bhushan project final
TRANSCRIPT
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BHUSHAN POWER AND STEEL LIMITEDCHANDIGARH
PREPARED IN PARTIAL FULFILLMENT OF
INDUSTRIAL TRAINING
SUBMITTED BY:
NITESH PARMAR
UE 89047
5TH SEMESTER
MECHANICAL ENGINEERING
U.I.ET
PANJAB UNIVERSITY
CHANDIGARH
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COMPANY PROFILE
BHUSHAN PROFILE
To offer the best product, the widest range and excellence of quality and service in
steel.
To ever strive for greater growth in turnover and profitability through the best in
technology and equipment, total management, integration in Operations and
professionalism in., people.
To build on the existing strength to take the group to an even greater Future and to
contribute out best at all times in the service of Shareholders, the industry and the
country.
In all these commitments, Bhushan has an unshakable faith in its strengths and
resolve, and an unswerving obsession to excel and to improve upon its already notable
achievements.
At Bhushan Commitment is in; I word STEEL - SOLID.
BHUSHAN-THE BEGINNING
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MR. Brij Bhushan, the Prime Mover, a visionary entrepreneur founded the
BHUSHAN Group more than 20 years ago in Chandigarh. Making a moderate start with
manufacture of hinges and rail tracks fasteners in the early 70s with a capital less than alakh of rupees, the group has continuously grown by modernizing, expanding and
integrating its facilities/ operations.
Joined by his young and dynamic sons Sanjay and Neeraj in the 80s and taking
advantage of the liberalized environment in the steel sector, Brij Bhushan Singh has
propelled the group to the success earning it a permanent place among the large
players of the steel industry. With turnover of Rs. 2200 crores, cash profit of over Rs.180crores and net worth o f Rs. 500 crores.
All this has been achieved with the share holding entirely within the Bhushan family, a
remarkable testimony to its entrepreneurial skills and financial acumen. The group has
come a long way in a relatively short span.
THE WIDEST PRODUCT RANGE
Steel billets/ ingots, rolled products, rounds tire rods, flats, narrow strip, GALVANIEZED
PIPES, wide width cold rolled (CR) cold and continuous annealed/ galvanized steel soils
and sheets. THE BEST IN EQUIPMENT AND TECHNOLOGY
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By selecting state of art technology from supplied having foreign collaborations the
Group has benefited in terms of distinct project / product while optimizing on cost. The
technology sources being Sendzimir of USA for Rolling Mills, Stein Heulley of France
for continuous annealing - cum- galvanizing. GEC of UK for steel furnace.
CONSTANT MODERNIZATION AND UP GRADATION
By continuous steel searching and quick decision marking, the Group has always ahead of
the industry setting up modern equipment like Electric, Are Furnace, Continuous Casting,
Ladle refining facilities, Continuous Annealing, etc. enabling the Group to head the cyclicalnature of the steel industry and maintain a trail blazing record of growth and profitability.
STRONG PROJECT MANAGEMENT AND LOW CAPITAL COST
By close monitoring, high involvement of promoter directors, skilled negotiation
.Departmental supervision and high levels of promoters equity and plough back of
internal cash generations. The group has successfully implemented its project on
schedule and with low capital cost.
To illustrate, the capital cost per ton for the wide width CR Coils project of Bhushan
Steel and Strips Limited is about 2350per ton as compared to over Rs. 6000 per ton
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for existing projects in the industry and over Rs. 9000 per ton for projects. BSSLs CR
Coils plant was commissioned in less than 12 months from the date of sanction of
Institutional Team Loans. The capitals cost of integrated steel melting and rolling
facilities in Bhushan industries Limited and that of steel melting, rolling and
galvanized pipe making Bhushan Metallics Limited about Rs. 1000 per tone Imparting
significant cost advantages, a critical success factor in todays competitive
environment.
BHUSHAN INDUSTRIES LIMITED Bhushan Industries Limited is an integrated steel plant, located at Chandigarh, with
facilities for manufacturing 1.5 lakh tones per annum of steel billets and rolled
products rounds, flats, narrow strips and rail track fasteners. From a modes start in
1973. It has grown through expansion. Backward integration, up gradation of its
facilities and has today reached a turnover level of Rs. 2200 crores with cash profit of
about Rs. 170 crores and net worth of about Rs. 550 Crores.
The facilities include most modern electric arc furnaces, lade refining. Continuous
casters, oxygen plant, rolling mills, pollution control equipment and other auxiliary
facilities
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Excellence in product quality, a wide range close access of the main steel markets,
dedication if the Bhushan team and the Steel Solid commitment of Bhushan, today made
Bhushan Industries Limited, one of the largest mini steel plants in Northern India.
BHUSHAN METALLICS LIMITED
The operations of Bhushan Metallics Limited, are even more integrated, and facilities
for manufacturing 1 lakh tones per annual of rolled steel products wore rods, rounds,
narrow strip and ER W galvanize and black pipes and tubes at Chandigarh and
Derabassi, 15 kilometers from Chandigarh in Punjab. Bhushan Metallics Limited hastoday a turnover of crores. Its facilities include high productivity rolling mills, and tube
mills with captive steel melting and casting production capacities.
Product excellence takes the highest priority and its standards have won for the
company a growth share of the market under the brand name KALINGA. Its
integrated level of operations, low level of debt and quality of services ensure a high
level competitiveness amongst its product segments.
BHUSHAN STEEL AND STRIPS LIMITED
Taken over as a sick company in 1987 by the Bhushan Group, the company took big
leap forward with project of 1.2 lakh tones per annum of CRCA coils
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The project was commissioned in January 1990 within a period of 12 months from the
section of instructional loans and 7 months form the date of disbursement. The peace
of growth in terms of turnover and profitability has been phenomenal, and for 1992-
1993, the turnover was Rs. 28 crores and the Gross Block at about Rs. 50 crores. A
remarkable turnover was just Rs. 8 crores and net worth Rs. 20 lakh.
Bhushan Steels Strips plant facilities companies 2 most modern 20- Hi Sendzimir Mill
and related balancing facilities including HR/CR slitters, continuous picking line, skin
pas mill with stretch leveler,bell annealing furnace, cut to length link and auxiliary
equipment and also state of art continuous annealing cum galvanizing line. With the setting up of a continuous annealing cum galvanizing line based on the state
of the at 1 technology from Stein Heurtey of Furnace, the company is now amongst
the top three technology from Stein Heurtey of Furnace, the company is now amongst
the to three integrated wide width CRC coil / galvanized sheet manufacturers in the
private sector manufacturing widths of up to 1.25 meters and thickness down to 0.12
mm. The continuous annealing facilities are the first of its kind in the private sector
and would meet the stringent requirement of the automobile sector
The company is the largest CR coils / galvanized coils/ sheets manufacturer in the
Northern India with the plant located in the Western
CLASSIFICATION OF STEELS
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RAW MATERIAL
The factory uses scrap as the raw material. This raw material is purchased from
different scraps agencies like Kandla and Raigarh. A heavy electromagnetic is used toseparate the iron from big heaps of scrap. An overhead crane drives the
electromagnet.
Steels are alloys, the essential ingredients of which are iron and carbon (max 2%) ;
the carbon is distributed throughout the mass of steel not as element of free carbon
but as a compound with iron.Steel also contains definite amounts of inventible
impurities, which include silicon, manganese, sulphur and phosphorous, Alloyingelement are added to these carbon steels to produce special purpose steel.
CLASSIFICATION OF STEEL:
Steels can be grouped into following four categories:
Plain carbon steel.
Alloy Steels.
Special alloy steels.
Cast steels.
PLAIN CARBON STEELS:
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These steel contain only carbon and iron. Si, Mn. S and P exist as impurities. These
have
Negligible effect on steels when their extent does not exceed:
0.3 0.4% Si
0.5 -0.8% P and
0.4% S
Plain carbon steel can be classified according to their carbon content.
a) Low carbon or mild steel 0.05 0.3% C
b) Medium carbon and 0.30 0.6% C
c) High carbon steel 0.60 1.50% C
EFFECT OF IMPURITIES
Sulphur combines with iron chemically to produce iron, which forms the grain
boundaries. Iron supplied, because of its melting point, produces red shortness insteels, cause brittleness at forging temperatures.
Phosphorous is also a harmful impurity in steels, because it causes brittleness Silicon
is very good deoxidizer. It removes the gases and oxides, prevents blowholes and
thereby makes the steel tougher and harder. Manganese also serves as good
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deoxidizer and purifying agent. It also combines with sulphur to form manganese
sulphide and hereby reduces the harmful effects of sulphur remaining in steel; it
makes metal ductile
A) LOW CARBON STEELS: Low carbon steels are used extensively in industrial
products.
CONSTRUCTION INDUSTRY
The product application include: pipes, tubes, storage tanks, railroad, cars, automobile
frames, nuts, bolts, automobile bodies and galvanized steel sheet. These steels are
soft, very ductile, easily machined, easily welded and unresponsive to heat treatment
due to low carbon content.
B) MEDIUM CARBON STEELS:
These steels can be hardened and tempered. These steels can be used for products
requiring greater strength and wear resistance, typical product application include:
forging casting axles shafts crankshafts. Connecting rods etc.
C) High Carbon Steel
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These steels respond better to heal treatment as compared to medium carbon steel.
So, these have high strength, hardness and good resistance to wear. Typical product
applications include: forging and wide verities of tools such as drills, taps, reamers,
dies, hand tools, cutlery , chisel, shear blades, planer tools, spring wire, cable and wire
rope, this arc not so ductile, in higher carbon ranges, the extreme hardness is
accompanied by excessive brittleness.
Steel is said to be alloyed when its composition incorporates specially introduced alloying
elements or when the Si or Mn content exceeds the usual percentage, the aims for allowing
are following:
To produce fine grained steel.
To improve wear resistance, corrosion resistance
To improve harden ability and hardnessTo improve mach inability
To improve weld ability
To improve electrical properties
To improve physical properties at temperatures
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To improve tensile strength, ductility elastic properties etc.
ELECTRIC ARC FURNACE
SECTIONS IN PLANTThere are nine sections in this factory. This whole process goes through these sections
only, from melting to rolling. There are following sections:
1. Melting shop
2. Casting shop.
3. Rolling shop.
4. Physical strength testing section.5. Spectro and chemical lab.
6. Microscope lab.
7. Machine shop.
8. Electric section.
9. Finishing section.
PROCESSStarting from melting shop, steels caps and raw materials are charged in the furnace with
the help of overhead crane of capacity 60 ton. The crane lifts the charge bucket, which is
then titled in the furnace. Then after 40 to 90 minutes, molten metal is tapped in the
furnace. Then this label is transferred to the ladle refining furnace. Where the metal is
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refined by adding some additives. After 30 to 40minutes the ladle is transferred to the
continuous casting machine section, before this some metal in solid state
After this casting process goes on the casting of billets or size 4sq inches, 5sq inches,5.5sq inches is done. Then from casting sections billets are cut into the required pieces and
size and then they are heated in oil furnace at suitable temp. After heating billets, they are
frequently passed through rolling mills, - where required shape is done on different grades.
MACHINE SECTION
In machine section rolls mill arc designed for the production of different shapes.Machine section consists of following things:
Lathe
Milling Machine
Shaper
GrindersTools and gas wielding set.
ELECTRICAL SECTION
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Here the whole supply to the factory and machine are controlled. It is a prohibited
area because, it consist of huge transformers, which can hazard
FINISHING SECTIONIn finishing the round bars are sulphuric or hydrochloric and in diluted from to remove dust
and layers of oxide from the surface. Some irregularities on the surface of the bar. Some
irregularities in the bar are removed with the help of pneumatic grinder, which works with
the help of pressure of 7to8 kg/sq cm. Grinders, which works with the help of pressure of 7
to 8 kg/sq cm.
DESCRIPTION OF PLANT
Contents
1. INTRODUCTION
2. RAW MATERIAL
3. ELECTRIC ARC FURNACE
4. CONTINUOUS CASTING
5. REHEATING FURNACES6. ROLLING MILLS
7. ACID BATH
8. FINISHING
9. COLOR CODING
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10. MACHINE SHOP
11. OXYGEN PLANT
ELECTRIC ARC FURNACE
HISTORY
In 1878, Siemens made use of electric current for melting iron. French
Metallurgist, Paul Toussaint Heroult, placed the first direct electric arc steel
making furnace in operation in 1899.
Initial arc furnaces were of low capacities (
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Modern electric arc furnace produces a wide range of steels and no longer and
considered suitable only for making a limited range of high quality steels of special
composition.
ELECTRIC STEEL MAKING FURNACES
The following two types of furnaces are used for manufacturing of steel.
Electric direct arc furnace
High frequency induction furnace
Bhushan Ltd. makes use of electric direct arc furnace.
ELECTRIC DIRECT ARC FURNACE
CONSTRUCTION
A direct arc furnace consists of a heavy steel shell linked with refractory brick and
silica for acid lined furnace and magnetic for basic lined furnaces. Acid liningspreferred when good stall scrap low is Sulph
Phosphorous is available so that removal of these elements is not required the heats
are produced much faster.
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A basic Lining is advantageous because inferior scrap may be used make good steel
and basic process removes & P from the melt.
However the heats take longer time than in acid line furnaces. Moreover basic
refractories are costlier than acid refractories.
The roof of the direct are furnace consist of steel roofing in which silica bricks are used
in position.
The direct arc furnace may be charged either from the charging door, which also
serves for removing slag from the molten metal or from the furnace which is made to
lift off and swing clear of the furnace a few spare roofs can be made available all thetimes as the roof does not have a very long life.
Depending upon whether it is of two phases or three electric furnaces two or three
graphite electrodes are inserted through the holes in the roof in to the furnace
Electrodes can be raised up and down.
For a 59 ton furnace each electrode carries a current of the order of 25000 amperes.
Electrodes guides placed on the furnace roof are water cooled to dissipate damaging
heat.
All the furnaces rest in bearings on their two sides and bearings in turn are mounted
on turn ions thus the furnace can be titled backward or forward for charging, running
of the slag and pouring the metal in to the ladle
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OPERATIONThe interior of the furnace is preheated before placing the metal charge in the
furnace, preheating is done by alternative striking and breaking the arc between the
vertical electrodes. And the used electrodes prices kept on the hearth, after
preheating, the electrodes pieces placed on the hearth removed.
The furnace is charged either by swimming over the roof or through the charging
door. For melting cast iron, the furnace is acid linked and a large proportion of the
metal charge consists of scrap having sand adhered to it. For melting steel, the charge
is unusually, steel scrap and depending upon its sulphur and phosphorous contents,
an acid or basic lined furnace is employed.
Once the cold charge has been placed on the hearth of the furnace, is electric arc is
drawn between the electrodes and the surface of the metal charge by lowering the
electrodes down till the current jumps the gap between the electrodes and the charge
surface. The arc gap between the electrode & the charge is regulated by automatic controls,
which raise or lower the electrodes & maintain desired electric arc gap by maintaining
constant arc voltage. Smaller arc lengths produce more intense; however there is a
little fear of contaminating molten metal with graphite.
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1. Three arcs burning simultaneously produce a temperature of the order of 11000 F,
and readily it flux, stand, and the metal scrap.
The slag formed due to melting of flu x, sand etc. covers the molten pools of metal.
Slag present on the top of the molten metal bat reduces its oxidation, refines the
metal, and protects the roof and sidewalls from the large amount of the heat radiated
from the molten metal. The molten pool increases in size with passage of tine till the
whole of the scrap is melted. The molten pool increases in size with passage of time
the whole of the scrap is melted.
Before pouring the Liquid metal into the ladle the furnace is titled backwards and the
slag is poured off the charging door.
The furnace is then titled forwards and the molten metal is emptied into the ladles.
Hearth, sidewalls and the roof of the furnace arc required with the help of suitable
refractory materials after each heal.
ADVANTAGES OF ARC FURNACE: -
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Additions to the charge are made so as to form slags which have a refining section on
the metal. Unlike crucible furnace, arc furnace undertakes a definite metal refining
sequence.
Molten metal is refined to proper analysis & is heated to a suitable pouring
temperature.
Electric furnaces and lend themselves to close temperature and heat control.
Analysis of melt can be kept to accurate limits.
A direct arc furnace has a thermal efficiency as high as 70%.
It is not difficult to control the furnace atmosphere above the molten metal.
CHEMICAL REACTION IN ELECTRIC ARC FURNACE: -
The oxidation reactions are: -
2FeO + Si SiO2 + 2 Fe
FeO + Mn MnO + Fe
MnO + Si2 MnO.SiO2
FeO + SiO2 FeO.SiO2
FeS + MnO + C MnS + Fe + CO
2P + 5 FeO 5Fe + P205
P205+ 3 FeO (FeO) 3.P205
(FeO) 3. P205 + 3CaO (CaO) 3.P205
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In the next stage, lime, powdered coke and fluorspar from a new slag: -this produces a
strongly reducing slag .which serves to deoxidize the bath and to remove, the sulphur as
gas. Apparently the electric arc forms calcium carbide from the lime and coke and this is
the effective agent in converting sulphur to CaS.
The stage gives a very high degree of desulphurization and a good deoxidation. In this
reducing environment the necessary alloys, ferromanganese, ferrochromium etc. can be
fed into the molten steel bath without loss due to oxidation.
Deoxidation occurs because of some Mn felt unoxidized in the oxidation stage: -
Mn + FeO MnO + FeThen
MnO + C Mn + CO
Co tends 10 maintain a reducting atmosphere in the furnace.
Under arc action, lime react carbon to form calcium carbide.
CaO + 3C CaC2 + CO
Further deoxidation occurs where FeO and MnO react with CaC2
3 MnO + CaC2 3Mn + CaO + 2Co
3 FeO + CaC2 3Fe + CaO + 2CO
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Sulphur present in the molten metal bath as either FeS or MnS is eliminated in the
following way.
FeS + C + Cao Fe + CO + CaS
3 FeS +2CaO + CaC 2 Fe + 2CO + 3CaS
MnS + C + CaO Mn + CO + CaS
CaS joins the stage thereby removing sulphur from the melt and this competes the
refining of molten metal
CONTINUOUS CASTING
In essential, the process consist of pouring molten metal into a short vertical mentaldie or mould (at a controlled rate), which is open at both ends, cooling the melt rapidly
and with drawing the solidified product a continuous length from the bottom of the
mould at a rate consistent with that of pouring. The process is used for producing
blooms, billets and rolling structural shapes; this is cheaper than for ingots. Any shape
of shape of uniform cross section such as: round, rectangular, square, hexagonal.
Gear toothed and the process can produce many other forms. The process is mainly
employed for copper, brass etc. and increasingly with cast iron and steel.
Since the mould is an open cylinder of the required cross section, a metal block must
be placed at the lower and of the mould to support the molten metal and it has
solidified. The object of the process must be to achieve such a steady state of thermal
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equillbrium that the casting solidifies before leaving the mould. The mould is cooled
by circulating water around it. The solidification zone is localized in the water cooled
mould when casting non ferrous metals. However, ferrous metals conduct heat
comparatively slowly. Freeze only skin deep wile in the mould. They are further
cooled with water sprays throughout after leaving the mould. The solidified casting is
with drawn gradually from the bottom end of the mould at a controlled speed by the
withdrawing moulds.
The process may go on almost indefinitely but required lengths of billet. Bloom or slab
are cut up during their movement with the cutting touch, moulds are made of graphite or
copper to prevent the adhesion & welding of the melt of the moulds, its surface is given a
coating of ceramic powder of steel casting or of a lubricating type parting compound often
containing graphite or molybdenum disulphide. Some systems employ vibration or
reciprocating mould to prevent the casting from sticking.
The continuous, casting machine consists of apron, tendis car and with drawl unit.Different types of tendis cars for different types of casting like open casting etc. The apron
gives secondary and is arc of radius about 401. The cased steel moves on roller of M.S. The
rollers are driven by a dc motor. The speed of roller vary between 0.99-1.25 m/s in the with
drawl unit.
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The mould is given a moment with the help of motor coupled with a cam. The earn has
a stroke of 10-12 mm & motor has 100 rpm speed. The temperature is about 1600oC
in ladder & drops to 900oC for final casted product. The ceramic wool is used to
prevent threads of nuts in the tendis car.
ELECTRIC ARC FURNACE DESIGN
There are basically eight parts of EAF (Electric Arc Furnace):
Furnace shell and roof
Water cooled shell walls
Tilting system
Furnace superstructure
Electric column assembly.
Power supply system
InterlocksFURNACE SHELL AND ROOFS
Water cooled rim the furnace shell conventionally well meant of heavy boilerplate
features an extremely simple but study design. The shell construction and water
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cooled rim are laid out to withstand the heavy powerful mechanical and thermal
stresses that go with furnace duty with plenty of spare.
Short charging times the size of the full lace shell is dimensioned to accept the
required amount of scrap with a density of 950 kg / m2 for the nominal liquid steel
heat. Assuming one recharging operation.
Spout length to meet melting shop needs the pouring spout welded permanently to
the shell is obtained in two standards length5. Which are? Selected depending on
tapping method and ladle size. S Special can also be supplied for special cases.
Tight slogging door scaling because the staging door in installed with a 3 inclination,its own weight ensures solid contact with the water cooled frame and therefore
effective sealing. The slagging door is raised and lowered hydraulically.
Simplified roof changing the arched roof is supported by a watercooled roof ring.
During swinging out, the roof hands on the roof support arms. The two are joined with
four bolts combined with four insert plates. All that is required for roof changes is to
withdraw the insert plates from outside; there is no need to unscrew the bolts. This
BBC solution makes roof hanging easy.
WATER COOLED SHELL WALLS
Refractory material saving and shortened meltdown time the ma benefits of using
water cooled elements in the upper part of the shell are
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Reduction of refractory material consumption
Shorter downtimes for lining work
Shortened meltdown time as a result of higher applied meltdown.
The shell design of the Brown Boveri Arc Furnace Type AM permits the installation of
various types of wall elements.
They are installed in the upper half of the interior shell wall above the slag line. In all,
75% if the shell wall surface is water cooled.
The cooling water supply and return lines are connected to the furnace cooling water
system. Built in flow monitors and thermocouple takes care if cooling water super divisionwater and control the power in the individual phase
WATER COOLED ROOF
Low roof lining wear the effect of the water cooled shell can be enhanced by
cooling the roof water as well the water cooled roof consists of two parts: And A
central bricked up section like that in a normal roof a water cooled, ring shaped
section around the central part. The later comprises nearly 85% of the total roof
surface. The central section is replaceable without dismantling the entire roof.
TILTING SYSTEM
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The furnace shell rests on two on two cradles that permit forward and backward
tilting. During tilting, the cradles run on a pair of horizontal tracks anchored
permanently on the foundation. The two centering studs on each track made with the
cradle to assure correct furnace positioning. To guide plates provide immediate
correction of any shell positioning outage.
Conventionally furnace cradles describing the arc of a circle make it physically
impossible to achieve an automatic, stable righting moment with a reasonable arc
radius.
To solve this problem the 1313C design employs a specially calculated cradle curvedat affords a minimally righting moment under any operating conditions between tilting
positions of ) and +410. This means that the full or empty will return automatically to
be neutral position at a preset speed, without the aid I the hydraulic system, from any
tapping or lagging position
Another benefit of the BBC curve formed is that cradle has a shorter distance to rollthat it would with the conventional form.
FURNACE SUPERSTRUCTURE
The Superstructure is formed by a main beam, two roof support arc and the electrode
column assembly. The platform and railing on the roof support arms provide safe
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access to the electrode clamps and the roof suspension plants. The platform is raced
by built on ladder.
Lifting and swiveling column separate from furnace for charging the furnace
superstructure with the roof is raised from the shell and swung away. The hydraulic lifting
mechanism is mounted permanently on the foundation separate from the Tiltable furnace
unit.
ELECTRODE COLUMN ASSEMBLY
Improved operating reliability (easy cylinder replacement) the electrode columnassembly consists.
Of three positioning columns, which are guided vertically in rollers and are shifted up
and down by a single hydraulic cylinder incorporated each column.
The cylinders are supported at both ends with hall and socked heads. This estimates
cylinder jamming and provides clear separation between guiding and actuation.
For overhauls, the cylinder can be removed upward without prior dismantling of the
positioning columns.
POWER SUPPLY SYSTEM
a) Optimal electrode connection the power is supplied to the electrodes from the
cable connection via power tubes to be contract jaws on the electrode arm. The
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contract jaws are pressed against the electrodes by the steel collars. Power
tubes, contract jaws and collars are water- cooled. The collars are released
hydraulically for resetting the electrodes
o No hot phases the copper power tubes are carried on antimagnetic supports
and are electrically insulated from the electrode arms. To keep the mutual
spacing of the individual phases equal, the center phase conductor is elevated
in relation to the outside phases. This provides systematical current distribution.
INTERLOCKS Faulty manipulations eliminated because operating reliability has top priority in arc
furnace operation, logical interlocks are indispensable. Based on decades of
experience, Brown Boveri has developed reliable interlock system that makes manual
work on the arc furnace perfectly safe.
The following motion sequences are protected by electrical and hydraulic interlocks
provided as standard equipment:
Lifting and swiveling of furnace superstructure
Furnace superstructure.
Furnace tilting, forwards backwards
Electrode positioning
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Electrode releasing and clamping
Control equipment
Furnace operation and monitoring
a) Information at a glance
The control cubicles contain the equipment for protecting and supervising the high voltage
installation including the furnace transformer, plus all devices for controlling and
monitoring the auxiliaries.
the main control desk contains the manual control for the
Electrode drives
Electrode release
Roof lifting and swiveling mechanism
Tilting Lock
Furnace tilting
Furnace on /off switch.
Instruments indicate the transformer primary voltage, power factor, and electrode
voltage and current. Fault indicators are provided for the main furnace functions.
The furnace can he tilted from the main control from a separate desk set up next to
the pouring spout.
SELECTION OF OPERATING POINT : -
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Uncomplicated pre selection of setting the appropriate voltage step o the furnace
transformer top changer and the set point fro are resistance for automatic electrode
control are selected with luminous push button on the main control desk . A total of 20
different are resistance set point can be programmed. The digital set- point input is
made for all three phases set point of 119% is available to allow for possible thermal
asymmetries (elimination of the hot phase). The automatic electrode control system
takes care comparing the actual arc readings with the set points. Deviations are
connected automatically by hydraulic electrode positioning system.
Optimal maintenance of operating point the admissible working range of the furnaceis limited by the maximum and minimum transponder steps, the maximum meltdown
power level. The momentary a precise operating point within these limits.
Option manual or automatic operation selection of voltage step resistance set point
cal also be carried out automatically with the Brown Boveri Melt control unit.
HYDRAULIC SYSTEM
The following motion sequences on the furnace are hydraulically powered:
Movement of electrodes
Actuation of furnace roof.
Furnace tilting
Actuation tilting
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opening of electrode clamps locking of furnace shell.
a) Compact design rules erection and maintenance costs the individual hydraulic
actuators re supplied by a control hydraulic unit. Constructed along modular
lines, the hydraulic unit takes very little space. The neat, compact arrangement
of all equipment like pumps, filters, valves, cooler etc. reduces erection and
maintenance costs substantially.
operated electrically from that control operated by the electronic electrode
control system. In order to ensure a high degree of safety, all solenoid operated
valves are provided with indicating lamps. In an emergency, the valves can also
be operated manually.
Servo valves featuring high control capability- fast acting, flow battle types valves
are used for electrode actuation. This means that the outstanding feature of the
electrode control system can be fully exploited.
With the Brown Boveri hydraulic control system it is also possible to override theautomatic control and operate any of the electrodes manually without the necessity of
switching over from one mode to another.
Air receiver powers emergency operation a compressed air supply is used to setup
an air cushion above the hydraulic fluid as energy accumulator. The energy
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accumulator delivers energy for the following furnace motions in the event of power
failure (pumps inoperable). Raising electrodes to tapping position Opening and closing
the slagging door three times Returning furnace to neutral position.
Swivelling and closing furnace roof
First class- engineering components including the hydraulic fluid water glycol are
used as hydraulic medium. This pressure fluid is highly suitable for industrial plants in
which fire
Damage and explosion from the hydraulic medium must be avoided at all costs.
The viscosity / temperature behavior of water glycol is much better than that of
material hydraulic oils. It requires no special sealing material, is virtually non
toxic and can be filtered readily;
e) Short response and actuation times the operating pressure is 100 bar. Because
the system always works at full pressure, short reaction times are ensured
regardless of momentary pump delivery rates. Especially noteworthy are thehigh electrode displacement speeds achieved with this advanced hydraulic
system.
Maximum raising and lowering speed with automatic control: 150 mm/s.
COOLING WATER SYSTEM
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Components subjected to very heavy duty and exposed ton furnace heat is water
cooler is water cooled so that they can function properly.
Effective water cooling keeps thermally stressed components from over heating
high current conductors, transformer and hydraulic tank are fitted with the
necessary cooling water headers, returns and connections at the factory. Normally
one connection to the existing steelworks cooling water system the furnace cooling
water distributor system.
Open cooling circuit with pressure less return houses are used for the cooling watersupply and returns lines to both live and dead parts. Normally the cooling water
returns are carried pressurelessly to a collection funnel to from an open circuit.
The funnel provides a simple and effective visual check on the individual circuits. Flow
rates are corrected with regulating valves as required. The criterion applied in the setting
the flow is that the limit temperature of 65 C should not be exceeded at the hottest point.
CHARGING EQUIPMENT
BACKET CHARGING: -
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Effective charging equipment cuts down unproductive time scrap is normally
charged with buckets. Two different types re used:
Orange peel bucket
Clam shell bucket
The bottom of the orange and peel bucket comprise of separate, trapezoidal
segments held together by a chain. A pin fastener is pulled out of release the chain and
allows the scrap to drop out as the orange peel segment opens.
The bottom of the chamshell bucket consists of two moveable half shells that are
opened by the charging crane with a rope or chasin. This frees virtually the entire bucketcross section to permit the scrap to drop
Out. With this types bucket, it is important to keep the side base opening shell from
contacting furnace parts. Above all, the furnace roof must be swung out far enough.
Either type of bucket can be used with Brown Boveri AM are furnace.
CONTINUOUS CHARGING
Adaptable to various charging system charging material like sponge iron pallets .
Limestone, and etc. can be charged continuously through furnace roof with app
operate charging equipment. Conventional transport equipment such as vibrating
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chutes, conveyer belts and so on is primarily in use. The charging material is fed into
the furnace through a hole in the roof. Installations now in operations have
demonstrated that the J3J3C are furnace design is also very adaptable to this type of
equipment.
LAYOUT
The various components of an arc furnace installation are laid out to suit the
conditions prevailing in each individual case.
Concept based on high degree of flexibility and space utilization the furnace
transformer should, always be installed as close as possible to the furnace to keptconductor reactance low. The main control desk is normally place to provide an
unobstructed view of the arc furnace. The other components can be installed either in
rooms directly behind the furnace transformer and the control room or one storey
lower.
A high degree of flexibility is afford