Process

• There are two types of induction furnaces, coreless and channel. Coreless induction furnaces are used most often to contain and melt down metals. They use a large refractory envelope made of an alloy that can withstand electromagnetic forces to hold the metal being melted. The electromagnetic coil itself is wrapped around the refractory container, and a charge is applied to the coil. The combination of the electric charge and the field created by the coil itself creates strong magnetic forces in the metal, usually referred to as "eddies" that sweep through the metal's substance. These eddies create heat in the metal, a natural product of the metal's resistance to the electromagnetic field, and this heat is raised to such a level that the metal melts. After being melted, the field still creates waves in the metal and keeps it constantly moving.
  
  Channel furnaces are used more often to hold molten metal at specific temperatures but are also sometimes used to melt metal. The coil, usually water-cooled, surrounds a refractory just like the coreless system, but instead of containing the metal, the refractory has only a channel that allows the molten metal to flow through it from a main repository. The metal flows in one end, is heated, and then flows out the other end in a continuous stream of molten metal. This means that if the furnace is being used to melt the metal, it needs to have starting mass of already molten metal to begin the cycle.
  
  

Uses

• Induction furnaces can be used with almost every type of metal--especially the alloys that are more difficult to make, since the precise temperatures of the furnaces make these alloys easier to form. Induction methods are used to melt rare-earth materials, form silicon products and create zinc or aluminum-based materials.
  
  While a version of an induction furnace can be created at home, you will probably only be able to make a weaker version of the factory models, and even that will create several hazards such as electrocution or burns. Smaller induction furnaces are used to treat metals rather than melt them, giving them additional stability or magnetic properties they did not have before.