Ainsm

Smarajit Sarkar
Department of Metallurgical and Materials Engineering
NIT Rourkela

 The OBM vessel is essentially a Bessemer-like
converter fitted with a special bottom .
 The tuyeres are inserted from the bottom in such a
way that the oxygen would be surrounded by a
protective hydrocarbon gas like propane.
 On entry propane cracks down in an endothermic
reaction and takes up some of the heat-gene-rated by
the entry of oxygen.
 The relative feed rates of these two fluids are adjusted
to obtain optimum temperatures at the tuyere tip and
thereby ensure its reasonable life as well as speed of
refining.
 The deposition of carbon, which is a product of
cracking, also helps to protect the bottom from heat
generated due to the refining reactions at the tips of
tuyeres.

 Inorder to promote turbulence in the bath and thereby
ensure good slag-metal contact, the tuyeres are
arranged only on half the converter bottom.
 Experience dictated that provision of a few bigger
tuyeres is better than large number of fine tuyeres.
Maintenance problems are minimised without loosing
in terms of metallurgical requirements of turbulence.
By this arrangement, it is ensured that the direction of
metal circulation is upwards in the tuyere half of the
vessel, and downwards in the other half.
 This arrangement is also helpful in minimising the
damage to tuyeres while charging scrap, since it can
now be charged on that part where there are no
tuyeres.

Oxidation of carbon : Bottom blowing increases sharply the
intensity of bath stirring and increases the area of gas-metal
boundaries (10-20 times the values typical of top blowing) .
 Since the hydrocarbons supplied into the bath together with
oxygen dissociate into H2, H2O and CO2 gas bubbles in the
bath have a lower partial pressure of carbon monoxide (Pco )
 All these factors facilitate substantially the formation and
evolution of carbon monoxide, which leads to a higher rate of
decarburization in bottom blowing

 The degree of oxidation of metal and slag

 Removal of phosphorous: Since the slag of
the bottom-blown converter process have a
low degree of oxidation almost during the
whole operation, the conditions existing
during these periods are unfavorable for
phosphorus removal

 Almost 98% oxygen being reacted with metal in OBM and
hence that much scrap rate is lower in the OBM. If scrap is
cheaper the top blowing can offer some cost advantage in
this respect.
 The iron losses in top blown are nearly 5% more than
those in OBM. Very low carbon steers are achievable in
top blowing only at the expense of extra iron loss in slag.
But this is readily achievable in OBM.


 This also, leads to situation wherein higher carbon levels
can be obtained by 'catch carbon techniques' easily in
LD than in OBM, at low P contents.
 The stirring intensity, which is estimated to be nearly ten
times more in OBM than in LD gives better partition of
phosphorus and sulphur, higher manganese and lower
oxygen at turndown result-ing in better ferroalloy
recovery.

Since the slag of the bottom-blown converter process have a low

degree of oxidation almost during the whole operation, the

conditions existing during these periods are unfavorable for

phosphorus removal. Only at the end of blowing, when the bath is

low in carbon, the oxidation degree of the slag increases

sharply, thus favouring dephosphorization. At that

moment, phosphorus passes intensively to slag. When using lumpy

lime in the charge, it is difficult to make medium or high carbon

steels with a low content of phosphorus. The metal must be blown

to a low carbon content, so as to form an oxidizing slag at the end

of heat, and then carburized in the ladle.

 Problems arise when the layer of foaming slag created on the
surface of the molten metal exceeds the height of the vessel and
overflows, causing metal loss, process disruption and environmental
pollution. This phenomenon is commonly referred to as slopping.

Better mixing and homogeneity in the bath offer the following
advantages:
 Less slopping, since non-homogeneity causes formation of
regions with high supersaturation and consequent violent
reactions and ejections.
 Better mixing and mass transfer in the metal bath with closer
approach to equilibrium for [C]-[O]-CO reaction, and
consequently, lower bath oxygen content at the same carbon
content

 Better slag-metal mixing and mass transfer and
consequently, closer approach to slag-- metal
equilibrium, leading to:
o lower FeO in slag and hence higher Fe yield
o transfer of more phosphorus from the metal to the slag (i.e.
better bath dephosphorisation)
o transfer of more Mn from the slag to the metal, and thus
better Mn recovery
o lower nitrogen and hydrogen contents of the bath.
 More reliable temperature measurement and sampling of
metal and slag, and thus better process control
 Faster dissolution of the scrap added into the metal bath

•A small amount of inert gas, about 3% of the volume of oxygen
blown from top, introduced from bottom, agitates the bath so
effectively that slopping is almost eliminated.
•However for obtaining near equilibrium state of the system
inside the vessel a substantial amount of gas has to be
introduced from the bottom.
•If 20-30% of the total oxygen, if blown from bottom, can cause
adequate stirring for the system to achieve near equilibrium
conditions. The increase beyond 30% therefore contributes
negligible addition of benefits.

• The more the oxygen fraction blown from bottom the
less is the post combustion of CO gas and
consequently less is the scrap consumption in the
charge under identical conditions of processing.
• Blowing of inert gas from bottom has a chilling effect
on bath and hence should be minimum. On the
contrary the more is the gas blown the more is the
stirring effect and resultant better metallurgical results.
A optimum choice therefore has to be made
judiciously.

As compared to top blowing, the hybrid blowing
eliminates the temperature and concentration
gradients and effects improved blowing control, less
slopping and higher blowing rates. It also reduces over
oxidation and improves the yield. It leads the process
to near equilibrium with resultant effective
dephosphorisation and desulphurisation and ability to
make very low carbon steels.

 What is blown from the bottom, inert gas or oxygen?
 How much inert gas is blown from the bottom?
 At what stage of the blow the inert gas is
blown, although the blow, at the end of the blow, after
the blow ends and so on?
 What inert gas is blown, argon, nitrogen or their
combination?
 How the inert gas is blown, permeable
plug, tuyere, etc.?
 What oxidising media is blown from bottom, oxygen or
air?
 If oxygen is blown from bottom as well then how much
of the total oxygen is blown from bottom ?

 The processes have been developed to obtain the combined ad-vantages
of both LD and OBM to the extent possible. Therefore the metallurgical
performance of a hybrid process has to be evaluated in relation to these
two extremes, namely the LD and the OBM. The parameters on which this
can be done are :

 Iron content of the slag as a function of carbon content of bath

 Oxidation levels in slag and metal

 Manganese content of the bath at the turndown

 Desulphurisation efficiency in terms of partition coefficient

 Dephosphorisation efficiency in terms of partition coefficient

 Hydrogen and nitrogen contents of the bath at turndown

 Yield of liquid steel

The oxidizing conditions of a heat in a steelmaking plant, the
presence of oxidizing slag, and the interaction of the metal with the
surrounding atmosphere at tapping and teeming - all these factors
are responsible for the fact that the dissolved oxygen in steel has a
definite, often elevated, activity at the moment of steel tapping. The
procedure by which the activity of oxygen can be lowered to the
required limit is called deoxidation. Steel subjected to deoxidation is
termed 'deoxidized'. If deoxidized steel is 'quiet during solidification
in moulds, with almost no gases evolving from it, it is called 'killed
steel'.

 If the metal is tapped and teemed without being deoxidized, the reaction
[O] + [C] = COg will take place between the dissolved oxygen and
carbon as the metal is cooled slowly in the mould. Bubbles of carbon
monoxide evolve from the solidifying metal, agitate the metal in the
mould vigorously, and the metal surface is seen to 'boil'. Such steel is
called 'wild'; when solidified, it will be termed 'rimming steel' .
 In some cases, only partial deoxidation is carried out, i.e. oxygen is only
partially removed from the metal. The remaining dissolved oxygen
causes the metal to boil for a short time. This type of steel is termed
'semi-killed'.

 Thus, practically all steels are deoxidized to some or other extent so as
to lower the activity of dissolved oxygen to the specified limit.
 The activity of oxygen in the metal can be lowered by two methods: (I)
by lowering the oxygen concentration, or
(2) by combining oxygen into stable compounds.
 There are the following main practical methods for deoxidation of steel:
(a) precipitation deoxidation, or deoxidation in the bulk;
(b) diffusion deoxidation;
(c) treatment with synthetic slags; and
(d) vacuum treatment.

The advantages of continuous casting (over ingot
casting) are:
 It is directly possible to cast blooms, slabs and
billets, thus eliminating blooming, slabbing mills
completely, and billet mills to a large extent.
 Better quality of the cast product.
 Higher crude-to-finished steel yield (about 10 to
20% more than ingot casting).
 Higher extent of automation and process control.

 Solidification must be completed before the withdrawal
rolls.

 The liquid core should be bowl-shaped as shown in the
Figure and not pointed at the bottom (as indicated by the
dotted lines), since the latter increases the tendency for
undesirable centerline (i.e. axial) macro-segregation and
porosity

 The solidified shell of metal should be strong enough at
the exit region of the mould so that it does not crack or
breakout under pressure of the liquid.

 The surface area-to-volume ratio per unit length of
continuously cast ingot is larger than that for ingot
casting. As a consequence, the linear rate of
solidification (dx/dt) is an order of magnitude
higher than that in ingot casting.

 The dendrite arm spacing in continuously cast
products is smaller compared with that in ingot
casting.

 Macro-segregation is less, and is restricted to the
centreline zone only.
 Endogenous inclusions are smaller in size, since they
get less time to grow. For the same reason, the blow
holes are, on an average, smaller in size.
 Inclusions get less time to float-up. Therefore, any
non-metallic particle coming into the melt at the later
stages tends to remain entrapped in the cast product.

In addition to more rapid freezing, continuous casting
differs from ingot casting in several ways. These are
noted below.

 Mathematically speaking, continuously cast ingot is
infinitely long. Hence, the heat flow is essentially in the
transverse direction, and there is no end-effect as is the
case in ingot casting (e.g. bottom cone of negative
segregation, pipe at the top, etc.).
 The depth of the liquid metal pool is several metres long.
Hence, the ferrostatic pressure of the liquid is high
during the latter stages of solidification, resulting in
significant difficulties of blow-hole formation.


 Since the ingot is withdrawn continuously from the mould, the frozen
layer of steel is subjected to stresses. This is aggravated by the
stresses arising out of thermal expansion/ contraction and phase
transformations.
 Such stresses are the highest at the surface. Moreover, when the
ingot comes out of the mould, the thickness of the frozen steel shell
is not very appreciable. Furthermore, it is at around 1100-
1200 C, and is therefore, weak. All these factors tend to cause
cracks at the surface of the ingot leading to rejections.
 Use of a tundish between the ladle and the mould results in extra
temperature loss. Therefore, better refractory lining in the
ladles, tundish, etc. are required in order to minimise corrosion and
erosion by molten metal.

Primary steelmaking is aimed at fast melting
and rapid refining. It is capable of refining at
a macro level to arrive at broad steel
specifications, but is not designed to meet
the stringent demands on steel quality, and
consistency of composition and temperature
that is required for very sophisticated grades
of steel. In order to achieve such
requirements, liquid steel from primary
steelmaking units has to be further refined in
the ladle after tapping. This is known as
Secondary Steelmaking.

 improvement in quality
 improvement in production rate
 decrease in energy consumption
 use of relatively cheaper grade or
alternative raw materials
 use of alternate sources of energy
 higher recovery of alloying elements.

 Lower impurity contents .
 Better cleanliness. (i.e. lower inclusion
contents)
 Stringent quality control. (i.e. less variation
from heat-to-heat)
 Microalloying to impart superior properties.
 Better surface quality and homogeneity in
the cast product.

 The term clean steel should mean a steel
free of inclusions. However, no steel can
be free from all inclusions.
 Macro-inclusions are the primary harmful
ones. Hence, a clean steel means a
cleaner steel, i.e., one containing a much
lower level of harmful macro-inclusions.)

 In practice, it is customary to divide
inclusions by size into macro inclusions and
micro inclusions. Macro inclusions ought to
be eliminated because of their harmful
effects. However, the presence of micro
inclusions can be tolerated, since they do
not necessarily have a harmful effect on the
properties of steel and can even be
beneficial. They can, for example, restrict
grain growth, increase yield strength and
hardness, and act as nuclei for the
precipitation of carbides, nitrides, etc.

 The critical inclusion size is not fixed but
depends on many factors, including service
requirements.
 Broadly speaking, it is in the range of 5 to 500
µm (5 X 10-3 to 0.5 mm). It decreases with an
increase in yield stress. In high-strength
steels, its size will be very small.
 Scientists advocated the use of fracture
mechanics concepts for theoretical estimation of
the critical size for a specific situation.

 Precipitation due to reaction from molten steel or during
freezing because of reaction between dissolved oxygen
and the deoxidisers, with consequent formation of
oxides (also reaction with dissolved sulphur as well).
These are known as endogenous inclusions.
 Mechanical and chemical erosion of the refractory lining
 Entrapment of slag particles in steel
 Oxygen pick up from the atmosphere, especially during
teeming, and consequent oxide formation.
 Inclusions originating from contact with external sources
as listed in items 2 to 4 above, are called exogenous
inclusions.

With a lower wettability (higher value of σMe – inc

), an inclusion can be retained in contact with the
metal by lower forces, and therefore, can break
off more easily and float up in the metal. On the
contrary, inclusion which are wetted readily by the
metal, cannot break off from it as easily.

 Carryover slag from the furnace into the ladle
should be minimised, since it contains high
percentage of FeO + MnO and makes efficient
deoxidation fairly difficult.

 Deoxidation products should be chemically
stable. Otherwise, they would tend to
decompose and transfer oxygen back into liquid
steel. Si02 and Al203 are preferred to MnO.
Moreover the products should preferably be
liquid for faster growth by agglomeration and
hence faster removal by floatation. Complex
deoxidation gives this advantage.


 Stirring of the melt in the ladle by argon flowing through
bottom tuyeres is a must for mixing and
homogenisation, faster growth, and floatation of the
deoxidation products. However, very high gas flow rates
are not desirable from the cleanliness point of
view, since it has the following adverse effects:
o Too vigorous stirring of the metal can cause
disintegration of earlier formed inclusion conglomerates.
o Re-entrainment of slag particles into molten steel.
o Increased erosion of refractories and consequent
generation of exogenous inclusions.
o More ejection of metal droplets into the atmosphere with
consequent oxide formation.

The varieties of secondary steelmaking
processes that have proved to be of
commercial value can broadly be categorised
as under:
 Stirring treatments
 Synthetic slag refining with stirring
 Vacuum treatments
 Decarburisation techniques
 Injection metallurgy
 Plunging techniques
 Post-solidification treatments.

 It is a simple ladle like furnace provided with bottom plug for argon
purging and lid with electrodes to become an arc furnace for heating
the bath.
 Another lid may be provided to connect it to vacuum line, if required.
 Chutes are provided for additions and an opening even for injection.
 In short it is capable of carrying out stirring, vacuum
treatment, synthetic slag refining, plunging, injection etc. all in
one unit without restraint of temperature loss, since it is capable
of being heated independently.

Every ladle furnace need not be equipped with
all these arrangements. As per the requirements
of refining the ladle furnace may be provided
with the necessary facilities. For example if gas
content is no consideration, vacuum attachment
may be eliminated. The principal component of
the facilities are shown in next slide
schematically.

 The ASEA-SKF furnace is a special variety of LF furnace only.
 The SKF furnace is essentially a teeming ladle for which additional
fittings are provided.
 The metal in the ladle is stirred by an electromagnetic stirrer
provided from outside.
 The ladle shell is made of austenitic stainless steel for this reason.
 Two ladle covers are employed. One of these fits tightly on to the
ladle forming a vacuum seal, and is connected to a steam ejector
unit for evacuation of the ladle chamber.
 For vacuum decarburisation oxygen lance is introduced through a
vacuum sealed port located in the cover.

 When the decarburisation and vacuum degassing is over
the first cover is replaced by the second cover which contains
three electrodes. Final alloying and temperature adjustments
are then made.
 Steel can also be desulphurised by preparing a reducing
basic slag under the electrode cover.
 The process is schematically shown in next slide. The nearly
re-fined steel in only one of the primary steelmaking
processes can be treated in this furnace by carrying out the
following operations :

 Tapping primary furnace into the SKF ladle directly .
 Controlled stirring during the entire secondary processing
 Vacuum treatment including minor decarburisation
 Extensive decarburisation for stainless steelmaking.
Deoxidation.
 Desulphurisation and deslagging. Alloying to desired
extent.
 Temperature adjustment.
 Teeming from the same SKF ladle.

 Quality improvement of steel can also be brought about after
steel is refined and cast into ingots from the primary refining
furnace, by remelting and casting once again. Typical examples
of this type is zone refining which is adopted to produce purer
metals.
 The other two techniques that have been developed are meant
for the production of, not pure metals, but alloy steels of better
cleanliness and low sulphur contents. The vacuum arc
remelting, VAR(750kWh/ton) for short and the electro slag
refining, ESR (900-1300kWh/ton) for short, are commercially
used for further refining of steels after these are cast into ingots.

 In both of these processes the steel ingot
produced by the primary refining forms the
electrode to be drip-melted into a water cooled
copper mould.
 In VAR melting is carried out under vacuum and in
ESR it is in open atmosphere.
 In VAR arc is struck between the electrode and
the mould and it generates the heat required for
melting the electrode.
 In ESR a slag layer is used to act as a resistor
between the electrode and the mould and which is
responsible for melting the electrode. The slag
also acts as a refining agent.

In both of these processes the electrode melts
progressively and is resolidified on the
mould, nearly unidirectionally.
 Because of the high temperature, small pool of
molten metal and almost unidirectional
solidification, both of these processes can produce
sound ingots of high density. The composition
of the product is nearly the same as that of the
original material but with improved
cleanliness, decreased segregation and with
practically no cavities. The ingot size ranges
from about 200 to 1500mm on industrial level

 The product of both of these processes is
exceptionally suited for the production of forgings of
high alloy steels. But because of high cost of such a
process, applications are limited to specialty products
like turbo rotor shafts and so on.
 In VAR the hydrogen and oxygen contents are very
low but in ESR they are like ordinary steels. In ESR
the choice of the slag composition is fairly critical since
it has to act as a resistor as well as a refin-ing agent.
These are essentially oxy-fluoride type reducing slag
like CaO-CaF2·



The ESR however has some advantages over VAR
and these are given below:
 Multiple electrode can be melted into a single
electrode.
 Spacing between the mould wall and the electrode is
not critical.
 Surface quality is superior requiring little or no
conditioning.
 Steel can be desulphurised to as low as 0·002%
sulphur.
 Round, square, hollow and rectangular shapes of
ingots can be produced.
 Ingots of much larger weight can be produced.

 Ladle degassing processes (VD, VOD, VAD)
 Stream degassing processes
 Circulation degassing processes (DH and RH).

 Molten steel is contained in the ladle. The two legs of the vacuum
chamber (known as Snorkels) are immersed into the melt. Argon is
injected into the up leg.

 Rising and expanding argon bubbles provide pumping action and lift
the liquid into the vacuum chamber, where it disintegrates into fine
droplets, gets degassed and comes down through the down leg
snorkel, causing melt circulation.

 The entire vacuum chamber is refractory lined. There is provision for
argon injection from the bottom, heating, alloy additions, sampling and
sighting as well as video display of the interior of the vacuum chamber.


Why RH-OB Process?
To meet increasing demand for cold-rolled steel sheets with improved
mechanical properties, and to cope with the change from batch-type to
continuous annealing, the production of ULC steel (C < 20 ppm) is
increasing.
 A major problem in the conventional RH process is that the time
required to achieve such low carbon is so long that carbon content at
BOF tapping should be lowered. However, this is accompanied by
excessive oxidation of molten steel and loss of iron oxide in the slag.
 It adversely affects surface the quality of sheet as well.

 Hence, decarburization in RH degasser is to be
speeded up. This is achieved by some oxygen
blowing (OB) during degassing.

 The RH-OB process, which uses an oxygen
blowing facility during degassing, was originally
developed for decarburization of stainless steel by
Nippon Steel Corp., Japan, in 1972.

 Subsequently, it was employed for the manufacture
of ULC steels.

 The present thrust is to decrease carbon content
from something like 300 ppm to 10 or 20 ppm
within 10 min. Cont…



Ferrochrome, which contains about 55 to 70% chromium is
the principal source of Chromium. This ferroalloy can be
classified into various grades, based primarily on their carbon
:ontent, such as:
 Low carbon ferrochrome (about 0.1 % C).
 Intermediate carbon ferrochrome (about 2% C).
 High carbon ferrochrome (around 7% C).

 Amongst these grades, the high carbon variety has the
drawback that though it is the least expensive, it raises the
carbon content of the melt. This is undesirable, since all SS
grades demand carbon contents less than 0.03%.
 Chromium forms stable oxides. Hence, the removal of
carbon from the bath by oxidation to CO is associated with
the problem of simultaneous oxidation of chromium in
molten steel.

 The higher the temperature, the greater is the tendency for preferential

oxidation of carbon rather than chromium. From this point of view, higher bath

temperatures are desirable; however, too high a temperature in the bath gives rise to

other process problems.

 The dilution of oxygen with argon lowers the partial pressure of CO, which

helps in preferential removal of CO without oxidising bath chromium. Attempts

were made to use this in the EAF, but the efforts did not succeed. Hence, as is the

case with the production of plain carbon steels, the EAF is now basically a melting

unit for stainless steel production as well. Decarburisation is carried out partially in

the EAF, and the rest of the carbon is removed in a separate refining vessel. In this

context, the development of the AOD process was a major breakthrough in stainless

steelmaking.

 AOD is the acronym for Argon-Oxygen
Decarburisation. The process was patented by the
Industrial Gases Division of the Union Carbide
Corporation In an AOD converter, argon is used to
dilute the other gaseous species (02, CO, etc.).
Hence, in some literature, it is designated as
Dilution Refining Process. After AOD, some other
dilution refining processes have been developed.
Lowering of the partial pressures, such as the
partial pressure of carbon monoxide, is achieved
either by argon or by employing vacuum

 The combination of EAF and AOD is sufficient for producing ordinary grades

of stainless steels and this combination is referred to as a Duplex Process.

Subsequent minor refining, temperature and composition adjustments, if

required, can be undertaken in a ladle furnace. Triplex refining, where electric

arc furnace melting and converter refining are followed by refining in a

vacuum system, is often desirable when the final product requires very low

carbon and nitrogen levels.

 About 65-70% of the world's total production of stainless steel is in the

austenitic variety, made by the duplex EAF-AOD route. If the use of AOD

converters even in the triplex route is included, the share of AOD in world

production would become as high as 75-80%.

 Conventional AOD, no top blowing is involved. Only a
mixture of argon and oxygen is blown through the
immersed side tuyeres. However, the present AOD
converters are mostly fitted with concurrent facilities for
top blowing of either only oxygen, or oxygen plus inert
gas mixtures using a supersonic lance as in BOF
steelmaking.

 Initially, when the carbon content of the melt is high, blowing
through the top lance is predominant though the gas mixture
introduced through the side tuyeres also contains a high
percentage of oxygen.
 However, as decarburisation proceeds, oxygen blowing from
the top is reduced in stages and argon blowing increased. As
stated earlier, some stainless steel grades contain nitrogen as
a part of the specifications, in which case, nitrogen is
employed in place of argon in the final stages.


 Simplified by Hiltey and Kaveney

 This process produces molten iron in a two-step reduction melting
operation. One reactor is melter-gasifier and the other is pre-
reducer. In the pre-reducer, iron oxide is reduced in counter-flow
principle. The hot sponge is discharged by screw conveyors into the
melting reactor.
 Coal is introduced in the melting-gassifying zone along with
oxygen gas at the rate of 500-600 Nm3/thm. The flow velocity is
chosen such that temperature in the range of 1500-1800 C is
main-tained. The reducing gas containing nearly 85% CO is hot
dedusted and cooled to 800-900 C before leading it into the pre-
reducer

 In the FINEX Process fine ore is preheated and reduced to DRI in a
train of four or three stage fluidized bed reactors.
 The fine DRI is compacted and then charged in the form of Hot
Compacted Iron (HCI) into the melter gasifier. So, before charging to
the melter- gasifier unit of the FINEX unit, this material is compacted
in a hot briquetting press to give hot compacted iron (HCI)

 since the melter- gasifier can not use fine material (to ensure
permeability in the bed).
 Non-coking coal is briquetted and is fed to the melter gasifier where
it is gasified with oxygen

As a standard guide the temperature rise
attainable by oxidation of 0·01 % of each of the
element dissolved in liquid iron at 1400°C by
oxygen at 25°C is calculated assuming that no
heat is lost to the surroundings and such data are
shown below .

 Ahindra Ghosh and Amit Chatterjee: Ironmaking and Steelmaking Theory and Practice, Prentice-
Hall of India Private Limited, 2008
 Anil K. Biswas: Principles of Blast Furnace Ironmaking, SBA Publication,1999
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 R.H.Tupkary and V.R.Tupkary: An Introduction to Modern Steel Making, Khanna Publishers.
 David H. Wakelin (ed.): The Making, Shaping and Treating of Steel (Ironmaking Volume), The
AISE Steel Foundation, 2004.
 Richard J.Fruehan (ed.): The Making, Shaping and Treating of Steel (Steeelmaking Volume), The
AISE Steel Foundation, 2004.
 A.Ghosh, Secondary Steel Making – Principle & Applications, CRC Press – 2001.
 R.G.Ward: Physical Chemistry of iron & steel making, ELBS and Edward Arnold, 1962.
 F.P.Edneral: Electrometallurgy of Steel and Ferro-Alloys, Vol.1 Mir Publishers,1979
 B. Ozturk and R. J. Fruehan,: "Kinetics of the Reaction of SiO(g) with Carbon Saturated Iron":
Metall. Trans. B, Vol. 16B, 1985, p. 121.
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