Probation report

Submitted by: Asad ullah

4/14/2023

Submitted to:
M.aLI SYED
 Chapter 1

INTRODUCTION
Hot rolling is a metalworking process in which metal is heated above the recrystallization temperature
to plastically deform it in the working or rolling operation. This process is used to create shapes with
the desired geometrical dimensions and material properties while maintaining the same volume of
metal. The hot metal is passed between two rolls to flatten it, lengthen it, reduce the cross-sectional
area and obtain a uniform thickness. Hot-rolled steel is the most common product of the hot rolling
process, and is widely used in the metal industry either as an end product or as raw material for
subsequent operations.
The non-uniform initial grain structure of metal consists of large columnar grains growing in the
direction of solidification. This is usually brittle with weak grain boundaries and may contain defects
such as shrinkage cavities, porosity caused by gases, and foreign material such as metallic oxides. Hot
rolling breaks the grain structures and destroys the boundaries, giving rise to the formation of new
structures with strong boundaries having uniform grain structures. Starting materials such as blooms
or slabs at an elevated temperature flow from the continuous casting process directly into the rolling
mills. In smaller operations the materials start at room temperature and must be heated either in a
soaking pit, or by induction heating before being fed into the mill.

Flow chart
 What is Rolling Process

Rolling Process is a deformation process in which Metal(s) in its semi-finished or

finished form is passed between the two opposing rollers, which reduces the
metal’s thickness through the compression process. The rollers rolls around the
metal as it squeezes in between them.

Types of Rolling Mills

 Two-High Rolling Mill:

It Consists of two High stands, and two rolls placed exactly one over the Other. In this type of
Rolling Mill, the Rollers rotates in Opposite direction and their direction changes after each Metal
pass. The Metal (Ingot) is passed continuously and approximately 25-30 passes are required to
convert Ingot to Bloom.
 Three-High Rolling Mill:
It consists of three high stands and three Rollers present in the same vertical plane. The Top and
bottom roller rotate in the same direction, and the middle roller rotates in the Opposite Direction.
In this type of Rolling mill, the Direction of the drive is not changed after each pass. It is more
Productive and easier with respect to the two-High Rolling Mill.

 Universal Rolling Mill:

It consists of two vertical rollers and two Horizontal rollers. The Vertical rollers are arranged
between the bearing of horizontal rollers in the vertical plane. It is widely used to produce blooms
from Ingot, and for rolling wide flange H-Section beams.
 Plant Briefing
There are 3 areas of the girder mill which names are following:

1. Billet yard area

2. Mill side area

3. Workshop area

Flow Diagram

Billet yard

RH Rough
FFC Dead lifty
Furance stand

Stand no Stand no
Conveyor Live lifty
09 01

Cooling Hot saw Hot saw Hot saw

Bed 01 cuuter 01 cutter 02 cutter 03

Hot saw Hot saw Cooling

cutter 05 cutter 04 Bed 02
MCB 01

MCB 02

Cold Saw Cold Saw

cutter 01 cutter 02
Billet Yard:
The area in which billets installs for the implementation of girder making. From this area billets
charge in the re-heating furnace through the charging bed.

Billet side area has 3 over-head cranes for carry the billets, loading and unloading. And the capacity of
each crane is 20ton.

Furance
A furnace is a device used for high temperature heating. The heat energy to fuel a furnace maybe
supplied directly by fuel combustion. Furnace is essentially a thermal enclosure and is employed to
process raw materials at high temperatures both in solid state and liquid state. Pusher type reheat
furnace dual fired. In this type of furnace cold steel stock is pushed forward with the help of pusher at
charging side. Earlier these furnaces were designed for heating billets. The length of earlier furnace
was sort in length 16m and 7m wide and sloped downward longitudinally towards the discharge and
in order to permit easy passage of steel stock through the furnace. After extending the furnace a new
heating zone is added to furnace and now new size of furnace is 7m wide and 21m in length.

Furnace Capacity
The old capacity of furnace was 30T per hour but after extension new capacity is 45T per hour.
Explanation: In steel plants reheating furnaces are used in hot rolling mills to heat the steel stock
(Billets) to temperature of around 1300 degree centigrade which is suitable for plastic deformation of
steel and the heating material is low or medium steel. The heating process in a reheating furnace is a
continuous process where the steel stock is charged at the furnace entrance heated in the furnace and
discharge at furnace exit. Heat is transferred to the steel stock during its traverse through the furnace
mainly by means of convection and radiation from the burner gases and the furnace walls. Reheating
furnace is categorized in Four zones.

 Recuperative zone or recovery zone

  Preheating zone
 Heating Zone
 New heating zone
 Soaking Zone
The target exit temperature of steel stock in governed by the requirement of the process of rolling
which is dependent on rolling speed stock dimension and steel composition.

Mill Side Area:

In Mill side there are total nine stands including one Rough stand every stand have there own working
principle.

Rough stand
In Rough stand Billet is pass from it at recrystallization temperature with the help of rollers so
according to the requirements three or more pass are decided according to the requirements.In this
stand rough shape of grider is formed. The rough stand has three big shaft rotating known as the
pinion shaft which can deliver equal amount of power in each pass through this stand the pinion shaft
gear teeth should be less than 20 There is two corners of girder one is web and second is flange in this
mill they made 6”x4”,7”x4”,8”x4”,9”x4” girder size this selected according to the billet size generally
billet size is 6”x6” and 5”x6” this shows that the flanges size remains same and the web size changes.

Working principle
At the start D.C motor have 2500rpm we need to reduce the rpm and increase the torque the output
shaft of D.C motor is attached with a input of Pulley that reduces its rpm,(Input of pulley has a small
diameter as we know by increasing the diameter the number of rpm is reduced and torque is
increased)

Fly Wheel
A flywheel is a mechanical device that stores rotational energy. It consists of a heavy disc or wheel
that is mounted on an axle and can rotate freely. The primary function of a flywheel is to regulate and
maintain the speed of a machine.

Reduction Gear
Reduction gearboxes, also known as torque multipliers or speed reducers, are employed to reduce the
output speed of the motor. Reduction gearboxes are very simple to manufacture, such as a gear train
between a motor and machinery.The ratio of the outputs to the input gear is such that it allows the
output shaft to move more slowly, thereby supplying increased torque and reduced speed.

Pinion Gear
Basically, the function of pinion gear is to transmit equal amount of torque and rpm that is received at
the input shaft of pinion gear.

Calculation no of RPM
RPM of D.C motor = 735rpm
Dia of small pulley =650mm
Dia of large pulley =1600mm
Gear Ratio =1:5
650
RPM at input of gear= × 735
1600
¿ 298.5 rpm
298.5
RPM at input shaft of Pinion gear=
Gear ratio
298.5
5
¿ 60 rpm

Discussion
So,in this way we calculate the total rpm which are required,60 rpm is delivered after reduction
at the input shaft of pinion gear so,our rollers of rough stands are rotating at 60rpm to make
rough shape of grider.

Cutting section
After the final finishing of girder from the stands the auto cutter cut the girder according to required
size there are five cutters and at the end which can cut the girder according to the required size
moreover the cutting section contains two cooling bed bed which is fully control by operator and the
bed moved by the chains and comes down from the surface.Cutter are operated hydraulically which
are responsible the movement of cutter.
Coupling:
A coupling is a device used to connect two shafts together at their ends for the purpose of transmitting
power. The primary purpose of couplings is to join two pieces of rotating equipment while permitting
some degree of misalignment or end movement or both.

Types of Coupling
There are two types of coupling one is Rigid coupling and other is flexible coupling we are using Gear
coupling as it is type of flexible coupling the reason we are using this type of coupling is that Gear
couplings are mechanical devices that connect two rotating shafts to transmit torque between them.
They consist of two hubs with external teeth or gears, which are connected by a sleeve or coupling
ring with internal teeth or gears.. The primary function of a gear coupling is to transmit power and
torque between two shafts while allowing for some misalignment between them. Gear couplings are
designed to handle high torque and provide a reliable and durable connection that can operate in harsh
environments.
 Schematic Diagram

Conclusion:
The working principle of all other stands are same as discuss in above except working of flywheel.
Because flywheel has to transfer power when sudden jerk of WAPDA is comes.Stand no 05 gives the
fine finishing to the grinder and stand no 09 imposed the stamp of company on grinder. Stand number
1,2 and 7 are Classic stand because they are operated manually and others stands are Universal stand
because they are operated hydrucially
CHAPTER NO 03
Bearings
 A bearing is a mechanical element that supports load, constrains relative motion
between moving parts to only the desired motion..
 The term “bearing” is derives from to bear a bearing being a machine element that
support part to bear (i.e., to support another)

 Bearing Terminology

 Types of Bearings
 LOAD DIRECTION AND NAME

 BEARING LIFE
The bearing size to be used for an application can be initially selected on the basis of
its load ratings in relation to the applied loads and the requirements regarding service
life and reliability.
Types of Load Life and Reliability
1. Static Load
2. Dynamic Load

 Static And Dynamic Loads Life:

Dynamic bearing loads life :

1. Life of an individual bearing is define as the number of revaluations which the
bearing run before the first evidence of fatigue crack in the ball and race.
2. The minimum life is one million revolutions.

Rating Life (L10):

It is defined as a number of revolutions that 90% of the bearing will complete or
exceed before the first evidence of fatigue crack.

 Static bearing loads

1. The basic static load rating C0 is used in calculations when the bearings are to rotate at
very slow speeds (n < 10 r/min).
  Bearing Desigination
First digit:
The first digit indicates the type of bearing e-g 6 indicates deep groove bal bearing.

Second Digit:
The second digit indicates the series of bearing.
0 – Extra Light
1 – Extra Light
2 – Light
3 – Medium
4 – Heavy

Third and forth digit:

 From third and forth digits we will calculate the bore size of bearing by
multiplying them by 5
 e-g (6 x 5 = 30)
 Suffix
1. 2RS & C3
 2RS - both sides are covered with rubber seal
 C3 – Greater than normal
  Bearing Arrangements

TYPES Of Arrangements
1. Locating and non-locating bearing arrangements,
2. Floating bearing arrangements.

 Locating and non-locating bearing arrangements

The locating bearing at one end of the shaft provides radial support and at the same time
locates the shaft axially in both directions. It must, therefore, be fixed in position both on
the shaft and in the housingThe non-locating bearing at the other end of the shaft provides
radial support only. It must also allow axial displacement so that the bearings do not
mutually stress each other, e.g. when the shaft length changes as a result of thermal
expansion.

 What are Fits

Fit is defined as a degree of tightness or looseness between two mating parts to perform
definite function when they are assembled together.

Types of Fits
Clearance fit
Transition fit
Interference fit
 Clearance fit
In this type of fit the shaft diameter is always less than the hole diameter.

 Interference fit
In this type of fit the minimum diameter of the shaft is always greater than the maximum
size of the hole.

 Transition fit
This type of fit lies mid way between clearance fit and interference fit. In this type size limits
on the mating parts so selected may give clearance fit or interference fit depending on the
actual sizes of the parts.
 Selection of Fits
When selecting a fit, the factors discussed in this section should be considered,
together with the general guidelines provided.

1. Conditions of rotation
Conditions of rotation refer to the bearing ring being considered in relation to the
direction of the load ( table 1). Essentially, there are three different conditions:
“rotating load”, “stationary load” and “direction of load indeterminate”.
CHAPTER NO 04
HYDRAULIC SYSTEMS
Hydraulics is a mechanical function that operates through the force of liquid pressure.In
hydraulics-based systems, mechanical movement is produced by contained, pumped
liquid, typically through hydraulic cylinders moving pistons.

 Working Principle
 The reservoir holds hydraulic fluid.
 The hydraulic pump moves the liquid through the system and converts mechanical
energy and motion into hydraulic fluid power.
 The electric motor powers the hydraulic pump.
 The valves control the flow of the liquid and relieve excessive pressure from the
system if needed.
 The hydraulic cylinder converts the hydraulic energy back into mechanical energy.

 Pumps
A pump is a mechanical device used to force a fluid (a liquid or a gas) to move forward
inside a pipeline or hose. They are also used to produce pressure by the creation of a
suction (partial vacuum), which causes the fluid to rise to a higher altitude.
 Classification
  Schematic Flow Diagaram

 The hydraulic actuator

 It is a device used to convert fluid power into mechanical power to do useful work.
The actuator may be of the linear type (e.g., hydraulic cylinder) or rotary type(e.g.,
hydraulic motor) to provide linear or rotary motion, respectively.
 The pressurized hydraulic fluid delivered by the hydraulic pump is supplied to the
actuators, which converts the energy of the fluid into mechanical energy. This
mechanical energy is used to get the work done.

TYPES OF ACTUATORS
1. Linear Actuators (Hydraulic cylinders)
2. Rotary Actuators (Hydraulic motors)
a. Continuous rotary actuators
b. Semi rotary actuators

Functions Of Actuators :
1) To produce motion in one line
2) To produce continuous rotary motion
3) To produce rotary or oscillatory motion less than 3600
4) To apply a force and clamp the job.

 The hydraulic Pump

 It is used to force the fluid from the reservoir to the rest of the hydraulic circuit by
converting mechanical energy into hydraulic energy.
  A pump which is the heart of a hydraulic system converts mechanical energy into
hydraulic energy. The mechanical energy is delivered to the pump via prime mover
such as the electric motor. Due to the mechanical action the pump creates a partial
vacuum at its inlet. This permits atmospheric pressure to force the fluid through
the inlet line and into the pump. The pump then pushes the fluid into the hydraulic
system.
Importance of Pump :

1. They convert mechanical energy into hydraulic energy.

2. The Volumetric efficiency of the pump is relatively high
3.They have high-performance characteristics under varying speed and pressure
requirements
4.Pumps used to generate high pressure in the hydraulic system

 Valves
 Valves are used to control the direction, pressure, and flow rate of a fluid flowing
through the circuit.
Motor 1 – Off 2 – Forward 3– Return 3 2 1 Load Direction control valve Pump Oil
tank Filter Actuator Pressure regulator.
 A fluid power system can be broken down into three segments. The power input
segment consisting of the prime mover and the pump. The control segment consisting
of valves that control the direction, pressure, and flow rate. The power output
segment, consisting of the actuators and the load. This unit is devoted to each of the
following categories of control valves.
1. Directional control valves
2. Pressure control valves
3. Flow control valves
 DCVs control the direction of flow in a circuit, which among other things; can
control the direction of the actuator. PCVs control the pressure level, which controls
the output force of a cylinder or the output torque of a motor. FCVs control the flow
rate of the fluid which controls the speed of the actuators.
Different types of valves and their functions

1. Pressure relief valves – Relief valve opens and bypasses fluid when pressure
exceeds its setting. These are used mostly in all circuits.
2. Pressure-Reducing Valve – This type of valve (which is normally open) is used
to maintain reduced pressures in specified locations of hydraulic systems.
3. Unloading Valves – high-low pump circuits where two pumps move an actuator at
a high speed and low pressure, punching press.
4. Counterbalance valves – They are used to prevent a load from accelerating
uncontrollably. This situation can occur in vertical cylinders in which the load is a
weight. This can damage the load or even the cylinder itself when the load is
stopped quickly at the end of the travel.
  Oil Tank or Reservoir:

 This is an oil storage tank in which hydraulic oil is stored. The oil passes through
various pipelines and after doing useful work in actuator; the oil returns to the oil
tank. In the regions of low temperature, oil heaters are attached to air tanks.
 Reservoir is used to hold the hydraulic liquid, usually hydraulic oil.
 Pipelines :

 Pipelines (Fluid Conducting elements): It is the functional connection for oil flow in
the hydraulic system. The efficiency of oil flow is greatly influenced by the physical
characteristics of piping systems.
 There are two pipes:
a) The pipe which carries pressurized oil is called pressure pipelines
b) Pipes that carry low pressurized oil or used oil (are called as return pipelines).
 Hoses, pipes, pipe fitting are the parts of the fluid power pipeline.
 Filters

 It is used to remove any foreign particles so as keep the fluid system clean and
efficient, as well as avoid damage to the actuator and valves.
 When hydraulic fluids are contaminated, hydraulic systems may get damaged and
malfunction due to clogging and internal wear. They require filtration to remove
contaminants.
 Filters are classified as
i. Reservoir filters:
ii. Line filters
iii. Off-line filters
iv. Other cleaning equipment

Functions of Filter:
1) Take care of the cleanliness of the components.
2) Reduce the maintenance.
3) To remove silting.
4) To increase the system reliability.
5) To prevent the entrance of solid contaminants to the system.
 Accumulators

 Accumulators are devices that store hydraulic fluid under pressure. Storing hydraulic
fluid under pressure is a way of storing energy for later use. Perhaps the most
common application for an accumulator is supplementing the pump flow in a
hydraulic system in which a high flow rate is required for a brief period of time.

Types of Accumulators ;
1. Weight loaded accumulator
2. Spring-loaded accumulator
 3. Gas-charged accumulator
4. Piston type
5. Bladder type
6. Diaphragm type
Hydraulic Power Pack :

 The hydraulic power unit (power supply unit) provides the energy required for the
hydraulic installation.
 The main components of power packs are – The reservoir (tank), Drive (electric
motor), Hydraulic pump, Pressure relief valve, filter, and cooler.
 The pump or motor unit may be mounted on the tank or separately a packs are
usually available in either horizontal or vertical configurations. The basic unit
may be piped to the cylinders or actuators through a suitable control valve.
The hydraulic power packs consist of a reservoir/tank that house the hydraulic fluid,
which is the working medium.