OF INDUCTION MELTING
*To heat the iron upto 1400 C cupola consumes
55 kg. /ton of fuel against 500 kWH
of Induction.· Cupola uses extra 60 kg/ton
fuel to super heat the melt 100 C
compared to 65 kWH /ton consumption
of induction.Elimination of pig-iron.
*Utilization of low cost borings and turnings
gives on effective metal coast saving of
*The metal loss is only 1% compared to 5-10 %
in cupola.The consumption of refractory
is 10 kg./ton in induction.
*Heat efficiency of cupola is 10-15% but the
over all heat efficiency in Induction is
*Sampling, adjustment of temperature, holding
of temperature is impossible with cupola.
*The composition in cupola alter three times
per day. Changes of carbon, silicon in the
melt are negligible in Induction for holding for few
Over arc furnace
Cooler, quitter, cleaner and safer working condition,
due to elimination of noisy arcs & gaseous product.·
Elimination of Electrode consumption (5-15kg./ton).
*Shorter melting time, due to no 'carbon pick-up'
which eliminates the oxidizing operation
and result in lower power consumption.
*Fast and complete homogenization of alloy due
to stirring action.· Lower oxidation
loss.· Better power utilization of
equipment.· Ability to hold metal temperature
for long period of time.
*Elimination of stock control equipment when
melting clean scrap.
*Elimination of sample taking and analysis of
each melt, due to more predictable melting.
Specialty of melting iron
*A continuous supply of molten metal.
*Excellent temperature control.· Elimination
of air pollution problems without costly
*Elimination of sulphur pick-up and silicon loss.
*Easier control of carbon content.
*Higher physical properties in the iron.
*More nearly uniform hardness of iron .
*Complete homogenous metal because of stirring
*Increased fluidity that allows lower pouring
*Excellent, reproducible chemistry control.
*Ability to hold iron over prolonged periods
without discernible change in chemistry.
*Melt losses on the order of only 2% for normal
gray iron, and even better on Si and alloy
*Elimination of effect of humidity variations
on iron quality.
*Highly automated controls
*Elimination of need for highly skilled operator.
*Comfortable, clean, cool working conditions.
*Reduction of slag disposal problems.
*Elimination of coke and limestone storage and
*Elimination of pig bed because cold ladle metal
can be returned for rehashing .
*Heating of ladles pouring temperature by filling
two or three times and returning chilled
metal to the furnace.
*Continuous pouring schedule releasing space
required for mold storage.· Simplified
charging and reduced labour requirements.
*Regulation of rates to suit requirements without
incurring chemistry and temperature problems.
*Ability to melt borings, turnings, and scrap
materials with excellent recovery and no
charge formality other than the charge opening of the
*Accurate and rapid chemistry without
*Ability to super heat.
*Fire hazards is minimum. The Induction furnace
does excellent job in eliminating segregation
with no labour.
*It is cold top, less oxidation and higher recovery.
*Better utilisation of available space
*Used for melting steel & alloys requiring
lower carbon than that obtainable in crucible
& are furnace.
*Induction melting in acids lining of rolling
mill scrap yields a steel with all qualities of
acids steel which are so valuable for gun & aeroplane
and other steel requiring good
*Heat resisting steel, die & other complex
steel , and refractory chromium alloys can
be melting in acid or basic linings without substantial
alteration of composition.
*Manganese steel scrap can be remelted without
substantial loss of manganese.
Aluminium melting : *
*The increased thermal resistance of oxide coated
particle of Aluminium is the chief reason
why they are difficult to melt in furnace operated on
the principle of radiation,
convection and conduction. This difficulty is overcomes
by induction .
*As the emissivity factor of Aluminium is very low,
heat given to the path through surface or
the surface load is very low, but the induction surface
rating is more than 3 times than others.
*Because of the stirring actions there is uniform
temperature throughout the bath in Induction
*In fuel fired or electric furnaces the bath
temperature is uneven and vary from 500
C to 750 C, because of this melting loss and gas absorption
is very high but it is very low in Induction
because of stirring action .
*Another advantage of electro magnetic stirring
is that in many case the ingredients of
high melting point like Copper or Nickel can be dissolved
directly thus eliminating the use hardeners.
*The hydrogen 'ofcourse' is not present or produced
on the gaseous covering of the bath contained
, in Induction furnaces as it is a cold top. The hydrogen
absorption in the path is eliminated.
*The most of the users of the Induction furnace
in the foundry report that they are not
using the fluxes and they have found only one half the
degassing agent to be necessary as compared
with other furnaces.
*The reverberatory furnace of good condition
can rarely prevent the melting loss of much
less than 5% and a crucible furnace of tilting variety
is ranged between 2-3% while the melting
loss is of 0.8% in Induction.
*The precision alloying is possible by directly adding
*The zinc loss is minimum
*The metal loss is less than 1% compared to 5%
in fuel fired furnaces. The high Frequency
furnaces melts hard materials of Tungstan-Cromium-Carbide
group and which can be casted in form moulds
as a temperature of 2000 to 2300 C.
Galvanizing induction furnace
The Induction melting unity provides an entirely
new approach with refractory container of essentially
unlimited life which do not in any way contribute
to the formation of dross from job.· The
galvanizer will agree however that 10% can be
gained by elimination of iron kettle and at least
10% by perfect temperature control.
Vaccum induction furnace
*One of the main characterised of vacuum melt
alloys are their consistent properties e.g.
vacuum melted copper is practically free from volatile
impurities, and better than o.f. h.c. copper.
*Low carbon content of less than 0.005% is possible
in vacuum Induction melting. This is better
than are melting.· Vacuum melted magnetic materials
give better performances than by any other
*It is easier to control boron in vacuum Induction
melted alloys. only 15 ppm of boron in waspaloy
doubles the rapture life · The vacuum melted
bronze could be brazed where as the other
is not .
*The vacuum melted bronze could be brazed where
as the other is not.
*The vacuum melting of 'cleanliness' alloys (52100)
gives a marked increase in bearing life.
*It is used for production of finished castings
by lost wax investment process to increases
both titanium and aluminium content in Nickel base alloys
and there-by achieve high temperature strengthening
associated with the precipitation hardening
Induction heating is ideal method of heating. This
gives a very short zone than any other process.·
Induction Heater is preferred in floating zone technique,
zone leveling, crystal pulling and levitation.·
The stirring action of Induction melting increase the
efficiency of the zone refiner.
Levitation induction melting
*Rapid alloy preparation and also alloying addition
can be made while the melt is in levitation.
*The charge touches no crucible or container
during the heating, melting and draining
*The heated or molten charge can be protected
by a suitable atmosphere and vacuum.
*The molten charge can be drained gradually or
dropped as a whole and it may even be feasible
to solidify the still levitated melt and drop it solid.
*Volatile impurities can be distilled or pumped
*Used for melt purification and homogenization
*Gas -metal reaction kinetic studies, solidification
studies, Liquids slag and refractory reaction
studies can be conducted.
*Working in weightless condition permits the
creation of special alloys which can not
be product by other means.