presentation on electric induction furnace by stead fast engineers pvt ltd

7/24/2019 Presentation on Electric Induction Furnace by Stead Fast Engineers Pvt Ltd

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Presentation on electricInduction furnace by

Stead Fast Engineers Pvt Ltdhttp://www.steadfastengg.com/
http://www.steadfastengg.com/http://www.steadfastengg.com/


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Definition.

Electric induction furnace is type of meltingfurnace that uses electric current to melt the metal.

Once molten, the high frequency magnetic field can

also be used to stir the hot metal, which is useful in

ensuring that alloying additions are fully mixed into

the melt.

Induction furnaces are used in most modern

foundries as a cleaner method of melting metals

than a reverberatory furnace or a cupola.

Sizes ranges from ilogram of capacity to a

hundred tonnes capacity.


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!etals which are melted in an induction furnace

include iron and steel, copper, aluminum, andprecious metals because it is a clean and non"

contact process it can be used in a vacuum or inert

atmosphere.

#acuum furnaces mae use of induction heating for

production of specialty steels and other alloys that

would oxidize if heated in the presence of air.

$he basic principle of induction furnace is theinduction heating.


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Induction heating

Induction heating is a form of non contact heatingfor conductive materials.it is process of heating an

electrically conducting ob%ect by electromagnetic

induction where eddy currents are generated within

the metal and resistant leads to %oule heating of themetal.

&rinciple of induction heating is mainly based on

two well nown physical phenomena.

'. Electro"magnetic Induction(. $he )oule Effect


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Electro-magnetic induction$he energy transfer to the ob%ect to be heated

occurs by means of electromagnetic induction.

*ny electrically conductive material placed in a

variable magnetic field is the site of induced electric

currents, called eddy current which will eventually

lead to %oule heating.


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Joule heating$he %oule heating , also nown as ohmic heating andresistive heating is the process by which the passage

of an electric current through a conductor releases

heat.

$he heat produced is proportional to the square of the

current multiplied by the electrical resistance of the

wire.

+ I-t


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Induction heating relies on the unique

characteristics of radio frequency energy thatportion of the electro magnetic spectrum below

infrared and microwave energy.

Since heat is transferred to the product via

electromagnetic waves the part never comes intodirect contact with any flame the inductor itself does

not get hot and there is no product contamination.

Induction heating is a rapid clean non"polluting

heating. $he induction coil is cool to the touch. $heheat that builds up in the coil is constantly cooled

with circulating water.


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Features of i ductio fur ace

*n electric induction furnace requires an electric coil

to produce the charge. $his heating coil is

eventually replaced

$he crucible in which the metal is placed is made of

stronger materials that can resist the required heat

and the electric coil itself cooled by a water system

so that it does not overheat or melt.

$he advantage of the induction furnace is a clean

energy efficient and well controllable meltingprocess compared to most other means of metal

melting.


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$he induction furnace can ranges in size from a small

furnace used for very precise alloys only about a

ilogram in weight to a much larger furnaces made to

mass produce clean metal for many different

applications.

/oundries use this type of furnace and now also more

iron foundries are replacing cupolas with induction

furnaces to melt cast iron as the former emit lots of

dust and other pollutants.


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Construction of induction furnace. $here are many different design for the electric

induction furnace but they are center aroundbasic idea.

$he electrical coil is placed around or inside of

crucible, which holds the metal to be melted often

this crucible is divided into two different parts. $he lower section holds the melt in its purest form

,the metal as the manufacturers desire it , while

the higher section is used to remove the slag, the

contaminants that rise to the surface of the melt. 0rucibles may also be equipped with strong lids to

lessen how much air has access to the melting

metal until it is poured out maing a purer melt.


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Fig:


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Types of induction furnace$here are two main types of induction furnace, corelessand channel.

'"0oreless induction furnace, $he heart of the coreless induction furnace is the coil, which

consists of a hollow section of heavy duty, high conductivitycopper tubing which is wound into a helical coil.

0oil shape is contained within a steel shell.

$o protect it from over heating the coil is water cooled, the

water being recirculated and cooled in a cooling tower.

$he crucible is formed by ramming a granular refrectorybetween the coil and a hollow internal.

$he coreless induction furnace is commonly used to melt all

grades of steels and irons as well as many non"ferrous

alloys.


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("0hannel Induction /urnace$he channel induction furnace consists of a refrectory

lined steel shell which contains the molten

metal.*ttached to the steel shell and connected by a

throat is an induction unit which forms the meltingcomponent of the furnace.

$he induction unit consists of an iron core in the form of a

ring around which a primary induction coil is wound.

$his assembly forms a simple transformer in which themolten metal loops comprises the secondary

components. $he heat generated within the loop causes

the metal to circulate into the main well of the furnace.


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$he circulation of the molten metal effects a useful

stirring action in the melt.0hannel induction furnaces are commonly used for

melting low melting point alloys and or as a holding

and superheating unit for higher melting point alloys

such as cast iron.

AdvantagesHigher Yield. $he absence of combustion sources

reduces oxidation losses that can be significant in

production economics.Faster Startup. /ull power from power supply is

available instantaneously1 thus reducing the time to

reach woring temperature.


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Flexibility.2o molten metal is necessary to start

medium frequency coreless induction melting

equipment.Natural Stirring. !edium frequency units can give a

strong stirring action resulting in a homogeneous

melt.

Cleaner elting. 2o bi"product are produced due tocleaner melting environment.

Co!pact "nstallation. 3igh malting rates can be

obtained from small furnaces.


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#nergy Conservation. Overall energy efficiency in

induction melting ranges from 44 to 54 percent, and is

significantly better than combustion processes.

Disadvantages$he one ma%or drawbac to induction furnace usage

in a foundry is the lac of refining capacity1 charge

materials must be clean of oxidation products and of

nown composition, and some alloying elements may

be lost due to oxidation.

emoval of S 6 & is limited, so selection of chargeswith less impurity is required.

presentation on electric induction furnace by stead fast engineers pvt ltd

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