Electric Arc Furnace: Principles, Classification and Application in Steelmaking
1. Definition and Advantages of Electric Arc Furnace
An electric arc furnace (EAF) is an electric furnace that melts ores and metals by high temperatures generated by electric arcs between electrodes. When an electric arc is formed via gas discharge, energy is highly concentrated, and the temperature of the arc zone exceeds 3000℃.
For metal smelting, electric arc furnaces feature greater process flexibility than other steelmaking furnaces. They can effectively remove impurities such as sulfur and phosphorus, allow easy control of furnace temperature, and occupy a small floor area, making them ideal for melting high-quality alloy steel.
Generally speaking, any industrial furnace heated by electric arcs generated by metallic or non-metallic electrodes is defined as an electric arc furnace.
2. Classification, Furnace Structure and Power Grades of EAFs
Classified by arc form: three-phase electric arc furnace, consumable electrode arc furnace, single-phase electric arc furnace and resistance arc furnace.
Furnace structure of steelmaking EAF: it consists of furnace roof, furnace door, tapping spout and furnace body. The furnace bottom and furnace walls are lined with basic or acidic refractory materials.
Classified by transformer capacity per ton of furnace volume: regular power EAF, high-power EAF and ultra-high-power EAF.
3. Working Principle of EAF Steelmaking
Electric power is delivered into the furnace through graphite electrodes for EAF steelmaking, and the electric arc formed between the electrode tips and furnace charge serves as the heat source for steel melting.
Using electric energy as the heat source, the furnace atmosphere can be adjusted freely, which brings outstanding benefits for smelting steel grades containing abundant oxidizable elements.
Shortly after the invention of electric arc furnaces, they were applied to alloy steel smelting and achieved rapid development.
4. Development Trend of EAF Steelmaking
With the improvement of EAF equipment, advances in smelting technology and the development of the power industry, the production cost of EAF steelmaking has kept declining.
At present, EAF steelmaking is not only used for alloy steel production but also widely adopted to produce ordinary carbon steel. The proportion of steel output from electric arc furnaces in the total crude steel output of major industrial countries keeps rising year by year.