electric furnace, heating chamber with electricity as the heat source for achieving very high temperatures to melt and alloy metals and refractories. The electricity has no electrochemical effect on the metal but simply heats it.

Modern electric furnaces generally are either arc furnaces or induction furnaces. A third type, the resistance furnace, is still used in the production of silicon carbide and electrolytic aluminum; in this type, the furnace charge (i.e., the material to be heated) serves as the resistance element. In one type of resistance furnace, the heat-producing current is introduced by electrodes buried in the metal. Heat also may be produced by resistance elements lining the interior of the furnace.

Electric furnaces produce roughly two-fifths of the steel made in the United States. They are used by specialty steelmakers to produce almost all the stainless steels, electrical steels, tool steels, and special alloys required by the chemical, automotive, aircraft, machine-tool, transportation, and food-processing industries. Electric furnaces also are employed, exclusively, by mini-mills, small plants using scrap charges to produce reinforcing bars, merchant bars (e.g., angles and channels), and structural sections.