STRENGTH OF MATERIALS

Stress : Force of resistance offered by a body against the deformation

Load : External force acting on the body
Strain; Ratio of the change in length to the original length e = δl / l
Tensile stress : When the resistance offered by a section of a member against an
Increase in length = load/ area of cross section = W/a

Shear force : force acting tangentially along a surface

Shear stress : Shear resistance or Shear load = R

Shear area area of cross section L* i

Bearing stress : If the compressive load is not uniform over the cross section are then the
resulting compressive stess induced is Bearing stress

Induced stress( simple stress): The total resistance offered by the component per unit area
of cross section.

Allowable stress = Ultimate compressive strength

Factor of safety

Shear Strain : Transverse Displacement

Distance from the lower face

Hooks law : Intensity of Stress = A constant

Strain
Youngs Modulus / Modulus Of Elasticity : In case of a axial loading the ratio
of the intensity of tensile or compressive stress to the corresponding strain is a constant
E = stress(f)/strain(e)

Shear modulus or Modulus of Rigidity : Ratio of shear stress corresponding shear strain
is found to be a constant
C , N ,G = Shear stress (fs)
Shear strain (ϕ)
Bulk modulus : ratio of direct stress to corresponding volumetric strain is constant with in
certain limit.

Poisson`s Ratio : Lateral Strain = 1/m

Longitudinal strain

Bending Moment : At any section of beam is the algebric sum of all the moments of
external force acting on either side of the section under consideration.

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Flexural formula – M/I = f/y or M = FI/y
f.I/y - resistance moment
Moment of resistance : The resisting moment offered by a beam section to resist the
bending moment at the section.

Polar moment of inertia = Shaft section/ maximum radius, This ratio is called polar
section modulus T/J = fs/R ,the term J/R is polar section modulus = πD4/32
Bearing characteristic number : ZN/p , Z- absolute viscosity,N-speed of the journal , p is
the bearing pressure.

Co efficient of fluctuation of energy: The ratio of maximum fluctuation of energy to the

net work done per cycle. K e = dE/E
Equalent twisting moment: √M² + √T² = T e

Factor of safety : Ultimate Stress

Design{allowable} Stress
Shear force: the resultant force acting on any one of the parts normal to the axis of the
member.

Bending Moment: is the algebric sum of moment of forces and reactions acting on one
side of the section.

Hogging bending moment: tendency of the bending moment at section is to bend it so as

to produce convexity above the centre line is called hbm.

Point of contraflexture: A section at which the B.M is zero is the point of contraflexture.

Simple bending: Between A and B the beam is absolutely free from shear but is subjected
to a bending moment Wa. This condition of the beam between A and B is called Pure
bending or simple bending.
The bending equation : M/I = f/y =E/R

Section modulus = Moment of inertia about neutral axis

Distance of the most distant point from the neutral axis
Z = I / Y max

Torsional rigidity : torque required to produce a twist of 1 radian per unit length of the
shaft
Torsional stiffness: the amount of torque required to twist the shaft through 1 radians

2
Buckling load or critical or crippling load: When members start bending i.e buckling
when the axial load reaches a certain critical value.Once a member shows signs of
buckling it will lead to the failure of the member. This load at which the member just
buckles is called buckling load.

Slenderness ratio: The ratio L/K = effective length/ Least radius of Gyration

Euler’s formula
1.When both ends ends of the column are pinned ( hinged)
Crippling( critical) load = P = π²EI/ l²
2. When one end of the column is fixed and the other end is free
Crippling load = P = π²EI/4 l²
3. When both ends of the columns are fixed
Crippling Load = P = 4 (π²EI/ l²)
4.When one end of the column is fixed and other end is pinned
Crippling load = P = 2 π²EI/ l²

Rankine ‘s formula for critical stresses

P = Crushing load
1 + α (L/K)²
Crippling load = safe load * factor of safety
Maximum normal stress theory
½( M + √M+√T²)- equivalent bending moment

Unwin’s formula for rivets

d = 6.05√ t

Volumetric strain : Change in volume

Original Volume

Longitudinal strain = change in length / original length

Circumferential strain = change of circumference/original circumference
Centre of gravity: of a body is that point through which the resultant of the system is
parallel forces formed by the weights of all the particles of the body posses for all
positions of the body.

Uniform Lamina : Lamina where particles within equal areas of the lamina are equal to
weight

Radius of Gyration: Of a given lamina about a given axis is that distance from the given
axis at which all elemental parts of the lamina would have to be placed so as not to alter
the moment of inertia about the given axis.

3
Perpendicular Axis theorm: If I ox and I oy be the moments of inertia of a lamina about
mutually perpendicular axes OX and OY in the plane of the lamina Ioz be the moment of
ineretia of the lamina about an axis normal to the lamina and passing through the point of
intersection of the axes OX and OY

Parallel Axis theorm: The moment of inertia of a lamina about any axis in the plane of
the lamina equals the sum of the moment of inertia about a parallel centroidal axis in the
plane of the lamina and the product of the area of the lamina and the square of the
distance between the two axes.

Effective span: the horizontal distance between the centres of the end bearings

Mechanism : the study of the physical arrangement of various links and their relative
motion

Links : is a rigid body paired with other parts of machine for the purpose of transmitting
force or motion. a) Rigid b)Flexible c)fluid

Constrained motion: A change in position of a body with respect to a fixed point is called
motion. If motion takes place in a definite direction it is called constrained motion.
a)Completely constrained: If constrained motion is obtained by its own link, eg. Shafts
with a collars in a bearing ,rectangular bar moving in a rectangular hole.
b)Successfully constrained( partially constrained) motion: Is one in which the constrained
motion is not complete by its own links but obtained by some other means. Ed. Foot step
bearing , Rotor on a vertical shaft.
c)Incompletely constrained motion:If motion between two links takes place more than
one direction Eg. A circular bar moving in circular hole.

Kinematic Pair:A joint between two links that permits relative motion is called kinematic
power and links are called pairing elements
a)Sliding b) turning c)rollingd)Screw pair e)spherical - Nature of Relative motion
a)Lower b) Higher - Contact between pairing elements
a)Closed b)Open – Mechanical arrangements

Turning pair: Crankshaft turning in a bearing , connection between cross head and
connecting rod
Rolling Pair:Ball and roller bearings
Screw :Sliding and turning takes place
Spherical pair – ball and socket

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Lower Pair :is one which permits surface contact between two links while in motion
Eg.Connection between connecting rod and crank shaft, steering gear,shaft revolving in a
bearing , piston and cylinder liner.

Higher Pair:which permits only point or line contact while in motion eg. Cam & follower
Belt, rope ,chain drives ,ball & roller bearing,mating gear teeth.

Kinematic chain: when a no of links are joined by means of kinematic pair the resulting
system is called Kinematic chain.
L = 2p – 4 ( L – no of links, p – no of pairs)
Structure ( locked chain): arrangements of links in which no relative motion exists
Eg. Bridges,roofs

Inversion: is the making of different mechanisms by fixing different links.

Four – link mechanism consists of 4 lower pair 1)four bar chain(quadric cycle chain) 2)
the slider – crank chain
Practical examples of these mechanisms are
1.Coupled wheels of locomotive ( Double – crank mechanism)
2.Beam engine ( crank -lever mechanism)
3.The watt mechanism,pantograph,steering gear mechanism- (Double lever mechanism)

Slider- Crank mechanism: has four links with three turning pairs and one sliding pair.
This is employed in reciprocating engines
The four possible inversions are
1.Quick return mechanism (slotted lever type) – shaper
2.whitworth quick return -, Slotter Shaper
3.Pump : air pump , hand press
4.Slider crank chain – reciprocating engine

Double slider : having two turning and two sliding pairs- used in Elliptical trammel
Oldham’s coupling – inversion of double slider chain is used to connect two parallel
shafts placed at a smaller distance.

The frictional forces always acts parallel to two contacting surfaces.

Static friction: The friction acting on the body which is at rest

Limiting friction: the limit beyond which the force of fricion cannot increase.

5
Kinetic or Dynamic friction:the friction acting on a body which is actually in motion

Co efficient of fiction: the ratio of limiting force of friction to the normal reaction. F =µR

Angle of friction: The angle between the resultant reaction and the normal reaction at
limiting condition. Tanϕ = µR/ R

Angle of repose: the maximum angle of the inclined plane at which a body can remain in
equllibrium on the plane entirely by the friction. F = W sin θ and R = W cos θ ,µ = F/R =
tan θ , θ is angle of response.

Cone of friction: : Cone which is generated by rotating the resultant reaction about the
normal reaction
Screw friction .
For lifting load P1 = w .tan(α +ϕ)
Efficency – Ideal torque / actual torque = Tan α
tan(α +ϕ)

Sensitiveness: it is the ratio of the ratio of the difference between the maximum and
minimum equilibrium speed to the mean equilibrium speed of the governor.
Sensitivity= ω / ω1- ω2

Isochronism : a governor is said to be isochrous if it runs at a particular speed for any

position of sleeve within the working range.

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 THERMO DYNAMICS

The branch of science which deals with the various types of energy transformations and
relationship between the various properties of the working substance

Boyle’s law : The volume of a given perfect gas varies inversely as its absolute pressure
provided the temperature is kept constant
V directly proportional to 1 / P , pv = constant , p1 v1 = p2 v2 , p – absolute pressure

Charle’s law: The volume of a given mass of a perfect gas varies directly as its absolute
temperature provided the pressure is kept constant
V = T , V/T = constant , v1/t 1 = v2/t2
Or At constant pressure any perfect gas changes in volume by 1/273 th of its original
volume at 0 degree for every 1 degree change in its temperature.

Joule’s law: The internal energy of a given quantity of gas depends only on temperature

Regnault’s law: The two specific heat cp(specific heat at constant pressure) and cv
(specific heat at constant volume) of a gas do not change with the change of temperature
& pressure

Avagardo’s law : equal volume of different perfect gas at same temperature and pressure
contains equal no of molecules.
m1v1 = m2v2 , mv -= constant
The value of molecular volume is 22.41m³/kg mole at NTP

Daltons law: Resultant pressure of the mixture of two or more gases would be equal to
the sum of the pressure that individual gas would exert if it occupies the mixture volume
and mixture temperature .
M = Ma ( 1 + va/vg) , Ma – mass of air in the condenser,va – specific vol of air in m³/kg
corresponding to the partial pressure Pa of air , vg – vol of dry saturated steam

Perfect gas : Pv = mRT ,P – absolute pressure, v – vol of gas ,m – mass in kg

R – characteristic gas constant, T – absolute temp of gas
R= 287J/Kg/K ( S.I) , 29.27 mkgf/k

Universal gas constant :

Rµ= 8314 J/Kgmol/k ( S.I) , 848 m kgf/kgmol/k (mks)
Pv = n Rµ T

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Zeroth Law of Thermodynamics:
If two bodies are in thermal equilibrium with a third body,separately then they are also in
thermal equilibrium with each other.

First Law of thermodynamics

Heat and mechanical work are inerconvertible.
If w is the amount of mechanical work converted from heat energy H
W œ H , W = JH , J – constant of proportionality or joules equalent of heat
J = 4.1868 KJ/Kcal or 426.934kgfm/kcal
In other words” When a thermodynamic system executes a cyclic process,the algebric
sum of work transfer is proportional to algebric sum of heat transfer.
ɸdw =J ɸdq

Second law of thermodynamics

Clausius Statement
Hear flow from a hot body to a cold body unaided,but it is impossible for a heat body to
flow from a cold body to hot body without the aid of an external work.
Kelvin – Plank’s Statement
It is impossible to construct an engine working on cyclic process whose sole purpose is to
convert all the heat energy supplied to it in to an equivalent amount of mechanical work
Or
No heat engine converts or can convert more than a fraction of heat supplied to it in to
mechanical work, a large part is necessarily rejected as heat.
Heat converted into work = W
Heat energy taken in by the engine Qs

Law of conservation of energy

Energy can be neither created nor destroyed but can be transferred from one form to the
another
Q = W + ∆ U ∆ U – change in internal energy ,Q – total heat supplied or rejected
W – work done in heat units

Stefan’s law
The total amount of heat radiated per second per unit area of a perfectly black body is
directly proportional to the fourth power of absolute temperature.
E = σ T∆ 4 σ = 5.66 * 10 ¯ 8 W ¯2 K¯4

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Isothermal process(Constant temperature)
Temperature of a given mass of gas is not allowed to change Q = mRT logₑr
Isobaric – Pressure remains constant
Isochoric – Volume remains constant

Hyberbolic process
The process in which product of the pressure of the gas and the volume remains constant.

Constant Volume process

The volume of the given mass of gas is not allowed to change
∆ µ = m Cv( T2 – T1)

Adiabatic Process
No heat is added or withdrawn from the system under consideration

P2V2 – P1V1 or MR (T1 – T2) =W

1- γ γ -1

Polytropic Process
The process in which the relation PVⁿ = constant holds good is known as Polytropic
process ,V –volume , n – the polytropic exponent

Throttling Process
When a gas or vapour is expanded through an aperture of minute(narrow) dimension like
a valve which is slightly opened is known as throttling process

Free Expansion
In this process the fluid expands suddenly in to a vaccum chamber through an orifice of
large dimension,No heat is supplied or rejected there is no work done during this process
temperature remains constant.

Enthalpy
The sum of internal energy and the external workdone(Pressure volume produced) of the
given quantity of gas both expressed in the same units is called enthalpy

H = E + pV E – internal energy , pV – External work done ,J –mechanical equalent

J

Internal Energy: Of a substance is the energy possessed by it due to its molecular

arrangement and activity

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Entropy
Measure of the unavailability of heat energy for transformation in to work.It is calculated
property of matter. The quantity of heat added or rejected divided by absolute
temperature of gas at that time measure change in entropy
dɸ = dQ/ T
Specific entropy = entropy/ mass

Latent heat of vapourisation(h fg) – The quantity of heat required at constant pressure to
convert one kg of water at saturation temperature into dry and saturated steam.

Mollier Diagram: (Enthalpy – Entropy) – relation between Specific enthalpy( on vertical)

And specific entropy (On horizontal)

Conduction – Is the process of transmission of heat from thehot region to the cold region
of a body with out the movement of the particles of the body

Convection: Is the process by which heat is transmitted through a substance from one
point to another by the actual movement of the heated particles of the substance.The
density of heated particles of fluid decreases.

Fourier’s Law of conduction

The rate of flow of heat (Q) through a single homogenous solid is directly proportional to
the area of section(A) at right angles to the direction of heat flow and to the change of
temperature with respect to the length of the path.
dT/dX of the heat flow

Radiation: Is that mode of heat transfer which requires no material medium or is the
property of all substances and each continuously emits energy.

Absorptivity : Of a surface is defined as the fraction of radiation energy incident upon

that surface from all directions and over all wave lengths that is absorbed by the surface

Reflectivity : Fraction of radiation energy incident on that surface from all directions and
overall wavelength that is reflected back in to space α + ρ = 1 (for opaque)

Transmissivity: Transparent surface is defined as the fraction of radiation incident upon it

that passes through the surface.

Emissivity: The ratio of energy emitted by a real surface to that emitted to a black body at
same temperature.It has value between 0 and infinity.

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Carnot Cycle: Two adiabatic and two isothermal process
Efficency = work done work done = Heat supplied – Heat rejected
Heat supplied
η = R(T1 – T2) log ₑͬ or η = T1 – T2
RT1 log ₑͬ T1
This is a reversible cycle and the reverse cycle of Carnot is used as a Refrigeration cycle

Rankine Cycle( Vapour power Cycle)- modified form of carnot

It uses Super heated steam.This is not a Reversible cycle and efficency is used as the
ideal or standard efficency of Stean engine plant.
η = h1-h2 or n(p1-v1 – p2v2)
h1-hf2 n-1

Brayton Cycle or Joule Cycle

Consists of two reversible isobars(constant pressure) and two reversible adiabatics.The
cycle is open and is used on Aircraft , industrial gas turbine installation. Efficency
depends upon either compression ratio or the pressure ratio.
η = 1 –(P1/P2)ͬ -¹/ͬ or 1 – 1/(γp) ͬ -¹/ͬ

Otto cycle
1. Adiabatic expansion 2. heat rejection at constant volume 3.Adiabatic compression
4.Heat addition at constant volume
η = T1 – T3 = 1 – T3
T1
Diesel Cycle
1.Adiabatic expansion 2. heat rejection at constant volume 3.Adiabatic compression
4.Heat addition at constant pressure

η=1–ͬ ¹¯ͬ (p ͬ - 1)
ͬ p -1
Vander Waal’s Equation
- Perfect gas equation ( P + a/v²) ( v – b) = RT
- Or ( P + a/v²) ( v – b) = N KbT
- Correction of inter molecular force
- Correction of size of the molecules

Mayer’s Relation
Cp – Cv = R (Cp – Cv= 5/2R – 3/2R)

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Vertical boiler – Cochran
Horizontal – Lancashire boiler (fire tube)
- Locomotive (fire tube)
- Nestler (fire tube)
- Babcock and Wilcox ( water tube)
Forced Circulation – la mount boiler ( water tube)
- Benson ( water tube)
- Loeffler ( water tube)
- Fluidised bel combustion

Solid Fuel – Peat , Lignite ,Bituminous coal , Anthracite

Liquid fuel- Gasoline , Paraffin ,Heavy fuel oil
Gas – Natural gas, LPG, Refinery oil gas, Coal gas, Carburetted water gas, Blast furnace
gas , Blue water gas, Producer gas

12
 PRODUCTION TECHNOLOGY

Pitch Circle : A circle representing imaginary friction wheels

Circular pitch : Distance between the corresponding point of successive teeth measured
along the pitch circle. It is equal to width of a tooth and a space measured on the Pitch
Circle P = ∏ d / T [ d – pitch circle diameter,T – no of teeth ]
Diametrical Pitch : Ratio of number of teeth of a gear to the pitch circle diameter.
Pd= T / d
Module – ratio of pitch circle diameter in mm to the no of teeth
m = d / T = 1/ Pd [ module is the reciprocal to the diametrical pitch]

Working depth : Sum of addendum of two mating gears.

Pressure Angle : angle between common normal at the point of tooth contact and
common tangent to the pitch circle

Back Lash : difference between the thickness of engaging tooth to the width of the recess
on the pitch circle

Cams : is a machine element which drives another an other element through a specified
motion by direct contact.
Types of cams:
1. wedge –the reciprocating(translatory)motion of the cam is transformed in to
reciprocating or oscillating motion of the follower.
2. Radial( Disc cams) – the follower reciprocates in a plane right angle to the axis of
the cam
3. Cylindrical : the follower reciprocates or oscillates in a plane parallel to the axis
of the cam
Cam profile : it is the out line of the disc cam on which the follower is always in contact
during its motion.
Trace point : it is the reference point on follower and is used to drive pitch curve.

Pressure angle: it is defined as the angle between the direction of follower and normal to
the pitch curve. This angle is limited to 30˚

Base circle: the circle drawn with minimum radius from the cam centre to the cam profile
Splines:are a number of keys integrated with shaft

Broaching: is a fastest machining operation by using a boach tool, it is made up of series

of cutting edges(teeth)which are gradually increase in size along its length.It is applied
for machining external flat and countour surfaces,internal surfaces of various shaped
holes,cutting key ways and splines.Length of broach depends on the amount of metal
removal ,length of stroke,amount of accuracy and degree of finish

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Gears
Spur gears: Used to connect two coplanar parallel shafts

Bevel gear : Used to connect two coplanar intersecting shafts

Spiral gears: Used to connect two non –intersecting ,non coplanar shafts

Wormgears: Used to connect skew shafts(non-coplanar shafts)which are at right angles

Open belt drive: is used to connect the parallel shafts rotating in the same direction.
Cross belt drive: is used to connect two parallel shafts rotating in opposite direction.
Quarter-turn drive: is used to connect two shafts which are at right angles to each other
Angle of contact : the angle over which the belt is in contact with the pulley

Gear ratio: the ratio of larger no of teeth to the smaller number of teeth

Velocity ratio: is defined as the speed of the driver gear to that of the driven or follower
gear = N 1/N2 = d2/d1

Balata belt: balata gum is used and will withstand temperature above 50˚

Bearing: A machine element which support another element and at the same time
constrains the relative motion of the part with minimum friction

Guide or slide : when there is a sliding or translatory motin the bearing may be called
slide or guide.

Radial(journal) bearing: load acts radial to the axis of the shaft

Full journal bearing: When the angle of contact of the bearing with the journal is 360˚

Partial journal bearing:When the angle of content of the bearing with the journal is 120˚

Thrust bearing: carries a load collinear to the axis of the shaft

Pivot or footstep bearing: if the shaft is vertical and terminates in the bearing

Collar bearing:If the shaft continues through the bearing

Sliding contact bearing: bearings that donot use rollers or balls as load supporting
material are termed as sliding bearing.

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Cutting tool nomenclature
Shank : The shank is that part of the tool on one end of which the point is formed or the
tip or bit is supported.

Base: The base is the surface of shank which bears against the support and takes the
tangent pressure of the cut.

Heel : The heel is the edge between the base and flank immediately below the face.

Face: The face is the surface on which the chip impinges as it is cut from the work.

Point: The point is end of the tool which is shaped to produce the cutting edges and face.

Flank: The flank is the surface or surfaces below and adjacent to the cutting edge. These
are the surfaces of the tool facing the work.

Nose: Is the curve formed by joining the side – cutting and end cutting edges.

Pitch – is the distance fr om one point on a screw thread to the corresponding point on the
next thread measured parallel to the axis.It is the reciprocal to no of threads per unit
length of screw , Pitch = 1/T

Lead – distance advanced by a nut on a bolt in one revolution. L = p(pitch)

Effective diameter or pitch diameter : is the diameter where the width of the tool is equal
to the space between successive teeth.

Tool edges:
Back rake angle: The back rake(top rake angle) is the angle between the face of Tool and
a line parallel to the base of the shank measured in a plane parallel to the centre line of
the point and at right angles to the base.
The purpose of back rake angle is to control chip formation and to guide the direction of
the chip flow.

Side – rake angle : angle betweereamingn the face of a tool and a line parallel to the
base.It guides the direction of chip flow.It is usually ground from 6˚ to 15˚

Relief angle: The angle between a plane perpendicular to the base of a tool and ground
flank immediately adjacent to the cutting edge.

15
Side relief angle : The angle between the portion of the flank immediately below the
cutting edge and a line drawn through this cutting edge perpendicular to the base.The side
relief angle permits the tool to cut with out rubbing.

End – relief angle : is the angle between the portion of the end flank, immediately below
the cutting edge and a line drawn through that cutting edge perpendicular to the base.

Clearence angle: is the angle between a plane perpendicular to the base of a tool and that
potion of the flank immediately adjacent to the base.

End clearance: is the secondary relief angle between the palne perpendicular to the base
and end flank immediately adjacent to the base.

Side clearance: The secondary relief angle between the plane perpendicular to the base
and side flank immediately adjacent to the base.

Nose: The curve formed by joining the side cutting and end cutting edges.

Nose radius: the angle included between the side cutting edge and end cutting edge is
called nose angle and the radius of the curve is called nose radius.

Cutting speed:is expressed in terms of meters per minute and it is the speed at which the
metal is removed by the cutting edge from the work piece.
In lathe V = πdN/1000 m/min

Feed: is defined as the distance of the cutting tool advance per revolution.

Depth of cut: The distance between the unfinished surface of the work and bottom of the
cut. depth of cut = d- dc/2

Twist drill nomenclature

Web: the central portion of the body which separate the flute and runs through entire
length of drill.

Cutting lip or edge: the edge formed by intersection of flank and face correspond to the
cutting edge of a single point tool.

Heel: The edges formed by the intersection of flutes and body clearance.

Margin:Narrow surface along the groove which keeps the drill aligned is called as margin

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Milling cutter nomenclature
Arbor: It is a spindle on which the milling cutter is mounted and driven.

Gash: Gash or flute is the chip space between the back of one tooth and the face of the
next tooth.

Fillet: The curved surface which joins the face of one tooth to the back of the tooth
immediately ahead.

Lip angle: included angle between the land and the face of tooth.

Radial rake: The angle between face of the cutter and a radial line passing through the
tooth of cutting edge.Ranges between 10˚ to 20˚

Axial rake: is the angle between the face of the tooth and axis of the cutter.

Low carbon or mild steel : 0.15 – 0.45 % carbon

Medium carbon : 0.45 – 0.8 % carbon

High carbon steel ( tool steel): 0.8 – 1.5 % carbon ,machining soft materials at low speeds

HSS(High speed steel ) – 18 % tungsten ,4 % chromium , 1 % vanadium(18-4-1) –

general pupose

Molybednum HSS -6% molybdenum,6%tungsten,4%chromium,2%vanadium

And 0.8 to 1% carbon ( 6-6-4-2)

Super HSS{cobalt) – Cobalt – 2- 15% ,steel – 20 % ,tungsten- 4%, chromium – 2%,

Vanadium & cobalt– 12 % ,used for machining hard surfaces and abrasive materials

Stellite( Cast alloys) :Cobalt 45%,chromium 35%,tungsten18%and carbon 2% , iron is

Very low ( 3 – 4%) , used for machining hard cast iron and steel.

Cemented carbides :Powder mixing of tungsten,titanium carbide and Metallic cobalt.

Ceramics: Finely divided oxides(Al² O³ and 10 % of other oxides of magnesium, titanium

nd chromium powders)- for maching abrasive castings and hard steel

Tungsten carbide : For machining grey cast iron,stainless steels,die cast alloys,non –
Ferrous

17
Titanium carbide and nickel (molybdenum)- for precision measuring requiring high
quality finish

Stainless steel(ferritic stainless steel) – greater amount of nickel (15 – 20%) , 0.1 %
Carbon
Martensitic stainless steel – 11 – 14 % chromium , 0.35 % carbon
Austenitic steel – 18 % chromium , 8 % nickel
Steel is an alloy of iron and carbon with content upto maximum 1.5% , the main
constituents are Austenite,Martensite,Troostite,Sorbite
Dead mild steel : up to 0.15% carbon

Melting point of wrought iron is 1530˚C

Carbon – 0.020 % ,silicon – 0.120% ,Sulphur -0.018%,phosphorous- 0.020%,slag -0.07%
1)Grey cast Iron : Carbon – 3 to 3.5%,silicon – 1- 2.75%, manganese – 0.40- 1% ,
phosphorus – 0.15 – 1 % , sulphur – 0.02 – 0.15%
2)White cast iron : Carbon – 1.75 -2.3%, silicon – 0.85 -1.2 %, manganese -0.10 -0.40%
Phosphorus -0.05 -0.20 %, sulphur – 0.12 – 0.35%
3)Malleable cast iron –obtained from white cast iron by annealing a) white hearth
process b)Black hearth process

1.Blast furnace - Pig Iron[ smelting Iron ores]

2. Cupola - Cast Iron [Pig iron + coke + Lime stone]
3. Puddling/Aston - Wrought Iron
or Byera Process
4. Cementation Process,Crucible - Steel
Open hearth,Bessemer,Duplex,Ld process

1.Copper + Zinc alloys - Brass

2.Copper + Tin - Bronze
3.Copper + Tin + Zinc - Gun metal
4.Copper + antimony + Tin - Babbit
5.Nickel + Chromium + Iron - Nichrome
6.Copper + Manganese + Magnesium - Duralumin
3.5٪ - 4.5٪
7. Nickel (80%) + chromium( 14%) + Iron - Iconel

18
1.Test of Hardness : 1.Scrath 2. Identation [ Brinells method]

2.Test of ductility : 1. Based on elongation produced in specimen

2.Based on total reduction in sectional area
3.Test of resistance : Izod Impact test
4.Test of Fatigue : Wobler experiment
5.Test of surface roughness : Interferometer
6.Test of Angular Displacement : Autocollimator

Metal Ore
1.Nickel - Iron sulphide
2. Cadmium - Greenockile
3.Magnesium – dolomite , magnesite,carnallite ,Kieserite,brucite
4. Antimony - Stibnite
5.Aluminium – bauxite
6.Lead – galena
7.Tin – stannic oxide, cassiterite
8.Zinc – Zinc blende
9.Vanadium - patronite

Ferrous: Latin – ferrum – iron

Measuring furnace temperature – Pyrometer

a)Thermo- Electrical b) Optical

Properties of Metals

Strength: ability of a material to resist the externally applied forces with breakdown or
yielding .

Stiffness: ability of material to resist deformation under stress

Ductility:Property of material enabling it to be drawn in to wires with application of

tensile force.

Malleability: Special case of ductility which permits material to be rolled or hammered in

to thin sheets

19
Toughness: Ability of material to resist fracture due to high impact load.

Brittleness: It is the property of a material with permanent distortion.

Hardness: ability of metal to cut another metal . It resist wear, scrathing,deformation and
machinability.

Fatigue Strength: Maximum shear stress( under varying loads) at which material will
operate with out failure is known as Fatigue strength on Endurance limit.

Resilence: Ability of a material to store energy with in the elastic limit(with out
permanent deformation)

Creep : Slow and progressive deformation of a material with time at constant stress.

Slip: the relative motion between the belt and pulley.

Phase: is physically and chemically homogenous portion of a system,separated from the

other portion by a surface,the interface.
Phase rule: F = C+N – P , F – No of degrees of freedom , C- No of components in the
system , P – no of phase in equilibrium , N – no of external factors

Coating : If material is deposited as liquid or gas from a liquid or gas medium the process
is known as coating.

Cladding : If the added material is solid during deposition process is called cladding.

Hot dipping : Process of coating the base metal by dipping it in molten bath
a. Galvanising b.Parkerising c. Anodising

Galvanising : Process of producing the zinc coating on iron or steel by hot dipping
Parkerising: Process of providing phosphate coating on work surface by hot dipping.
Anodising: Process of producing oxide film on aluminium bars,The film is produced by
electro – chemical reaction.
Jigs: is a work holding device which also locates or guides the cutting tool with respect to
the work piece.It is not fastened to the machine on which it is used. Drilling , reaming ,
tapping and counter boring operations are done.

Fixtures : is a work holding device but does not locates or guides the cutting tool .It is
fastened to the table or base of the machine. Milling ,turning ,grinding ,welding are done.

20
 Blanking : Process of cutting out desired shape from the strip or sheet by a single blow
of the punch .It is used to make flat punch.

Piercing: Is a process of making a desired hole by using a punch and die

Lancing: is a cutting operation in which hole is partly cut(no metal is actually removed)
And bending down the cut portion
Notching: Process of cutting out the edges of the strip to obtain the desired outer contour
of the work piece.
Shaving: is a process of finishing the edge of the blank to an accurate size. The clearance
provided for die is very small to give required tolerance.
Trimming : process of finishing the edges of a part by removing the flush or excess metal
around it.
Embossing : is a shallow forming operation which uses a matched punch and die.It is
used for decorative sheetwork and to obtain impression of desired form.
Coining: Coining is a squeezing operation in which the metal flows in to a cavity
between the punch and die .It is employed for making coins ,medals and similar articles.
Swaging: Operation is similar to coining operation except that metal is not confined in
the die.
Drawing: is a process of producing hollow shapes such as cups and dishes from flat sheet
metal a) Deep drawing b) Shallow drawing
Deep drawing – height of the component is greater than the dia or the width
Shallow drawing: The height of component is less than dia or width
Bulging : is a forming operation in which the portion of a drawn shell or tube is expanded
Bending : is a cold working process , metals on the outside of the bend is stressed in
tension while inside is compressed a ) V-bending b) Edge bending
Extrusion : is used for making spur gears,brass,aluminium
Normalising: consists of heating steel (20-50˚C) above its upper critical temperature(for
hypo-eutectoid steels) or ACM line (for hyper-eutectoid steel).It is held at this
temperature for about 15 minutes and then allowed to cool down in still air.

Permanent mould(Gravity die) casting: A casting made by pouring molten metal in to a

mould made of some metallic alloy or other material of permanence.

Slush casting: use a permanent mould,it is used for casting low-melting temperature
alloys and hollow castings,In this process molten material is poured in to the metallic
mould.The metal is retained in the mould long enough for outer skin to solidify.

Die casting(Pressure die) :casting in which uses the permanent die (mould) and molten
metal is introduced in to it by means of pressure.1.Hot chamber 2.Cold chamber die cast

Centrifugal casting:process in which molten metal is poured and allowed to solidify while
the mould is revolving,the casting produced by centrifugal forces is known to be.

Investment casting:(lost wax or precision )The casting produced by this method are with
in very close tolerance and donot require subsequent machining- wax pattern is used.

21
Hypo- eutectoid steel – process provides a homogenous structure consisting of ferrite and
pearlite.Steel less than 0.8% carbon content are hypo-eutectoid and 0.8% more of carbon
is known as hyper-eutectoid (.Pearlite and cementite)

Spherodising: form of annealing in which cementation in the granular form is produced

in structure of steel. Improves machinability of steels but lowers hardness and tensile
strength.

Austempering: hardening process in which steel is heated above the critical temperature
at about 875˚C ,where structure consists entirely of austenite.It is then suddenly cooled
by quenching it in a salt bath maintained at a temperature of about 250 to 525 ˚C so as to
facilitate the transfer of austenite in to bainite,then steel is cooled in air

Mastempering: Usally done in alloy steels, it is free from internal stresses.

Carburising: The process of inducing carbon to low carbon steels in order to give a hard
surface is called carburizing a)Pack or Solid carburizing b)Gas carburizing

Nitriding: Process of case or surface hardening in which nitrogen gas is employed inorder
to obtain hard surface of steel.Carried in electric furnace 450 -550˚C

Cyaniding: Process in which carbon and nitrogen are absorbed by metal surface to get it
hardened .Sodium cyanide or potassium cyanite salt – 850 - 950˚C

Induction hardening – In which surface to be hardened is surrounded by an inductor

block which acts as a primary coil of a transformer.High current is passed.

Recrystallisation temperature : At which the new grains are formed in the metal

Hot working: Working of metals above the recrystallisation temperature.

Hot Working Process:

Hot rolling : converting large sections in to desired shapes eg. I beam , rails, structural
sections ,plates,sections,plates, sheets
Operation consists of passing the hot ingot through atleast two rolls rotating in opposite
directions ( Ingot –carried in blooming mill,it is rolled in to blooms.

Hot forging: Heating the metal to plastic state and then pressure is applied it in to desired
shapes and sizes.

22
Hot spinning: Heating the metal to forging temperature and then forming in to desired
shape on a spinning lathe.The parts of circular cross sections which are symmetrical
about the axis of rotation are made by this process.

Hot Extrusion : It consists of pressing a metal inside a chamber to force it out by high
pressure through an orifice which is shaped to provide the desired form of finished parts
.The rods tubes ,structural shapes ,flooring strips and lead converted cables are product of
extrusion.a) Direct (forward) Extrusion b) Indirect(Backward) Extrusion.

Hot drawing or cupping: It is mostly used for production of thick walled seamless tubes
and cylinders performed in two stages 1) Drawing a cup of hot circular plate with die and
punch 2)Reheating the drawn cup and drawing it further in to desired length and
thickness.

Hot Piercing: Used to manufcture seamless tubes.In its operation the heated cylindrical
billets of steel are passed between two conical shaped rolls operating in the same
direction. A mandrel is provided between the rolls which assist piercing and control the
size of the hole( as the billet is forced over it)

Cold working: Working of metal below their recrystallisation temperature. The increase
in hardness due to cold working is called work hardening.

Cold rolling: Employed for bars of all shapes, rods,sheets and strips.The hot rolled
articles are first immersed and washed in a weak solution of sulphuric acid and process is
known as Pickling. The cleaned articles are passed through rolling mills.
Cold forging( Swaging) : Metal is allowed to flow in some pre determined shape
according to design of dies by a compressive force of impact.

Cold heading: Used for making Bolts ,Rivets and similar headed parts, done in cold
header machine. The rod is fed to the machine where it is cut off and moved in to head or
die.

Rotary Swaging: Used for reducing the diameter of round bars and tubes.

Cold spinning : Best suited for aluminums and other soft metal. The operation is similar
to hot spinning except this is carried in room temperature.

Cold Extrusion: similar to hot extrusion , with help of punch and dies. The tubes for
Shaving cream and tooth paste and such other thin walled are made by Impact Extrusion.

23
Cold Drawing: Employed for bars,rods,wires,tubes etc.
1) Bar drawing
2) Wire drawing : Pickled,washed and coated to prevent oxidation ,passed through
several dies of decreasing diameter to provide desired reduction in size.
a) Single – draft b) Continuous – drawn process
Tube drawing: similar to bar drawing.
Cold bending: is a rolling process
1)Cold roll forming
2)Roll bending

Cold Peening: Process used to remove the fatigue resistance of the metal by Upsetting
and Compressive stresses in its surface.
Pattern: Is a model or replica of desired casting which when moulded in sands forms an
impression called mould.The mould when filled with molten metal form Casting

Shotting: process of dropping molten metal through a sieve or small orifice in to

water.This produces spherical particles of larger size.

Apparent density:
Ratio of volume to weight of loosely filled mixture.

Chemical Reduction
This method is used for producing iro, copper, molybdenum,nickel and cobalt powders.
The process consists of reducing metal oxides by means of carbon monoxide or hydrogen
Extruding: employed to produce components with high density and excellent mechanical
Properties.Cold extrusion is employed for cemented carbide drills and cutters , the hot
extrusion is mostly for refractory metals ,beryllium and nuclear solid fuels.

Reaming: Process of making a hole smoothly and accurately to size

Forming: is a process of producing special contours on work surface by using form tool.
Parting off (cutting of) is the operation of separating the finished surface from a bar stock
Counterboring:enlarging the hole for part of its depth with a counter borer.
Counter sinking:forming chamfers at the edge of a hole with countersinking tool(60˚-90˚)
Spot facing:machining the surface around a hole

Shaping machine(shaper) : is used for machining flat surfaces. The work is held
stationary on the table,the tool carried in the tool head reciprocates past the work with the
help of horizontal ram. 1.Crank and slotted mechanism 2. whitworth quick return
3.hydraulic system for quick return mechanism

24
Slotter : is similar to shaper except that in a slotter the ram holding the tool reciprocates
in vertical axis and it is intended to cut grooves ,key ways and slot of various shapes.
1.whitworth quick return

Planer: Intended to produce flat surfaces. The major difference is that in planer the
cutting tool is stationary and table holding the work reciprocates past the stationary tool.
1. Table drive mechanism 2. Feeding mechanism

Milling:The material is removed as the work is fed against a rotating multi point cutter,
the cutter rotates at a high speed and removes metal at a very fast rate.Milling machines
are used for horizontal and vertical surfaces.

Welding: Is a process of joining two similar or dissimilar metals by fusion with or

without the application of pressure and with or without the use of filler material.
Or
Edges of the metals to be joined are melted and molten metal pool is allowed to run
between the edges which solidifies there to form a welding.

Autogeneous Welding: Process of joining similar metals with help of filler rod of same
metal.
Heterogeneous Welding: Process of joining dissimilar metals using filler rod.

Types of welding:
1)Pressure or Forge – the workpieces are heated to plastic state and then work pieces are
joined together by applying pressure on them. No filler material is used.

Blacksmith Electric Arc Friction

Resistance welding

a).Spot b).Seam c).Projection d).Upsetting e).Flash butt f).Percussion

2) Non pressure or fusion welding: In non pressure the edges of workpieces to be joined
and filler material are heated to temperature above the melting point of metal and then
allowed to solidify.

Heat arc Gas Chemical reaction

Electric Arc Oxy- Acetylene Thermit

a)Carbon arc, b)Metal arc, c) Submerged arc ,d) Inert

25
Spot Welding:is used for welding cap joints ,joining components made from plate
material having 0.025 mm to 1.25mm in thickness
Roll spot welding: W hen the spot welds on two overlapping pieces of metals are spaced

Seam welding: If the spot welds are suficently made close so that overlap and make a
leak proof seam (joint), the process is called seam welding. This process is best adopted
for metal thickness ranging 0.025mm to 3 mm.

Projection welding:Similar to spot welding except that one of the metal pieces to be
welded has projections on its surface at the points where welds are to be made.

Upset Butt: Two parts of metal having same cross section are held by two heavy water
cooled electrode jaws and forced together. Used to weld rods,pipes,small structural
shapes of uniform section parts.

Flash butt: The heat required for the welding operation is derived from the arcing that
occurs in the space between the parts to be joined . Used in manufacture of Steel
containers and mild steel HSS drills and reamers.

Percussion: The welding heat is obtained from the arc produced by a rapid discharge of
stored electrical energy. This process is used for welding Stellite tips to tools,copper to
aluminium or stainless steel , cast iron to steels, silver contact tips to copper.

Friction welds: Heat is obtained by rotating friction. The two pieces to be welded
together are mounted in chucks on the same horizontal axis. Mainly used for joining
Round bars.

Arc: Is a fusion welding process in which the welding heat is obtained from an electric
arc between the work(or base metal) and rod.
Stud arc: the stud arc welding is a direct current arc welding process and is used for
welding metal studs to the flat metal surface.

Coating factor – ratio of diameter of electrode with coating to the core diameter
Lightly coated(flux) electode – C F – 1.25 to 1.3
Medium coated – CF – 1.4 – 1.5
Heavily coated – CF – 1.6 – 2.2

Themit :The ends of the pieces to be welded are cut to provide a parallel sided gap. This
gap is filled up with wax which becomes the pattern of the weld . Mixture of Iron oxide +
aluminium is Thermit. Welds are used to join iron and steel parts such as rails ,truck
frames, broken Gear teeth etc. Working based on exothermic rection.

26
Arc cutting : Process of arc cutting purely a melting by electric arc of metal along a
desired line of cut.
Sub merged arc welding : Used for production of long continous weldings of components
having 12 to 50 mm thickness
TIG – Welding aluminium , stainless steel .titanium
MIG – Steel ,Stainless steel, Heat resisting alloys, Non-ferrous alloys

Oxy – Arc cutting( Arcos Lectrox) : is used for cutting those metals which are impossible
to cut by standard methods. High chrome-nickel,stainless steels,bronze, brass , copper,
aluminium , cast iron.

Brazing: A low melting alloy is introduced between the edges to be joined and the joint is
formed by adhesion. The flow of the metal between the edge is due to capillary action.
(filler material having melting point above 400˚C is Spelter)

Soldering: Joining of two metal pieces by means of heat and filler metal whose melting
point is lower( below 400˚ C) than melting points of metal to be joined.

1.Welding of low carbon steels or mild steel –

Forge welding, resistance welding,Arc welding and gas welding
2.Medium carbon steels
Arc welding, resistance welding,gas welding , Thermit welding
3.Stainless steel
Butt Welding , Oxy – acetylene , Metal arc
4. Cast steel
Gas welding with a neutral flame
5.Cast Iron
Metal arc, Braze welding ,Oxy-acetylene
6. Aluminium
Inert gas, atomic hydrogen welding, brazing, spot, seam and flash welding.
7.Copper
Metal arc, carbon arc - borax flux,Oxy-acetylene
8.Nickel alloys
Meatal arc, resistance, oxy – acetylene

Testing
1.) Destructive :Tensile , Bending , Impact , Hardness
2.) Non – Destructive: X-ray, Magnetic, hydraulic , Air –pressure tests

27
Notching: the opening left at the corners of seams and edges are known as notches and
operaton is called Notching.

Hollowing or blocking:It is the process of beating the sheet metal in to a particular shape
such as a sauce pan , lid or bowl .It is usually done on the hollowing block which is a
wooden block with hollow cuts in to it.

Sinking: Process used to sink the bottom for forming a tray with a flat rim.

Raising: The process of dinting the metal down to shape over a tool with a raising
hammer or mallet.

Planising: is a process which is applied to sheet with the main object of stretching the
metal with an improved surface. The process brings the article to its final shape and
import some degree of hardness to the metal.

Caulking and Fullering: makes the joint leakless or fluid tight in pressure vessel like
steam boilers , air reservoir,tanks and a process known as caulking is employed. Narrow
blunt caulking tool about 5 mm thick and 38mm breadth ,at an edge angle at 80˚

Fullering :making the joints staunch and tight is known as fullering. The fullering tool
with a thickness at the end equal to that of the plate is used in such a way that greatest
pressure due to blow occur near the joint with less risk of damaging the plate.

Briquetting or compacting: Process of converting loose powder particles in to green

compact of desired shape.

Sintering: Process of heating the briquetted component at an elevated temperature in a

furnace under reduced atmospheric conditions.Abilty which promotes bonding of particle

Screw thread : Is formed by a continuous helical groove on a cylindrical surface.

Tolerance: The difference between the upper limit and lower limit of a dimension.

Fit: degree of tightness or looseness between the two mating parts

Clearence: Is the amount by which the actual size of the shaft is larger than the actual size
of making hole in an assembly.

28
Interference: Amount by which the actual size of shaft is larger than the actual finished
size of mating hole in an assembly.

Allowance: is an intentionally prescribed difference between the lower limit and upper
limit of a size.

Tolerance zone: Zone between the maximum and minimumlimit sizes.

Zero line: Straight line cooresonding to basic size(size of a part by which limits of
variation are determined)

Upper Deviation: Algebric difference between maximum limit and basic size

Lower Deviation: Algebric difference between minimum limit and basic size

Actual Deviation: Algebric difference of actual size and basic size.

Mean Deaviation: Arithematic mean between Upper and lower deviation.

`
Micrometer - LC –Pitch/ no of divisions – accuracy – 0.01mm
Vernier - L.C – Smallest division/no of divison – accuracy – 0.02mm

Ring gauges – used to check the diameter of shafts or studs

Plug guage: Used to test accuracy of hole

Snap gauge: Checking external dimensions

Sine bar: Used either to measure angles more precisely or for locating any work to a
given angle with in very close limit
Sinθ = H / L or H2 – H1
L
Dividing head or Indexing head: It is used for supporting circular work pieces to mill
square end on to round bars,gear teeth and divide the periphery of circular blank in to
equal no of divisions.Used for measurement of angular dimension about a common
centre. Methods 1. Direct 2. Simple 3.Compound 4.Differential 5.Angular indexing.

Autocollimeter: Optical instrument used for measurement of small angular differences

Interferometer: Used for measuring flatness and determining the length of slip gauges by
making the use of light wave interference.

29
 MANAGEMENT

1. F.W.TAYLOR : FATHER OF SCIENTIFIC MANAGEMENT

2. HENRI FAYOL : FATHER OF PRINCIPLES OF MANAGEMENT
3. ELTON MAYO : FATHER OF HUMAN RELATIONS APPROACH
4. GILBERT : FATHER OF PRINCIPLE OF MODERN ECONOMY
5. HENRY GANTT : DEVELOPED DAILY BALANCE CHART

SIMO – Simultaneous motion cycle chart [ used for micro motion analysis of
a) short cycle repetitive job b) High order skill jobs

PERT – Programme evaluation review technique (basic tool is the network or flow
Plan) – project is broken down into different activities(An event oriented)
Estimation of activity time(optimistic,most likely,pessimistic)
CPM – Critical path method – An activity oriented approach ,Marks critical activities
CPP – Critical path planning , CPA – Critical path analysis

Wage Incentive Plans

(Piece rate , Halsey Plan , Rowan plan , Gantt plan, Bedaux plan ,Emerson efficiency
plan, group plan )

Break Even Point : is concerned with finding the point at which revenue and cost
agree exactly
= F / 1 – v/p , fixed cost – F , Variable cost per unit – v ,Selling Price(unit)- p

Plant Layout: disposition of various facilities(equipment,material,manpower etc) and

Services of plant within the area of the site selected previously.

Process layout(functional layout) : characterized by keeping machines or similar ope-

rations at one location. Generally employed for industries engaged in job order prod-
uction and non- repetitive kind of maintenance or manufacturing activity.

Product Layout : It implies that various operations on raw materials are performed in
Sequence and the machines are placed along the product flow line.This type of layout
is preferred for continuous production.

Combination layout: Combination of process and product

30
 HYDRAULICS

Cohesion: Property of fluid by which molecules of the same fluid are attracted .This
property enables the liquid to resist tensile stress. Eg.Mercury

Adhesion: Property of fluid by which molecules of different kinds of liquid are attracted
to each other or molecules of liquid are attracted to another body .Eg. Water molecule

Surface Tension : (σ ) of a liquid is its to resist tensile force.It is due to cohesion between
liquid molecules at its surface.

Capillarity : Implies the rise or fall of liquid level in a narrow tube when it is held
vertically in the liquid.This phenomenon is due to combined effect of cohesion,adhesion
and surface tension.

Specific wt of water at 4˚c – 9.81 KN/m³

Mass density of water – 1000 kg/m³
Specific gravity of water – 1

Newtonian fluids- for large class of liquid µ is independent of velocity gradient v/y such
fluids are Newtonian.

Paraffin base oils – Pennysylvania

Napthenic or Aspathic base – Gulf coast
Mixed base oil – Mid continent
Newton law of viscosity
δ = µA V/Y
µ – 1.12 * 10 ¯³N.s/m²

Atmospheric Pressure : At any place due to weight of air column above that place
Gauge Pressure : Is above atmospheric pressure
Vaccum pressure : Gives the value of pressure by which amount is less than atmospheric
pressure (Negative Gauge pressure)
Absolute Pressure : P atm + P gauge ( Positive pressure)
: P atm – P vacc ( Negative pressure)
Pascal’s law : The pressure applied at any point on any confined liquid is transmitted
equally to all directions.

Law of continuity: When a liquid flows through any stream or pipe the mass or volume of
liquid at any cross section remains same provided no additional liquid id added or
removed from it. δ a 1 v 1 = δ a 2 v 2

31
Bernoulli’s theorm : In a continuous stream of perfect in compressible liquid, the total
energy of a particle moves from one point to another.
Δ1/w + Z1 + V1²/2g = Δ2/w + Z2 + V2²/2g
Eg: Pitot Tube : It is used to measure velocity of flow in open channels as well as in
closed pipes.
Velocity Formula V = k √2gh
K = pitot tube coefficient – 0.95 to 1.0
Venturimeter : is a gauge used to measure the velocity of flow and thus quantity
(discharge) of liquid flowing in a pipe.
K = a1 a2 * √ 2g
√a1²- a2²
Theoritical discharge Q = cd . k√ h cd – co efficient of discharge(0.89-0.91)

Orifice Meter : device used to measure the discharge rate of flow

Q = c f .A √2 gh , cf – coefficient of contration (0.62 -0.70)
h – head of flow
Manometer :(Piezo,U –tube ,Inverted u tube)
By balancing the liquid column whose pressure is to be found out with the same
Or another column of different liquid.
Bourdans Pressure gauge :
By balancing the liquid column whose pressure is to be found out with dead wt
or spring force. These are used in steam boilers.
Darcy’s formula :
Loss of head due to friction in pipes .Equation gives head loss due to frictional or
turbulent f low through a pipe in terms of velocity of flow of fluid ,friction factor and
diameter of the pipe.
4f l v ² d – is the dia of the pipe , l – length of pipe
Hf = 2gd - velocity ,f – darcy’s friction factor or wall friction coefficient

Chezy ‘s formula : V = C √ mi m – hydraulic mean depth = area / perimeter

i – hf/L tan Ɵ

HGL & TEL

If ordinate (Z 1 + δ 1/ W ) is graphically joined to ordinate (Z 2 + δ 2/ W ) we get a line
called Pressure head line or Hrdraulic Gradient line ,Now if a line is drawn parallel to
HGL at a distance V² / 2 g we get Total energy line.

32
Reynold number : Distingushes between Laminar flow and turbulent flow
Rn = V d / kv , Rn – Abstract no ,d - diameter , V – velocity , kv – kinematic velocity

= absolute or dynamic viscosity

Mass density of liquid

Impulse turbine ( axial flow turbine) – Pelton Wheel , Turgo turbine

All the energy of water is converted into velocity before entering the wheel by expanding
through a nozzle or guide blades.There will be no pressure drop on the blades.

H = v1 ² - v2² h – total head of water , v 1 – velocity of water entering the turbine

2g v 2 – velocity of water leaving the turbine.

Reaction turbine : ( Pressure turbine) - Radial flow - Francis & Kaplan

Only a part of the pressure converted in the guide blades in to velocity energy , the
pressure of water is not constant when flow over turbine blades

Pumps : 1. Positive displacement pump a.) Reciprocating b.) Rotary

2. Rotodynamic pump - Dynamic pressure – Propeller pump – pressure is
developed by flow of liquid over blades of aerofoil section which is sufficient to lift the
water .It provides large discharges against small heads (9 mm – 12 mm) ,used in land
drainage, sewage purification ,bore – hole pumping.

ENGINEERING DRAWING
W L
A0 – 841 * 1189
A1 – 594 * 841
A2 – 420 * 594
A3 – 297 * 420
A4 – 210 * 297
System of projections
1.Perspective - Parallel( 1 point), Angular(2 point), Oblique(3 point)
If the rays are converging to a particular station point
2.Oblique ( 45˚) – Cavalier , Cabinet , General
When the rays are parallel but at an angle to the picture plane ,the projection is called
Oblique
3.Orthographic a) Axonometric - Isometric , Dimetric , Trimetric
b) Multiview – First angle projection , Third angle projection
If the rays are parallel as well as perpendicular to the picture plane, the projection is
called Isometric. – ( 30 ˚) , First angle symbol : Taper first , circle second

ELECTRICAL AND ELECTRONICS

33
Capacity of a battery: is based on the maximum current in amperes which will deliver for
a known period of time until it is discharged to a permissible minimu, voltage of each cell

Shunt generator: if field coils are connected in parallel to the armature

Seperately excited generator- if field coils are excited separately
Series generator: If field coils are connected in series to the generator
EMF equation
E = ϕNZ/60 * p/a volts , E – emf induced , ϕ – flux per pole in webers(wb), p – no of
poles,a- parallel paths on the armature ,n- armature speed,Z- total conductors on armature

Back emf: The conductor rotates about the shaft because of the flux density in the main
pole and current in the conductor. As the conductor rotates it also cuts the flux in forward
direction ,due to which emf induced in it as in the case of generator.This induced emf in
the conductor will be in a direction opposite to the applied voltage is known as back emf.

Instantenous value : the value of emf or current in an alternating quantity change with
time
Cycle:One complete set of positive and negative values of an alternating quantity .
Amplitude: Maximum value attained by alternating quantity either in positive or negative
direction is called amplitude.

RMS value( effective value or virtue value): is the steady current(dc) which when
flowing through a given circuit produces for a given time produces the same heat as
produced by the ac when flowing through the same circuit for the same time.
1.mid ordinate method 2. analytical method

Phase difference: The fraction of the time period by which the two quantities of an
alternating wave form differ

Power: In ac is the product of voltage and that part of the current

P = V I cosϕ watts, cosϕ - power factor of the circuit.

Polyphase: if more than one alternating cycle is generated

Phase voltage: The voltage between neutral and any one phase is called phase
voltage(Vph)

Line voltage: The voltage between one phase and any of the other two phases is called
Line voltage ( VL)

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Star connection: if the ends of each windings are connected together to form a general
neutral ,one for neutral and one for each phase
Power = 3 Vph I ph cos ϕ , but Vph = VL/√3 and I ph = I L
= √3 VL I L cos ϕ
Delta: if all the three coils are connected in series to form a closed circuit.
VL = Vph and IL =√3 I ph
= √3 VL I L cos ϕ

Transformer: is a static device which transforms electric power from one circuit to
another circuit raising or dropping the voltage or current without change in frequency.
For ideal transformer the primary volt amp is equal to secondary volt amperes.
V1/V2 = I 2/I1 =1/K ( k – transformer ratio =V2/V1)
Current transformers – measuring large alternating currents
Potential transformers- measuring large alternating voltages

Star –star – for small current ratings and balanced loads

Star- delta – Voltage is to be stepped down, neutral of the primary is earthed
Delta –delta –used in systems which carry large current at low voltages and also when
continuous supply has to be maintained.
Delta – star – where necessary step up voltage.
Choke : an iron core inductor having low resistance and high inductance.

3 phase Inductin motors –1) Squirrel cage –self starting,low starting torque ,speed nearly
constant ,can be operated continuously eg. Saw mills,lathe,fan,coveyors,elevators etc
,2) Slip ring – high strating torque, low starting current and speed can be varied eg.
Lifts, cranes, flour mills etc

Multiplying factor = (selected voltage range)(selected current range)

Full scale reading on the dial
Megger : used for measurement of high resistance and insulation resistance

Lenz law: the direction of induced emf in the choke will try to oppose the fall of current
in the circuit.
Capacitor : are a device which can store electrical charge when voltage is applied across
them and get discharged when a load is connected across them.
Rheostat : variable wire wound resistance which has power rating up to 100 W i
Ripple factor – Rms value of ac in the load/ average dc component in the load
Amplify: to increase the strength of signal output sufficient enough to drive a load
No of bells = log 10 ( p2/p1)
Osc.illator: a stable circuit produces continuous output swings to and fro between the
positive and negative limits and hence it is called oscillator

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