The main use of casting, smelting, heat treatment industry. For example, induction furnace for smelting molten steel and molten iron in foundry production makes use of induction heating effect of material to heat and melt the material. Under the influence of alternating electromagnetic field in induction furnace, the material generates eddy current and generates heat and melts. Induction furnace has outstanding advantages in the pure metals, including melting soft magnetic alloy, high resistance alloy, platinum group alloy, heat-resistant, corrosion resistant and wear-resistant alloy. It is mainly used for melting and insulation of various kinds of iron, brass, bronze, zinc and so on. The electric efficiency is more than 90%, which can make use of waste burden and lower the smelting cost.
At present, there are two kinds of induction heating equipment, medium frequency furnace and high frequency furnace in this field. The time of the medium frequency furnace appeared is earlier (ten years ago it has been used actually), the power of the single equipment is usually hundreds of kilowatts, the price is more expensive, the output current is big, and the coils are mostly made of the copper tube water-cooling. The high frequency furnace is usually about one thousand watts of power in a single equipment, the price is about more than 10 thousand, the output coils are mostly made of air-cooled and enameled wire, and the technology is being perfected at present. The greatest advantage of electromagnetic heating in these areas is the rapid heating. For instance, one industrial component is going to be quenched, it is easy to make the industrial component temperature up to 1000 degrees with a few seconds of electromagnetic equipment. The die casting and casting methods of some low melting point metal are also being replaced by induction heating.