Electric arc furnace (EAF) is commonly used in steel industry and plays an indispensable role in the production of specialty steel. EAF is a kind of furnace that utilizes high-temperature electric arc to melt baser metals, alloy chemicals and scrap steel. During the process, molten metal is purified and formed into required steel products.
The electric arc furnace has three distinct parts: melting chamber, roof, and electrodes. The melting chamber is usually cylindrical steel that is lined with refractory materials for insulation and to protect the vessel from the extreme temperatures generated by the arc. The roof sits on the top of the EAF and is used to protect the workers from the heat and light generated from the arc. The electrodes are comprised of graphite or copper and are used to generate an electric current that provides the energy to forge and shape the molten steel.
In its simplest form, the EAF is a batch melting device that melts a charge composed of scrap steel and alloying elements. When the electric arc is turned on, a short-circuit is created between the two electrodes, which instantly generates an extremely high temperature. This arc, which averages 10,000°F to 12,000°F (5,538°C to 6,649°C) is so intense that it can easily melt the steel scrap and other alloying elements within the EAF.
The molten steel is then refined through a process of oxidation. Pure oxygen is injected into the furnace and reacts with the impurities in the steel, burning them off. This process eliminates unwanted elements ranging from small amounts of nitrogen and sulfur to large amounts of slag and other materials. The waste products are then skimmed off the top of the molten steel and discarded, leaving pure steel behind.
The final stage of electric arc furnace refinement is the addition of additives or alloying elements. These added metals can completely change the characteristics of the steel from its original state. Alloy elements like chromium, molybdenum, nickel and vanadium are often added to increase the strength, hardness and corrosion-resistance of the steel.
The result of these processes is a refined steel product with improved properties for a variety of specific applications. The products range from sheet metal for use in auto manufacturing to stainless steel for kitchen appliances. Cold rolled steel and flat-rolled steel are two of the most commonly produced products, but virtually any kind of steel can be processed in an electric arc furnace.
Electric arc furnace is an invaluable tool of the steel industry. It provides precise control over refining and alloying elements, allowing manufacturers to produce precise grades of steel to meet the exact specifications of their customers. The technology found in EAFs also allows manufacturers to reduce waste, costs, and energy consumption while producing a higher quality product.
