“BY PROVIDING AND INSULATION LINING”

CARRIED OUT BY:K.S.V.S. APPARAO (08651A0305)

A.HIMABINDU (08651A0321)

M.SESHAGIRI RAO (08651A0343)

K.SRIKANTH (08651A0347)

M.VIKRANTH ANAND(08651AO358)

CARRIED OUT AT: NAVA BHARAT VENTURES LIMITED

PALONCHA,KHAMMAM(dist)

ANDHRAPRADESH.

GUIDED BY: G.ANAND RAO

HOD”Mechanical dept”

ABSTRACT

INTRODUCTION TO LADLE AND ITS DESIGN

FACTORS EFFECTING SKULL

METHOD TO REDUCE SKULL

FORMULATION USED FOR STUDY

MATLAB PROGRAM

MATLAB AND ANSYS RESULTS

CONCLUSION

In the era of nano and precise accuracies we have great concern of

productivity, finish in all levels of manufacturing which includes casting

process too.

A ladle is a component used for carrying the molten metal in the

casting process, this undergoes a considerable heat loss and metal gets

solidified and a skull will be formed. So we surely require to make an

alternative to reduce this skull to reach the required productivity and yield.

The work in the project is focussed to give a theoretical and analytical

information about the heat loss, problem of skull in the ladle, the

mathematical formulation used for solving of the problem is presented.

It also presents the results graphically and comparisons will be laid out

using MAT LAB Software.

LADLE:

In a foundry, a ladle is a vessel used to transport and pour out

molten metals. Ladles range in size from

1. small hand carried vessels that hold 20 kilograms (44 lb)

2. large steel mill ladles that hold up to 300 tones (330 tons).

Types:1. Casting ladle: a ladle used to pour molten metal into moulds to

produce the casting.

2. Transfer ladle: a ladle used to transfer a large amount of molten

metal from one process to another.

3. Treatment ladle: a ladle used for a process to take place

within the ladle to change some aspect of the molten metal.

The ladle under consideration is composed of three layers

1. mild steel (20mm) outer layer

2. Fireclay (80mm) middle layer

3. Graphite (120mm) inner layer

The ladle is used to carry (simn) metal at a temperature of about

2100 0k

The tapping time is 20min

The carrying and pouring time is 20min

The hot metal carried by the ladle is too hot and because of this heat

loss occurs this results in decrease of liquid temperature ,therefore

metal starts solidifying and a layer near the boundaries will be

formed, this it self is the skull.

Initial

final

Liquid alloy Graphite Brick M.S

L alloy skull Graphite Brick M.S

Ferro Alloys are used as inputs in the manufacture of iron and steel

for removal of oxygen and imparting specific properties. These are

alloys of iron and elements like manganese, silicon, chromium, etc.

While manganese and silicon alloys impart strength and hardness

and act as powerful deoxidizing agents, chromium alloys make steel

resistant to corrosion and heat.

Typical examples of end products comprise rail road rails, structural

steel, automobile bodies, etc. for manganese alloys.

The principal mechanisms responsible for heat loss from the molten

metal are:

1. Conduction into the walls of the ladle

2. Radiation from the top exposed surface

3. Possibly convection happens naturally

Consequently, a boundary separating

two different phases develops and moves in the matter during the

process.

Because of this the volume carried by the ladle reduces

Scrap might increase

Cleanliness of the metal will reduce

Wastage of liquid metal

Chip removal process requires

Figure -1

An expendable lining may be applied over the interior walls of a

metal handling vessel for molten metal, The expendable lining is

usually applied over a relatively permanent, e.g. refractory

brick, lining, Good insulator.

By pre-heating the ladle surface will

considerably reduce the heat loss thus

less solidification.

By providing a cap on the ladle will

reduce heat through radiation.

An insulation will be provided in between the layers of brick and

graphite

Liquid alloy skullgraphite insulation Brick M.S

Heat transfer equations were laid out for all the layers and interface

of skull

Finite difference formulation is chosen for solving the problem

For solving boundary conditions we have chosen explicit method

For phase change problems we have chosen fixed grid method

One- dimensional transient heat conduction equation

Thermal diffusivity

Over all diffusivity equation

Can be approximated with a forward finite difference formulation

Can be approximated with a central difference formulation

Combining both we get general equation to calculate temperature at

required time and distance step (n,i)

X(t) is the position of the solid-liquid interface (moving boundary)

clear all;

close all;

clc;

L=0.24;

T=2400;

maxk=4800;

dt=T/maxk;

n=48;

dx=L/n;

rho=6200;

deltah=450000;

Tm=2100;

Tdash=1400;

lamda=0.007;

cp=483;

alpha=lamda/(rho*cp);

h=91.5;

for i=1:n+1

if i<=48

t(i,1)=333;

elseif i==49

t(49,1)=953;

end

end

for k=1:maxk+1

t(1,k)=333;

t(n+1,k)=953;

end

for k=1:maxk

for i=2:n

if i<=4

r=0.38;

elseif i<=20

r=0.00952;

elseif i<=24

r=0.00164;

else

r=0.0612;

end

t(i,k+1)=r*t(i-1,k)+(1-2*r)*t(i,k)+r*t(i+1,k);

end

end

for k=1:maxkTidash=t(48,k);disp(Tidash);r1=(((rho*deltah*alpha)*(Tm-2*Tdash-Tidash))/(h*(Tm-Tdash)));r2=((lamda*(Tdash-Tidash))/(h*(Tm-Tdash)));R=r1-r2;disp(R);

end

With out insulation after tapping and before pouring respectively

With insulation of 20mm after tapping and before pouring

With insulation of 80mm after tapping and before pouring

Variation of skull with respect to time without insulation and

with insulation

Excellent insulating properties

Improved molten metal temperature control

Reduced labour cost /Lower energy cost

Safer /cleaner working environment

Improved metallurgical control

Improved Productivity

Reduced re-oxidation rate

Reduced slag carryover/fewer slag related inclusions

Improved ladle preparation productivity

Improved alloy recovery

Optimal balance between refractory life and clean ladle practice

When the insulation is provided the skull reduced to considerable

extent.

Comparison of the skull thickness via graphs

Ladle shell surface temperature with respect to temperatures and

time for system without lining and with lining

Rate of Heat Loss from Different Size Ladle with respect to

temperature and weight for system Brick Lining compared with

insulation lining

Typical cooling profile for ladle with respect to temperature and

weight remaining in the ladle for system Brick Lining compared

with insulation lining