REPORT OF VOCATIONAL TRAINING
at
ALLOY STEELS PLANT, DURGAPUR
STEEL AUTHORITY OF INDIA LIMITED
[09.06.2023 - 23.06.2023]
by
SIDDHANT ABHISHEK
ROLL NUMBER- 20UEI006
NATIONAL INSTITUTE OF TECHNOLOGY, AGARTALA
ACKNOWLEDGEMENT
I feel proud to say that due to the keen knowledge of the working members of Alloy Steels Plant, it
was very easy for me to earn a lot of knowledge regarding working in an industry.
I would like to thank Mr. Subhadip Chakraborty, Sr. Manager(HRD&OD) for allowing me to do the
training at Alloy Steel Plant.
I am greatly thankful to Mr. Ayub Ali Talukdar, DGM(EED/INSTRUMENTATION, E & TC) for his
kind support and guidance to successfully complete my training. I have been highly benefited by this
training and gained a lot of knowledge about the various processes and techniques used in the
production of steel in the Alloy Steels Plant.
I would also like to thank all the officers of Alloy Steels Plant who really helped me a lot and guided
me throughout the training session, without their help and support I would have been unable to
complete my training. These people have been really kind enough to provide me with all kinds of
contextual
information.
I am also thankful to the technicians and field operators for sparing their valuable time and taking the
effort of explaining to me the working of the various units of the plant. I am greatly thankful for their
cooperation. I was thoroughly guided by them throughout the training.
The information provided by each and everyone has helped me a lot and would also benefit me in
the long run. The tremendous effort put in by everyone has motivated me and made me gain
confidence in completing this report.
Siddhant Abhishek
B.Tech
Electronics & Instrumentation Engineering
Semester-6
N.I.T, Agartala
CERTIFICATE
It is hereby certified that Mr. SIDDHANT ABHISHEK student of 6 th semester
of NATIONAL INSTITUTE OF TECHNOLOGY, Agartala of Electronics and
Instrumentation Department has undergone a 2 weeks technical and
observational training at ALLOY STEELS PLANT, Durgapur (under STEEL
AUTHORITY OF INDIA LIMITED) from 9th June to 23rd June 2023 under my
Supervision
He has been regular and sincere with his work.
Wish him good luck for all his future endeavors
Mr. A. A Talukdar
DGM (EED/INSTRUMENTATION, E & TC)
ALLOY STEELS PLANT, DURGAPUR
Mr. Subhadip Chakraborty
Sr. Manager (HRD&OD)
ALLOY STEELS PLANT, DURGAPUR
Steel Authority of India Limited
Steel Authority of India Limited (SAIL) is one of the largest steel-making companies in India and one
of the Maharatnas of the country’s Central Public Sector Enterprises.
SAIL produces iron and steel at five integrated plants and three special steel plants, located
principally in the eastern and central regions of India and situated close to domestic sources of raw
materials. SAIL manufactures and sells a broad range of steel products.
Ownership and ManagementThe Government of India owns about 65% of SAIL’s equity and retains voting control of
the Company. However, SAIL by virtue of its “Maharatna” status enjoys significant
operational and financial autonomy.
PLANTS / UNITS AND SUBSIDIARIES
1. Bhilai Steel Plant
2. Bokaro Steel Plant
3. Durgapur Steel Plant
4. Rourkela Steel Plant
5. IISCO Steel Plant
6. Special Steel Plant
a. Alloy Steel Plant
b. Salem Steel Plant
c. Visvesvaraya Iron And Steel Plant
7. Ferro-alloy Plant
a. Chandrapur Ferro-alloy Plant
8. Subsidiaries
a. SAIL Refractory Company Limited
9. Other Units
a. SAIL Consultancy Division(Sailcon)
b. R&D Centre For Iron And Steel
c. Centre For Engineering And Technology
d. Management Training Institute
e. SAIL Safety Organisation
f.
Raw Material Division
g. Growth Division
h. Central Power Training Institute
i.
Central Marketing Organisation
j.
Central Coal Supply Organization
k. SAIL Refractory Unit(SRU)
l.
Logistics and Infrastructure
m. Collieries Division
ALLOY STEELS PLANT
In order to make India self-reliant in alloy & special steel production, ASP was set up in
January 1965 under Hindustan Steel Limited, now SAIL. Consultant for ASP was M/s
MN Dastur & Co. Technology know-how was from M/s Atlas Steels, Canada. Major
equipment supplier was JASCON - a Japanese Consortium, while the Reheating
Furnaces were supplied by Amco, Canada and Heat Treatment Furnaces supplied by
Wellman Incandescent.
ASP is located at Durgapur in Paschim Burdwan district of West Bengal around 175 KM
from Kolkata, along the Howrah-Delhi Main Railway line & Grand Trunk Road (National
Highway-19). It is spread over an area of around 4.67 Sq. KM (467.22 Hectare).
Quality Systems at ASP from BSI
●
ISO: 9001::2015 for entire plant
●
IATF: 16949::2016 for auto grade products
●
ISO: 14001: 2015 for environmental management
●
ISO: 45001: 2018 for occupational health and safety management
Product Mix
ASP has a diverse product portfolio of over 400 grades catering to critical end-use by strategic
sectors like Defence, Railways, Automobiles, Power Plants, Heavy Engineering & Manufacturing
Industries, including Steel Plants.
ASP's product basket includes Carbon Constructional Steels, Alloy Constructional Steels (Ni
bearing, Cr-Mo bearing & Cr-Ni-Mo bearing), Case Hardening Steels, Die Blocks, Creep Resistant
Steels, Spring Steels & High Mn Steels (Hadfield). ASP manufactures high impact resistant steels
(armour grade steels) for Defence application and special steels for Naval application. ASP also
manufactures Stainless Steels (Austenitic, Ferritic & Martensitic), including colouring of stainless
steel plates for decorative applications.
Value Added Products
ASP’s value added products includes Working Rolls like CRM ,Tandem, Reversing, Silicon Mill
Rolls, Table rollers, Foot rollers, Cladded Rollers, Guide Rollers, Ring rollers, Concast segment
rollers, Crane wheels, Wheels for slag cars,/ladle cars/transfer cars, Wheel-Axle assemblies, Peel
Heads, Beater Arm, Beater Head, Pull rods, Toothed Casings & bushes, Vertical/floating /Pinion
shafts, Bearing Housings, Grate bars, Hammers, Pinion/Gears, Couplings, Springs, Shear Blades,
Liners of (Hadfield Manganese Steel) and many more for sister units and private customers.
The various departments/ shops that are involved from the first stage to the final output
product are1. Steel Melting Shop
5. Conditioning Shop
2. Continuous casting Shop
6. Heat Treatment and Finishing
3. Blooming and Billet Mill
7. Plate Mill
4. Forge Shop
8. Roll Design and Roll Shop
9. Research and Control Laboratory
16. Auto Loco Repair Shop
10. Production Planning and Control 17.MED POWER & Fuel
Department & SHIPPING
11. Project & PCM Department
18. ERS & Crane
21. Mechanical Repair Shop & HM
19. Refractory Engineering Department
13. MM DEPT
20. P&A DEPTT
14. F&A DEPTT
21 EED & MED
15. C&IT
22.ELECTRONICS,INSRUMENTATION
,TELECOM & AUTOMATION DEPT
Blooming and Billet Mill (BBM)
Bloom
In the era of commercial wrought iron, blooms were slag-riddled iron castings poured in a bloomery
before being worked into wrought iron. In the era of commercial steel, blooms are intermediate-stage
pieces of steel produced by a first pass of rolling (in a blooming mill) that works the ingots down to a
smaller cross-sectional area, but still greater than 36 in2 (230 cm2).Blooms are usually further
processed via rotary piercing, structural shape rolling and profile rolling. Common final products
include structural shapes, rails, rods, and seamless pipes.
Billet
A billet is a length of metal that has a round or square cross-section, with an area less than 36 in2
(230 cm2). Billets are created directly via continuous casting or extrusion or indirectly via hot rolling
an ingot or bloom. Billets are further processed via profile rolling and drawing. Final products include
bar stock and wire.
Centrifugal casting is also used to produce short circular tubes as billets, usually to achieve a
precise metallurgical structure. They are commonly used as cylinder sleeves where the inner and
outer diameters are ground and machined to length. Because their size is not modified significantly,
they are not always classified as semi-finished casting products.
In copper production, a billet is 30 feet (9.1 m) long, about 8 inches (200 mm) diameter, of pure
copper.
Soaking Pit
It is a furnace for heating metals or materials suitable for hot rolling. In ASP there are 12 furnaces in
the soaking pit, one way horse shoe type dual fired furnace. Both furnace oil (low sulphur) and coke
oven gas can be used for heating. Each furnace is of 50 ton capacity. Both hot and cold materials
can be charged and accordingly heating cycles are selected. Pit covers are lifted & shifted from the
pit by mechanical arrangements through electrical motor drives, which are mounted on a cover
carriage. Ingot Boggy feeds the soaked material from the soaking pit to the mill. It moves on rails by
the side of the pits. Hot ingot is lifted from the pit by a soaker crane & is placed on the pot of the
ingot buggy, which then moves to the ingot receiving roll table then the pot is tilted on the roll table.
PIPING AND INSTRUMENTATION DIAGRAM OF SOAKING PIT ON SCADA
Here in the ASP plant the Furnace of the soaking pit is maintained at a temperature of 1500
degree celsius to maintain the furnace at this temperature 2 types of fuels coke oven gas
and are used along with heated air. As it is clear from the p&id diagram that the furnace is
fed with either coke oven gas or by using Regasified Liquefied Natural Gas (RLNG). The fuels
are passed through a safety valve. Also to make the combustion take place hot air is supplied. To
make the air hot it is passed through a Recuperator which takes air from the hot furnace to heat up
the incoming cold air and then this air is then fed into the furnace. The rest of the Heated air from the
furnace is then passed through a pit damper and then released into the air after treatment. To
maintain the temperature of the furnace various control loops and controllers are placed which
controls the temperature of the furnace by changing the various parameters like by increasing the
flow of gas to the furnace or by increasing air flow to the furnace all these actions are controlled by
various controllers.
FORGE SHOP
Forging is a manufacturing process involving the shaping of metal using localized compressive
forces. The blows are delivered with a hammer (often a power hammer) or a die. Forging is often
classified according to the temperature at which it is
performed: cold forging (a type of cold working), warm forging, or hot forging (a type of hot working).
For the latter two, the metal is heated, usually in a forge.
Some metals may be forged cold, but iron and steel are almost always hot forged. Hot forging
prevents the work hardening that would result from cold forming, which would increase the difficulty
of performing secondary machining operations on the piece. Also, while work hardening may be
desirable in some circumstances, other methods of hardening the piece, such as heat treating, are
generally more economical and more controllable. Alloys that are amenable to precipitation
hardening, such as most aluminium alloys and titanium, can be hot forged, followed by hardening.
PIPING AND INSTRUMENTATION DIAGRAM OF FORGE SHOP ON
SCADA
CONDITIONING SHOP
The main purpose of conditioning is to make the products (rolled or forged) fit for use in
desired applications. This is done through visual inspection and removal of defects by
grinding. Visual inspection is done after exposing the surface by grinding. pickling. sand or
shot blasting. In ASP grinding and shot blasting is followed. All activities regarding testing
and inspection are through this shop before dispatch. GRINDING isa method of exposing
the surface for visual inspection .It is done by removing the scale from the surface of rolled,
forged or treated materials. Sometimes grinding is made deeper to assess the depth of
defects. Different methods of grinding are employed for random checking of the surface
defects. Zig-zag, line and ring grinding is mainly followed to ascertain the surface quality.
Swing. auto-billet and slab grinders are main equipment's for this purpose. SHOT
BLASTING 0S another method of exposing the surface by blasting steel shots at high
speed on the surfaces of targeted material to remove the scales for visual inspection.
CONTINUOUS CASTING SHOP CASTING PROCESS
.Continuous casting is a process of teeming liquid metal in a short mould with a false
bottom through which partially solidified ingot is continuously withdrawn at the same rate at
which liquid metal poured in the mould. Different types of casting machines are available for
casting billet. blooms and slabs. The continuous casting machine is equipped with Electro
Magnetic Stirrer (EMS) in its mould for casting Blooms. Automatic mould level controller
(AMLC) is equipped with the machine for casting slabs. The ladle is raised onto a turret that
rotates the ladle into the casting position above the tundish. To start a cast, the mold bottom
is sealed by a steel dummy bar, which is held in place hydraulically by the Withdrawal and
straightening Unit. This bar prevents liquid steel from flowing out of the mold.
TUNDISH :- Tundish is a buffer container of liquid steel receives from ladle and supplies or
distributes to mould. It helps in many ways i) control the flow of liquid by maintaining the
metal level i) divides the flow into no of moulds.
STRAND COOLING / WATER SPRAYS :- Initial cooling (called primary cooling) is done in
mould. The solidification of the remaining liquid core is done by secondary cooling i.e. by
quenching using high pressure water sprays. The sprays are directed from all sides while in
it is accomplished from top and bottom.
THE MOULD :-The mould is the key equipment of the continuous casting. It is made out of
high conductivity copper and water cooled. It has open bottom and closed by dummy plug
bar in the beginning
AUTOMATIC MOULD LEVEL CONTROLLER (AMLC) :- is a device which controls the
metal level (liquid top meniscus) in the mould during casting. A refractory float is kept
hanging over the mould top liquid meniscus. During casting the changing of metal level in
the mould is sensed by the refractory float and ends signal for actuating or controlling
tundish stopper for regulating the metal flow in the mould.
STEEL MELTING SHOP
VACUUM ARC DEGASSING (VAD) unit is also called as vacuum arc degassing refining
(VADR).This is a single station unit in which the ladle sits in a vacuum tank and is stirred by
Argon gas through a plug at the bottom with provision for heating through electrodes and
alloying additions. Lime in the molten steel ladle, Argon supply is continued in all the
operational steps and the adjustment of flow rate is done for varied operations carried out
during processing. In this system, under vacuum, carbon-oxygen reaction and carbon
AL203 reaction under the high temperature arc are of great help in achieving low oxygen
content without any solid reaction product. Low Hydrogen levels are achieved by intense
mass transfer by argon and low partial pressure of hydrogen because of dilution of liberated
carbon monoxide. The greatest advantage of this process is the high degree of
desulphurization as high as 80% for production of steels with Sulphur levels as low as
0.005%. VAD is now a widely used method of producing clean steels in the world.
LADLE FURNACE (LF) :- Ladle Furnace is a simple ladle-like furnace used for heating the
liquid bath in ladle. Same ladle is used for tapping, teeming and other secondary refining
treatments. The ladle itself is used as a furnace holding the liquid bath provided with bottom
plug for argon purging. Separate arrangements are there for cover with electrodes to
become an arc furnace. The graphite electrodes are in place with suitable mechanism of
arm and column for rise and fall by hydraulic actuator movement regulated by hydraulic
power pack. Bunkers are provided for additions.
ARGON OXYGEN DECARBURIZATION (AoD). :- It is a time and cost effective process to
produce stainless steel of various grade. The processing is carried out here in a special
AOD converter. The vessel is lined with basic dolomite refractory bricks. Molten liquid metal
tapped from electric arc furnace is transferred to this vessel and blown with argon-oxygen
mixture in different proportions. In case of high nitrogen steels nitrogen can be fully
substituted by nitrogen as per the nitrogen specifications. The temperature of the liquid bath
rises at the end to above 1700°C. Coolants like Stainless scrap. nickel and other additions
can be made at this stage.
INGOT CASTING (TEEMING PROCESS). :- The process of pouring molten steel into ingot
moulds is called teeming. Tapped liquid from furnace is treated i.e. adjustment of chemistry
by alloying. degassing and deoxidation in secondary refining units either in VAD or VOD.
The refined steel is then directly poured into ingot moulds from top called top pouring and
when poured though trumpet and bottom of the ingot moulds called bottom pouring. lt helps
to avoid reoxidation of liquid meniscus.
VACUUM OXYGEN DECARBURIZATION (VOD) UNIT :- The unit is almost similar to VAD
except this unit does not have the facility of arching to increase the temperature of liquid
steel in ladle. In this unit there is a system of lancing oxygen from top with system for
regulated flow and drive mechanism for lowering and raising to reduce carbon percentage
in liquid steel. This is an important vacuum process for production of stainless steel. In this
process, the ladle is placed in a vacuum chamber and there is a provision for oxygen
lancing through vacuum tight glands and alloying additions.
THERMOCOUPLES
A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device
consisting of two dissimilar electrical conductors forming an electrical junction. A
thermocouple produces a temperature-dependent voltage as a result of the Seebeck effect,
and this voltage can be interpreted to measure temperature. Thermocouples are widely
used as temperature sensors.[1]
Commercial thermocouples are inexpensive,[2] interchangeable, are supplied with standard
connectors, and can measure a wide range of temperatures. In contrast to most other
methods of temperature measurement, thermocouples are self-powered and require no
external form of excitation. The main limitation with thermocouples is accuracy; system
errors of less than one degree Celsius (°C) can be difficult to achieve.
Seebeck effect
The Seebeck effect refers to the development of an electromotive force across two points of an
electrically conducting material when there is a temperature difference between those two points.
Under open-circuit conditions where there is no internal current flow, the gradient of voltage is a
temperature-dependent material property known as the Seebeck coefficient.
Types Of Thermocouple
There are various type of thermocouple available depending upon the range of operation
and cost of maintenance. The different types of thermocouple available are:-
Type K (chromel/alumel)
The most common general purpose thermocouple with a sensitivity of approximately 41 µV/°C,
chromel positive relative to alumel.
Type E (chromel/constantan)
This type has a high output (68 µV/°C), which makes it well suited to cryogenic use. In addition, it is
non-magnetic.
Type J (iron/constantan)
This combination has a more restricted range than Type K (0° to +750°C), but has a higher
sensitivity (55 µV/°C).
Type T (copper/constantan)
Often used as a differential measurement. There is no Curie point and thus no abrupt change in
characteristics because both conductors are non-magnetic. Range of －200° to +350°C,
sensitivity 43 µV/°C.
R-Type Thermocouple
The R-Type thermocouple is applicable for high-temperature. It consists of a high percentage of
(Rhodium) chemical elements than the S-Type which will make it more costly. This type is very
comparable to the S-Type in terms of the act. Sometimes, it is used in low- temperature applications
due to its stability and high accuracy.
Among the above different type of thermocouple the Thermocouple that are widely used and
developed indigenously in the ASP PLANT are:-
TYPE K
In K Type Thermocouple positive leg is composed of 90% nickel, 10%chromium and a negative leg
is composed of 95% nickel, 2% aluminum, 2% manganese and 1% silicon. These are the most
common general purpose thermocouple with a sensitivity of approx 41µV/°C.
The temperature range of K type thermocouple is from －200 °C to +1350 °C
TYPE R
In R Type thermocouple positive leg is composed of 87% Platinum and 13% Rhodium and a
negative leg is composed of 100% Platinum. These are comparatively costlier than Type K and
provides a sensitivity.
The temperature range of K type thermocouple is from 0°C to +1480°C
TYPE S
In S type thermocouple positive leg is composed of 90% aluminium and 10% Rhodium and a
negative leg is composed of 100% Platinum. It is the costliest among the three types of
thermocouple used in the ASP plant.
The temperature range of S type thermocouple is from -50°C to 1768°C.
PIPING AND INSTRUMENTATION
DIAGRAM
A piping and instrumentation diagram (P&ID or PID) is a detailed diagram in the process industry
which shows the piping and process equipment together with the instrumentation and control
devices.
Superordinate to the P&ID is the process flow diagram (PFD) which indicates the more general flow
of plant processes and the relationship between major equipment of a plant facility.
It is also known as “Process & Instrumentation Diagram”.
It contains detailed graphical representation of a process including the hardware and software
necessary to design, construct and operate the facility
P&IDs are originally drawn up at the design stage from a combination of process flow sheet data, the
mechanical process equipment design, and the instrumentation engineering design. During the
design stage, the diagram also provides the basis for the development of system control schemes,
allowing for further safety and operational investigations, such as a Hazard and operability study
(HAZOP). To do this, it is critical to demonstrate the physical sequence of equipment and systems,
as well as how these systems connect.
P&IDs also play a significant role in the maintenance and modification of the process after initial
build. Modifications are red-penned onto the diagrams and are vital records of the current plant
design.
SCADA
`Supervisory control and data acquisition (SCADA) is a control system architecture comprising
computers, networked data communications and graphical user interfaces for high-level supervision
of machines and processes. It also covers sensors and other devices, such as programmable logic
controllers, which interface with process plant or machinery.
The operator interfaces which enable monitoring and the issuing of process commands, like
controller set point changes, are handled through the SCADA computer system. The subordinated
operations, e.g. the real-time control logic or controller calculations, are performed by networked
modules connected to the field sensors and actuators.
The SCADA concept was developed to be a universal means of remote-access to a variety of local
control modules, which could be from different manufacturers and allowing access through standard
automation protocols. In practice, large SCADA systems have grown to become very similar to
distributed control systems in function, while using multiple means of interfacing with the plant. They
can control large-scale processes that can include multiple sites, and work over large distances as
well as small distance. It is one of the most commonly-used types of industrial control systems, in
spite of concerns about SCADA systems being vulnerable to cyberwarfare/cyberterrorism attacks
PIPING AND INSTRUMENTATION DIAGRAM OF FORGE SHOP ON SCADA
PIPING AND INSTRUMENTATION DIAGRAM OF FORGE SHOP ON
SCADA
CONTROLLERS
In control systems, a controller is a mechanism that seeks to minimize the difference
between the actual value of a system (i.e. the process variable) and the desired value of the
system (i.e. the setpoint). Controllers are a fundamental part of control engineering and
used in all complex control systems.
Before we introduce you to various controllers in detail, it is essential to know the uses of
controllers in the theory of control systems. The important uses of the controllers include:
1. Controllers improve the steady-state accuracy by decreasing the steady state error.
2. As the steady-state accuracy improves, the stability also improves.
3. Controllers also help in reducing the unwanted offsets produced by the system.
4. Controllers can control the maximum overshoot of the system.
5. Controllers can help in reducing the noise signals produced by the system.
Controllers can help to speed up the slow response of an overdamped system.
TYPES OF CONTROLLERS
P-Proportional Controller:
The proportional control concept is more complex than off control system. It is simpler than
PID Controller. A drawback of proportional controller is that it cannot the residual SP-PV
error in processes with Compensation e.g.-temperature control which requires an error
output.
PI-Proportional and Integral controller:
Pl controller is the most popular variation, even more than full pid controller. The value of
the controller output u(t) is fed to the controller input.
PID-Proportional integral and derivative controller:
It is control loop feedback mechanism widely used in industrial control systems and various
other applicationsRequiring continuously modulated. It continuously calculates an error
value as the difference between desired Set Point(SP) and processed variable(PV) and
applies a correction based on proportion, integral,derivative.
Programmable Logic Controller
PLC SETUP IN BBM SHOP
A Programmable Logic Controller (PLC) is an industrial computer that has been ruggedized and
adapted for the control of manufacturing processes, such as assembly lines, machines, robotic
devices, or any activity that requires high reliability, ease of programming, and process fault
diagnosis . PLCs are designed to be highly reliable and can operate in harsh industrial
environments. They can be programmed to perform a wide range of functions and are used to
automate industrial processes
There are three methods to programme a PLC device according to our needs:
1. Ladder logic diagram
2. Function block diagram
3. Sequential function chart
A PLC works by continuously scanning and executing a user-defined control program, following a
specific sequence: input scan, program execution, output scan, and housekeeping . During the input
scan, the PLC reads the status of input devices connected to its input modules. During program
execution, the PLC processes the control program stored in its memory, making decisions based on
the input data and executing control logic . During the output scan, the PLC updates the status of
output devices connected to its output modules. Finally, during housekeeping, the PLC performs
internal diagnostics and communication tasks .
LOAD CELL
Load cell is a sensor or a transducer that converts a load or force acting on it into an
electronic signal. This electronic signal can be a voltage change, current change or
frequency change depending on the type of load cell and circuitry used.
There are many different kinds of load cells.
Resistive load cells work on the principle of piezo-resistivity. When a load/force/stress is
applied to the sensor, it changes its resistance. This change in resistance leads to a change
in output voltage when a input voltage is applied.
Capacitive load cells work on the principle of change of capacitance which is the ability of
a system to hold a certain amount of charge when a voltage is applied to it. For common
parallel plate capacitors, the capacitance is directly proportional to the amount of overlap of
the plates and the dielectric between the plates and inversely proportional to the gap
between the plates.
Working Principle of Load cell
A load cell is made by using an elastic member (with very highly repeatable deflection
pattern) to which a number of strain gauges are attached.When the load is applied to the
body of a resistive load cell as shown above, the elastic member, deflects as shown and
creates a strain at those locations due to the stress applied. As a result, two of the strain
gauges are in compression, whereas the other two are in tensionDuring a measurement,
weight acts on the load cell’s metal spring element and causes elastic deformation.This
strain (positive or negative) is converted into an electrical signal by a strain gauge (SG)
installed on the spring element. The simplest type of load cell is a bending beam with a
strain gauge.
We use wheatstone bridge circuit to convert this change in strain/resistance into voltage
which is proportional to the load.
STRAIN GAUGE TYPE LOAD CELL
The four strain gauges are configured in a Wheatstone Bridge configuration with four
separate resistors connected as shown in what is called a Wheatstone Bridge Network.
An excitation voltage – usually 10V is applied to one set of corners and the voltage
difference is measured between the other two corners. At equilibrium with no applied load,
the voltage output is zero or very close to zero when the four resistors are closely matched
in value. That is why it is referred to as a balanced bridge circuit.
When the metallic member to which the strain gauges are attached, is stressed by the
application of a force, the resulting strain – leads to a change in resistance in one (or more)
of the resistors. This change in resistance results in a change in output voltage. This small
change in output voltage (usually about 20 mVolt of total change in response to full load)
can be measured and digitized after careful amplification of the small milli-volt level signals
to a higher amplitude 0-5V or 0-10V signal.
CONCLUSION
The opportunity of getting vocational training at such a famous and prestigious organization
is an opportunity of a lifetime. The training at Alloy Steel Plant was very helpful. It has
improved my theoretical concepts of Thermocouples, Controllers, SCADA and many more.
It helped me understand that despite technological advancement and modern machinery,
proper coordination between employees and their experiences is the key to a proper
functioning and growing plant.
From doing the training,I got a great experience of a real situation in an organization. It
helped me know about Indian steel industries and Alloy Steel pLnat’s process of operation
and its technical department operations. That is very similar to our theory but very
complicated and sensitive in the practical part. Through this training I came to know about
the strength, weakness, opportunities and threats of the steel industries and the future
expression of the company.
I had a chance to see the electric arc furnaces and the steel melting shop where the main
working of the steel plant is being done and I also saw the working of various shops of the
plant, which was very interesting. So the training was more than I expected and helped me
to understand more about the purpose of employing a metallurgical Electronics and
Instrumentation in a steel plant. The most important thing for any organization is an
individual's safety, not only for its employees but for every individual related to this
organization.
After two week of vocational training I came to the conclusion that:
“There is a little bit of SAIL in everybody’s life”