Electric arc heat is mainly used in electric furnace steelmaking, and the temperature is up to 4000 degrees centigrade in the arc action area. Smelting process is generally divided into melting stage, oxidation stage and reduction stage. In the furnace, it can not only cause oxidation atmosphere, but also cause reduction atmosphere, so the efficiency of dephosphorization and desulfurization is very high.
The main materials used for iron are scrap steel, accounting for about 70%, in addition to the addition of molten iron, pig iron, direct reduction iron, hot pressing block and so on. The smelting time is longer, at least two times as much as the converter's smelting time. The furnace temperature is high and easy to control and regulate. The arc temperature of the arc furnace is as high as 3000 to 6000 degrees, and the furnace temperature is above 2000 C, which is much higher than that required by smelting the general steel. It can be used for smelting alloy steel and stainless steel which can not be smelted by converter.
The atmosphere in the furnace is easy to control and adjust. In the different stages of the smelting furnace, it can not only cause the oxidizing atmosphere, but also can cause the reducing atmosphere, the former is conducive to carbon and phosphorus, which is in favor of deoxidation, desulfurization, oxidation, recovery of alloying metal elements and control liquid steel composition. The electric furnace equipment is simple, the investment is few, the construction plant is fast, the area is less, and it is easy to control the pollution.
But due to the high temperature energy generated by the electrode in the short circuit to provide large power consumption, power consumption of about 350-600kwh smelting 1 tons; high hydrogen and nitrogen content in finished steel. Because under the action of the arc, the water vapor of the air in the furnace is dissociated, the hydrogen and nitrogen generated, such as entering the molten steel, will affect the quality of the steel. The arc is a "point" heat source, and the temperature distribution in the furnace is uneven. When the pool is calm, the temperature of each part of the molten steel is quite different. The existence of carbon electrode will increase the carbon of molten steel, which makes it difficult to smelt low carbon steel.
Waste steel is a kind of energy - carrying resource, and the use of scrap steel can save a lot of energy. In large iron and steel complex, mining, mineral processing, sintering, coking, iron making, steelmaking and rolling, energy consumption and pollution emissions are mainly concentrated before steelmaking process. The study shows that the energy saving is 60%, and the water saving is 40%.
Scrap steel is also an environmental resource. Compared with steelmaking with iron ore, the waste steel can be reduced by 86%, 76% and 97%, which is conducive to cleaner production and waste reduction.