Induction furnaces are a type of electrical furnace that uses a combination of electrical resistance and hysteresis losses to heat metal. They tend to be cleaner and more energy-efficient than other types of furnaces. The furnace heats the metal by exposing it to the magnetic field around a coil-carrying alternating current. These enclosed structures use induction heating sources to produce heat for industrial purposes.
Induction furnaces operate by a process called electromagnetic induction, in which an electric current is passed through a metal coil creating a magnetic field. By passing the metal through this field, the metal is able to heat. In order to withstand long-term use, induction furnaces are made with a variety of heat-resistant (refractory) elements. The enclosed space within the furnace holds the material, gas or air being heated until the desired temperature is reached. Within an induction furnace, the heated area is easily controlled by the shape and size of the inductor coil, yielding a uniform, high-performance end-product. Induction furnaces are the most widely used type of furnace for melting iron and are increasingly popular for melting non-ferrous metals. Because they provide outstanding metallurgical control and are relatively pollution-free, induction furnaces have become a quite popular choice for heating purposes. Induction furnaces are also popular due to their ability to heat materials quite rapidly. Induction heating features a low level of noise, fumes and radiated heat, making it favorable for operators as well.
Applications for induction furnaces include baking, aging, brazing, annealing, curing, firing, drying, burn-off, foundry, hot pressing, laboratory uses, heat treating, quenching and preheating. While carbon steel is by far the most common material heated, induction heating is also used with many other conducting materials, such as stainless steel, aluminum, brass, copper, nickel and titanium. The operating frequency can range anywhere from 50 Hz to 400 kHz, or even higher. Induction furnaces come in two different types, which are coreless or channel. A coreless induction furnace is often used for melting steels, irons and non-ferrous alloys. Meanwhile, channel induction furnaces are used for low melting point alloys or to hold/superheat higher melting point alloys. Important factors to consider when selecting an induction furnace are its configuration, operating frequency, atmosphere, control, general specifications and features.