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Abstract- A new generation of industrial induction melting furnaces has been developed during the last 25 years. Present
practices followed in Induction Furnaces are discussed in this paper. Through a literature review account of various
practices presently being followed in steel industries using Induction Furnaces has been carried out with a view to gather
principal of working. This paper is related with the modeling of induction process and its development is discussed. The
computational techniques available for the modeling the process and the various methods for optimization is also
discussed in this review paper
. INTRODUCTION
A furnace is a device used for heating. The name derives from Latin fornax. The development of Induction Furnaces
starts as far back as Michael Faraday, who discovered the principle of electromagnetic induction. However it was
not until the late 1870’s when De Ferranti, in Europe began experiments on Induction furnaces. Induction furnaces
are used in a wide range of production and manufacturing facilities such as foundries and metallurgy plants.
Induction furnaces are used primarily because they are fairly clean, can melt materials quickly, and are generally
affordable to maintain and operate. They also allow for precise temperature and heat control. Because they gain heat
very quickly they do not have to be left running between operations and thus save on energy resources and help
manage operating costs.
Induction furnaces may be used to melt, braze, solder, treat, or shrink fit any material that is suitable for use with
induction heat. Treating materials may include annealing, hardening, or tempering. Induction heat may be used to
braze or solder copper, bronze, brass or steel. Shrink fitting may involve fitting parts for precision manufacturing.
Melting processes can be done on ant material that is compatible with induction heat. Such metals include steel
bronze, copper and brass.
The rest of the paper is organized as follows. Proposed embedding and extraction algorithms are explained in section
II. Experimental results are presented in section III. Concluding remarks are given in section IV.
II. TYPES OF INDUCTION FURNACE
The two basic designs of induction furnaces, the core type or channel furnace (Fig 2) and the coreless (Fig 3), are
certainly not new to the industry. The channel furnace is useful for small foundries with special requirements for large
castings, especially if off-shift melting is practiced Induction furnaces have increased in capacity to where modern
high-power-density induction furnaces are competing successfully with cupola melting. There are fewer chemical
reactions to manage in induction furnaces than in cupola furnaces, making it easier to achieve melt composition.
Induction melting produces a fraction of the fumes that result from melting in an electric arc furnace (heavy metal
fumes and particulate emissions) or cupola (wide range of undesirable gaseous and particulate emissions as a result of
the less restrictive charge materials).
International Journal of Latest Trends in Engineering and Technology (IJLTET)
Vol. 2 Issue 3 May 2013 178 ISSN: 2278-621X
Figure 1. Furnace used in Industries
The induction furnace provides a complex challenge for the researchers for the mathematical modeling since it
involves the different fields of physics together and its inter action is not fully understood till date. The researchers
around the world have provided their own modeling method and have verified with experimental results with good
accuracy. The induction furnace provides a complex challenge for the researchers for the mathematical modeling since it
involves the different fields of physics together and its inter action is not fully understood till date. The researchers
around the world have provided their own modeling method and have verified with experimental results with good
accuracy.
Figure 2. Channel Induction Furnace
International Journal of Latest Trends in Engineering and Technology (IJLTET)
Vol. 2 Issue 3 May 2013 179 ISSN: 2278-621X
Figure 3. Coreless Induction Furnace
Induction heating processes have become increasingly used in these last years in industry. The main advantages of
using these processes when compared to any other heating process (gas furnace.) are, among others, their fast heating
rate, good reproducibility and low energy consumption [1]. The induction heating process basically consists in
transmitting by electromagnetic means, energy from a coil through which an alternative current is circulating. Induced
currents in the conductive part due to the well-known Foucault law then heats the workpiece thanks to the Joule
effect. Induction heating processes are mainly used either at low frequencies (around 50 Hz), usually in order to reach
a temperature distribution as uniform as possible within the material before any forming process, or at much higher
frequencies (104–106Hz) in order to heat very locally near the surface, usually for heat treatments [2]. Most induction
heating processes are set up using engineering experience and a trial-and-error procedure in order to achieve the
corresponding goal (grain size control, uniform prescribed temperature, hardness map, etc.). Induction heating process
simulation, which couples electromagnetic and heat transfer equations, can be of great help for a more in depth
understanding of occurring physical phenomena. So far, various numerical models have been developed coupling
electromagnetism and heat transfer. Most models involve the well-known finite element approach [3–5] or mixed
finite element and boundary element approaches [6–8]. Even though mixed methods are interesting due to their
inherent ability to take into account open domains and inductor displacements, the global finite element approach has
been preferred since it involves sparse matrices (leading to reductions in terms of CPU time and memory
requirements) and is more suited for parallel computing. Most authors use the harmonic approximation, assuming that
all electromagnetic fields are sine waves when the input current is a sine wave. This approximation, valid when
considering linear magnetic materials, can yield to large errors when dealing with highly ferromagnetic materials
[3,9]. That is the reason why the time-dependent formulation has been preferred. Time dependent integration being
very time consuming when using a traditional weak coupling between all problems, the ultra-weak strategy has been
developed.
IV.REVIEWS
H.K.Jung has designed the optimal inductive coil in the induction heating process of A356 (ALTHIX) alloy billets of
76 mm diameter and 90 mm length to reduce the temperature gradient of the billet and to obtain a globular
microstructure was theoretically proposed and tested by reheating experiments. The optimal reheating conditions to
apply the thixoforming process were investigated by changing the reheating time, holding time, holding temperatures,
the capacity of the induction heating system, and adiabatic material size. This study shows that, the larger the pellet
size, the better the multi-step reheating, and the heating time and the capacity of the induction heating system must be
increased. In case of the three-step reheating process, the final holding time is the most important factor and 2 min is
suitable to maintain a globular microstructure.
International Journal of Latest Trends in Engineering and Technology (IJLTET)
Vol. 2 Issue 3 May 2013 180 ISSN: 2278-621X
Figure 4. Temperature distributions in the one-step reheating process of semi-solid alloy (fs.50%, ta1.10 min, Th1.5848C, th1.2 min): (a)
Q.7.796 kW.
The analytical technique has been developed by Dae-Cheol Ko et al.[3] in order to investigate the behavior of semisolid
material considering induction heating of the workpiece. The induction heating process is analyzed using the
commercial finite element software, ANSYS. The finite element program, SFAC2D, for the simulation of
deformation in the semi-solid state is developed in the present study. The behavior of semi-solid material is described
by a viscoplastic model for the solid phase and by Darcy's law for the liquid flow. Simple compression and closed-die
compression processes considering induction heating are analyzed. To validate the effectiveness of the proposed
analytical technique, the results of simulation are compared with those of experiment.
A general automatic optimization procedure coupled to a finite element induction heating process simulation has been
developed by Y. Favennec et al. [5] The mathematical model and the numerical methods are presented along with
results validating the model. The first part of this paper presents the direct induction heating mathematical model, the
related main numerical choices and especially the ultra-weak coupling procedure. The general optimization problem
is then presented with the full detailed transposition of the ultra-weak coupling procedure for the adjoint problem.
Numerical results provided at the end prove the efficiency and robustness of the adjoint model in optimizing
induction heating processes.
Double-channel induction furnaces are used extensively in many processing industries due, mainly, to their relatively
low operating costs. However, thermal stresses in the refractory lining caused by high temperatures during the loading
cycle can cause erosion of the lining and premature inductor failure. Prevention of premature failure by close
monitoring of the thermal regime of the inductor is very important to operators and relatively simple and reliable tools
need to be developed to this end. J.I. Ghojel [6] developed a such a tool using a thermal modelling software and
unidirectional axial channel flow speeds of the melt that are estimated from analysis based on the first-law of
thermodynamics. This analysis reduces the cost, complications and uncertainties associated with coupled multiple
field analysis approach. The results of the analysis show reasonable correlation with reported flow data and a
comprehensive set of scenarios can be devised on the basis of the developed approach to simulate start-up, transient
operation and steady state operation of double-channel induction furnaces.