Post on 02-Dec-2014
transcript
2011
Bhushan Power & Steel Ltd.
Navdeep Lakhera
[TRAINING REPORT-BHUSHAN POWER
& STEEL LTD.] Six weeks industrial training from 25 june 2011, at Bhushan Power & Steel Ltd.
COMPANY PROFILE
Bhushan Power & Steel Limited, a fully integrated 1.5 Million TPA Steel
making Company with turnover of INR3873 Crores (USD 950 Million)
and 7 World Class ISO 9000 Certified State of the Art Plants at
Chandigarh, Derabassi, Kolkata and Orissa in India.
A leading manufacturer of flat, rounds and long products including value
added products with total steel value chain right from Coal Mining,
Billets, HR Coils, Pig Iron, CR Coils, GP/GC, Precision Tubes, Black
Pipe/GI Pipe, Cable Tapes, Tor Steel, Wire Rod and Special Alloy Steel.
Successfully commissioned 1.5 Million TPA Greenfield Steel and Power
Plant in Orissa with HR Coil making facility
—First in Private Sector in the State of Orissa. For the Orissa plant,
technology and equipments are procured from world-renowned
companies like Lurgi from Germany, ABB Ltd., SMS Demag, Siemens
etc. Bhushan is selling its Value added range of products in Secondary
Steel through a large distribution network in India (comprising more than
35 sales offices) and Abroad.
A rock-solid foundation combined with continuous up gradation and
innovation has ensured that we have constantly surpassed our goals.
Our end-to-end portfolio offers a wide spectrum of products with
consistently superior quality. In addition to our export thrust, we supply
to fast-growing sectors like automotive, white goods, construction,
furniture, fasteners, telecommunication, etc.
COMPANY OVERVIEW
Commenced operations in 1989 with a capacity of 60,000 tons & a
turnover of USD 11.24 million.
Transformed to 3rd largest producer of Cold Rolled Steel after Steel
Authority of India (SAIL) & Tata Steel with an installed capacity of one
million tons and sales of more than USD 1 Billion.
Focused on niche high value added segment of automobile and white
goods & is today a leader in these segments. Recently started the
country’s largest Colour Coated line and first to manufacture the
Galume (zinc and aluminum coated sheets / coils).
Principal production facilities at Sahibabad, Uttar Pradesh, Khapoli,
Maharashtra and Dhenkana in Orissa (scheduled to be completed in
July 2009.
Invested in latest technology/ equipment without compromising over
cost.
First to set up a high tech plant in 1996 to cater to automobile and
white good sector, in technical tie-up with Sumitomo Metals, Japan.
BSL has a good debt-servicing track record.
Profit making and dividend paying company since inception.
RAW MATERIAL SOURCES
The company processed mild steel (MS). It receives raw material
from various sources:-
• B.S.P (Bokaro steel plant)
• R.S.P (Rourkela steel plant)
• Tata steel plant
• Essar
• The sizes of raw material ranges from 5.5 to 6mm thickness, 920
to 1600mm width.
TYPES OF RAW MATERIAL
• Mild Steel
• D (Drawing-0, 08 to 0.1 % carbons)
• DD (Deep Drawing -0, 06 to 0.08% carbon)
• EDD (Extra Deep Drawing -0.04 to 0.06 % carbon)
• O (Others – 0.12 to 0.13 % carbon)
• CS – 11 (Above 0.18 %)
VARIOUS PROCESSES
The various processes deployed at the Industry in cold rolling of steel
are:
• H.R. SLITTER (Hot Rolled Slitter)
• C.B.L. (Coil Build up Line)
• Pickling
• Cold Rolling Mill
• Rewinding
• Annealing
• C.R Slitter (Cold Rolled Slitter)
• CTL (Cut to length)
• Packing & Dispatch
H.R SLITTER (HOT ROLLED SLITTER) • This machine is used for slitting or cutting the hot rolled coils which
have been received as raw materials from various sources such as
Tata or Sail Bokaro. Initially, the hot rolled coils have width up to
1550 mm. The rolling mills which are set up in the plant cant roll
such wide coils. The width of the hot rolled sheet (Raw materials)
is decreased or the sheet is slit into two or three rolls, as the
requirement of the customer may be. The maximum width of the
coil that can be cut is 540 mm and minimum is 200 mm.
• Raw materials received have width up to 1550mm (approx.).
• Diameter of ring cutter is 395mm.
• Material of the cutter is high speed steel.
Parts of H.R Slitter
1. Coil stand
2. Coil car
3. Pay off stand
4. Uncoiler
5. Sunnbber
6. Feed table
7. Leveler
8. Pinch roller
9. Shear
10.Guide
11.Cutter slit
12.Loop pit
13.Tension rolling
14.Re coiler
COIL BUILD UP LINE (CBL)
• In CBL extra sheet is welded at the beginning and at the end of the
coil called the Leader and Tail end respectively. This strip called
Leader End is about 3 meters in length. This is done to increase
the yield of coil during rolling because initially some sheet is taken
in some initial rounds in rolling and thus the starting and ending
part of the coil cannot be rolled properly.
• Leader End is added to the coil to save yield and prevent wastage.
• Coil bend and damages in HR slitter are inspected here.
Parts of CBL
1. Uncoiler
2. Feed table
3. Leveler 1
4. Shear
5. Clamping Plate
6. Welding
7. Guide
8. Pressure Pad
9. Leveler 2
10.Tension rolling
11.Recoiler drum
PICKLING PROCESS
• The H.R coils as raw materials are somewhat rusted. They contain
oxide scales on their surface containing chemical compounds like
iron oxide FeO, Fe2O3 and Fe3O4.
• So as to improve the surface finish and to remove these oxides
pickling process is undertaken.
• Acid used is HCL.
• Coil is passed through 3 acid tanks, after that through 3 water
tanks.
• The acid proportion in first tank is 3 to 5% and in the second tank
is 7-10 % and in the third tank is 12 to 15 %.
• HCl used is dilute. Dilution varies from tank to tank.
• Coil is dried with hot air dryers and cold air blower.
• The temperature of the HCL ranges from 58 to 68 `C.
• Finally after sprinkled by rust preventive oil, it is finally recoiled at
the recoiler end.
• Parts of line are Acid tank, Uncoiler, feed table, Shear, Heat
exchanger, Water tank, Dryers, Tension trolling and Recoiler drum.
COLD ROLLING MILL
Cold rolling is a metallurgical process in which metal is passed
through a pair of rollers at a temperature below its recrystallization
temperature. This process hardens the metal, by compressing and
stretching the metal. There are two rolling mills namely Mill 1 and Mill
2. ln mill 1 coil of 545mm maximum width and mill 2 coil of 465mm
maximum width can be cold rolled. In both the mills there are 2 work
rolls and 2 backup rolls. Diameter of work roll is 210mm and Diameter
of backup roll is 550mm.
Cold rolling is done to reduce the thickness of the coil. The range of
the thickness reduced in the plant is from 3mm to 0.28mm. The
thickness obtained finally is according to the requirement of the
customer. The mill is operated by programmable logic controllers.
There is an operator assigned to each of the two mills. The operator
feeds various parameters into the system and then the process
proceeds automatically. The coil is first loaded into the pay off roll.
From here it passes to the entry tension roll and then it passes to the
delivery tension roll via the working rolls where it recoils. The tension
to the backup rolls is given by the hydraulic cylinders which then
transmit the load to the working roll which further transmits the load to
the sheet. There is 20 to 30 % reduction in thickness of the coil in one
pass. Non contact gauges are used in these mills which measure the
thickness of the sheet. The recoiling and uncoiling process takes
place at both entry and delivery tension roll. A coolant named as aqua
roll is also used.
1. Saddle table – it is actuated with the hydraulic cylinders help to feed the
strip into the leveler.
2. Bridle roller – these are used to release the tension in the strip and are
made of iron over which rubber is wrapped . there are two bridle rolls
when the speed of bridle rolls is more than recoiler then it will loosely
wrap over the recoiler drum.
3. Recoiler drum – this is the drum on which the slitted coil are recoiled
4. Tachogenerators –it sis used to control the speed of motor.
5. Hydraulic Power pack – it provides the oil to hydraulic system. There is
pump and directional valves. PC valves are used to control the supply of
oil.
Defects occurring during rolling process --
Roll mark
Soft mark
Skidding mark
Folding mark
Roll crack mark
Scratch mark
HISTORY
Growing from strength to strength
1970 - Started with very small initial outlay for manufacturing Door Hinges & later on, Rail Track Fasteners.
1973 - Manufacturing facilities set up for Tor Steel and Wire Rod in Chandigarh.
1981 - Rolling Mill Project commissioned at Chandigarh for Round and Narrow Strips.
1985 - Backward Integration Project for Steel Melting facilities.
1986 - Upgrading of Mini Steel Plant with continuous casting and ladle furnace facilities. 1997 - Commissioning of Narrow Width Cold Rolling Project at Chandigarh.
1998 - Commissioning of Precision Pipe Project at Chandigarh.
2001 - Commissioning of Cold Rolling & Galvanizing Complex at Kolkata.
2002 - Addition of narrow width Cold Rolling facilities at Kolkata.
2003 - Expansion of wide width Cold Rolling facilities, ERW Water Pipes & Tubes down stream facilities at Kolkata.
2004 - Further expansion of Cold Rolling facilities at Kolkata.
2005 - Commissioning of Orissa Project consisting of 4 DRI Kilns, Steel Making Facilities, Coal Washery and 100 MW Power Plant.
2007 - Commissioning of further expansion of Orissa Project consisting of HR Coil Mill, Steel making, Blast Furnance, Sinter plant, Coke oven plant, Oxygen plant and Lime & Calcining Plant.
2008 - Implementation of further expansion in Orissa Project in progress. Consisting of DRI Kilns, Coal Washery, Coal Mining, Power Plant & Steel Making facilities.
Annealing
During cold rolling of the coil, the density of imperfections and
dislocations increases. These imperfections have strain energy
associated with them. On annealing , metal tenda to loose excess
energy acquired during cold rolling and revert back to initial stage.
The general purpose of annealing is to reduce hardness, facilitate
machining and to relieve internal stresses.
This heat treatment process is given to the metal so as to achieve one
or more of the following objective:
To relieve the grains and provide homogeneous structure
To relieve internal stresses set to cold rolling
To soften the metal and thus improve its machinability
To effect changes in some mechanical, electrical and magnetic
properties.
To prepare further treatment or processing
Here only full annealing takes place, and we have 9 furnaces, 9
cooling hoods, 18 covers and 16 bases.
Base - on which coil with cover , cooling hood and furnace is
placed.
Cover – which covers the coil after the coils are loaded on the
basis.
Technical specifications of annealing furnace
Equipment - HSD fired type bright annealing furnace
Charge material - Cold rolled mild steel strips
Coil inner diameter - 508 – 600 mm
Coil outer diameter – 1850 mm (max)
Coil width - 200 – 500 mm
Strip thickness - 0.3 – 2.0 mm
Coil weight - 9MT (max)
MATERIAL HANDLING EQUIPMENT
To produce only 1 tones of finished rolled metal, it is necessary to haul about 40 tones
of various materials. In the course of production materials are moved and
transferred by means of hoisting and conveying machines and mechanisms are an
integral part of the production.
The major material handling equipment used in this plant are:
HOOKS:
Hook is a multipurpose gripping appliance which is widely used as a working
member of hoisting mechanism ( load cranes) and as an end elements of slings and
other lifting devices.
OVERHEAD BRIDGE CRANES:
Overhead bridge cranes are the most widely spread type of cranes in ferrous
metallurgy. They are different in their purpose, load capacity and design. A
traveling electric crane comprises a crane bridge having a traveling mechanism, a
trolley with a hoisting mechanism and control cab. The cranes travel along the
workshop or work site over cranes tracks. Depending on the crane purpose the
hoisting mechanism is provided with various lifting attachments; hook, load
beams, tongs mechanical grips electromagnet or clamshell. As distinct from a
hook crane, the clamshell crane trolley carries alongside with a traveling
mechanism two similar mechanisms; one for lifting the clamshell and other for its
locking.
COIL CAR:
This is a special hydraulic operated material handling equipment used to transport
coil from one part of the plant to another. It is also used to carry the coil under the
rails of overhead traveling crane, where the approach of the crane is not possible.
The coil car is similar to a massive trolley having wheels at the lower end.
These wheels move on the rail which are installed a few feet below the shop floor.
These
coil cars can be move up or down using hydraulic pressure. The forward
movement of the coil car is assisted by a gear pinion arrangement.