Melting furnaces are used to overheat solid materials until they liquefy. Often, thermal processing equipment is used to alter the surface or internal characteristics of materials by carefully elevating their temperature. In the case of metals, this typically increases ductility at the expense of both hardness and strength. This requires an industrial furnace capable of generating and maintaining temperatures below that of the material’s melting point.
A melting furnace, by comparison, generates overhot temperatures that exceed the metal’s melting point and cause decomposition of its physical structure which leads to liquefaction. This phase transition is utterly dependent on both temperature and pressure. Few metals can exist in a liquid state at ambient temperatures, with the exception of mercury (Hg) and known eutectics like gallium-based (Ga-) alloys.

To achieve a homogeneous molten mixture, the melting furnace must be capable of generating and maintaining the requisite temperatures over a sustained period.

Induction furnace
The medium frequency induction furnace is mainly composed of a power supply, an induction coil and a crucible made of refractory materials in the induction coil. The crucible is filled with metal charge, which is equivalent to the secondary winding of the transformer. When the induction coil is connected to the AC power supply, an alternating magnetic field is generated in the induction coil. Its magnetic lines cut the metal charge in the crucible, and an induced electromotive force is generated in the charge. Since the charge itself forms a closed loop, this secondary winding is characterized by having only one turn and is closed. Therefore, an induced current is generated in the charge at the same time. When the induced current passes through the charge, the charge is heated and melted. The intermediate frequency induction furnace uses an intermediate frequency power supply to establish an intermediate frequency magnetic field, which induces eddy currents inside the ferromagnetic material and generates heat to achieve the purpose of heating the material.