1. ATLAS ENGINEERING LIMITED
Internship Report
Group members:
Haris Haider (MY-008-T.E)
Abdul Aziz (MY-009-T.E)
NED University of Engineering & Technology

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PREFACE
This report is about the work we have done during our winter internship from 5th
December 2014 to 25th
December 2014 in cast iron foundry of Atlas Engineering Limited. Situated at Landhi, National Highway,
Karachi.
The primary goal of this report is to present the work done regarding our project titled as:
“To conduct root cause analysis and countermeasures to prevent/control shrinkage in bore of Drive
plate CD-70 casting”
The report is based on practical knowledge, assignment and task that we have completed. It also include
company brief introduction.

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AKNOWLEDGEMENT
First of all we are grateful to Almighty Allah for giving us opportunity to work in such a
pleasant environment and get this far in our project despite many problem and hurdles. It
is the indulgence to acknowledge our deep gratitude to management of Atlas Engineering
Limited for its advices and helping us with all knowledge and resources and also
providing whatever we asked for our need.
We are thankful of the staff and workers of Atlas Engineering Limited who fully
supported and cooperated us to increase our foundry knowledge and enhance our skills.
We put forward our special thanks to the following personnel:
 Mr. Sikander {Production Manager (Cast iron Product)}
 Mr. Qismat Ali {Assistant Manager (Cast iron Foundry)}
 Mr. Minhaj {Production Engineer (Cast iron Foundry)}
 Mr. M.Siddiqui (Supervisor, Hand moulding section)

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Table of Contents
S.no Contents Page no.
1 About company 4
2 Cast iron 5
3 Theoretically aspect of project 6
4 Introduction 6
5 Casting process 7
6 Effect of composition on properties 9
7 Shrinkage 9
8 causes 10
9 Preventions 10
10 Experimental aspect of project 13
11 Experiment no. 1 13
12 Experiment no.2 14
13 Experiment no.3 15
14 Experiment no.4 16
15 Suggestions & recommendations 17

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About Company
Atlas Engineering Limited:
Atlas Engineering Limited (formerly Allwin Engineering Industries Limited) was established in 1951 as a
partnership firm. It became a private limited company in 1963, and was converted into a public limited
company in July 15, 1966. Shirazi Investment (Private) Limited is its holding Company.
Atlas Engineering is one of the largest and oldest manufacturers of automotive parts and components in
the private sector in Pakistan
Atlas Engineering has state-of-the-art facilities to produce Cast Iron process pig iron and aluminum alloys
through various stages into high precision automotive components and has full access to technical know-
how and back-up of world renowned manufacturers like Honda Foundry, FCC and Shindengen Electric
Company, Japan.
The Company manufactures motorcycle pistons, cylinders, Aluminum Components, radiator assemblies
and radiator cores and a host of fully-machined cast iron parts. Various excellence awards have been
achieved for its quality.
The facilities at Atlas Engineering have been extended and modernized steadily over the last decade,
including CNCs, and semiautomatic machining lines are being added. Further expansion of facilities for
manufacturing piston and allied products are being undertaken. The production facilities are backed by
well-equipped quality assurance system, design and applied research facilities.
Atlas Engineering policy and operations are guided by the management approach of Atlas Group,
Organization development through self-development

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Cast Iron.:
Cast iron is iron or a ferrous alloy which has been heated until it liquefies, and is then poured into a
mould to solidify. It is usually made from pig iron. The alloy constituents affect its color when
fractured: white cast iron has carbide impurities which allow cracks to pass straight through Grey cast
iron has graphite flakes which deflect a passing crack and initiate countless new cracks as the material
breaks.
Gray Cast Iron:
Gray iron, or grey cast iron, is a type of cast iron that has a graphitic microstructure. It is named after the
gray color of the fracture it forms, which is due to the presence of graphite.[1]
It is the most common cast
iron and thA typical chemical composition to obtain a graphitic microstructure is 2.5 to 4.0% carbon and
1 to 3% silicon by weight. Graphite may occupy 6 to 10% of the volume of grey iron. Silicon is important
to making grey iron as opposed to white cast iron, because silicon is a graphite stabilizing element in cast
iron, which means it helps the alloy produce graphite instead of iron carbides; at 3% silicon almost no
carbon is held in chemical combination with the iron. Another factor affecting graphitization is the
solidification rate; the slower the rate, the greater the time for the carbon to diffuse and accumulate into
graphite. A moderate cooling rate forms a more pearlitic matrix, while a fast cooling rate forms a
more ferritic matrix. To achieve a fully ferritic matrix the alloy must be annealed.[1][4]
Rapid cooling
partly or completely suppresses graphitization and leads to the formation of cementite, which is
called white iron.[5]
The presence of graphite flakes makes the Grey Iron easily machinable as they tend
to crack easily across the graphite flakes most widely used cast material based on weight.
Properties of Gray Iron
Graphite morphology and matrix characteristics affect the physical and mechanical properties of gray cast
iron. Large graphite flakes produce good dampening capacity, dimensional stability, resistance to
thermal shock and ease of machining. While on the other hand, small flakes result in higher tensile
strength, high modulus of elasticity, and smooth machined surfaces
Mechanical Properties can also be controlled through heat treatment of the gray cast iron. For example, as
quenched gray cast iron is brittle. If tempering is accomplished after quenching, the strength and
toughness can be improved, but hardness decreases. The tensile strength after tempering can be from 35-
45% greater than the as-cast strength and the toughness can approach the as-cast level

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Theoretically Aspects of project
Introduction:
In current scenario the foundry industry is experiencing tremendous changes because of global
competition. Increasing demands and requirements to be produced in time and at very competitive price.
It is necessary to set new objectives and strategies in order to increase actual competitiveness.
Atlas Engineering Limited uses the Molasses Moulding Process for making mould and also shell mould.
An Economical and less skill requiring process and also this casting produces good surface finish and
excellent mechanical properties. However, along with this casting defects causing rejection before and
after machining operations continue to be a concern for variety of reasons.There are many casting defects
that can occurs in castings i.e “Slag/sand inclusion, Misrun, Blowhole, Extra metals, Miss-matching etc.
One of most important reason which is faced by cast iron foundry of AEL is shrinkage in particular part
“Drive Plate”. This is common problem faced by any of foundry. This kind of defects is non recoverable
and that’s why becoming the most important concern in cast iron foundry.
Main Problem:
Shrinkage in thicker section of the Drive Plate after machining.
Project Objective:
“To conduct root cause analysis and countermeasures to prevent/control shrinkage in bore of Drive plate
CD-70 casting”

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Casting Process:
Molding Process:
Drive plate is casted by sand casting process. In which AEL uses Hand molding method by using silica
sand with a binder of molasses.
Hand Molding Method of Sand Casting
Sand casting production mainly include hand molding and machine molding method. The operation of
hand molding is more simple and flexible, but the production rate is low, so it is suitable for small batch,
amount production.
Hand Molding (Manual Moulding) Methods
1. Whole pattern, two cases molding
When the largest cross section of casting parts is located on the top position, then this position could be
used as the parting surface, and the pattern could be made as a whole part as the following diagram.
The whole pattern is in the sand mold, so it can avoid mismatch of mold cases, and can guarantee the
high dimensional accuracy.
2. Two parts molding

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The patterns could be designed as two separated parts, and could be assembled with stop bolts as
following.
This molding method is simple and has very wide application. However, if the sand mold cases (sand
boxes) could not be fixed accurately, then mismatch will happen, and it will affect the accuracy of
castings. Moreover, the parting line will affect the surface quality too.
Melting Process.
AEL uses Induction furnace for melting and producing gray iron . AEL uses two induction furnaces at a
time which provide mass production requirements.
Induction furnace:
An induction furnace is an electrical furnace in which the heat is applied
by induction heating of metal. The induction furnace was first invented in 1877 in Italy. The first use of
the furnace was in 1927 in Britain. It wasn't until World War II, when the need for aluminum casting
grew significantly, that the induction furnace went into wider usage. In induction heating, a current
passes through a coil that surrounds the piece to be heated. The electric current frequency to be used
depends on the mass of the piece being heated. The induction coil (or induction heads for specific load
shapes) must be water cooled to protect them from overheating themselves. Although induction heating
usually uses less electricity than resistance heating, some of that gain may be lost due to the cost of the
cooling water and the heat that it carries down the drain. Induction heating is easily adapted to heating
only localized areas of each piece and to mass-production methods. Similar application of modern
production design techniques with rapid impingement heating using gas flames has been very successful
in hardening of gear teeth, heating of flat spring for vehicles, and a few other high production
applications.
Capacity of Induction furnace:
 1.5 ton

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Raw materials For Drive Plate:
 Pig iron,
 Steel scrap,
 Shop returns, ferroalloys, re-carburizer.
Casting Temperature:
 1450 – 1330o
C
Effect of composition on properties:
 Carbon: During solidification, Carbon precipitates to Graphite, which offsets shrinkage. Amount
necessary to achieve this: %C + 1/7%Si ≥ 3.9% Also, Carbon contents greater than this amount
decrease fatigue strength.
 Silicon: Graphitizing agent. Increasing amount of Silicon also increases amount of Ferrite. Increases
strength and hardness of this Ferrite and reduces impact resistance. Also, provides high temperature
oxidation resistance. For applications of high temperature, such as turbocharger housings, Silicon
contents of between 3.75% and 4.25% are required.
 Manganese: Acts as a Pearlite stabilizer and increases strength, but decreases ductility and
machinability.
 Nickel: Increases strength by promoting formation of fine Pearlite. Increases hardenibility.
 Copper: Used to form Pearlite upon solidification with high strength and good toughness and
machinability.
 Molybdenum: Used to stabilize structures at high temperatures
Shrinkage:
Cavity caused by liquid contraction. They are generally very irregular and have rough, dendrite-type
walls. They are usually found in interiors, in the thickness changing elements of the part, or in the inside
of extra-large zones, sometimes in the form of a surface depression in varying sizes.
GENERAL CHARACTERISTICS OF SHRINKAGE
They appear in the form of open cavities on the outside surface of a part, or closed cavities on the inside
of a part. The interior surfaces may be smooth (primary shrinkage) or have a dendritic morphology
(micro-shrinkage or secondary shrinkage). In certain eutectic alloys, primary shrinkages may appear with
dendritic interior surfaces.

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Given that it is a contraction defect, it is normally formed in final solidification zones (the part’s thermal
centres). This defect is formed in final solidification zones, which correspond to the part’s thermal centre.
They may appear in zones with interior angles, often revealed during machining operations, close to
cores, sprues, etc., due to the difficulty of heat evacuation, a phenomenon which slows down the liquid
metal solidification process.
Their occurrence depends on the alloy’s liquid-solid contraction. In the case of graphite casting,
spheroidal is more prone to secondary shrinkage (as far as micro or macro defects are concerned) than
laminar, due to their different solidification patterns.
CAUSES
Technically, shrinkages are produced in the phase in which liquid becomes solid, due to the severe
contraction that the metal has to undergo in process. So the geometrically extra-large zones, as they cool
down at a slower rate than the rest of the part, provide material to the zones that cool faster, generating
dendritic caverns (shrinkages) in the interior. The causes behind the appearance of shrinkages are:
 Unsuitably designed part to be cast, as well as inadequate casting methods.
 The main cause is the contraction that the metal undergoes between the semi-solid
state and final solidification. The lower the metal’s tendency to contract, the lower
the risk of this defect appearing.
 In graphite casting, an expansion is produced due to the formation of graphite at the
heart of the metallic material. This phenomenon can cause swelling inside the
moulds and increase the parts’ volume.
 The feeding difficulties that are produced as the solid fraction increases must also be
taken into account: diameter and/or incorrect design of the risers, use of metal entry
points with thin sections, which solidify quickly, incorrectly designed parts
(ISOLATED EXTRA-LARGE SECTIONS), etc.
 The use of high casting temperatures (which increase the mould’s instability due to
the intense heat, slowing down the solidification period) or excessively low
temperatures (with a fast solidification of entry points or necks, even in the risers)
Preventions
 The preventive action to be taken to stop shrinkages from appearing is as follows:
 Suitable and adequate metal composition, inoculation treatment. Efficient feeding of the
part. Use of an appropriate casting temperature.
 Modification of the design to obtain more uniform sections of metal. If necessary, use
coolers for the thicker sections. Level out the cooling speed of the extra-large zones by
homogenizing the thicknesses, preventing the generation of extra-large zones. To do so,
you must always design the part to be obtained, endeavoring to ensure that the changes in
sections are progressive, avoiding any abrupt section changes. Prevent the formation of
extra-large sections, or at least limit abrupt section changes, by joining sections. Some
examples of this are shown below.

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Before machining of pattern:
After Machining of pattern: Groove of 1mm
 In the pattern’s manufacture, keep the machining ridges constant at a minimum of 5 mm
and up to a maximum of 15 mm. In this way, mortices, holes and, in general, deep
machining or machining in extra-large zones, must always be made on the pattern and
never be left blind to be obtained at a later date in the part that has been cast by
machining.
 In this way, in the mortices of extra-large zones on the patterns, coolers will be included
inside the mortices or holes, known as controlled cooling. For this practice to be
implemented, the pattern must first have clearances in these zones to be able to house
the coolers. This is a common practice in iron and steel casting companies, and it is also
recognised in technical/scientific fields.
Diameter =
40 mm
Bore size=
12.5 mm
No Groove
Diameter =42mm
Bore size =
11.5mm

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Experimental Aspect of Project
Experiment no. 1
Objective:
To determine the causes of shrinkage by comparing respecting positions of drive plate.
Principle:
If the shrinkage defect occur at same position of gating system in all moulds then the shrinkage is due to
faulty gating design.
If the shrinkage defect position follows zig zag or irregular position in all mould,then the shrinkage is
considered due to disturbance of metal composition.
Procedure:
We take 4 mold of drive plate for observation.We do casting of these mold and allow them to solidify
slowly.
Observation
Position of
drive plate
Mould 1 Mould 2 Mould 3 Mould 4
1 ok ok ok ok
2 ok shrinkage ok ok
3 ok ok ok ok
4 shrinkage ok Shrinkage shrinkage
5 ok ok ok ok
6 ok Shrinkage ok Shrinkage
1st
Pair 2nd
Pair 3rd
Pair
Rejected Piece/Total Piece 1/8 3/8 2/8
% Rejction 12.5 37.5 25
Result:
The above table shows that the shrinkage is due the metal composition disturbance as well as location of
pattern with respect to gating also play a role.

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Experiment no.2
Objective:
Designing the gating system(modified gating system) that’s supports the well distribution of the melt
with same flow rate, avoiding the turbulence.
Principle:
If the parts are filled with the same flow rate at the same time, it will reduce the tendency of shrinkage.
Procedure:
The parts are arrange in form of circle having center pouring
Observation
No. of Parts 6
Accepted parts 4
Rejected parts 2
% of rejection 33
Result:
2 pieces rejected out of 6 pieces
Reason:
Distance between gate and riser is too far.
Disadvantage:
Pouring in inadequate manner

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Experiment no. 3
Objective:
To determine the effect of pouring Temperature
Principle:
The use of high casting temperatures (which increase the mould’s instability due to the intense heat,
slowing down the solidification period) or excessively low temperatures (with a fast solidification of
entry points or necks, even in the risers)
Procedure:
We take initial 2 moulds and last 2 mould of casting to observing the temperature effect.
Temperature range:
1450-1330o
C (less chance of shrinkage in these range)
Observation
Initial 2 molds at 1460oC Last 2 molds at 1300oC
Nos of parts 12 12
Rejected parts 2 2
% of rejections 16.67 16.67
Results:
Too low and too high temperature can cause shrinkage .

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Experiment no. 4
Objective:
To determine effect of over inoculation.
Procedure:
We take melt from furnace and pour it it into test ladle for study
Observation
Quantity Normal Inoculation High inoculation High
inoculation
100 2.8 kg/ladle 3.0 kg/ladle 3.2kg/ladle
%Rejection 2.0% 8.0% 14%
Result:
High inoculation increase shrinkage

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Experiment no. 5
Objective:
To compare the shrinkage in different gating design system.
Procedure:
We do casting for following gating design.
1.) 2.)
3.) 4.)
Observation:
Quantity Gating Design % Rejection
60 Design no.1 18%
50 Design no.2 (5 parts) 14%
60 Design no.3 16%
60 Design no.4 6%
Result:
Gating design no. 4 having good capability of supporting disturb condition

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Suggestion & Recommendations.
 Good Control of composition specially carbon and silicon (can reduce shrinkage drastically)
 Use the casting software such as magmasoft to determine the whole casting to solidification
process before practical
 Proper inspection of mould
Conclusion:
There is no one factor that contribute in the defect but it is the combine effect of all factors that is given
below.
 Gating design
 Composition
 Temperature
 Inoculant & Inoculation
 Pouring rate
 Molding material & strength
But the gating design plays a major role that can support the factors.