International Journal of Engineering, Management ... · the sand grains, it creates metal...
Transcript of International Journal of Engineering, Management ... · the sand grains, it creates metal...
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International Journal of Engineering, Management & Sciences (IJEMS)
ISSN-2348 –3733, Volume-3, Issue-2, February 2016
3 www.alliedjournals.com
Abstract— Green sand moulding process is traditional and
common in practice of manufacturing castings. Here, the focus
is made on use of cement, as binder instead of bentonites and
other additives. Number of samples in different compositions of
silica sand, cements,and additives was prepared and tested. The
important technological properties like Permeability, Green
strength and Shatter index were tested. The moulds prepared
with various compositions of cement and bentonites with silica
sand were poured by molten steel . The castings obtained was
inspected and the results shows that the addition of cement and
moisture at appropriate composition with silica sand increases
the surface quality, and reduce the mold defect such as metal
penetration, sand inclusion etc.
Index Terms— Silica sand, Cement, Casting, Bentonite,
Mould, Binder.
I. INTRODUCTION
The casting process involves the pouring of molten metal into
a mold therefore, the mold material and molding method
must be selected with care. The castings are made in sand
molds because metallic molds cannot be used for ferrous
metals production. Selection of the molding material and its
bonding system depends on the type of metal being poured,
the type of casting being made, the availability of molding
aggregates, the mold and core making equipment owned by
the foundry, and the quality requirements of the customer. A
thorough understanding of all of these factors is
necessary to optimize the molding system used in the
foundry. This article will discuss the various materials used to
produce molds for sand casting. These materials include
sands, clays, and additives[1].
Sand grain represents the coarse particles liberated by the
weathering of rocks. The natured moulding sand occurs as
deposit in various parts of our country such as Kanpur,
Jabalpur, Bhavnagar, Secundrabad, Guntar, Damodar,
Barakar, Burdwan and Jamalpur.[2]
Principle ingredient of moulding sands are Silica sand
grains,Clay(bond) and Moisture. [2]
Steel :-Steel is an iron-base alloy fairly low in carbon content.
All of the carbon in steel is dissolved in the iron so that no
carbon is present as graphite. The outstanding characteristics
of steel castings are their high strength and toughness. With
steel, it is possible to make castings stronger and tougher than
with any other common casting alloy. Steel retains its high
Manuscript received February 18, 2016
Avinaw Pratik, Student Department of Foundry and Forge
Technology,NIFFT Ranchi, India
Ajit Kumar, Student Department of Foundry and Forge
Technology,NIFFT Ranchi, India
strength even up to fairly high temperatures but can become
quite brittle as low temperatures. The main disadvantages of
steel as a casting alloy are: (1) it melts at a high temperature,
(2) has a high shrinkage during solidification, and (3) is
difficult to cast. Except for specially alloyed grades, steel will
rust or corrode and is magnetic. As a general rule, low-carbon
unalloyed steel is harder to cast than high-carbon or alloyed
grades. [3]
Defects in Casting:-
Metal Penetration:- When metal goes in to voids between
the sand grains, it creates metal penetration.This is a defect,
which causes casting surface to become rough, some times In
severe cases the metal may fill in the pores completely or
penetrate to a depth of few sand grains, leading to excessive
fettling time or, in extreme case even in scrapped casting.
Large casting poured with high metalostatic pressure undergo
more severe pouring condition are more prone to penetration
defect. [4]
Dirt inclusion, cuts and washes:-
Sand or dirt inclusion
could be the results of cuts and washes. Cuts and washes are
due to erosion of the sand by metal flowing over the mold or
core surface. These defects may occurs directly in front the
ingate or in other parts of the casting. [5] Erosion Scab: An erosion scab occurs where the molten
metal has been agitated, boiled or has partially eroded away
the sand leaving a solid mass of sand and metal at a particular
spot. Some of the sand that was eroded away generally finds
its way to the cope of the casting as dirt inoculations. [6,7]
Portland Cement:- Cement is a material with adhesive and
cohesive properties which make it capable of bonding
minerals fragments into a compact whole. For constructional
purposes, the meaning of the term "cement" is restricted to
the bonding materials used with stones, sand, bricks, building
stones, etc. The cements of interest in the making of concrete
have the property of setting and hardening under water by
virtue of a chemical reaction with it and are, therefore, called
hydraulic cement. The name "Portland cement" given
originally due to the resemblance of the color and quality of
the hardened cement to Portland stone – Portland island in
England. [8]
Setting
Setting refers to a change from a fluid to a rigid stage Cement
+ water → cement paste → lose its plasticity gradually→
when it lose its plasticity completely → setting occurs. The
stages of setting include:
Initial setting
Final setting
Sand Process Control for Steel Casting using
Cement Mould (A Case Study)
Avinaw Pratik, Ajit Kumar
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Sand Process Control for Steel Casting using Cement Mould (A Case Study)
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It is important to distinguish setting from hardening, which
refers to the gain of strength of a set cement paste. The two
first to react are C3A and C3S. The setting time of cement
decreases with a rise in temperature. The importance of
setting in concrete works comes from the importance to keep
the fresh concrete in the plastic stage for enough time
necessary to complete its mixing and placing under practical
conditions. But, from the economical side, it is important that
the concrete hardens at convenient period after casting. [9]
There are four main stages during setting. 1) Takes only few minutes after the addition of wate to the
cement. The rate of heat generation is high, due to
wetting of cement particles with water, and the beginning
of hydrolysis and reaction of the cement compounds.
After that the rate decreases to relatively low value.
2) Dormant Period:-
Takes 1-4 hours with relatively low speed.
The initial layer of the hydration begins slowly to
build on the cement particles.
Bleeding and sedimentation appears at this period.
3) Heat of hydration begins to rise again due to the
dissolution of the weak gel layer formed in the
beginning (first) on the surface of C3S crystals – so the
water able to surround the particles surfaces again – and
forming gel of calcium silicates with enough amount to
increase setting.
The activity reach its peak after about 6 hours for
cement paste, with standard consistency, and might
be late for paste with higher w/c ratio.
At the end of the stage, the paste reaches the final
setting stage.
4) Hardening and gain of strength Vicat apparatus – use to
measure the setting time for cement paste. Initial setting
time – refers to the beginning of the cement paste setting.
Final setting time – refers to the beginning of hardening
and gain of strength.
Advantages Of Cement Molding:
Useful bench life (15-20min)
Large size mold.
Good shakeout property.
Large size ferro casting.
Comprative bech life.
CO2, Fesi-less
Cement-10-20 min.
Dicalcium silicate-25-30 min.
Great hardness strength.
Considerable accuracy of mould making.
II. RESEARCH OBJECTIVE
The main objective of paper is to (1) make sound steel casting
.(2) Study the property of sand. (3) Study the green
compression strength, shear strength, shatter index and
permeability of sand mix using Portland cement as a binder
instead of bentonites. (4) Making mould by using appropriate
composition of both clay (Portland cement, bentonites) and
compare the result by casting of steel.
III. METHODOLOGY:
Steps involved:
(A) Testing of moulding sand.
Clay or A. F. S. clay content.
Moisture content.
Size and distribution.
(B) Preparation of the test specimen.
(C) Evaluating the properties of sand mix.
Green compression strength
Permeability
Shatter index
Shear index
(D) Melting practice of steel.
IV. EXPERIMENTAL ANALYSIS
Testing of moulding sand:
Clay or A. F. S. clay content:
The material which fails to settle at the rate of 25 mm/
minute is known as clay or AFS clay.
The sample under test is dried and cooled and then 50 gm is
taken into a jar. 475 cc of water and 25 cc of NaOH are added
to make the solution which is added to sand sample. The jar is
sealed and made to rotate at 60 rpm. After about an hour, the
jar is removed and it is filled with water upto 150 mm from
the bottom and the contents is allowed to settle for 10
minutes. Excess water above the level of 125 mm is siphoned
off. This is repeated a number of times allowing only five
minutes to settle. The remaining sand is filtered, dried and
weighed. The difference between this weight and the original
weight gives the weight of clay.
AFS clay includes all particles finer than 20 micron whether
they are clay, silt or organic matters. Thus AFS clay includes
even matter which will not function as clay.
True clay = AFS clay-(wt. of organic matter & moisture)
= silt + dead clay
Moisture content:
a) Heating to 110 C and then difference in weight gives this
value
b) Moisture teller: chemical reaction between calcium
carbide and moisture generates the acetylene gas and its
pressure is directly calibrated with the % of moisture present
in the sand sample.
Size and distribution
Grain size of foundry sand fall mainly within the range of 0.1
to 1.0 mm. Grain size and distribution of the base sand
influence many properties of moulding mixture. High
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International Journal of Engineering, Management & Sciences (IJEMS)
ISSN-2348 –3733, Volume-3, Issue-2, February 2016
5 www.alliedjournals.com
permeability is characteristics of coarse and uniformly
distributed sands while surface finish and low permeability
are characteristics of fine sand. Coarse and uniformly
distributed sand are associated with high flow ability and with
maximum refractoriness.
The grain size of sand is expressed by a number called ―grain
fineness number‖. To measure this, the sample sand which is
washed and dried is placed on a sieve set which contain
several sieve one above the other, having varying but known
number of meshes (mesh size).
The coarsest sieve is kept on the top and finest at the bottom.
Whole set is shaken for a definite length of time. The amount
of sand retained in each sieve is then collected, weighted and
expressed as percentage of the original sample weight. The
percentage collected in each sieve is multiplied by its own
multiplying number- a constant given for each sieve and all
the products are added to get total product.
G. F. N. = Total product / (Total sum of percentage
collected in each sieve)
Preparation of the test specimen
The test specimen used for measuring the physical properties
of sand mix can be cylinder with 2 inch (5.08 cm) dia 2inch
(5.08 cm) (AFS Standard). It was contracted by means of
three blow from (4 lb weight) falling from a height of 2inch
(5.08 cms) on the sand in a container. The appropriate
quantity of sand weighted out and placed in the container.
The container was placed below and rammed head lowered
gently until supported by sand. The handle operating the cam
was turned 3 times with 1 sec interval between the turns.
After the third rams, the top of rammer rod, or red mark
should come between the tolerance mark.
Evaluating the properties of sand mix
Green compression strength:
To determine compression strength of prepared specimens of
green sands and unbaked core sands by applying a
progressively increasing spring load to the specimen until it
collapses. The machine consists of a spring balance and a pair
of self-aligning compression heads all supported in a strong
metal frame. By means of a hand-wheel, a load can be
applied to a sand specimen held in the compression heads, via
the spring balance. The load required to cause the specimen
to collapse is recorded on the dial of the spring balance by
means of as lave pointer which indicates the compression
strength in psi using an AFS 2 inch diameter x2 inch height
specimen.
Three ranges of spring balance are available for this machine
:-
0-4.5 psi, 0-12.5 psi and 0-31 psi on a 2 inch diameter x 2 inch
height specimen. A sample holder is provided with each
machine to facilitate the positioning of the specimen in the
compression heads and in the case of the low capacity balance
a special sample plate is supplied on to which the specimen
can be stripped directly from the split specimen tube when
dealing with very weak sand mixes.
Permeability
Permeability is defined by the AFS as that physical property
of moulded sand which allows gas to pass through it. It is
determined by measuring the rate of flow of air through the
AFS standard rammed specimen under a standard pressure.
The general formula for the calculation of permeability may
be expressed as follows :-
Where , P = Permeability number
v = Volume of air in ml passing through the specimen
h = Height of test specimen in cm.
p = Pressure of air in cm of water.
a = Area of cross-section of specimen in cm2
t = Time in seconds.
Since the standard method requires that 2000 ml of air should
be forced through a specimen2 inches (5.08 cm) and 2 inches
diameter (20.268 cm2area), by substituting these values forv,
h, and a, and measuring the time in seconds, the formula
becomes :-
P= 30072/ (air pressure in cm of water x time in sec).
Alternatively, for routine control purposes, calibrated orifices
may be used to meter the rate of flow of air to the sand
specimen and by measuring the pressure between the orifice
and the specimens, the permeability may be obtained by
referring to the attached table or using the transparent direct
reading scale.
Shatter index
Shatter index is measured of toughness of the sand
mix.
For testing it standard sand sample(2" × 2") prepared
from the sand mix is weighed and placed on the
anvil of the testing machine. A steel ball of 510 g is
allowed to fall on the sand sample thriugh a standard
heigh. Broken pieces of sand sample is placed on 12
mm mesh sieve.
The amount of sand retained on sieve is weight and
shetter index is expressed as :
Weight of the sand mix retained on the seives ×100
Weight of the standard sand sample taken
It is indicative of the toughness of sand mix i.e high strength
and low deformation . its value can be between 30-90%
Green Shear Strength
(a) Place the shear test heads in the lower position in the
machine, with the head having the half round holder attached
to it in the pusher arm.
(b) Raise the weight arm slightly and insert an AFS standard 2
inch diameter x 2inch height specimen between the heads.
(c) Ensure that the magnetic rider is resting against the pusher
arm and that there is ¼ inch clearance between the rubber
bumper and the lug on the weight arm.
(d) Apply the load uniformly until the specimen shears.
(e) Read the lower edge of the magnetic rider on the scale
designated ―Green Shear‖.
Melting Practice:
2T capacity of induction furnace is used. 14 kg capacity of
ladle was used for taking the melt.
Induction furnace melting practice.
Raw Material: Generally foundry returns such as riser ,
gatings, rejected casting etc. were used as scrap.
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Sand Process Control for Steel Casting using Cement Mould (A Case Study)
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Table 1: Specification Of Ferro Alloy used :
FeSi ( low c)
Si 60-65%
C 0.1% max
S 0.05% max
P 0.05% max
Al 1.25% max
Composition Control:
Melt was adjusted by the addition of ferrosilicon ,
ferromagnese and other alloying. After achieving the required
composition the melt temp has raised to about 1620 o C and it
was poured to the ladle .
Ladle Used And Preheating OF Ladle:
14 kg capacity ladle is used. It was lined with basic lining
material i.e Magnesia powder with boric acid . the steel was
made up of mild steel. The ladle was preheated by producer
gas burner for 35 to 45 min to attain temperature of 600 0
C700 0 C.
Deoxidiant addition to ladle:
When the metal has about to tap , the molten metal has taken
into the ladle (about 10 kg). the deoxidant Al and Ca-Si where
added separately, to the each melt in the ladle and mixed
thoroughly to get completely distribution of deoxidant in the
solution . the addition of Al and Ca-Si were carried out in
different ways.
Aluminum addition: after taking melt into the ladle Al
shots were added to the melt and was stirrered.
Calcium silicate addition- at steel making temperature
the Calcium vapour pressure is 1.6 times the
atmospheric pressure . so if the Ca-Si is added in the
same way as Al it won’t mix with metal and the
vapour comes out . to avoid this the Ca-si powder
was kept inside a pipe of 10mm dia and injected into
the ladle. So, that it will be released at the bottom of
the ladle .with this practice good result were
achived.
As soon as mixing was over , the molten metal was
poured into the mold. Pouring of metal into molds.
V. RESULT AND DISCUSSION
Test performed on Rajmahal sand:
Clay percentage test:
Sample of 50 gm rajmahal sand is being taken and mix with
475ml of distilled water and 25ml Of NaoH . stirrer for 15
min then water is removed by siphon process then put it into
moisture teller for 20 min for dry.
Result- 47.7gm after removing clay.
Calculation:
50-47.7 = 0.046 percentage=.046*100= 4.6%
50
Sieve analysis:
Table 2: Sieve analysis for rajmahal sand. Sie
ve
size(
mm)
U
S std
sieve
num
ber
G
FN
(m
m)
% A
(mm)
=GF
N*2
%Com
mulative
Mul
tiplier
B
Pr
oduc
t
A
*B
1.4 14 .
4
.8 6 4.
8
1 18 .
7
1.4 2.2 9 12
.6
.71 25 2 4 6.2 15 60
.50 35 4
.5
9 15.2 25 22
5
.35 45 8
.3
16.
6
31.8 35 58
1
.25 60 1
5.8
31.
6
63.4 45 14
22
.18 80 1
1.8
23.
6
87 60 14
16
.12
5
12
0
5
.5
11 98 81 89
1
.09 17
0
.
7
1.4 99.4 118 16
5.2
.06
3
23
0
.
1
.2 99.6 164 32
.8
PA
N
.
2
.4 100 275 11
0
Calculation:
Total product of AFS no calculation=5145.4
AFS number = Total product /Total present retained
= 5145.4/100 = 51.45
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International Journal of Engineering, Management & Sciences (IJEMS)
ISSN-2348 –3733, Volume-3, Issue-2, February 2016
7 www.alliedjournals.com
Fig 1. Graph between sieve size and product of A
and B in Rajmahal sand.
Fig 2. Graph of percent retained on each sieve
vs. sieve number of Rajmahal sand.
Moisture test :
Sample of 50 gm clay sand taken (rajmahal) put it on hot dry
baking oven for 30 min.
Wt the sample after drying = 49.8 kg
Calculation:
(50-49.8)/50 = .004 = .004*100 = .4%
Test performed on allahabad sand :
Clay percentage test:
Sample of 50 gm allahabad sand is being taken and mix with
475ml of distilled water and 25ml Of NaoH . stirrer for 15
min then water is removed by siphon process then put it into
moisture teller for 20 min for dry.
Result- 48.5gm after removing clay.
Calculation:
(50-48.5)/50 = 0.03 percentage=.03*100= 3%
Sieve analysis:
Table 3: Sieve analysis for Allahabad sand.
Calculation:
Total product of AFS no calculation=4208.84
AFS number= Total product = 4208.84
= 44.2
Total present retained
95.14
Si
eve
size(
mm)
US
std
sieve
numb
er
GF
N
(mm)
%
A
(mm)=G
FN*2
%C
omm
ulativ
e
Mult
iplier
B
Prod
uct
A*B
1.4 14 .67 1.34 6 8.04
1 18 .2 .4 1.7
4
9 3.6
.71 25 1.2 2.4 4.1
4
15 36
.50 35 9.6 19.2 23.
34
25 480
.35 45 14.
9
29.8 53.
14
35 1043
.25 60 7.3 14.6 67.
74
45 657
.18 80 9.5 19 86.
74
60 1140
.12
5
120 3 6 92.
74
81 486
.09 170 .9 1.8 94.
54
118 212.
4
.06
3
230 .1 .2 94.
74
164 32.8
P
AN
.2 .4 95.
14
275 110
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Sand Process Control for Steel Casting using Cement Mould (A Case Study)
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Fig 3. Graph between sieve size and product of A
and B in Allahabad sand.
Fig 4. Graph of percent retained on each sieve vs.
sieve number of Allahabad sand.
Moisture test :
Sample of 50 gm clay sand taken (Allahabad sand) put it on
hot dry baking oven for 30 min.
Wt the sample after drying = 49.7 kg
Calculation: (50-49.7)/50 = .006 = .006*100 = .6%
Since Allahabad sand GFN is less than 50 and for steel
casting the GFN no should be more than 50 is required and
the refractoriness of Allahabad sand is less than rajmahal
sand and GFN no of rajmahal sand is 51.45 so we choose
rajmahal sand for the sand mix testing.
Table 4. Effect on Green compression strength with varying
percentage of moisture and cement.
Fig 5: Green Compression strength vs.
percentage of moisture.
Fig 6: Green Compression strength vs. percentage
of cement.
Effect of moisture and clay content on the molding
properties.
Percenta
ge of
moisture
Green compression
strength (kpa)
Percentage of cement
3 4 5 6 7 8
2 310 311 365 414 328 358
3 281 310 371 418 395 396
4 273 290 352 413 356 385
5 233 284 321 363 356 391
6 180 232 262 333 341 352
7 121 200 242 296 312 313
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International Journal of Engineering, Management & Sciences (IJEMS)
ISSN-2348 –3733, Volume-3, Issue-2, February 2016
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It can be observed from the figure that with the increase of
moisture content the green compressive strength increases
and reaches maximum value. However the further increase of
moisture decrease the strength.Clay acquire its bonding
action only in the presence of requisite amount of water when
The water is added to clay ,it penetrates into the mixture and
forms microfilm which coats the surface of each flake. the
molecules of water forming this film are not in original fluid
state but in a fixed and a definite position. The rigid coating
of grains may be forced together, causing a wedging action
and thus developing strength. The bonding Quality of the clay
depends on the maximum thickness of film it can maintain as
the moisture content increased, the water film become thicker
and the layers midway between the flakes become more
plastic at certain water, content, the randomly oriented water
particles produce clay with maximum stickiness or bond, up
to certain addition of water the clay flakes receive water
films. Creating on atmospheric gel firmly holding the sand
grain, creating the bond or adhesion and help to develop the
strength for the molding sand when rammed in the molding
box. Any further addition of water will not strengthen the
micro-coating, but will create loosening of bond there by
weakening it. Presence of much water causes excessive
plasticity and too little water fails to develop adequate
strength and plasticity. Thus it essential to control the water
addition to close limit. The correct amount of water which
gives the peak compressive strength to the sand mix is called
tamper water.
Table 5. Effect on Shatter index with varying percentage
of cement and moisture.
Percent
age of
moisture
Shatter index
Percentage of cement
3 4 5 6 7 8
2 81.3 82.2 84.1 85.9 81.2 80
3 80.2 82 83.9 85.3 84.3 83.1
4 79.3 81 81.2 87.2 84 84.3
5 77.4 79.3 79.2 82.1 83.7 86.3
6 77.1 78.4 78 81.2 78 84.3
7 76 77.2 77.6 78.6 75 80.2
Fig 7. Shatter index vs. percentage of moisture.
Fig 8. Shatter index vs. percentage of cement.
Effect of Moisture and Clay On Shatter index:
The effect of moisture and clay content on the shatter index of
molding sand mix. It can observed from the fig that the
shatter index increases with the moisture and clay content.
This implies that the amount of work necessary to break a
sand specimen increases with the moisture and clay content
with in the practical work limit.
Table 6. Effect on shear strength with varying percentage of
moisture and cement.
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Sand Process Control for Steel Casting using Cement Mould (A Case Study)
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Fig 9. Shear strength vs percentage of cement.
Fig 10. Shear strength vs percentage of moisture.
Table 7. Effect on permeability with varying percentage of
moisture and cement.
Percent
age of
moisture
Permeability
Percentage of
cement
3 4 5 6 7 8
2
3
4
5
6
7
26
4
30
0
31
3
31
3
32
8
34
1
27
5
27
5
31
3
32
8
32
8
34
1
23
5
23
5
24
3
25
3
26
4
27
5
21
2
21
9
22
6
23
5
24
3
25
3
20
5
20
5
21
2
21
9
22
6
23
5
19
8
20
5
21
2
21
2
21
9
22
6
Fig 11. Permeability vs percentage of cement.
Fig 12. permeability vs percentage of moisture.
Excessive moisture not only reduce the bond strength but
create problem to lower permeability, since the presence of
excessive clay and water closes the molds between the sand
grain by filling them. For given clay percentage permeability
of the sand mix increases with the increase of water content,
attains a maximum and subsequently decrease on further
increase in water . The permeability of sand mix is highest
when the clay particles absorbed that quantity of moisture
which imparts to them maximum stiffness so that they hold
sand grain furthest apart when sand is rammed. This
condition exits when the sand is at correct temper.
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Table 8. Effect on Green compression Strength with varying
percentage of moisture and cement after 1hr.
Fig 13. Green compression strength vs percentage of
moisture after 1 hr.
Fig 14. Green compression strength vs percentage of cement
after 1 hr.
Table 9. Effect on Shatter index with varying percentage of
moisture and cement after 1hr.
Percentage
of
moisture
Shatter index (after 1hr)
Percentage of cement
3 4 5 6 7 8
2 83.4 85.6 84.2 80 79.2 79.4
3 85.2 88.2 84.4 84.3 80.2 76
4 87.3 81.4 90.3 91.6 86 84.3
5 82.4 83.2 92.3 90.2 83.7 85.3
6 76.8 78.4 88.7 82.3 78 76
7 74.4 77.2 76.3 78.2 75 71.3
Fig 15. Shatter index vs percentage of moisture after 1 hr.
Fig 16. Shatter index vs percentage of moisture after 1 hr.
Percentage
of
moisture
Green compression
strength (kpa) (after 1 hr)
Percentage
of cement
3 4 5 6 7 8
2 316 331 379 365 345 323
3 292 321 368 392 370 352
4 284 296 356 482 373 358
5 272 271 321 472 414 421
6 211 235 285 338 395 413
7 198 215 262 287 348 384
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Sand Process Control for Steel Casting using Cement Mould (A Case Study)
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Table 10. Effect on shear strength with varying percentage of
moisture and cement after 1hr.
Percentage
of
moisture
Shear strength(kpa) (after 1 hr)
Percentage of cement
3 4 5 6 7 8
2 78 79 81 83 73 74
3 81 86.2 88 84 83 88
4 84 90.6 94 98 81 85
5 76 84 83 82 76 79
6 77 79 80 75 74 77
7 65 63 77 72 68 71
Fig 17. Shear strength vs percentage of moisture after 1 hr.
Fig 18. Shear strength vs percentage of cement after 1 hr.
Table 11: Varying percentages of cement, moisture and
sodium silicate.
Sample A B C D E F
Cement% 4 5 6 7 8 9
Moisture% 0 1 2 3 4 5
Sodium
silicate%
.8 1 1 2 3 3
Green strength
(KN/m2)
10 43 48 52 54 32
Shatter index
(no)
77 75 73 70 68 65
Green
permeability
(no)
135 133 124 112 100 92
Fig 19. Graph showing effect of cement, Moisture and sod.
Silicate on green strength.
Fig 20. Graph shows the effect of moisture ,sod .silicate on
green strength ,shatter index and green permeability.
Fig 21. Effect of moisture, cement and sod. silicate on
permeability.
Table 12: Cement Mold using Sodium Silicate
Cement 8% Sod silicate 4%
Moisture 3%
Sand (rajmahal) 40 kg
Mulling time 6 min
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Fig .22 Sample of cement mold using sod. silicate.
Table 13: Cement Mold without Sodium Silicate
Cement 6%
Moisture 4%
Sand (rajmahal) 40 kg
Mulling time 6 min
Fig .23 Sample of cement mold using Rajmahal
sand.
Fig 24. Cement mold casting sample after
Machining
Table 14: Cement Mold using Allahabad sand.
Cement 6%
Moisture 4%
Sand (Allahabad) 40 kg
Mulling time 6 min
Fig 25. Sample of cement mold using Allahabad
sand.
Fig 26. Bentonite Mold Casting sample (Failure
occur At Time of Machining
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Sand Process Control for Steel Casting using Cement Mould (A Case Study)
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Fig 27. Cement Mold and Bentonite Mold for gear
casting.
Fig28.Gear made in bentonites mold.
Fig 29. Gear made in cement mold
VI. CONCLUSIONS
1) By graph we found that at 6% of cement and 4% of
moisture the Green Compression Strength , shatter index
and permeability is better.
2) Making the mold of composition of 6% cement and 4%
moisture in Allahabad and Rajmahal sand gives better
surface finish less sand fusion take place with respect to
bentonites mould of composition 6% of 4% of moisture.
3) 8% cement, 3% moisture, 4 % sodium silicate is not much
better in comparison to 6% cement ,and 4% moisture
giving 20 min setting time.
4) Fettling done easily in case of cement mold when gear
manufactured .
5) Tooth of gear do not break in case of cement mold but in
case of bentonites it breaks.
REFERENCES
[1]. American Foundrymen's Society, Foundry sand Handbook,‖ 7th
ed.,1963.
[2]. R.D. Cadle, ―particle size determination,‖ Interscience Publishers,
inc., New York,1955.
[3]. Nuhu A. Ademoh and A.T. Abdullahi, Assessment of foundry
properties of steel casting , International Journal of Physical Sciences Vol. 4
(4), 2009, pp. 238–241.
[4]. Svoboda, J.M., and Gieger, G.H. ―Mechanisms of Metal Penetration in
Foundry Molds,‖ AFS Transactions, Volume 77, pp. 281-288, 1969.
[5]. Unit Sand Control, A.R. Krishnamoorthy, Foundry, Nov – Dec, 2000,
pp. 13 – 20.
[6]. Design Casting to Avoid Foundry Defects, R. Johns, AFS Transaction,
1980, Vol – 88, pp. 199 – 209
[7]. Hand Book of Casting Defects Causes & Remedies, A.K.Gupta. 1982,
pp. 41 – 60, 144 – 150.
[8]. R.R. Keienburg, Particle Size Distribution and Normal Strength of
Portland Cement,PhD Thesis, Karlsruhe University, Germany (1976).
[9]. P. Navi, C. Pignat, Simulation of cement hydration and the
connectivity of the capillary pore space, Advanced Cement Based Material 4
(2) (1996) 58–67.
Avinaw Pratik- M.Tech. (Foundry-Forge Technology) from NIFFT Ranchi
in 2013 and B.Tech (Mechanical ) from RVSCET Jamshedpur. Paper
entitled
(1) ―Effect of section thickness on
microstructure and hardness of grey
iron‖Published in IJERT Vol. 3
Issue 7, July – 2014 .
(2) ―Multi- Objective Optimization of
Forging of an Automotive
Component‖ published in IJEMS
(Allied Journal) Volume-2, Issue-1,
January 2015.
Ajit Kumar-M.Tech. (Foundry-Forge
Technology) from NIFFT Ranchi in 2013 and
B.Tech (Production Engineering) from BIT
Sindri Dhanbad in 2011. Paper entitled
(1) ―Effect of section thickness on
microstructure and hardness of
grey iron‖Published in IJERTVol.
3 Issue 7, July –2014
(2) ―Multi- Objective Optimization of
Forging of an Automotive
Component‖ published in IJEMS
(Allied Journal) Volume-2, Issue-1, January 2015.
(3) ―Mechanical properties and structural evolution during Warm
Forging of Carbon Steel‖ published in IJEDR Volume 3, Issue
3,2015