Facts

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  An induction furnace pouring melted metal, courtesy Pees Induction An electric induction furnace is used by manufacturers to melt metal. Unlike more traditional methods, which involve heating the metal through an external means like fire, the induction furnace melts metal with an electrical charge. This furnace sends alternating electrical currents through the metal, heating it quickly and creating what are known as "eddy currents" that dissolve the metal into a more liquid state. Because electric induction is more precise than other melting practices, it can be used to create specific alloys and melt resistant metals. The electric induction furnace is used widely in manufacturing across the world.
• An electric induction furnace requires an electric coil to produce the charge. This heating coil is eventually replaced, and can be bought separately from the rest of the furnace. The 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. The induction furnace can range in size, from a small furnace used for very precise alloys only about a kilogram in weight to a much larger furnaces made to mass produce clean metal for many different applications.
• There are many different designs for the electric induction furnace, but they all center around a basic idea. The electrical coil is placed around or inside of the crucible, which holds the metal to be melted. Often this crucible is divided into two different parts. The 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, or the contaminants that rise to the surface of the melt.
  
  So that the slag can be easily removed, there are often specific electrodes place at the top of the crucible to keep it in a semi-liquid state. Crucibles may also be equipped with strong lids to lessen how much air has access to the melting metal until it is poured out, making a purer melt.
• The electric induction furnace was created in the early 1900s by several different inventors who capitalized on each other's experiments to create a more efficient model. Some of the first induction furnaces had only one electric coil, although these were eventually replaced with two-coil version that could create the necessary electrical eddies more easily.
  
  Lids were removed from designs to allow easier removal of the slag. The entire crucible was mounted on a tilting mechanism that allowed the melt to be poured out. Water cooling systems were also added to cool the coils.
• The induction furnace is used to melt many different sorts of metals, from common steel to more exotic alloys or precious metals. Iron, copper and aluminum are also melted in an induction furnaces. Because it is fast and easy to control, this furnace is used by almost all manufacturing plants when making steel or aluminum.