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CHAPTER ONE WELDING
Welding is the process of permanently jointing two or more pieces of
material, often metallic, together by the application of heat, pressure,
Or both
1.1 Shielded Metal Arc Welding (SMAW)
The heat generated melts a portion of the tip of the electrode, its
coating and the base metal in the immediate area of the arc. A weld
forms after the molten metal a mixture of base metal (work piece),
electrode metal, and substance from the coating on the electrode
which solidifies in the weld area
Fig. 1.1
SMAW
1.2 Submerged Arc Welding (SMAW)
The flux is fed into the weld zone by gravity flow through a nozzle.
The thick layer of flux completely covers the molten metal and
protects the metal from spat
process. The flux also acts as thermal insulator, allowing deep
penetration of heat into the work piece.
The consumable electrode is coil of bare round wire and is fed
automatically through a tube (welding gun)
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Submerged Arc Welding (SMAW)
The flux is fed into the weld zone by gravity flow through a nozzle.
The thick layer of flux completely covers the molten metal and
protects the metal from spatter, sparks and fumes of the SMAW
process. The flux also acts as thermal insulator, allowing deep
penetration of heat into the work piece.
electrode is coil of bare round wire and is fed
automatically through a tube (welding gun)
Fig. 1.2
SMAW
The flux is fed into the weld zone by gravity flow through a nozzle.
The thick layer of flux completely covers the molten metal and
ter, sparks and fumes of the SMAW
process. The flux also acts as thermal insulator, allowing deep
electrode is coil of bare round wire and is fed
1.3 Gas Metal Arc Welding (GMAW)
In gas metal arc welding (GMAW) the weld area is shielded by an
external source of inert gas, such as argon, helium, carbon dioxide
or various other gas mixtures.
The consumable bare wire is fed automatically throu
the weld arc. In addition to the use of inert shielding
are usually present in the electrode metal itself to prevent oxidation
of the molten weld puddle
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Gas Metal Arc Welding (GMAW)
In gas metal arc welding (GMAW) the weld area is shielded by an
external source of inert gas, such as argon, helium, carbon dioxide
or various other gas mixtures.
The consumable bare wire is fed automatically through a nozzle into
the weld arc. In addition to the use of inert shielding gas, d
are usually present in the electrode metal itself to prevent oxidation
of the molten weld puddle
Fig. 1.3
GMAW
In gas metal arc welding (GMAW) the weld area is shielded by an
external source of inert gas, such as argon, helium, carbon dioxide,
gh a nozzle into
gas, deoxidizers
are usually present in the electrode metal itself to prevent oxidation
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1.4 Defects Of Welded Joints
1. Porosity
Caused by trapped gases released during solidification of the weld
area by chemical reactions during welding or contaminants
2. Incomplete fusion
Poor weld beads
3. Incomplete penetration
Occurs when the depth of the welded joint is insufficient
4. Slag inclusion
Are compounds such as oxides, fluxes, and electrode coating
materials that are trapped in the weld zone
1.5 Welding inspection
1. Ultrasonic
Ultrasonic
nondestructive testing is
well established as a
method of insuring the
integrity of structural
welds in steel, titanium,
and aluminum, being
able to identify cracking,
porosity, incomplete
penetration, inclusions,
and lack of sidewall
fusion, and similar Fig. 1.4
defects that can compromise ultrasonic inspection
weld strength
2. Dye penetrant inspection
Nondestructive testing
low surface tension is poured on to
the surface of the welded joint it
seeps into the crack or cavity.
Wiping the surface of the p
metal and weld leaves liquid in the
crack
3. Visual inspection
The experienced inspector will examine the joint visually,
dimension or weld depth by universal weld gauge and fillet angle
by simple fillet weld gauge
Fig. 1.5
Simple fillet weld gauge
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Dye penetrant inspection
Nondestructive testing if liquid has
low surface tension is poured on to
ce of the welded joint it
seeps into the crack or cavity.
Wiping the surface of the parent
metal and weld leaves liquid in the
Fig. 1.4
Dye penetrant inspection
experienced inspector will examine the joint visually,
dimension or weld depth by universal weld gauge and fillet angle
by simple fillet weld gauge
Fig. 1.5 Fig. 1.6
Simple fillet weld gauge Universal weld gauge
Dye penetrant inspection
experienced inspector will examine the joint visually,
dimension or weld depth by universal weld gauge and fillet angle
Fig. 1.6
Universal weld gauge
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CHAPTER TWO FLUID POWER
Fluid power is technology that deals with the generation, control and
transmission of power using pressurized fluids. It can be said that fluid
power is the muscle that moves industry. This is because fluid power is
used to push, pull, regulate or drive virtually all the machines of
modern industry
2.1 Hydraulic pumps
A pump which is the heart of the hydraulic system converts
mechanical energy into hydraulic energy. The mechanical energy is
delivers to the pump via prime mover such as an electric motor. Due
to 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
2.1.1 Gear pump
a. External gear pump
Develops flow by crying fluid between the
teeth of two meshing gears. One of the gears
connected to drive shaft connected to prime
mover. The second gear is driven as it
meshes with the driver gear
Fig. 2.1
External gear pump
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b. Internal gear pump
This pump consists of an internal
gear or pinion, a regular spur gear
or ring gear and crescent shaped
seal. As power is applied to an
internal gear the motion of the
gear draws the fluid from reservoir
and forces it around both sides of
the crescent seal which acts seal
between the suction and discharge Fig. 2.2
ports when the teeth mesh on the Internal gear pump
side opposite to the crescent seal, the fluid forced to enter the
discharged port
2.1.2 Piston pumps
A piston pump works on the principle that a reciprocating piston
can draw in fluid when it retracts in the cylinder bore and
discharge it when it extends
a. Axial piston pump
That contains a cylinder
block rotating with the drive
shaft. However, the
centerline of the cylinder
block is set at an offset angle
relative to the center line of
the drive shaft
Fig. 2.2 axial piston pump
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b. Radial piston pump
This design consists of a pintle to
direct fluid in and out of a
cylinder. A cylinder barrel with
pistons and rotor containing
reaction ring for pumping action
the reaction ring is Fig. 2.3
moved eccentrically with respect Radial piston pump
to pintle or shaft axis. As the cylinder barrel rotates the piston
on the one sides travel outward
2.2 Directional Control Valve
Direction control valve are used to control the direction of flow in
hydraulic circuit. Any valve (regardless of its design) contains ports
that are external openings through which fluid can enter and leave
via connecting pipe lines
1. Check valve
Is two ways that used to
permit free flow in one
direction and prevent any flow
in the opposite direction.
Fig. 2.3
Check valve
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2. Three ways or four valves
Three ways valves contain
three ports and four ways
contain four ports they are
typically of the spool design. A
spool is a circular shaft
containing lands that are large
diameter sections machined
to slide in a very close fitting
bore of the valve body. The
spool can be actuated by
compressed fluid or gas or
pneumatic, mechanically (cam
and spring), manually and solenoid Fig. 2.4
Four ways valve
2.3 Hydraulic cylinder
Pumps perform the function of
adding energy to the hydraulic
system for transmission to some
output location. Hydraulic cylinder
does just the opposite as a linear
motion. They extract energy from
the fluid and convert it to
mechanical energy to perform
useful work
Fig. 2.5 Hydraulic cylinder
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2.4 Hydraulic motors
A limited rotation hydraulic motor provides rotary output
motion over a finite angle. This device produces high
instantaneous torque in either direction and requires only a
small space and simple mounting
Hydraulic motors can rotate continuously and as such have the
basic configuration as pumps. However, instead of pushing n
the fluid as pumps do, motors are pushed on by the fluid
In the way hydraulic motors develop torque and produce
continuous rotary motion
Hydraulic motors types
a. Gear motor
b. Piston motors
CHAPTER THRE DIESEL ENGINE
A diesel engine (also known as a compression
internal combustion engine
initiate ignition to burn the
chamber. This is in contrast to spark
engine (gasoline engine) or
to gasoline), which uses a
3.1 How diesel engines work
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CHAPTER THRE DIESEL ENGINE
A diesel engine (also known as a compression-ignition engine) is an
internal combustion engine that uses the heat of compression
to burn the fuel, which is injected into the combustion
. This is in contrast to spark-ignition engines such as a
(gasoline engine) or gas engine (using a gaseous fuel as opposed
), which uses a spark plug to ignite an air-fuel mixture
How diesel engines work
Fig. 3.1
Diesel Cycle PV
ignition engine) is an
heat of compression to
combustion
ignition engines such as a petrol
(using a gaseous fuel as opposed
fuel mixture
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The diesel internal combustion engine differs from the gasoline
powered Otto cycle by using highly compressed hot air to ignite the
fuel rather than using a spark plug (compression ignition rather than
spark ignition).
In the true diesel engine, only air is initially introduced into the
combustion chamber. The air is then compressed with a
compression ratio typically between 15:1 and 22:1 resulting in 40-
bar (4.0 MPa; 580 psi) pressure compared to 8 to 14 bars (0.80 to
1.4 MPa) (about 200 psi) in the petrol engine. This high
compression heats the air to 550 °C (1,022 °F). At about the top of
the compression stroke, fuel is injected directly into the compressed
air in the combustion chamber. The fuel injector ensures that the
fuel is broken down into small droplets, and that the fuel is
distributed evenly. The heat of the compressed air vaporizes fuel
from the surface of the droplets. The vapor is then ignited by the
heat from the compressed air in the combustion chamber, the
droplets continue to vaporize from their surfaces and burn, getting
smaller, until all the fuel in the droplets has been burnt. The start of
vaporization causes a delay period during ignition and the
characteristic diesel knocking sound as the vapor reaches ignition
temperature and causes an abrupt increase in pressure above the
piston. The rapid expansion of combustion gases then drives the
piston downward, supplying power to the crankshaft.
Fig. 3.2 Diesel engine process
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3.2 Engine parts
Fig. 3.3
Engine parts
1. Piston cylinder
A cylinder is the central working part of a reciprocating
engine or pump, the space in which a piston travels.
Multiple cylinders are commonly arranged side by side in a
bank, or engine block, which is typically cast from aluminum
or cast iron before receiving precision machine work. The
reciprocating motion of the pistons is translated into
crankshaft rotation via connecting rods.
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Fig. 3.4
Piston
2. Crank shaft
It is the part of an engine that translates reciprocating linear
piston motion into rotation. To convert the reciprocating
motion into rotation, the crankshaft has "crank throws" or
"crankpins", additional bearing surfaces whose axis is offset
from that of the crank, to which the "big ends" of the
connecting rods from each cylinder attach
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Fig. 3.4
Crank shaft
3. Fuel injector
The injector on a diesel engine is its most complex
component and has been
the subject of a great deal
of experimentation. In any
particular engine, it may be
located in a variety of
places. The injector has to
be able to withstand the
temperature and pressure
inside the cylinder and still
deliver the fuel in a fine
mist. Getting the mist
circulated in the cylinder so
that it is evenly distributed Fig 3.5 Fuel injector
is also a problem, so some diesel engines employ special
induction valves, pre-combustion chambers or other devices
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to swirl the air in the combustion chamber or otherwise
improve the ignition and combustion process.
4. Turbo charger
Turbochargers are a type of forced induction system. They
compress the air flowing into the engine. The advantage of
compressing the air is that it lets the engine squeeze more
air into a cylinder, and more air means that more fuel can be
added. Therefore, you get more power from each explosion
in each cylinder. A turbocharged engine produces more
power overall than the same engine without the charging.
This can significantly improve the power-to-weight ratio for
the engine
Fig. 3.6 Turbocharger
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CHAPTER FOUR INDUSTRIAL SAFETY
4.1 Industrial safety
Is recognizing and evaluating the problem size and eliminate control or
reduce the danger from the bad effect of this danger and also to
training and educate the workers on this type of industrial safety
equipment.
Normal physical conditions:
The worker must work in the original life condition to make safe on his
healthy.
The normal physical conditions are: -
1- temperature at 37-37.8C 2- relative humidity 45% 3- Air at 1 atmosphere 4- uncontaminated air and dust free 5- acceleration at 1g = 9.8 m/sec
2 6- day light 7- noise less than 80DB
The environmental conditions are:-
1- Too hot or too cold. 2- Noise. 3- Sufficient light. 4- Color. 5- Relative humidity. 6- Vibration of the machine.
7- Air particulate. 8- Gases of high harm. 9- Water and chemical vapors.
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4.2 Air Pollution:
Types of air pollutants:
1-Dust:
Is contain the smoke and fine dust and fibers, the different between
these types of dust is it volume and length.
2-Gases:
Is the gases produced by the act of the industrial operations and
manufacturing process.
3-Vapors:
Is a vapors produced from the vaporization of the water and benzene
and toluene and alcohol.
4-Smoke:
Is a small droplet of a diameter from (0.001 to 1)?
4.3 Fire Accidents:
The combustion is a very fast combination of two or more material with
high flammability in sufficient of a suitable catalyst.
Type of fire:
• complete combustion
• incomplete combustion
4.4 Accidents:
The accident is a sudden chock occurs to the work.
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Accident types:
• General accident far away from the work area.
• Industrial operations accidents.
• Disaster accidents (normal disaster).
The losses occur from the accidents:
1- Losses in the materials machine and work. 2- Stop the work to a certain time interval. 3- Worker injury.
4- Loss in the production of a well trained worker. 5- Healing the worker cost. 6- Give money for the dead and high injury workers.
4.5 Problems occurs in work area
There are much trouble may occur in the working such as:
• The human mistakes or the folly behavior.
• The ability of the worker to deal with the machine.
• Bad weather condition (noise, humidity).
• Worker inattention.
• Stairs bad construction.
• Stresses for any reason.
• Human sociology.
• The bad cleaning of the work area.
• Holes in the floor without attention.
• Bad organizing of the internal transport.
• Transmission of motion belt uncovered.
• Transportation mistakes(mechanical, etc)
• Bad use of hand tools.
• Foal of bodies on workers without saving.
• Toxic material escaping.
• Flame causes improvement.
• Walls foaled on the workers.
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• Atomic radiation.
• Sudden conditions.
• Bad system organization of the factory management.
• Workshop machine and the revolving body volatile.
• Explosion and fire accidents.
• Transportation’s accidents.
• Electrical mistakes.
• Brake down of building and machine.
• Surface condition unsuitable.
4.6 Engineer Rule:
The engineers have the digest rule in the accident happening or
accident protection. So we will now discus it now:
1- Building and machine maintenance. 2- Organizing and clean the work area. 3- Worker training on the industrial safety equipment’s. 4- Check on the worker health periodically. 5- Presents to the good worker or the best one on using the
industrial safety equipment. 6- Be sure on the safety of the hand tool.
7- Training and paste a instruction notes.
8- Applies the physical engineering giving to improve relaxation
the worker in his work.
9- Make protection on the danger machine especially in the
revolving machines.
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4-7 protection from Workshops Machine:
To make sure that the workshops machine is in safe usage for the
workers. The following Precautions Must Be Taken into
Consideration:
1- The machine must be stopped during maintenance. 2- No one deal with the machine except the training worker. 3- The industrial safety equipment must be taken in to
consideration. 4- Ensure of installing the tools on the machine. 5- Light availability.
6- Cleaning tools must be available and use on the chip cleaning. 7- Make a wall around the revolving parts of the machine.
4-8 Safety Instructions and Sings:
Safety signs in the company departments are hanged on all walls
and all labors and engineers follow their instructions.
Fig. 4.1 safety instructors
Recommended