply.
Everyday electric motors operate by magnetic forces surrounding a
coil, with electric current in the windings of the coil. Let's call this sort of
device by the name "current motor". Electric motors in everyday life are
invariably "current motors", but "voltage motors" exist too. They operate
because of voltage-forces between charged objects. The microscopic motors
used in cutting-edge nanotechnology are voltage motors. The linear
chemical-motors inside your muscles are voltage motors. The spinning cilia
on the tail ends of bacteria are little voltage motors. The mechanical
enzymes which assemble the 'energy molecules' of our body are voltage
motors.
The pressure concept
Voltage is sort of like "electrical pressure", but it's not really
pressure. Real electrical pressure is an attraction/repulsion force which is
45
felt by physical objects. Electrical forces only exist when charged matter is
being attracted or repelled, and if charged matter is absent, there can be no
pressure, yet there can still be voltage. Analogy: if e-fields are like gravity,
then voltage is like height above the earth. Voltage is not really force or
pressure, in the same way that height above the earth is not a kind of
"weight." Without the Earth and without height above it, "weight" cannot
exist. Without electric charge and without voltage, electric
attraction/repulsion cannot exist.
Voltage drop
Voltage drop is the reduction in voltage in an electrical circuit
caused by overload. In electrical wiring national and local electrical codes
set guidelines for maximum voltage drop allowed in a circuit, to ensure
reasonable efficiency of distribution and proper operation of electrical
equipment (the maximum permitted voltage drop varies from one country to
another).Voltage drop may be neglected when the impedance of the
interconnecting conductors is small in relation to the other components of
the circuit. For example, an electric space heater may have a resistance of
ten ohms, and the wires which supply it may have a resistance of 0.2 ohms,
about 2% of the total circuit resistance. This means that 2% of the supplied
voltage is actually being lost by the wire itself. Excessive voltage drop will
result in unsatisfactory operation of electrical equipment, and energy will be
wasted in the wiring system. Voltage drop can also cause damage to
electrical motors. In electronic designs for power transmission, various
techniques are used to compensate for the effect of voltage drop on long
circuits or where voltage levels must be accurately maintained. The simplest
way to reduce voltage drop is to increase the diameter of the cable between
the source and the load.
Voltage drop in direct current circuits
A current flowing through the non-zero resistance of a practical
conductor necessarily produces a voltage across that conductor. The dc
resistance of the conductor depends upon the conductor's length, crosssectional area, type of material, and temperature. If the voltage between the
conductor and a fixed reference point is measured at many points along the
conductor, the measured voltage will decrease gradually toward the load.
The longer is the conductor the current passes through, the more of the
voltage is "lost".
46
If the load current increases, the voltage drop in the conductor also
increases.
A principle known as Kirchoff's Law states that in any circuit, the
sum of the voltage drops across each component of the circuit is equal to the
supply voltage.
Voltage drop in alternating current circuits
In alternating current circuits, additional opposition to current flow
occurs due to the interaction between electric and magnetic fields and the
current within the conductor; this opposition is called "impedance". The
impedance in an alternating current circuit depends on the spacing and
dimensions of the conductors, the frequency of the current, and the
magnetic permeability of the conductor and its surroundings. The voltage
drop in an AC circuit is the product of the current and the impedance of the
circuit. Electrical impedance, like resistance, is expressed in ohms and falls
under Ohm's law for direct current circuits.
Text 3
Non–Traditional Methods for Making Small Holes
Not too long ago, a hole the size of a human hair (about 0.003 inch
in diameter) was about the smallest hole that could be made by using
conventional machine tools on a production basis.
Today, advances in the fields of medical devices, communications,
optics, electronics, computers and others have created a need for holes that
are straighter, more accurate, better defined — and in many cases much
smaller in diameter than a human hair.
Ttoday, that need is being met by not–so–new but little–known
non–conventional hole–making techniques, some of which are described in
the following pages.
These techniques not only have prompted the development of
machine tools designed with small hole making in mind, but they also have
produced specialized contract shops that, by serving the trend toward
miniaturization, are on the leading edge of new–product development.
47
Laser Micro drilling
Recent improvements in ultraviolet (UV) light lasers have made
them a very competitive tool for micro drilling and other micromachining
applications.
The Gator is a compact, diode–pumped solid–state laser (DPSSL)
made by Lambda Physic Inc., Ft. Lauderdale, Florida.
It offers a combination of high peak power, high repetition rates
and beam quality that makes it suitable for drilling holes as small as 10
micrometers (0.0004 inch) diameter in stainless and carbon steels, titanium,
ceramics, silicon and other hard materials up to about 1 mm thick.
“Drilling small holes by laser has been around for 30 years,”
explains Mike Heglin, vice president of scientific and industrial sales for
Lambda Physic.
“The first systems were installed to drill numerous, small, cooling holes in
turbine components for the aircraft/aerospace industry.”
Until recently, such systems required a lot of maintenance —
replacement of the optics, periodic replacement of the flash lamp, realigning
the optics within the laser, and so forth. Despite the constant attention,
maintaining uptime remained a problem. Would–be users were afraid to buy
a laser for fear that they'd need someone with a Ph.D. to keep it running.
Shorter Pulses Equal Better Holes
“The diode laser has changed all that,” Mr. Heglin continues.
“Diodes allow the laser to run with the reliability of, say, an electric motor.
We expect our lasers to provide 20,000 to 30,000 hours of continuous
operation — that's up to 10 years of running depending on the number of
shifts that the customer operates.”
Mr. Heglin notes that while the quality of laser–drilled holes has
been acceptable for most applications in the past, it did not measure up for
more demanding applications such as holes for fuel injection components.
The new diode laser produces a pulse that is much shorter, 15 nanoseconds
(billionths of a second), compared to milliseconds for the older style lasers.
That plus a much shorter wavelength results in a greater cutting
efficiency. Less heat is generated in the part as well: Because of the high
power intensity created by the short pulse, much of the material is removed
in a photo–ablative state rather than a thermal melting state, which results in
a much smaller recast layer and better quality holes.
48
A study conducted by Lambda Physic demonstrated that its Model
G1064 Gator (with an average power greater than 10 watts) can drill holes
in 1 mm–thick steel plate at a rate of 10 mm per second.
Close–ups of holes drilled in varying thicknesses of steel attest to
the quality of the holes.
Mr. Heglin adds with satisfaction that some automotive companies
and their suppliers reevaluated the use of lasers for drilling fuel injection
components and have put systems into production. He cites as another
example of precision laser drilling nozzles used in the manufacture of
fibers.
In addition to providing more accurate, better defined, drilled
holes, the laser drilling process offers a lot of flexibility.
Once the laser beam creates a starting hole, it can, just as with CO 2 laser
cutting or wire EDMing, be moved like a jigsaw to create a hole of any
desired size and shape.
Laser drilling is faster than, say, the EDM process, and it requires
no hard tooling.
Also, where EDM drilling and EB drilling are limited to processing
conductive materials, the laser drill can be used to drill materials ranging
from soft plastics to the hardest metals even diamonds.
Finally, the Gator and other diode lasers are relatively
compact — the Gator is the size of a toaster oven — which means that they
can usually be accommodated easily in existing production lines and
relocated when production requirements change.
Electron Beam Drilling
Electron
Beam
(EB)
drilling
was
developed
by
Karl–Heinz Steigerwald in Germany in the early 1950s, to drill holes in
jewel bearings for mechanical watches.
His work eventually led to the creation of Steigerwald Strahltechnik
GmbH (Munich, Germany), a company that manufactures EB drilling
machines capable of producing holes from about 0.002 inch to 0.060 inch in
diameter in metals and other conductive materials from 0.010 inch to 0.250
inch thick.
EB drilling is similar to the laser drilling in that energy is created
and
precisely focused on a work piece to bring about highly localized melting.
In the EB process, an electrically heated cathode produces electrons that are
accelerated by an electrical field applied between a cathode and anode at a
49
very high voltage.
A modulating electrode controls the intensity of the electron beam, which is
focused onto the work piece through an electromagnetic lens to power
densities of 100 million watts or more per square centimeter.
A CNC control, specially designed for the EB drilling process,
controls the main drilling parameters and the axial movements of the work
piece and beam.
Its main job is keeping the pulse duration and beam current level
consistent from pulse to pulse (unless variations are required by the drilling
programme).
In the EB drilling process, the focused electron beam concentrates
so much power at the hole so that it creates a “vapour capillary” surrounded
by a cylinder of molten material.
As the depth of cut increases, the beam gets in the way of the
molten metal, preventing it from escaping out of the bore.
For the purpose of expelling the molten material and to help
maintain uniform size from hole to hole, a backing material is applied to the
underside of the work piece material being drilled.
When the electron beam breaks through the work piece material,
the backing material reacts to the beam by producing a large volume of gas
that expands explosively up the capillary, taking with it the molten material.
A trace amount of molten material is left behind as a recast layer, however
it does not create oxidation problems since the EB drilling is done in a
vacuum.
2000 Holes/Second
The most important advantage of the EB drilling process is its
ability to produce very large numbers of holes quickly. The process can
create a hole with a single millisecond (thousandth–of–a–second) pulse of
the electron beam, and the work piece and beam move relative to each
other making possible extraordinary hole–making rates.
For example, 100 micrometer diameter holes can be drilled in
0.3 mm–thick sheet at 1,500 to 2,000 holes per second.
A is true of most hole–making processes, the time required to make
the hole varies inversely with the size of the hole and the thickness of the
material. Thus, the rate drops off to a “mere” 20 holes per second when EB
drilling 5 mm–deep, 0.7 mm–diameter holes — still many times faster than
any other process.
50
Thus, in applications where the part requires tens of thousands or
millions of tiny holes, such as a very fine filter screen, the EB drilling
process is hard to beat.
Work pieces drilled by the EB process tend to fall into two groups:
flat sheets of metal that are typically wrapped around a mandrel to form a
cylinder for processing as shown above; and work pieces with symmetrical
and asymmetrical shapes Both types of parts are mounted on work piece
holders with up to four– and five–axis movement capabilities.
For a cylindrical part, the most common movement is continuous
rotation about its major axis.
The beam moves simultaneously with the part, in a “flying beam”
fashion, to produce the holes in the shortest possible time.
Holes of various shapes (straight walls, bowed–walls, large or
small bell–mouthed openings, and so forth) can be formed by varying the
drilling parameters. The EB drilled hole typically is characterized by a
slight bell–mouthing at the beam entry point.
There are no breakthrough problems: The underside of the hole is
typically sharp and burr–free. Oval holes and slots can be produced as well
as round holes.
The holes can be normal to the work piece surface or drilled at
angles up to 25 degrees.
The repeatability of the EB drilling process provides hole size
accurate to ±0.001 inch and location accuracy to ±0.0005 inch.
Aspect ratios (hole depth to diameter) of 25:1 can be achieved.
Finally, the EB drilling process is largely automatic. Once the
work piece–drilling programme is downloaded to the machine, the
operator's responsibilities consist primarily of monitoring the operation of
the machine and loading–unloading work pieces.
According to the manufacturer, the EB drilling generator has no
parts that wear in use. The cathode filament, which is inexpensive, is the
only replacement part.
Owens Corning uses the EB drilling process to fabricate parts for
its proprietary glass–making equipment.
The parts are made at the company's Ridgeview Electron Beam
Drilling and CNC Machining facility in Duncan, South Carolina, which also
provides contract machining services to firms in the aerospace, food,
filtration, consumer products and other industries.
51
6 Million Holes/Part
“Most of the parts that we EB drill are used in filter applications,”
explains Will Bowman, general manager of OC Ridgeview.
“For example, for one of our customers we EB drill 6 million
0.006–inch–diameter holes in a 0.125–inch–thick, stainless steel disk just
over 24 inches in diameter.”
Typically, holes are drilled in ceramics while they are in the green
state, but with EB drilling, we can drill holes in fired alumina work pieces
up to 0.250 inch thick..
OC Ridgeview will process orders as small as one part. Mr.
Bowman emphasizes, however, that for the EB drilling process to be cost
effective, the part should require several hundred holes from 0.001 inch to
0.060 inch in diameter.
“We can hold size tolerances of ±0.001 inch,” he adds. “If the
application requires tighter tolerances, EDM is probably the better process.
If the application calls for fewer holes, laser drilling may be best. But when
the application calls for hundreds to millions of holes, we offer the most
efficient process.”
EDM Microdrilling
A third process for making small holes is EDM microdrilling. The
EDM microdrilling machine is essentially a sinker or ram–type EDM
machine with some interesting modifications that enable it to drill holes as
small as 0.0002 inch in diameter.
Pure tungsten wire is the preferred electrode material for some
users because of its exceptional wear resistance; the fabricated electrode
retains its size and shape longer, making for longer tool life and greater
hole–to–hole consistency.
52
APPENDIX 1
Скорочення: одиниці вимірювання
A
ampere
ампер
AU astronomical unit
астрономічна одиниця
bbl barrel
барель
bu bushel
бушель
C
degree Celsius
градус Цельсія
cal calorie
калорія
cd candela
кандела
cg centigram
сантиграм
cl centiliter
сантилітр
cm centimeter
сантиметр
dB decibel
децибел
dl deciliter
децилітр
dm decimeter
драм
dr dram
дедвейт
emf electromotive force
ерс
eV electron volt
електрон-вольт
F
farad
фарад
F degree Fahrenheit
Градус Фаренгейта
ft foot
фут
g gramme
грам
gal gallon
галон
gr grain
гран
GRT gross registered tonnage брутто
H henry
генрі
ha hectare
гектар
hl hectoliter
гектолітр
hp horsepower
кінська сила
hr hour
година
Hz hertz
Герц
in inch
дюйм
j
joule
джоуль
K
(degree) Kelvin
градус Кельвіна
kHz
kilohertz
Кгц (кілогерц)
kl
kilolitre
кл (кілолітр)
km
kilometer
км (кілометр)
kW
kilowatt
Квт (кіловат)
kWh
kilowatt hour
Квт/ год.
53
l
m
mg
MHz
mi
min
ml
mm
mo
mol
mph
MW
N
oz
pk
pt
qt
rd
ton
V
W
yd
yr
liter
meter
milligram
megahertz
mile
minute
milliliter
millimeter
month
mole
miles per hour
megawatt
Newton
once
peck
pint
quart
rod
ton
volt
watt
yard
year
л (літр)
м (метр)
мг (міліграм)
Мгц (мегагерц)
миля
хвилина
мл (мілілітр)
мм (міліметр)
місяць
моль
миль на годину
Мвт (мегават)
ньютон
унція
пек
пінта
кварта
род
т (тонна)
в (вольт)
вт (ватт)
ярд
р. (рік)
54
APPENDIX 2
Основні фахові терміни з перекладом
1. Chapter 1
combustible rock – займиста порода
volatile matter – летюча речовина
strip mining – відкрита розробка
waste rock – пуста порода
blasting – вибухові роботи
haulage – транспортування
adit – прохід
shaft – шахта
room- камера
pillar –колонна
noxious gases – отруйні гази
bitumen – бітум
coking- коксування
luster – блиск
explosive – вибуховий
shovel - лопата
dragline – скребковий екскаватор
belt conveyor – стрічковий транспортер
colliery – кам`яновугільна шахта
2. Chapter 2
continuous casting – безперервна розливка
hot rolling – гаряча прокатка
blast furnace – доменна пічь
slab- сляб
mill – прокатний стан
ingot – зливок
ratio – співвідношення
to roll - прокочувати
torch – різак
adjusting – регулюючий
stack – купа
tilting-table – похилий стол
roll table – рольганг
exertion – напруження
55
gear – привід
pig iron – чавун
open –hearth furnace – мартенівська пічь
2. Chapter 3
embeded computer – вмонтований компьютер
ubiquitous – всюдисущий
opcode - код операцiї
compiler – компілятор
capacitor – конденсатор
quadrant electrometer - квадрантний электрометр
impedance - повний опір
permeability - проникність
micro-drilling – мікро-свердлення
flash lamp - импульсна лампа
nozzle - випускний отвір
hard tooling – металеві инструменти
pulse duration - тривалість імпульсау
56
ЛІТЕРАТУРА
1. Англо-русский горный словарь. Под. ред. Л.И. Барона. М.1968.
2. Корунець І.В. Theory and Practice of Translation. Вінниця, «Нова
книга», 2003.
3. Карабан В. Переклад англійської наукової і технічної літератури:
Граматичні труднощі, лексичні, термінологічні та жанровостилістичні проблеми. Вінниця, «Нова книга», 2003.
4. Ганич Д.И., Олейник И.С. Руссо-украинский и украинско-русский
словар. – Х., 1993. – 650с.
5 Адамчик М.В. Великий англо-український словник. – Донецьк:
“Видавництво Сталкер”, 2002.
57
58