Design of Pig Casting Machine - IJET

IACSIT International Journal of Engineering and Technology, Vol.2, No.6, December 2010 

ISSN: 1793-8236 

Design of Pig Casting Machine 

S.N. Waghmare, C.N. Sakhale, M.S.Giripunje and V.M. Sonde 

Abstract—Paper reports the design and development of Pig 

casting machine. A machine is utilized for conveying pig mould 

from one station to another with the help of conveyor; the paper 

describes design calculations, modeling and calculation of load 

torque, its economical viability. The machine is presently 

commissioned in one of the renowned steel plant. Paper also 

describes working and construction of machine in detailed. 

Index Terms—Chain Conveyor, PIG casting, Mould, Chain 

pull, Metal transfer Launder 

I. USE OF CHAIN CONVEYOR AS PIG CASTING MACHINE 

A. What Is Pig Casting Machine: 

In Steel Industries iron is produced in Blast Furnace by 

reducing iron ore (iron oxide) with carbon (coke) at 

temperature of 12000C to 13000C. The iron metal collects at 

the bottom of blast furnace and is tapped out from time to 

time. About 50 to 300 ton of molten metal can be tapped at a 

time in hot metal ladle. The iron in the molten form is 

transferred to steel melting shop for conversion to steel. Parts 

of the iron metal are converted to small pieces called as PIGS 

in continuous casting machine called as Pig Casting Machine 

(Pcm). 

These pieces of iron produced in PCM are marketed in 

sizes of 10 to 45 kg/pc. Such small sizes of pieces are 

produced in PCM by pouring the hot molten metal into the 

mould having small pockets. The metal is there after 

solidifies by cooling with air followed by water cooling. This 

solidifies pieces called as Pigs if they are big in size & piglets 

if they are small in size. The Pig Iron is used as raw material 

for production of big size iron casting and other application 

such as conversion to steel of different grade. 

Manuscript received September 23, 2010. (Write the date on which you 

submitted your paper for review.) 

Subhash N. Waghmare, Author is working with the Priyadarshini College 

of Engineering ,Nagpur-Maharashtra State, India-440019 as Lecture in 

Mechanical Engineering Department. (corresponding author to provide 

phone: 9423423905; fax: +91 7104 237681; e-mail: 

subhaswaghmare1981@rediffmail.com ). 

Chandrashekhar N Sakhale, Co- Author, is working with the 

Priyadarshini College of Engineering ,Nagpur-Maharashtra State, 

India-440019 as Lecture in Mechanical Engineering Department. (e-mail: 

chsakhale@gmail.com). 

M.S.Giripunje, Co- Author is working with the Priyadarshini College of 

Engineering ,Nagpur-Maharashtra State, India-440019 as Lecture in 

Mechanical Engineering Department. (e-mail: mngiripunje@yahoo.co.in). 

V.M.Sonde, Co-Author is working with the Priyadarshini College of 

Engineering ,Nagpur-Maharashtra State, India-440019 as Lecture in 

Mechanical Engineering Department. 

586 

II. DESCRIPTION OF PIG CASTING MACHINE 

A. Metal transfer Launder: 

The hot metal drawn in ladle from blast furnace is poured 

into a metal transfer launder of PCM for casting the pigs. The 

metal transfer launder has a fabricated casing, which is lined 

with refractory. A continuous slope is maintained in the 

refractory for smooth flow of molten metal from receiving 

point to the discharge point. The launder casing is anchored 

to the pouring end platform. 

B. PCM Strand 

The PCM strand is an endless chain carrying the pig 

moulds. The strands are placed at an inclination. The level of 

the inclination is decided on the height required for receiving 

the molten metal and for discharging the cast pigs into the 

transport wagons. The molten metal tapped from the blast 

furnace and collected in the ladle and then poured in the 

metal transfer launder of PCM, through which molten metal 

is discharged into the traveling moulds for casting. The rate 

of pouring of metal and the take up rate of metal by the PCM 

are equalized by adjusting the rate of tilting of the ladle and 

the speed of the conveyor chain of the PCM strand. 

The PCM has LH and RH set of chain links. The chain 

links are fully machined. These chain links are steel casting 

joined to each other through a hollow shaft and bushing on 

which the link can run. Replicable bushes are forced fit to the 

link and then grubbed for preventing rotating motion 

between the bush and the link. The LH and RH chain links 

are assembled on a hollow shaft. At the borehole of the chain, 

a hardened bush is provided through which the hollow shaft 

passes through. A rectangular flange is provided to the 

hardened bush, which engages, the machined housing 

provided in the chain link. This arrangement maintains the 

correct relative motion between the sprocket teeth and the 

chain links and minimizes the wear of the sprocket teeth. 

Split pins are provided on the hollow shaft for preventing 

fall out of the chain links. The chain links travels on the 

rollers fixed to the technological structure of the PCM. The 

rollers are spaced such that the chain links remain always 

supported on the rollers. On the ascending track the rollers 

carry the load of the chain and the moulds filled with metal 

whereas on the descending track, the moulds become upside 

down and the chain gets supported on the bottom rollers on 

its other side. The rollers are provided with a collar for 

preventing derailment of the chain. The rollers are mounted 

on the brackets. Holes are provided at the base plate of the 

brackets for anchoring the roller assembly to the ascending 

and descending tracks of PCM. Bearing caps of the rollers are 

provided with seals for preventing ingress of moisture and 

atmospheric dust. Protection guards are also provided


ISSN: 1793-8236 

beyond the bearing caps, which act as a secondary protecting 

to the system. Moulds are anchored to the chain at LH and 

RH links. The chain duly fitted with moulds forms the train. 

The chain links pass through the sprocket assembly at the 

discharge end and at pouring end. Motor gear unit drives the 

sprocket assembly at discharge end whereas the sprocket 

assembly at pouring end is free to rotate on its bearings. The 

PCM drive is coupled to the drive sprocket assembly by a 

geared coupling. The sprocket assembly at the pouring end is 

made to float to render compensation for expansion of chain 

links and for overcoming jams due to external reasons. A 

self-regulating tensioning device is provided at the individual 

sprocket assembly at the pouring end. The tensioning device 

consists of the following: 

• A fabricated base frame fitted with slide rail. 

• Bearing housing with guide seat matching with the 

slide rail for the base frame and clevis for connecting 

the tension rod through pins. 

• Tension rod having one end to connect to the bearing 

housing through pin and the other end threaded for 

adjusting the spring tension. 

• Compression springs. 

• Nut to suit the tension rod threading. 

The drive consists of the following: 

• AC sq. cage induction motor 

• A pin and bush coupling between motor and gear box 

• A helical gear box for speed reduction. 

• A geared coupling between the gear box out put shaft 

and the shaft of the drive sprocket assembly. 

A spillage chute is provided below the ascending track of 

the strand at the location where metal is discharged from the 

metal transfer launder to the pig mould. The metal spilled at 

this location due to mismatch of rate of flow of metal and take 

up rate of metal by PCM, falls on the spillage chute. 

A pig-knocking device is provided at the discharge end 

sprocket assembly for quick discharge of the pigs from the 

mould. The pig-knocking device has a cam & follower 

mechanism for free fall of the knocker on the cast pig. The 

pig-knocking device mainly consists of the following: 

A cam disc fitted to the drive shaft of discharge end sprocket 

assembly. The cam profile is matched to the sprocket teeth 

for accurate positioning of the knocker and for cent percent 

repeatability of the striking points. 

The cam actuates a lever mechanism. 

A roller moving on the shaft is provided at the end of the 

lever coming in contact with the cam. The other end of the 

cam is connected to the shaft of the knocking device. 

A Knocker arm with one end fitted to the shaft of pig 

knocking device and the other end having a knocker disc. 

Springs are provided on the knocker arm for absorbing the 

shock of the impact of the knocker above the tolerance limit. 

A Pig impact device consisting of a chain suspended to the 

technological structure is placed in front of the discharge end 

sprocket assembly. The purpose of the impact device is to 

absorb the impact of the pigs falling from the moulds at the 

discharge end. The pigs ejected/dislodged at discharge end 

loose the kinetic energy to the impact chain and fall on to the 

discharge chute. 

A discharge chute is placed below the discharge end 

sprocket for transferring the pigs to the product collection 

587 

wagons. A sand bag is provided at the pig-receiving end of 

the discharge chute for absorbing the impact of the falling 

pigs. The angle of the discharge chute is selected to around 

450 to the vertical to enable easy transportation/sliding of the 

pigs. The bed of discharge chute is made of rail section, 

which gives long life and offers minimum frictional force to 

the sliding pigs. The discharge chute is anchored to the 

technological structure of the PCM strand. 

A grizzly is placed below the return track of PCM strand 

for preventing fall of stickers on to the ground. The first 

termination point is before the lime splashing unit and the 

second at 1 meter above the ground level near the tail end. A 

chute is provided at the first termination point for collection 

of stickers at the ground level. The grizzly is anchored to the 

technological structure of PCM and an adequate clearance is 

provided between grizzly and traveling moulds such that 

stickers cannot get entrenched between them. 

A water trough is provided below the pig moulds at the 

ascending track for collection of surplus pig cooling water. 

The trough is connected to the return water pipeline which 

discharges the water to the return water trench running 

underground and on to the circulating water tank. 

C. Mould 

Metallic moulds are provided in PCM for casting pig iron. 

The mould has cavities for dividing the castings into 4 parts 

called piglets. The mould is designed with varying section 

thickness to maintain optimum heat transfer during the 

casting campaign. 2no. Support brackets are provided in a 

mould at opposite ends for anchoring the mould to the LH 

and RH chain of PCM. The support brackets are kept tilted to 

match the inclination of PCM strand so that the mould 

surface remains horizontal. 

The moulds anchored to the PCM chain forms the Train. 

For preventing spillage of metal during pouring of metal in 

moulds, the moulds are required to be interlocked with each 

other. The moulds are thus designed with twin interlocks as 

described below. When the metal is poured in the moulds, it 

can get spilled out between the front and rear matching 

surfaces of the pair of moulds. For preventing such spillage, 

the rear side of the mould is made in the form of a prism with 

a reverse tapered bottom surface. The front side of the mould 

is made with a rising nose. The front side of the hide mould 

engages the reverse tapered bottom surface with the leading 

mould making a perfect interlock. When the moulds are 

being filled up, the molten metal can leak from either side of 

moulds, where the anchor brackets are provided. For 

preventing this leakage ribs, are provided in the moulds and 

curvatures on either side. The ribs of the preceding and 

succeeding moulds thus interlock with each other. Overflow 

notches are provided at the rear side of the mould. These 

notches limit the filling level of the mould the excess metal 

cascades to the downstream mould. 

The moulds are consumable spares of PCM. The life of 

the mould depends upon the consistency and uniform 

filling of mould during casting campaign. In a casting 

campaign if all the hollow/pockets/cavities of the mould are 

not filled with the molten metal and the moulds with hallow 

pockets/cavities travel upwards, water gets filled up in the 

empty hollow/pockets/cavities at the water-cooling stage of


ISSN: 1793-8236 

the stand, which causes thermal shocks and might result in 

the cracking of the moulds. 

D. Lime Milk Preparation and Splashing System: 

For preventing sticking of metal to the moulds, the 

moulds are coated with lime powder. Lime coating is done 

by spraying lime milk on the interior of the mould during 

their return passage. Lime powder is slaked before it is 

discharged into the lime milk preparation tank. The slaking of 

lime is done in a classifier. The purpose of providing a 

classifier is to remove the grit continuously from the 

lime powder and to prepare the slaked lime for its transfer 

to the lime milk preparation unit. The lime milk preparation 

unit is a steel tank fitted with an impeller, driven by a motor 

gearbox unit. Continuous mechanical agitation makes a 

uniform lime milk suspension, which is pumped to the lime 

milk splasher unit. A port is also provided in this tank for 

receiving the return lime milk from the splasher unit. 

Slurry pumps are provided for transferring the lime milk 

from the lime milk preparation tank to the splashing tank. 

The capacity of the slurry pump is selected such that about 3 

times the volume of slurry required for coating the mould can 

be circulated. The excess quantity is returned to the lime milk 

preparation unit. Continuous circulation of lime milk 

between the lime milk preparation unit and the splashing unit, 

helps in getting a uniform lime milk suspension at the lime 

milk preparation unit as well as at the lime splashing unit 

and also avoids sedimentation at any location. 

The lime milk-splashing unit works on the principle of 

scooping of lime milk, by continuous rotation of a paddle 

impeller partially submerged in the lime milk. For this 

purpose, two discs fitted on a shaft are housed in the 

fabricated body of the lime-splashing unit. At the periphery 

of the disc, are provided the scoops. The speed of the disc is 

adjusted such that adequate splashing velocities are 

achieved for coating of time on the cavities of the moulds. 

The location of the splashing unit is selected such that the 

return mould remains at adequate Temp. for immediate 

sticking of the lime to it and that the coated mould does not 

hold any water by the time the mould reaches the pouring end. 

Gland seals are provided at the exit points of the splasher 

body to prevent leakage of lime milk at these locations. 

The paddle shaft is supported on antifriction bearings and is 

coupled to a motor gearbox unit through a bush and pin type 

coupling. For the purpose of cleaning and maintenance a 

manhole is provided at the lower end of the splasher tank. 

Ports are provided in the splasher body for entry of lime milk 

and for outflow of the lime milk into the return line of the 

lime milk preparation unit. Interconnecting pipes and pipe 

fittings are provided in the lime milk preparation unit and 

splasher unit for making ring mains. Grating is provided at 

the topside of the splasher unit to prevent falling of sticker in 

the tank. 

E. Water Cooling System 

In the PCM, solidification of molten metal is achieved in 

two stages, first stage being natural air-cooling and the 

second stage being direct water quenching. The duration of 

air-cooling is selected such that the top surface of the cast 

metal reaches a plastic state so that the water spray for 

quenching can commence without any explosion. The 

efficiency of the water-cooling system is a vital factor, which 

governs the temperature of the pigs discharged from PCM. 

The conventional types of nozzles used in spraying of water 

on the pigs, has demerit of choking of nozzles because of 

unavoidable dust/carbon/lime particles getting mixed with 

the cooling water. The unique water spraying system 

designed & supplied by us for the various PCM overcomes 

the problems faced in conventional spraying systems. In our 

system water spraying is done through the flute holes 

provided on the top side of the water runner. A specially 

designed rotor is provided for adjusting the water flow which 

has self cleaning feature in built in it. Two/three circuits of 

water spray are provided for avoiding pressure drop in 

cooling water pipelines. Water pipelines are suspended from 

the technological structure of PCM. Large sized nozzles for 

flooding of spillage chute are provided. Large size spray 

nozzles are also provided at the discharge end for cooling of 

the discharged pigs (at the wagons). Regular pipeline 

connections are provided at the lime milk preparation unit for 

preparing lime milk. Water distributor is provided near the 

pouring end platform. The inlet of the distributor receives 

water from the circulating pump of PCM installed at the 

pump house located near/above the underground return water 

tank. The water distributor has two main outlets, first for 

water-cooling of mould/pigs and second for wagon spraying. 

A direct water connection from BF central water supply is 

recommended for the lime milk preparation unit and for the 

maintenance water taps points. 

F. Technological Structure of the PCM 

The PCM is supported on a technological structure. For 

convenience of operation and maintenance, following 

technological platforms, walkways, ladders/staircases and 

material handling facilities are provided. 

Pouring end platform with railing. It is recommended to 

have refractory flooring at the platform as the hot metal may 

spill over the place. 

Discharge end platform with railing. The discharge end 

sprocket assembly, strand drive, pig impactor, 

wagon-spraying unit and discharge chute are mounted on the 

platform. 

Walkways with railings along the sides of PCM strands 

(with common middle walkway for twin strand). 

Staircases/ladders with railing for reaching the walkways 

at lower lever and discharge end platform. 

Covered shed above the discharge end platform. 

III. ANALATICAL CALCULATION FOR MAXIMUM CHAIN 

PULL 

To enable the most suitable chain to be selected for a 

particular application it is necessary to know full application 

details such as the following: 

• Type of conveyor. 

• Conveyor centre distance and inclination from the 

horizontal. 

• Type of chain attachment, spacing and method of 

fixing to the chain. 

• Number of chains and chain speed. 

588


ISSN: 1793-8236 

• Details of conveying attachments, e.g. weight of slats, 

buckets, etc. 

• Description of material carried, i.e. weight, size and 

quantity. 

• Method of feed and rate of delivery. 

The preferred method of calculating the tension in a 

conveyor chain is to consider each section of the conveyor 

that has a different operating condition. This is particularly 

necessary where changes in direction occur or where the load 

is not constant over the whole of the conveyor. For uniformly 

loaded conveyors there is a progressive increase in chain 

tension from theoretically zero at A to a maximum at D. This 

is illustrated graphically in Fig. 14 where the vertical 

distances represent the chain tension occurring at particular 

points in the circuit, the summation of which gives the total 

tension in the chain. Thus, in Fig. 4.1 the maximum pull at D 

comprises the sum of: 

Fig 3.1: Maximum Chain Pull Diagram 

(a) Pull due to chain and moving parts on the unloaded 

side. 

(b) Extra pull required to turn the idler wheels and shaft. 

(c) Pull due to chain and moving parts on the loaded side. 

(d) Pull due to the load being moved. 

If it is imagined that the chains are ‘cut’ at position X then 

there will be a lower load pull or tension at this position than 

at Y. This fact is significant in the placing of caterpillar drives 

in complex circuits and also in assessing tension loadings for 

automatic take-up units. This principle has been used to 

arrive at the easy reference layouts and formulae to which 

most conveyor and elevator applications should 

conform. 

A. Data Collected 

S.N. Title Calculation 

1 Hot metal ladle carrying capacity 40 Ton 

2 Rate of pouring 01 ton /min 

3 

Weight of one Piglet for easy charging in 

foundries 

11.5 kg 

4 Total kg of piglet in one mould 04 

5 Total weight in one mould 

11.5 x 4= 45 

kg 

6 Size of pocket in mould 

7 

8 

9 

10 

11 

12 

Density of molten metal (at liquid state) 

Keeping the length of one pocket 

Total volume required for 11.5 kg of pig let 

Since we have considered length of pocket 

250mm 

So cross sectional area will be 

Considering the heat transfer rate for 

cooling of molten metal in pig mould, after 

pouring the temperature of pig mould 

should come down below 6000C Size of 

pig mould was decided as 

Width of mould kept as 310 (305 pitch & 

5mm for over lapping) 

6.8 ton /cum 

250mm 

11.5/6.8=1.6 

91 lit. 

1691/25=65 

sqcm 

Cross 

sectional 

area will be 

of triangular 

shape of 10 x 

13cm 

1050 x 310 x 

250 

13 Molten metal pouring per mould 

45 kg at 

13000C 

14 To carry 1Ton of molten metal in one min 1000/45=22. 

589 

total no of pig mould required 

22 No of pig 

mould 

15 Since pitch of pig mould 305 mm 

17 

The speed of the pig casting machine 

comes out to be 

22.22 x 305 

= 6777.1 mm 

i.e. = 7 

m/min 

18 U = Coefficient of friction for bearing, 0.0064 

19 

f = Coeff. of friction for the track 

Resistance, 

0.1 

20 T = Torque, Nm 

21 Pitch Diameter of sprocket 1000 mm 

22 Length of Machine c/c 42 mtr 

B. Chain Pull Calculation 

The system to be chain sliding & Material Carried 

• From Renold Designer Guide book we consider BS 

series Index 400. 

• Total Load on Chain Conveyor from take up point = 

45 x 37 mtr = 1665 kg 

• Estimated mass of chain & mould = 30 kg +128 kg = 

158 kg 

• Load in one mtr distance =1000/305 = 3.2786 

• Weight per mtr = 3.2786 x 158 = 518 kg 

• Weight of APRON in empty condition(Wa) (weight 

of chain link & pig mould) = 518 x 42 = 21756 kg 

• 21756 x 9.81 = 213426.36 N (213.42 KN) 

• Weight of APRON In Carrying condition (W)= 

213426.36 N + (1665 x 37 x 9.81) = 817771.41 N = 

817.77 KN 

Tension Calculation 

Tension T3 

T3-T2 = Wa x f, T3 = T2 + (213426.36 x 0.1) , T3 = 

21342.63 N 

Tension T4 

T4 (SR) = Sprocket Resistance Tension 

T4 (SR) = T3 (1+U) = 21342.63 (1+0.0064) = 

21479.22 N 

T4 (CB) = Chain Binding Tension 

T4 (CB) = 0.07 x T4 (SR) =0.07 x 21479.22=1503.54 N 

T4 = T4 (SR) + T4 (CB) , T4 =22982.76 N 

Tension T1 

T 1(TR) = Track Resistance Tension 

T 1(TR) = T4 + W x f = 22982.76 + 817771.41 x 0.1= 

104759.9 N 

T1 (SR) = Sprocket Resistance Tension 

T1 (SR) = T1 (TR) (1+U) = 104759.9 (1+0.0064)= 

105430.36 N 

T1 (CB) = Chain Binding Tension 

T1 (CB) = 0.07 x T1 (TR) = 0.07 x 104759.9= 7333.193 

N 

T1 = T1 (SR) + T1 (CB) + T1 (TR) 

T1 = 112763.554 N = 112.763 KN 

As per Renold Designer Guide Book Design is Safe Since 

it is below 400 KN 

C. Calculation Of Bearing Pressure 

Weight of PIG mould & piglet = 45 + 128 = 173 kg x 

9.81= 1697.13 N 

Load of Chain Over pitch of 305 mm = 30 kg x 9.81 = 

294.3 N 

Total Load on Roller = 1697.13 + 294.3 = 1991.43 N


ISSN: 1793-8236 

Bearing Pr of Roller = 1991.43/1403 = 1.41 N/mm2 

Roller material Cast steel 1030, Bearing Pr 3.2 N/mm2 

Bearing Pr is Below permissible range so design is safe. 

D. Power Calculation 

(112763.554 x chain speed)/ 1000= KW 

(112763.554 x 0.1167)/1000 = 13.159 KW 

For vertical lift 

Work Done = mgh=((158+ 45) x 9.81 x 8)/1000 = 15.93 

kw 

Total kw Reqd. = 13.159 + 15.93= 29.09 KW. 

Figure 3: Figure 4 : 

IV. FUTURE MODIFICATION 

In this system of PCM overall weight of the system can be 

reduced by reducing the weight of chain link, 

By Selecting high tensile strength alloy and reducing the 

weight of chain link will not make much difference in the 

cost of chain link. 

But since weight of chain link is reduced which is 

consisting ¼ of the weight of chain mould & roller assembly 

will result in selection of lower weight of roller & supporting 

structure 

This will also result in reduction of power requirement for 

PCM drive system. 

Since all the strength of different components are related to 

the strength & weight of chain link. 

Considering the above aspect it is possible to reduce the 

cost of overall system of pig casting machine. 


Figure 7: Figure 8: 

REFERENCES 

[1] Alexandrov, M. P.,1978, ” Material Handling Equipment ”, Mir 

Publications; Moscow , Ussr 

[2] Spivakovsky, A. And Dyachkov, V., 1985,” Conveying Machine “ Vol 

I, Mir Publications ;Moscow, 

[3] Renold Design Data Book 

[4] Design of Machine elements by – B.D. Shiwalkar 

[5] Design Data for Machine elements – B.D. Shiwalkar 


ANNEXURES 

List of Figures 

Figure 1: Tail End Sprocket View of Pig Casting Machine 

Figure 2: Strand View of Pig Casting Machine 

Figure 3: Discharge End View of Pig Casting Machine 

Figure 4: View of Drive at Driven End 

Figure 5: View of Lime Splasher 

Figure 6: Discharge End View of Pig Casting Machine with 

Water Cooling 

Figure 7: View of Pig Casting Machine with Air Cooling 

Figure 8: View of Drive End Sprocket 

Figure 9: View of Launder & Hot Metal Ladle 

Figure 10: View of Launder & Filling Of Mould With Hot 

Metal 

Figure 11: View of Pouring Hot Metal In Launder 

Figure 12: View of Filling of Molten Metal In Launder 

Figure 13: View of Hydraulic Tilting System of Ladle 

Figure 14: View of Slag Formation in Hot Metal Ladle 

Figure 15: View of Discharge of Piglets at Discharge End Of 

Pig Casting Machine 




590


ISSN: 1793-8236 

Figure 15: 

Figure 16 : 

Figure 17: 

Figure 17: 

T1 

T2 

TENSION VARIATION ALONG THE CHAIN 

T3 

T4 

591

Design of Pig Casting Machine - IJET

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