Furnace Technology
Gas purging in the
induction furnace
Grant Cullen from Capital Refractories
Ltd explains how the company has its
gas diffuser technology for the induction
furnace products in use throughout the
world following its initial trials just over
two years ago.
C
apital Refractories made a Patent Application
encompassing the system’s technology. Over 1,000
gas diffuser units have now been supplied and are in use,
from these a mass of information has been accumulated
that clearly demonstrates the wide ranging benefits which
can be attained by application of this technology.
Gas diffusers, or as they are more commonly known,
‘porous plugs’ have been in use for more than 25
years, originally being developed for use in steel ladles
operated in electric arc furnace and basic oxygen vessel
steelmaking. They are an integral part of the process
route for secondary steelmaking.
Vacuum tank ladle degassing and temperature
homogenising in steel ladles eliminated many of the
problems associated with variable temperatures during
multi-ladle continuous casting sequences. Over the
years, these characteristics, both metallurgical and
practical, have been established and well documented.
The principal advantages identified are temperature and
compositional homogenisation, degassing and cleaner
steel.
Gas diffuser availability
Gas diffusers have been available for foundry ladle
applications but have never made the impact seen in the
tonnage steel industries, or more recently in reverbratory
aluminium melting and holding furnaces.
‘Classical’ steelmaking methods such as the electric
arc which has two distinct melt phases in which oxidation
where deleterious gases like hydrogen and nitrogen
can be removed during the carbon/oxygen reaction and
reduction where oxygen and those oxidation products
can be removed.
Induction furnace melting does not promote these
reactions, whilst hydrogen, nitrogen and oxygen can be
absorbed by the melt from the atmosphere. This pickup
can be inhibited by processes that have been developed
to shroud or blanket the melt, making use of the fact
that inert argon gas is denser than air by blowing argon
gas onto the melt, or dripping liquid argon, as has been
described by the SPAL process.
Whilst significant progress has been made using these
methods to improve metal quality, neither of these
methods of delivering argon can address other issues that
include melt homogenisation, reduction in gas content
of that already in the charge materials such as oxide
films on scrap, or promote the removal of non-metallic
inclusions from the melt to the slag.
Capital Refractories, as a major supplier of induction
furnace linings, believed that the benefits identified
above could be introduced to coreless induction melting,
350
undertaking a programme of development.
For success, seven principles needed to be attained:
• Permeable ceramic able to resist penetration if in contact
with liquid metal.
• Capable of delivering small volumes of purging gas in a
controllable manner.
• Compatibility with the Capital Refractories’ range of lining
materials in the sintered state.
• Able to operate for the life of the induction furnace lining.
• Ease of installation and operation.
• Cost effective.
• Safe.
From this programme a range of gas diffusers was
developed for use with a range of induction furnaces from
40 to 10,000kgs + capacity. This, together with a proven
mode of installation and operation, addresses all seven
principles.
Installation and case studies
Figs. 1 to 5 of the operation of an induction furnace
melt indicate how the process operates.
Since the process was introduced, significant feedback
has been received from users, those benefits identified
including temperature homgenisation, improvement in
casting quality, reduction in nitrogen content, cleaner
metal and increase lining life.
Further explanation of these identified benefits may be
found in the following customer case studies.
Temperature homogenisation
A UK producer of high nickel alloys (Monel, Inconel,
Incalloy) using a brick lined, five-tonne furnace had severe
erosion associated with excessive temperature on the
furnace barrel approximately 250mm up from the furnace
base. The introduction of argon gas via a gas diffuser
immediately eliminated this problem.
Calculation of the original temperature in this zone
indicated that it was in the order of 2,000°C. This has
enabled the client to have a melt campaign on a lining
of two weeks where previously they were relining every
weekend.
Improvement in casting quality
A Sheffield foundry operating a 300kg induction
furnace melting predominantly 13%Cr/4% nickel alloy
steel suffered a scrap rate due to casting defects
associated with gas in the metal that at times exceeded
20% and in addition caused significant reworking of many
more pieces.
After the introduction of the gas diffuser and argon
purging, scrap castings due to gas defects were
eliminated and reworking was significantly reduced.
It is believed that this improvement (there were no
other changes to practice) was due to reduction in gas
content of nitrogen in the metal.
Reduction in nitrogen content
A UK specialist foundry producing MoCrV high alloy
iron in a 600kg induction furnace experienced high scrap
rates on hydraulic seals castings, almost all castings
being scrapped when nitrogen levels exceeded 0.04%.
Prior to introducing the argon purge in the furnace, the
average nitrogen was 0.041%.
Argon was introduced during meltdown and right
up until tapping. After the first week of argon purging
FTJ December 2007
Furnace Technology
average nitrogen was 0.033%. Lower nitrogen
returns were subsequently recycled back to
the furnace, the figure then falling to 0.022%.
There have been significant cost savings
from the massive reduction in scrap rate and
also in not having to remelt accumulated own
arisings and degass in an AOD.
Cleaner metal
A US foundry specialising in NiHard and
NiResist irons together with a wide range
of steel alloys for wear parts applications
has reported a significant reduction in nonmetallic inclusions since introducing the gas
purging process to its induction furnace. The
first indication of this came via the furnace
operatives who reported that the volume of
slag appeared to be greater on melts treated
with argon. Subsequent metallographic
examination confirmed cleaner metal.
A Dutch foundry manufacturing castings
for the North Sea oil industry was an early
proponent of the gas diffuser system after
trials showed improvements in impact
strength of steel thus treated due to
reduction in inclusion count.
Fig 1. This illustrates a typical
induction furnace melt with
atmospheric gases above the melt,
dissolved gases (H2 and N2) in the
melt plus typical non-metallics
Fig 2. The argon gas is turned on
and flow is established via the gas
diffuser, through the lining and
into the melt
Increase in lining life
An increase in lining life was an
unexpected gain from the development of
the process, although it was anticipated that
homogenising temperature (as previously
described) would have a positive effect on the
condition of the lining. A significant number
of clients now report increase in lining life
since introducing the process.
A lost wax foundry in east Lancashire
melting grade 316 stainless steel averaged 80
melts on a lining although the company had
to reline after reaching around this number
of melts due to slag build up on the furnace
sides which progressively reduced capacity.
Subsequent to introducing the gas diffuser,
the lining was so clean during the first
campaign that it was wrecked at 120 melts,
although upon examination it was discovered
that the lining could have comfortably run
a further week. The foundry now averages
140 heats per campaign and reports superior
casting surface-finish after shot blasting
compared with previous casts.
Again, the amount of slag rising to the melt
surface and being removed is greater than
prior to introducing the purging process.
A stainless foundry near Milwaukee in the
US reported that its first campaign achieved
156 melts compared to 70-80 previously,
the company now being in the process of
converting a further nine furnaces to the gas
diffuser system.
Capital Refractories Ltd; tel:
(+44) 1246 811163; fax: (+44) 1246 819573;
e-mail: info@capital-refractories.com
www.capital-refractories.com
FTJ December 2007
Fig 3. The swarm of argon gas
bubbles start to float non-metallics
to the surface of the melt. Gases
in the melt diffuse into the argon
bubbles, which have lower partial
pressures
Fig 4. The argon passing through
the melt, as well as floating
non-metallics to the top, forms a
blanket on the melt, shielding the
melt from those atmospheric gases.
If deemed a requirement, argon
can be turned on as soon as the
charge is added, displacing the air
and ensuring melting is conducted
in an inert atmosphere
Fig 5. The slag, containing those
non-metallics floated out of the
melt during the gas purging, can
be removed prior to tapping thus
preventing potential entrainment
in the castings. The blanket of
argon will continue to shield the
metal during tapping. For certain
metals, argon purging in the
ladle may be advisable, as well as
shrouding the mould
351
Furnace Technology
Understanding refractory corrosion
Because consumables related to melting operations are
expensive, in order to keep costs in check, a thorough
understanding of the processes involved is highly desirable.
I
n their paper ‘Corrosion resistance of castables in
channel furnaces for ferrous foundry’ presented
at the 2007 WFO Technical Forum organised by
the WFO and VDG, J Soudir and L Ronsoux from
Calderys Central Research Department, St. Quentin
Fallavier, France, said that corrosion of refractory
in service is a complex phenomena, which has a
multitude of origins and processes. Therefore,
predicting corrosion resistance and thus selecting
a precise product for a given application can be
difficult.
A possible way to approach chemical corrosion
mechanisms and identify castable and slag
characteristics that are interesting to evaluate
to help in selecting the correct refractory, is to
consider relation (1), that gives the speed of
dissolution of a given refractory compound into a
liquid slag.
SpD = dn/dt = D.A.(Cs-C)/e
(1)
SpD: speed of dissolution of the considered
compound; t: time; C: concentration of the
considered compound in the slag at time t; Cs:
concentration of considered compound when
saturation of the compound in the melt is reached;
Cs-C: gap to saturation, the driving force of the
dissolution; D: coefficient of diffusion of the
considered compound in the slag; A: area of the
interface compound/slag; e: thickness of the
boundary layer.
The authors said that, looking at the various
parameters of this relationship and following the
initial remarks, it is evident that D is directly linked
process. Access to this data in
simple systems is possible, but
will not be easy to determine
in the case of complex multicomponent castable and slag
systems; e is a function of slag
viscosity (from temperature)
and from agitation level,
which is almost impossible to
determine in practice.
It thus appears that trying to
foresee the corrosion resistance
of several castables in a given
application by the evaluation of
the corrosion speed is not really
feasible as it is impossible to
obtain all the data describing
the system (refractory, slag,
operating conditions). It is
restrictive, as it takes no
account of thermo-mechanical
phenomena such as thermocycling, mechanical stresses etc.
The aim of this particular
paper was to propose several
simple ways to obtain an
initial evaluation of refractory
corrosion resistance.
Guidelines were proposed on
characteristics to be taken
into consideration regarding
castables, slags and their
systems to permit the first
castable selection or ranking.
Characteristics
and parameters on
castables
Refractoriness
Fig. 1. Configuration of the interface refractory/slag.
to temperature, thus Sp increases with T; A is the
real contact area between slag and refractory, SpD
thus being directly influenced by the infiltration
capability of slag. Porosity and capillary structure
of the castable, regarding slag viscosity or
wettability will be parameters to evaluate.
Cs-C is the driving force of the dissolution
352
One of the first parameter to
take into consideration is the
refractoriness of the castables
under consideration, which
can be tested in several ways.
One of the easiest and quickest
is to estimate the liquidus
temperature of the castable
matrix (fraction below 100µm),
expressed in a ternary system in
order to be able to use ternary
phase diagrams.
Infiltration resistance and
behaviour
It has already been mentioned
that infiltration of slag into
refractory is a phenomenon of
major importance. Infiltration
of liquid into a refractory
can be divided into two main
cases. These are infiltration of
a capillary system by a wetting
liquid (slag at the upper part
of channel furnace bath for
example) or penetration of nonwetting liquid under pressure
(iron at the bottom of vessel for
example.
Looking at the parameters
influencing infiltration depth
of slag against time, it is
clear that only the equivalent
radius Re is a physical
refractory parameter that has
a direct influence and must be
taken into consideration for
castable selection or ranking.
Access to Re can be achieved
using a simple test method
consisting of measuring
infiltration depth of the oil
with well-known rheological
characteristics (selected to be
close to estimated physical
characteristics of slags at
operating temperature) at room
temperature against time.
Infiltration speed, values of
Re, as far as total accessible
porosity for the tested castables
after treatment at operation
temperature can thus be
established.
Values of Re may vary with
treatment temperature and
time for a given castable, as
the capillary structure may
change with sintering time.
This is particularly the case for
castable containing fume silica,
closing porosity and modifying
tortuosity after long sintering
time, resulting in a strong
reduction of infiltration speed.
Characteristics and
parameters on slags
One of the first physical
characteristics of slag to
take into consideration is its
viscosity. This characteristic
cannot be easily measured or
estimated from data banks for
complex slag composition.
However, one way for
getting an initial feeling and
ranking of slag consistency
FTJ December 2007
Furnace Technology
at a given temperature, is to
measure deformation and
flow temperature using hot
microscopy.
Ranking of slag capability
to infiltrate castable (ranking
of viscosity) can also be finetuned taking into account
potential slag modifications
during infiltration of
refractory (modification due
to temperature decrease
against infiltration depth or
chemical composition changes
due to refractory component
dissolution).
Testing modified slags (for
example those containing
increased amount of manganese
oxides or SiO2, MgO, Cr2O3
etc gives an initial first idea
about slag viscosity changes
that can results from process
modification. Examples of these
include increase of manganese
oxides level in slag due to
changes of quality melted or
from dissolution of refractory
compound (SiO2, MgO or Cr2O3
from castable additives) during
slag penetration.
Characteristics and
parameters on system
castable plus slag
As previously mentioned,
gap to saturation Cs-C is an
important parameter describing
the system (refractory: slag)
and governing the speed of
dissolution. Nevertheless
this parameter is difficult
to access without powerful
thermodynamical calculation
tools, and anyway only
describes the behavior
of individual refractory
components and not the global
refractory behavior. Thus
several more easily accessible
characteristics of the systems
(refractory:slag) are listed
below, that can be considered
as providing a global picture
of the ‘chemical compatibility’
of the systems, and thus a first
way of ranking castables.
Refractoriness of the
system (slag-matrix)
The composition of this
system can be approximated
FTJ December 2007
using the hypothesis that all the porosity of the
castable is located in the matrix, and that 100% of
the porosity is infiltrated by slag. Refractoriness
is estimated reading liquidus temperature of this
composition and phases present at 1600°C in a
ternary phase diagram, especially the amount of
solid phase remaining.
Ranking of castables will thus be done
considering the highest percentage of solid phase
remaining and the highest solidus temperature.
Chemical compatibility of the system
(slag –matrix)
The first rough ranking of the compatibility
permitted from the refractoriness evaluation can
be fine-tuned by taking into consideration rules of
further slag oxides (as Fe or Mn oxides) or alkali,
or special addition in castables (MgO from A.M
spinel, Cr203 for example).
This fine-tuning can be achieved using
basics information from binary phase diagrams
as eutectic temperature (when existing) and
satu­ration composition of a given refractory
compound (MgO, Cr2O3 etc) into the considered
slag component. The highest compatibility will
be considered for systems having the highest
eutectic temperature and the lowest saturation
concentration.
Acidity and basicity of slags and castables
Another easy way to rank castables against given
slag, or to fine-tune first ranking established from
previous methods involves calculating the acidity
or basicity index using the relationship (2) (basicity
index) applied to slag and to refractory matrix.
infiltration depth between
the two cycles will reduce the
thickness of the slag infiltrated
layer spalling at each cycle
due to the different thermal
expansion coefficient of the
infiltrated area.
This can be achieved by
selecting a castable with a
low Re and also by a castable
containing additives that will
strongly increase the viscosity
of the penetrating slag
after dissolution in the first
millimeters of slag penetration.
In the case of an acidic slag,
these additives can be SiO2
and Cr2O3, but not MgO from
Al2O3.MgO spinel, which would
decrease penetrating slag
viscosity, and thus increase
penetration speed.
Cupolas under the
spotlight
In the paper ‘Cupola melting
and coke consumption’ Dr M
Lemperle from Küttner GmbH &
Co. KG, Germany, said that the
coke consumption of cupolas
has been a frequently discussed
issue, higher coke rates
resulting in both a lower melt
rate and higher costs.
In the past, research work
B = ([CaO]+[MgO]+[FeO]+[MnO])/([SiO2]+[TiO2]+[P2O5])
has focused on the properties
Simplified formula : B = ([CaO]+[MgO])/[SiO2]
of the different coke grades
(2)
employed, today every operator
The ranking of castables would thus be carried
agreeing that coarse foundry
out by considering the closest indexes and
coke combined with low
avoiding as much as possible using the most basic
reactivity shows best results.
castables for high acidic slags and reverse.
Unfortunately, such an ideal
coke is not always available, at
least not reasonably priced.
Conclusions
This forced foundrymen to
employ cheaper alternative
Applying these simples comparison methods, and
fuels instead of foundry coke,
for example the simplest one from the last point,
blast furnace coke, anthracite,
can help avoid wrong and devastating selection as
form coke and even natural
Al2O3.MgO spinel-containing products (basic) for
gas having been employed to
application involving high acidic slags.
replace part of the expensive
If associated with a minimum knowledge of
foundry coke. All these
degradation mechanisms in furnace and foundry
alternative fuels, however,
practice, these simples methods can allow the finecould not really offer smooth
tuning of a castable selection or help find the route
operation or economy.
to refractory performances improvement.
In many cases it was reported
For example, a focus on castable infiltration
that the lower price of the
resistance, especially infiltration speed, will be the
solution for solving the problem of high wear due
alternative fuel was used up
to lining spalling resulting from rapid infiltration
by a higher consumption.
associated with thermal cycling.
Furthermore, there are many
In such a case, thermal cycling resulting from
other influences on the coke
the process cannot be improved as a foundry
rate, which are not always
process parameter. But reducing the slag
understood and considered.
353
Furnace Technology
Moisture, ash content and ash composition
of coke
It is clear that high moisture and ash contents will
increase coke consumption because the energy
carrier carbon will decrease accordingly. The water
content of the coke should certainly be measured
from time to time in order to be aware that any
unexpected higher coke consumption could be
attributable to the increased moisture in the coke.
Coke ash contains mainly silica and alumina,
therefore acting strongly acidic. The higher the SiO2
/ CaO ratio the more limestone has to be charged
to reach the required basicity. Addition of limestone
means higher coke consumption, a higher slag
rate and the decomposition of limestone into lime
and CO2 according to CaCO3 => CaO + CO2 which
requires energy.
Besides the coke properties, other effects also
influence coke consumption.
Equivalent oxygen enrichment
If the blast is reduced and 20% of the withdrawn
amount is replaced by pure oxygen the overall
oxygen rate into the furnace remains unchanged.
Because of the relation melt rate = const x total O2
the melt rate will not change for equivalent oxygen
enrichment.
As a result, however, the iron temperature will
increase because less nitrogen has to be heated
up. This allows coke reduction in the range of 10%
to 15% per 2% equivalent oxygen enrichment and
reduces the temperature to the initial value.
Heat losses by shell cooling
An example of this highlighted in the presentation
involved a 30 tonne per hour unlined shell cupola
using 100m3 per hour of cooling water with a typical
∆T of 15 °C. For this type of cupola this means
a heat loss of 100m3 per hour x 15°C x 4180kJ
per m3°C = 6300MJ per hour. This corresponds to
approximately 220kg per hour of coke with a CV of
29MJ per kg.
This may be compared to a 30 tonnes per hour
cupola with refractory lined shell using 100m3 per
hour of cooling water with a typical ∆T of 3°C that
reduces the coke losses to 44kg per hour. Coke
savings are 220kg - 44kg = 176kg coke per hour.
Coke savings by increased hearth height
Conditioning the blast
Increase of hot blast temperature by 100°C
results in coke savings of approximately
1.4%. Today, metal recuperators are available
for hot blast up to 750°C, drying of the blast
may save about 1% of coke.
Oxidation and reduction reactions
Alloying additives like ferro-silicon (FeSi),
silicon carbide (SiC) and ferro-manganese
(FeMn) are unfortunately burnt-off to some
extent and form SiO2 and MnO2, which are
lost in the slag. High amounts of heat are
released, however, during this burn-off
reaction. This also saves coke but at high
costs and often explains very low coke
consumption claimed by some operators.
Special advantage can be taken from low
grade SiC that contains larger amounts of
carbon. This material in briquette form may
be available at lower price and serve as a
coke substitute.
Reduction of iron oxides present on the
scrap surface and the reduction of SiO2 in
the coke ash consume high amounts of heat
which have to be covered by additional coke.
To counteract this, rusty and small sized
scrap with high specific surface areas should
be avoided.
Pre-heating zone
Pre-heating the scrap charge to its melt
temperature has to be accomplished above
the coke bed. The height of the cupola shaft
has therefore to be designed according to
the size and composition of the metallic
materials that are to be processed.
Steel scrap of large dimensions in
particular may not reach the required melt
temperature in short shafts being typically
designed for small shredder scrap, pig
iron and returns. In these cases the hearth
suffers from heat deficiency that has to be
compensated by additional coke.
Manual of
Foundry
Technology
The complete manual can be purchased at a
cost of £30.00 (ICME Member) or £110.00 (nonmember). Alternatively individual chapters may
be purchased at a cost of £15.00 each.
Postage and package should be added at 15%
of total order price (surface mail). Airmail prices
should be sought from ICME bookshop.
Tel: +44 (0) 1568 797111.
Fax: +44 (0) 1568 797197.
Email: icmebookshop@rivers-media.co.uk
354
FTJ December 2007
Furnace feeding using
mobile charging devices
Mobile charging devices are used for feeding
melting furnaces, especially induction units for
iron as well as for rotary-type furnaces used in
secondary aluminium melting plants.
T
he two designs of the
charging devices differ
from each other in several
characteristics. Those
associated with induction
furnaces comprise a carriage,
a vibrating feeder including
unbalance motors and a
pontoon-shaped bin. A version
equipped with an additional
transverse carriage base frame
allows the feeding of numerous
furnaces by one charging
device.
In general, the bin must be
capable of receiving the mass
of the inserted material that
corresponds to the furnace
content, the required volume of
the bin being roughly calculated
by assuming a medium density
of 1.6t/m³. Attention should be
paid to the fact that, due to an
unfavourable filling (gradient),
the utilisation of the volume is
not optimal and therefore only
around two-thirds of the total
volume of the bin is effectively
utilised.
An asymmetric design
results in a good material flow
behaviour within the bin, the
material flow on one side being
forced and slowed down on
the other; this avoids material
sticking and bridging.
Typical materials are scrap,
press bales and return scrap.
A limiting of the maximum
dimensions per unit up to
around 400mm is required to
allow an undisturbed operation
and material flow. The charging
of the machine bin is normally
A unit designed for an aluminium rotary furnace
FTJ December 2007
Maximum
efficiency may
be achieved by
incorporating the
furnace chargers
into the original
plant design
effected by means of a crane magnet or an
attached charging container incorporating a bottom
dump flap.
Noise level considerations
An increasingly important aspect is the noise
level reduction during charging and operation
of the charging device, the following noise
reducing concepts having been well proven in this
application:
* Use of a sandwich-construction for the bin and
vibrating feeder. That means these parts are
fitted with a replaceable wear lining comprising a
highly damping rubber layer inserted between the
machine body and the wear lining.
* The vibrating feeder, which is arranged beneath
the bin, operates with low amplitude and conveys
the material with a vertical acceleration of around
1g. Due to this, no micro-throw occurs during the
feeding operation, which results in a significantly
reduced noise level. An adequate design of the
vibrating feeder incorporating these parameters
makes a frequency inverter become unnecessary.
At the outlet side, the charging device is fitted
with a docking flange which is almost closed, its
contours being designed in such a way as to allow
it to dock onto the opened furnace lid. The result
is an efficient isolation of the noise source and
fumes at the section where the materials drop in
A charging machine suitable for an induction furnace
installation
355
Furnace Technology
the furnace.
Charging devices for the feeding of
rotary furnaces
This version, used in aluminium
melting plants, is different from the
types used for induction furnaces
because the charge is typically press
bales made from aluminium sheet,
shredded aluminium scrap and a
covering salt.
Key feature is the elongated
discharge chute nozzle that leads
into the centrically arranged feeding
opening in the rotary furnace during
the feeding process. In order to avoid
temperature losses within the furnace,
the charging process has to take place
quickly. For this reason the vibrating
conveyors operate at high amplitudes,
allowing a high conveying speed.
The chute is highly stressed due to
the highly dynamic bending moments
resulting from the extensive thermal
load as well as un-calculable loads
arising from collisions caused by the
rotation of the furnace with nonsmelted aluminium compressed bales.
The endurance strength in the chute
area can be significantly influenced
by the design engineer who has to
maximise the structural strength
without increasing the weight.
Furthermore, the application of highquality, heat-resistant material offers a
favourable effect.
As the materials do not melt as
quickly as demanded, the travelling
gear of the machine is temporary
used to feed the furnace by powerful
backwards and forwards movements
with additional aluminium bales. The
installation of an all-wheel driven
travelling gear has been well proven in
this mode of operation.
The consideration of an exhaust
cover to reduce the dust and smoke
emissions is more complicated
than that for a crucible furnace.
Nevertheless, it is possible to install
an efficient multi-gap exhaust device
in the front section of the bin.
The electrical control is executed,
depending on customer needs, using
the conventional relay technique
or the PLC. The execution of power
supply must be paid particular
attention as it can be provided using a
spring-loaded cable reel, a trail cable
or an energy chain. The spring-loaded
cable reel is often chosen due to its
stability.
Jöst GmbH;
Tel: (+49) 2590 98208 202;
Fax: (+49) 2590 98101;
email: info@joest.com
www.joest.com
356
The advantages of
oil fired crucibles
Over some decades now, the availability
of natural gas and the comparatively low
energy running cost of modern gas-fired
and electric furnaces has resulted in a
sharp decline in the overall demand for
oil fired units. However, Morganite Molten
Metal Systems, continues to offer a range of
products for those parts of the world unable
to access gas or power electricity.
M
anual oil fired crucible furnaces are available as lift
outs up to 235kg of copper; bale-outs up to 600kg of
aluminium and 500kg of copper; central axis tilters up to
300kg of copper and hydraulic tilting lip pour furnaces to
600kg aluminium or 1500kg of copper.
The general description and sizes of these can be found in
pdf form at www.morganmms.com under ‘library, furnaces,
data sheets’.
They are capable of melting a wide range of metals and
alloys from zinc, aluminium, copper based alloys, through to
iron.
The Morgan manual oil burner system has the advantage
of simplicity, tolerance to a wide range of fuel oils, and can
raise temperatures high enough to melt iron to 1450°C. The
only supply requirements are gravity supply of oil in the
viscosity range of 25-40 seconds Redwood 1, with a head of
three metres and an electrical supply sufficient to operate the
combustion air fan motor, typically 3kW. Heavy fuel oils can
also be used in conjunction with fuel line heating to reduce
their viscosity to the operating range.
The simple, robust controls are all manually adjusted to
give fast melting or holding and they require little or no
maintenance, other than routine cleaning.
For further detailed information contact:
Morganite Molten Metal Systems. Tel: +44 (0) 1905 728200.
Furnace Technology in India
The latest advances in melting technology will be covered at the
68th World Foundry Congress to be held in Chennai, India in
February 2008.
There will be a wide ranging mix of technical debate, backedup with visits to some of the leading lights of the metal casting
industry in India.
Technical papers covering the latest furnace design and
developments will give delegates a comprehensive overview
of the on-going improvements in the supply of quality melting
technology.
The 68th World Foundry Congress will be held at the Chennai
Trade Centre, Chennai, India from 7-10 February 2008.
The full programme of technical papers, works visits, social and
partners programme is now available at www.wfcindia08.com or
from the Institute of Indian Foundrymen.
email: info@wfcindia08.com
FTJ December 2007