The vocational training report describes the author's visit to the Bhilai Steel Plant, focusing on its key operations like the Refractory Materials Plant, Foundry & Pattern Shop, and Merchant Mill. It outlines the plant's history, various safety practices, and detailed manufacturing processes for refractory materials, including lime and dolomite bricks. The report was submitted as part of a Bachelor's degree in Mechanical Engineering and attests to the author's own work and understanding gained during the training.

1. A VOCATIONAL TRAINING REPORT
ON
BHILAI STEEL PLANT VISIT TRAINING
A Training Report Submitted to
CHHATTISGARH SWAMI VIVEKANANDA TECHNICAL
UNIVERSITY, BHILAI (C.G.), INDIA
For the partial fulfilment of the award of degree for
BACHELOR OF ENGINEERING
In
MECHANICAL BRANCH
By
PIYUSH VERMA (3933714033)
Under the Training Incharge of
Prof.-SURENDRA SAHU
DEPARTMENT OF MECHANICAL ENGINEERING
BHILAI INSTITUTE OF TECHNOLOGY, RAIPUR
Village – Kendri, Near Abhanpur, New Raipur – 493661 (C.G.) India
SESSION 2015-2016

2. DECLARATION
We the undersigned solemnly declare that the Vocational Training report on
RMP, Foundry& Pattern Shop and Merchant Mill is based on my own work
carried out during the course of my study under the supervision of Mr. MANISH
MISHRA, HOD Department of Mechanical Engineering, BIT Raipur.
We assert that the statements made and conclusions drawn are an outcome of
the Industrial Training. We further declare that to the best of our knowledge and
belief that the report does not contain any part of any work which has been submitted
for the award of B.E. degree or any other degree /diploma/certificate in this
University.
Signature
Name: PIYUSH VERMA
Roll No.: 3933714033
Enrollment No: AP6928

3. CERTIFICATE
This is to certify that the work incorporated in this Vocational Training
on“RMP, Foundry& Pattern shop, Merchant mill”is the report of Industrial Visit
carried out by Mr. Aditya Tiwari under the guidance and supervision of (Training In
charge Plant) award of the degree Bachelor of Engineering in the student of
Mechanical Engineering of Chhattisgarh Swami Vivekananda Technical University,
Bhilai (C.G.), India.
To the best of my knowledge and belief the report embodies the work of the candidate
himself.
 Has duly been completed.
 Fulfils the requirement of the ordinance relating to BE/B.Tech. Degree of
the University.
 Is up to the desired standard both in respect of contents and language
For being referred to the examiners.
Approved By Training Incharge
Prof. MANISH MISHRA Mr. ADITYA TIWARI
(HOD, MECH) (Asst. Professor)
Forwarded to Chhattisgarh Swami Vivekananda Technical University, Bhilai

4. LIST OF FIGURES
i. RMP-2
i. Twin Shaft Parallel Flow Regenerative Lime Kilin
ii. Rotary kilin
iii. Bricks
ii. Foundry And Pattern Shop
i. Tools
i. Showel
ii. Hammer
iii. Sprue Pin
iv. Trowel
v. Spike Or Draw Pin
vi. Lifters
ii. Production Sequence In Sand Casting
iii. Types Of Pattern
i. Single Piece Pattern
ii. Split Pattern
iii. LoosePiece Pattern
iii. Merchant mill
i. T.M.T (Thermo Mechanically Treated Rod)
ii. Angles
iii. Channels
iv. Round Bars

5. TABLE OF CONTENTS
i. Intoduction of Bhilai Steel Plants(B.S.P)
ii. Safety (Do’s and Don’ts) in the industry
iii. RMP-2
i. Lime Shop
i. The Kilin
ii. The Process
iii. Kilin Operation
ii. Rotary Kilin
i. Descriptions
ii. Principle Of Working
iii. Kilin Operation
iii. Brick Shop
i. Introduction
ii. Main Equipments
iii. Process Of Manufacturing Of Magnesia Carbon Bricks
iv. Testing
iv. Foundry and Pattern Shop
i. Introduction to Foundry
i. Casting Terms
ii. Tools
iii. Sands Mould Making Procedure
iv. Moulding Sand Properties
ii. Introduction to pattern
i. Types Of Pattern
ii. Pattern Design
v. Merchant Mill
i. Products OfMerchant Mill
ii. Process Description
iii. Results

6. Bhilai Steel Plant (B.S.P)
Introduction:-
A symbol of Indo-Soviet Techno-economic collaboration, is one of the first
three integrated steel plants set up by Government of India to build up a sound base
for the industrial growth of the country. The agreement for setting up the plant with a
capacity of 1 MT of Ingot steel was signed between the Government of erstwhile
U.S.S.R. and India on 2nd February, 1955 and only after a short period of 4 years,
India entered the main stream of the steel producers with the commissioning of its
first Blast Furnace on 4th February, 1959 by the then President of India, Dr. Rajendra
Prasad. Commissioning of all the units of 1 MT stage was completed in 1961. A
dream came true-the massive rocks from the virgin terrains of Rajhara were converted
into valuable iron & steel.
In the initial phase the plant had to face many teething problems, mostly unknown to
the workforce at the time, but by meticulous efforts and teamsprit, these problems
were surmounted and the rated capacity production was achieved only within a year
of integrated operation of the plant. Thereafter, the plant was expanded to 2.5 MT
capacity per year, and then to 4 MT of crude steel per year, with Soviet assistance. All
the units of the plant have been laid out in sequential formation according to
technological inter-relationship so as to ensure uninterrupted flow of in-process
materials like Coke, Sinter, Molten Iron, Hot Ingots, as well as disposal of
metallurgical wastages and slag etc., minimizing the length of various inter-plant
communications, utilities and services.

7. Safety (Do’s and Don’ts) in the Industry
1. Do’s-
1. Punctuality (timeliness),
2. Maintaining healthy and cordial relationship with the people in
organization.
3. Understanding the work culture.
4. Obeying direct orders from the seniors.
5. Showing a sense of belonging with the organization.
6. Maintaining proper Line and Staff Relationship with the seniors and
subordinates (If Any).
2. Don’ts-
1. Do not take the training lightly and casually.
2. Do not give an impression that you are doing the training just for the
sake of it. Put your heart and soul.
3. Do not involve in internal politics.
4. Do not reveal you weaknesses.
5. Do not lie to your seniors.
6. Do not waste your time.
7. Do not copy any material. Be original.
8. Do not go for leave unless it is indispensable.
9. Do not ask for favours.

8. REFRACTORY MATERIALS PLANT (RMP)-II
Introduction:-
Refractory Materials Plant (RMP-II) was set up during 4 MT expansion of BSP to
prepare and supply the required quantity of Lime, Sintered Dolomite and Tar Bonded
Dolomite Bricks to SMS-II.
It has three main units:
1. Lime Shop
2. Rotary Kiln
3. Brick Shop
1.0 Lime Shop:
1.1 The Kilns:
There are two nos. of identical vertical shaft kilns commissioned in the year
1984, with capacity 330 T /DAY for each kiln. One kiln is to make Lime and other
Calcined Dolomite for Converters.
1.2 The process:
Low Silica lime stone of feed size (30-50 mm) or Dolomite having feed size 30-
60mm are weighed and charged to skip charging bunker.
The limestone is charged at common service hopper at kiln top, and from this material
is fed into kiln shaft. The charged limestone burns in parallel flow, while the
combustion air get heated when passing through column of limestone above the
burners. The waste gases are conducted to the other shaft, which pass their sensible
heat to the limestone in the preheating zone. The burning in parallel flow allows a
very high heat exchange. The hot flame comes in contact with the crude limestone
avoiding over burning. Final calcination of charge is carried out by waste gases. Lime
is soft-burnt. High combustion air temperature and a very favourable fuel
consumption are achieved through regenerative preheating where waste heat is almost
completely utilized.
The two shafts are filled with the charge and connected to each other by a channel.
Only one of the shafts is heated by fuel and other is heated by the waste gases coming
out through the channel from fuel-heated shaft. Lime is simultaneously burnt in both

9. the shafts. At fixed intervals reversal takes place. During reversal, the two shafts are
alternately charged and burnt lime is continuously discharged from both shafts. Since
the temperature is high, cool air is blown from below in both the shafts for cooling the
product, which is then discharged.

10. 1.3 Kiln Operation
PARAMETERS OF KILN OPERATION
The operation of MAERZ kiln is characterized by the following parameters:
A) BURNINGTIME
B) AIR VOLUME
C) FUEL RATE
D) WEIGHT OF CHARGE
A) BURNING TIME
With a MAERZ kiln the shafts are heated periodically. Fuel is fed always to only one
shaft (as well as the combustion air), whereas through the other shaft waste gases flow
to the stack.
The burning time is the time during which fuel is fed to the shaft, i.e. the time
between opening and closing of the fuel valves.
The time required for reversing from one shaft to the other is called REVERSING
TIME. This is the time between closing the fuel valve (S) of the shaft which has been
fired last and opening the fuel valves of the following shaft to be fired. Burning time
plus reversing time is called CYCLE TIME.
The adjustment of a determined burning time is by means of the kiln automation by
adjusting the Digital Counter.
B) AIR VOLUME
As regards the air volume, we distinguish between combustion air volume and
cooling air volume.
Combustion air and cooling air are supplied by volumetric blowers. The control of the
air volume is function of the driving system of the blowers. With MAERZ Kilns there
are following possibilities.
Combustion air as well as cooling air blowers are driven independently from each
other by motors which.
(i) Run only with one speed
(ii) Run with determined speed stages.
Combustion air and cooling air blowers are coupled (pulleys) and are driven by
motors according to item (i). The volume of combustion and cooling air can thus be
controlled by the choice of determined speed stages or by varying the speed of the
continuously variable speed motor.

11. C) FUEL RATE:
The fuel admitted is determined by the specific heat consumption of the kiln.
The control of the fuel input is affected by adjusting the flow rate of the dozing pump
in case of fuel oil fired kilns, and by adjusting the gas flow control valve in case of
gas fired kilns.
D) WEIGHT OF CHARGE
This is the quantity of limestone charged into one shaft during a reversing period.
The weight of charge is determined by the cycle time to be fixed during kiln commissioning.
1.4 Quality (Specification of R/M & Product)
S.No. Chemical Composition Limestone Lime for SMS-II
1. CaO 53% (Min.) 88% (Min.)
2. MgO 2.5% (Max.) 4% (Max.)
3. SiO2 1.5% (Max.) 2.5% (Max.)
4. Al2O3 1.7% (Max.) 3% (Max.)
5. L.O.I. 42.5% 6% (Max.)
6. Reactivity - >320 ml with 4 N HCL in 4 min.
7. Size 30-50 mm 5-50 mm
2.0 Rotary Kiln:
2.1 Brief description:
There is one Rotary kiln for production of calcined lime for SP-3 Rotary kiln was
commissioned in the year 1985. The capacity of kiln is 200 T/day of calcined lime
and other details of kiln are as below:
A. Length of Rotary kiln = 82.5 M
B. Diameter of Rotary kiln = 3 M
C. Length of Rotary cooler = 22.5 M
D. Diameter of Rotary cooler = 3 M
E. Charging system = by scooping device

12. 2.2 Principle of working:
Weighed raw material is fed with the help of scooping device and fuel is fired from
discharge end. Material travels during slow rotation of kiln and heat is transferred to
material due to radiation from refractory, final product is discharged into Rotary
cooler and after cooling, product is continuously discharged on conveyor belt.
2.3 Kiln operation:
Various operating parameters of kiln operation are:
A. Quantity of feed material.
B. Rotation of kiln.
C. Quantity of fuel.
D. Combustion air volume.
A. Quantity of feed material
Rate of feed material (T/hr) depends on the production rate. It can vary 0-20 T/hr.
Feed quantity is weighed by belt weigh system called "Merrick feeder".
B. Rotation of Rotary kiln
Maximum rotation of kiln is 0.9 RPM and it depends upon the kiln production and
product also. Kiln rotation is more in case of calcinations and lower in case of
sintering.
More retention time is required for sintered process. Rotation of Rotary cooler is fixed
(2 RPM).
C. Quantity of fuel
PCM, C.O. gas & both at a time can be used. Rate of flow of fuel is depending onthe
production and process. Duplex burner has been installed to feed PCM or gas.
Flue gas after burning, passes through rotary kiln and goes to chimney by natural
draught or forced draught. ±5 mm WC draught is maintained.
D. Combustion air volume
Two blowers have been installed to supply combustion air for initial firing of fuel
(20% of total combustion air). Rest of combustion is supplemented by controlling
draught.

13. 2.4. Quality: Calcined Lime to SP-3
S.NO. Chemical Composition Lime Stone Calcined Lime
1 Cao 53.0 % (min) 88 % (min)
2 MgO 2.5% (max) 4 % (max)
3 SiO2 1.5 % (max) 2.5 % (max)
4 Al203 1.7 % (max)
5 LOI -- 6 % (max)
6 Size 10-35 mm (-) 3 mm
7 Reactivity - 320 ml (Min.)
3 Brick Shop
3.1 INTRODUCTION:
Brick Shop was commissioned in the year 1985. The main function was toproduce
Tar Bonded Dolomite Bricks for converter vessel of Steel Melting Shop No.2.
The production of tar bonded dolomite bricks for converter was stopped in the year
1987 because of poor life and production of Magnesia-Carbon Bricks started in the
year 1996. Some refractory masses were developed in the year 1990. At present shop
is producing following refractory items which affect cost savings.
S.No. Item/Product Used at
1. MagnesiteMass SMS-II
2.Runner Mass B.F.
3. Twin Hearth sleeve SMS-I
4. Well filler Mass SMS I
5. Magnesia Carbon Bricks SMS-II

14. 3.2 MAIN EQUIPMENTS:
S.No. Equipment Nos.
1. Hydraulic Press 02
2. Mixer (Planetary type) 02
3. Tube Mill 01
4. Curing kiln 02
5. E.O.T. Crane 01
3.3 PROCESS OF MANUFACTURING OF MAGNESIA CARBON BRICKS:
Manufacturing activities are divided into following steps (as written below):
a) Mixing
b) Ageing
c) Pressing
d) Curing
e) Testing
a) Mixing:
Fraction of 2.5-3.5 mm sea water magnesia along with resin are mixed in LAEIS
mixer for one minute and then lower fractions of sea water magnesia are added and
mixed for few minutes in the mixer. Subsequently pitch and graphite powder are
added and thoroughly mixed for required duration of time.
b) Ageing:
After getting homogeneous mix, it is stored for 16-24 hours depending upon weather
temperature. In this way resin is better absorbed by refractory ingredient sand this
helps in elimination of lamination formation during pressing.
c) Pressing:
Mix so prepared after uniform ageing is pressed at 1400 kgs/cm2 in the available
1600 T Russian presses. Cold crushing strength is between 200 to 220 kg/cm2 and
bulk density is 2.75 to 2.80 gm/cc in green condition. Neither cracking nor peeling off
of layer is observed. Size is uniform between ± 2mm tolerance. Rejection during
production is negligible.

15. d) Curing:
In order to develop strength these bricks were required to be heat-treated. Inabsentia
of tempering furnace it was decided to construct curing furnace with in house
resources and curing technology was decided to get maximum crushing strength.
3.4 TESTING:
Testing & inspection play vital role for success of any product. These bricks are tested
regularly by RCL.
3.4.1 BRICK QUALITY NORM:
1. Apparent Porosity - 4 % (max)
2. Bulk density - 2.9 (min) gm / cc
3. Cold crushing strength - 400 kgs /cm2 (min)
4. Dimensional check - ±2mm in length & ±1 mm in width & thickness
5. Coked Porosity - 10 -12 %
II) Coked Porosity:
Coked Porosity test is conducted as follows:
A sample is covered with petroleum coke from all sides and kept in a muffle furnace.
It is kept in the furnace for 1hour at 1000 °C. Furnace in then switched off.
After natural cooling at room temperature the sample is tested for porosity.

16. 4. SALIENT FEATURES OF RMP-II:
a) Screening facilities for the limestone have been provided for smooth operation of
the shaft kilns.
b) The temperature of the waste gases coming out of the lime shaft kiln is less than
150 °C.
c) All the raw materials and products are transported by means of belt conveyor sand
there is no storage yard separately for RMP-2 adjacent to the shop.
d) In-house development of curing kiln for MgO-C bricks.
e) Modification of Rotary burner: burning of C.O. gas, PCM & both.
In-house developments / Achievements and application:
a) Developed many refractory items as written below:
1. Runner Mass.
2. Well filler Mass.
3. Mag-C bricks.
4. Twin hearth Sleeves.
5. Magnesite Mass.
b) Enhanced the production of lime kiln (330 T/day to 410 T/day).
c) Commissioning of Duplex burner at Rotary Kiln.
d) Record life of 6252 Converter Heats with in-house produced Magnesia Carbon
bricks. In the year 2006-07

17. FOUNDRY AND PATTERN SHOP
Introduction of Foundry:
Foundry practice deals with the process of making castings in moulds,
formed in either sand or either material. This is found to be the cheapest method of
metal shaping. Further, castings may be made to fairly close dimensional tolerances
by choosing proper moulding and casting process.
1. casting terms:
In the following chapters the details of sand-casting, which represents the
basic process of casting would be seen. Before going into the details of the
process, defining a number of casting vocabulary words would be appropriate.
Flask: A moulding flask is one which holds the sand mould intact. Depending
upon the position of the flask in the mould structure, it is referred by various
names such as drag, cope and cheek. It is made up of wood for temporary
applications or more generally of metal for long-term use.
Drag: Lower moulding flask.
Cope: Upper moulding flask.
Cheek: Intermediate moulding flask used in three-piece moulding.
Pattern: Pattern is a replica of the final object to be made with some
modifications. The mould cavity is made with the help of the pattern.
Parting Line: This is the dividing line between the two moulding flasks that
makes up the sand mould. In split pattern it is also the dividing line between
the two halves of the pattern.
Bottom Board: This is a board normally made of wood, which is used at the
start of the mould making. The pattern is first kept on the bottom board, sand
is sprinkled on it and then the ramming is done in the drag.
Facing Sand: The small amount of carbonaceous material sprinkled on the
inner surface finish to the castings.
Core: It is used for making hollow cavities in castings.
Pouring Basin: A small funnel-shaped cavity at the top of the mould into
which the molten metal is poured.

18. Sprue: The passage through which the molten metal from the pouring basin
reaches the mould cavity. In many cases it controls the flow of metal into the
mould.
Runner: The passageways in the parting plane through which molten metal
flow is regulated before they reach the mould cavity.
Gate: The actual entry point through which molten metal enters the mould
cavity.
Chaplet: Chaplets are used to support cores inside the mould cavity to take
care of its own weight over-come the metallostatic forces.
Chill: Chills are metallic objects, which are placed in the mould to increase
the cooling rate of castings to provide uniform or desired cooling rate.
Riser: It is a reservoir of molten metal provided in the casting so that hot
metal can flow back into the mould cavity when there is a reduction in volume
of metal due to solidification.
2. TOOLS:
The tools and equipment needed for moulding are: Moulding board,
moulding flasks (boxes), shovel and moulders tools.
Moulding Tools:
It is a wooden with smooth surface. It supports the flasks and the pattern,
while the mould is being made.
Moulding Flask:
It is a box, made of wood or metal, open at both ends. The sand is rammed in
after placing the pattern to produce a mould. Usually, it is made of two parts.
Cope is the top half of the flask, having guides or the aligning pins to enter.
Drag is the bottom half of the flask having aligning pins.
Showel:
It is used for mixing and tempering moulding sand and for transferring
the sand into the flask. It is made of steel blade with a wooden handle.

19. Hammer:
It is used or packing or ramming the sand around the pattern. One of its
end, called peen end, is wedge shaped and is used for packing sand in spaces,
pockets and corners, in early stages of ramming. The other end, called the butt
end, has a flat surface and is used for compacting the sand towards the end of
moulding.
Strike off Edge:
It is a piece of metal or wood with straight edge. It is used to remove the
excess sand from the mould after ramming, to provide a level surface.
Sprue Pin:
It is tapered wooden pin used to make a hole in the cope sand through
which the molten metal is poured into the mould.
RiserPin:
It is straight wooden pin used to make a hole in the cope sand, over the
mould cavity or the molten metal to rise and feed the casting to compensate
the shrinkage that take place during solidification.

20. Trowel:
It is used to smoothen the surface of the mould. It may also be used for
repairing the damaged portion of the mould. Trowels are made in many
different styles and sizes, each one suitable for a particular job.
Spike or Draw Pin:
It is a steel rod with a loop at the other end. It is used to remove the
pattern from the mould. A draw Screw, with a threaded end may also be used
for the purpose to draw metal patterns.
Silk:
It is a small double ended tool having a flat on one end and a spoon on the
other. It is used for mending and finishing small surfaces of the mould.
Lifters:
Lifters are made of thin sections of steel of various widths and lengths,
with one end bent at right angles. These are used for cleaning and finishing the
bottom and sides of the deep and narrow pockets of the mould.
Gate Cutter:
It is a semi- circular piece of tin sheet, used to cut gates in the mould.
Gates are meant for easy flow of molten metal into the mould.

21. Bellows:
It is a hand tool, used to blow air to remove the loose sand particles from
the mould cavity.
Vent Rod:
It is a thin rod used for making vents or holes in the sand mould to allow the
escape of mould gases generated during the pouring of molten metal.
Core Box:
A core box is designed to mould cores. It is made of either wood or metal,
into which core sand is packed to form the core. Wood is commonly used for
making a core box, but metal boxes are used when cores are to be made in
large numbers. Specially prepared core sand is used in making cores.
Pattern making
Mold making
Preparation
of sand
If necessary
core making
Raw
material
Melting
Pouring
Solidification and
cooling
Removal of sand
mold
Cleaning &
Inspection
Finished casting
Production sequence in sand casting

22. 3. Sand Mould making procedure:
The procedure for making a typical sand mould is described in the following steps
First, a bottom board is placed either on the moulding platform or on the floor,
making the surface even. The drag moulding flask is kept upside down on the bottom
board along with the drag part of the pattern at the centre of the flask on the board.
There should be enough clearance between the pattern and the walls of the flask
which should be of the order of 50 to 100mm. Dry facing sand is sprinkled over the
board and pattern to provide a non-sticky layer. Freshly prepared moulding sand of
requisite quality is now poured into the drag and on the pattern to a thickness of 30 to
50mm. The rest of the drag flask is completely filled with the backup sand and
uniformly rammed to compact the sand. The ramming of the sand should be done
properly so as not to compact it too hard, which makes the escape of gases difficult,
nor too loose, so that the mould would not have enough strength. After the ramming is
over, the excess sand in the flask is completely scraped using a flat bar to the level of
the flask edges.
Now, with a vent wire, which is a wire of 1- to 2-mm diameter with a pointed end,
vent holes are made in the drag to the full depth of the flask as well as to the pattern to
facilitate the removal of gases during casting solidification. This completes the
preparation of the drag.
The finished drag flask is now rolled over to the bottom board exposing the pattern.
Using a slick, the edges of sand around the pattern is repaired and the cope half of the
pattern is placed over the drag pattern, aligning it with the help of dowel pins. The
cope flask on top of the drag is located aligning again with the help of the pins. The
dry parting sand is sprinkled all over the drag and on the pattern.
A sprue pin for making the sprue passage is located at a small distance of about 50
mm from the pattern. Also, a riser pin if required is kept at an appropriate place and
freshly prepared moulding sand similar to that of the drag along with the backing sand
is sprinkled. The sand is thoroughly rammed, excess and scraped and vent holes are
made all over in the cope as in the drag.
The sprue pin and riser pin are carefully withdrawn from the flask. Later, the pouring
basin is cut near the top of the sprue. The cope is separated from the drag and any

23. loose sand on the cope and drag interface of the drag is blown off with the help of
bellows. Now, the cope and the drag pattern halves are withdrawn by using the draw
spikes and rapping the pattern all around to slightly enlarge the mould cavity so that
the mould walls are not spoiled by the withdrawing pattern. The runners and the gates
are cut in the mould care-fully without spoiling the mould. Any excess or loose sand
found in the runners and mould cavity is blown away the bellows. Now, the facing
sand in the form of a paste is applied all over the mould cavity and runners, which
would give the finished casting a good surface finish.
4. Types OF SAND MOULDS:
In order to produce sound castings, moulds are required to have some specific
properties.
Some of them are the following:
1.It must be strong enough to withstand the temperature and weight of the
molten metal.
2.It must resist the erosive action of the flowing hot metal.
3.It should generate minimum amount of gases as a result of the temperature of
the molten metal.
4.It should have good venting capacity to allow the generated gases to
completely escape from it.
Moulds that are used for sand casting may broadly be classified as
1. Green sand moulds
2.Dry sand moulds
3.Skin dried moulds
Green SAND MOULDS:
Green sand is the moulding sand which has been freshly prepared from silica grains,
clay and moisture. In a green sand mould, metal is poured immediately and the
castings taken out. These are most commonly used and are adapted for rapid
production, whereas the moulding flasks are released quickly.

24. Dry SAND MOULDS:
These are the green sand moulds which are completely dried by keeping in an oven
between 150 to 350c for 8 to 48 hours depending on the binders in the moulding sand.
These moulds generally have higher strengths than the green sand mould and are
preferred because they are less likely to be damaged during handling.
Skin dried mould:
Though the dry sand mould is preferable for large moulds because of the expense
involved, a compromise is achieved by drying only the skin of the mould cavity with
which the molten metal comes into contact, instead of the full mould. The skin is
normally dried to a depth of 15 to 25 mm, using either torches or by simply allowing
them to dry in atmosphere.
Other sands:
Though moulding sands are the prime mould materials used in a foundry, there are a
number of other materials, which are also used for a number of specific properties.
Facing sand:
This sand is used next to the pattern to obtain cleaner and smoother casting surfaces.
Generally, sea coal or coal dust(finely divided bituminous coal of 2 to 8%) is mixed
with the system sand to improve the mould ability and surface finish. The sea coal
being carbonaceous, will slowly burn due to heat from the molten metal and give off
small amounts of reducing gases.
Mould wash:
Purely carbonaceous materials such as sea coal, finely powdered graphite or
proprietary compounds are also applied on to the mould cavity after the pattern is
withdrawn. This is called the mould wash and is done by spraying, swabbing or
painting in the form of a wet paste. These are used essentially for the following
reasons:
1. To metal penetration into the sand grains and thus ensure a good casting finish
2.To avoid mould-metal interaction and prevent sand fusion.

25. For deposing the mould wash, either water or alcohol can be used as a
carrier. But because of the problem of getting the water out of the mould, alcohol is
preferred as a carrier. The proprietary washes are available in powder, paste or liquid
form. The powder needs to be first prepared and applied whereas the paste and liquid
can be straightaway applied.
Backing sand:
This is normally the reconditioned foundry sand is used for ramming the
bulk of the moulding flask. The moulding flask is completely filled with backing sand
after the pattern is covered with a thin layer of facing sand. Since the casting is not
affected to any great extent by the backing sand, it usually contains the burnt facing
sand, moulding sand and clay.
Parting sand:
This is the material, which is sprinkled on the pattern and to the parting
surfaces of the mould halves before they are prepared, to prevent the adherence of the
moulding sand. This helps in easy withdrawal of the pattern and easier separation of
the cope and drag flasks at parting surface. It is essentially a non-sticky material such
as washed silica grains.
5. Moulding sand properties:
The properties of moulding sand are dependent to a great extent on a
number of variables. The important among them are
 Sand grain shape and size,
 Clay type and amount,
 Moisture content, and
 Method of preparing sand mould.
Introduction to Pattern:
A pattern is the replica of the desired casting, which when packed in a suitable
material, produces a cavity called the mould. This cavity when filled with molten
metal, produces the desired casting after solidification.

26. 1. Types of pattern:
These are various types of patterns depending upon the complexity of the
job, the number of castings required and the moulding procedure adopted.
Single piece pattern:
These are inexpensive and the simplest type of patterns. As the name indicates,
they are made of a single piece as shown in fig. This type of pattern is used only in
cases where the job is very simple and does not create any withdrawal problems. This
pattern is expected to be entirely in the drag.
Split pattern or two piece pattern:
This is the most widely used type of pattern for intricate castings. When the
contour of the casting makes its withdrawal from the mould difficult, or when the
depth of the casting is too high, then the pattern is split into two parts so that one part
is in the drag and other in the cope.

27. Gated pattern:
This is an improvement over the simple pattern where the gating and runner
system are integral with the pattern. This would eliminate the hand cutting of the
runners and gates and help in improving the productivity of a moulder..
Cope and drag pattern:
These are similar to split patterns. In addition to splitting the pattern, the cope and
drag halves of the pattern along with the gating and risering systems are attached
separately to the metal or wooden plates along with the alignment pins. They are
called the cope and drag patterns.
Match plate pattern:
These are extensions of the previous type. Here, the cope and drag patterns along
with the gating and the risering and mounted on a single matching metal or wooden
plate on either side.
Loose piece pattern:
This type of pattern is also used when the contour of the part is such that
withdrawing the pattern from the mould is not possible. Hence during moulding, the
obstructing part of the contour is held as a loose piece by a wire.
Follow board pattern:
This type of pattern is adopted for those castings where there are some portions,
which are structurally weak and if not supported properly are likely to break under the
force of ramming.

28. Sweep pattern:
It is used to sweep the complete casting by means of a plane sweep. These are
used for generating large shapes, which are axi-symmetrical or prismatic in nature
such as bell-shaped or cylindrical.
Skeleton pattern:
A skeleton of the pattern made of strips of wood is used for building and final
pattern by packing sand around the skeleton.
2. Pattern design:
While designing a pattern, the following must be considered.
1. Avoid abrupt changes in cross section.
2. Avoid sharp corners and edges, to enable smooth flow of molten metal.
3. Provide the following pattern allowances.
a. Shrinkage allowance, to allow for shrinkage when casting cools in the
mould.
b. Slight taper or draft, to allow easy withdrawal of the pattern from the
mould.
c. Machining allowance, to take care of the machining on these surfaces.

29. MERCHANT MILL
Introduction:-
The purpose of this mill is to make the final merchant products, which can be directly
sold to merchant.
THE MERCHANTS PRODUCTS ARE –
1. T.M.T (Thermo Mechanically Treated) rod 25, 28, 32, 36, 40, 45(in mm).
2. Angles 50×50, 75×75, 90×90 (in mm).
3. Channels 100×50, 75×40(in mm).

30. 4. Round bars 28, 32, 36, 40, 50, 53, 60, and 67(in mm).
Layout-

31. Process description-
1. 350 mm semi continuous high capacity mill
2. Raw materials used are billets of size 100x100, 105x105, 110x110, 150x150
and shaped billet of size 122x135x80, length ranging from 5 M to 6 M.
3. Three rolling lines
a. The first line of rolling consists of 8 stands.
b. After the 8th stand there is a chain drive to deliver the bar from first
line to 2nd line of rolling that is from stand 8 to stand 9.
c. There is a second chain transfer after 10th stand for delivering the bar
from 2ndline to 3rd line of rolling.
d. The 3rd line of rolling has two stands 11and 12, connected by the
approach and delivery roll tables.
4. The chain transfers are used while rolling structures only.
5. There are two repeaters in between 8th and 9th stand and in between 10th and
11th stand. When the repeaters are used, chain transfers are not used.
6. Repeaters are used for rounds upto 67 mm dia. and TMT bars upto 45 mm.
7. The turn-over devices or tilters are installed on the rolling lines between
stands 1 & 2, 5 & 6 and 9 & 10. These are used for turning over billets by 90°
before delivering them to the respective stand (as per requirement).
8. Roughing group comprises of stands 1,2,3,5 being 500 mm two high
horizontal stands and 4th stand is a 400 mm, 2 high vertical stand.
9. Intermediate group comprises 6,8,9 stands of 400 mm 2 high horizontal and
7th stand 400 mm two high vertical.
10. Finishing group consists of 10th stand of 400 mm and 12th of 350 mm 2 high
horizontal stands and 11th being 350 mm 2 high vertical.
11. The length of the roll barrels used for different stands are given below
12. 1, 2, 3 & 5 1000 mm
13. 4, 7, 11 & 12 600 mm
14. 6, 8, 9 & 10 800 mm

32. 15. The finished bar (except TMT bars) from stand 12 travels on the delivery roll
table through the switch point bifurcator to the cooling bed. The bifurcator
distributes the flow of bars to both side of cooling bed. The length of cooling
bed is 90 m.
16. In case of TMT, the finished bar from stand 12 travels through Thermax
pipes in which this is subjected to rapid water quenching system(at a water
pressure more than 16 kgf/cm2).
17. The final product is straightened in the straightening machines, cut to desired
lengths in the cold shears and bundled &dispatched to the destinations in the
finishing and shipping area.
18. There are two cold shears installed in the line of rolling, one on each side to
cut the rolled bars into desired lengths. The lengths are adjusted by the shear
adjustable gauge before cutting into suitable lengths. The bars are weighed
and bundled. A card indicating the heat number, weight, and quality is
attached to the binding wire and kept on the stack.
19. Stage inspection for the rolled profile is carried out during the process of
rolling for finding out rolling defects, surface defects, steel defects and any
other mechanical defects. Samples from each cast are sent to laboratory for
mechanical testing and for ascertaining chemical composition.
20. There are fifteen cranes in the mill provided on the different bays for load
lifting, roll changing etc.
Result
The rated capacity of merchant mill is 5 lakh tons per year. The product sold
to merchants and further used for construction purpose.

33. REFERENCES
1. A text bookof Production Technology Vol. I / O.P. Khanna /
Dhanpat Rai Publications
2. Manufacturing Technology (First Edition) / P N Rao / Tata
McGraw-Hill Publishing Company Ltd
3. Website :- https://www.sail.bhilaisteel.com/