Views:12 Author:Site Editor Publish Time: 2020-10-21 Origin:Site
The development history of electric arc furnace
French Heroult (P.L.T.Héroult) used the high temperature of the electric arc of the electrode to develop an alternative energy source for coal and invented the electric arc furnace for industrial direct smelting from 1888 to 1892. At first, the electric arc furnace was only used for the production of calcium carbide and ferroalloys. It was not until 1906 that it was developed for steelmaking, which enabled the economical and large-scale recycling of steel scrap. The electric arc furnace converts electric energy into heat through the arc generated between the end of the graphite electrode and the charge to melt the charge and complete the subsequent high-temperature metallurgical reaction. Because it uses electric energy, it is convenient to adjust the atmosphere in the furnace, so it can smelt various types of alloy steels including easily oxidizable elements. With the development of the power industry, the continuous improvement of process equipment and the improvement of smelting technology, the application of electric arc furnaces is becoming more and more extensive, and the production capacity and scale are getting larger and larger. The maximum capacity of the electric arc furnace was 100t in the 1930s, 200t in the 1950s, and 400t electric arc furnaces were put into production in the early 1970s.
Especially in the past 50 years, the technical performance of electric arc steelmaking furnaces has gradually improved, and the production cost has dropped significantly. The proportion of electric furnace steel in developed countries in Europe and America has exceeded 50%.
The development of modern electric arc furnace smelting technology advances with the times. From the 1960s to the 1970s, the main focus was on the development of ultra-high power power supply and related technologies. High-power electric arc furnaces (HP) and ultra-high-power electric arc furnaces (UHP) are relative to ordinary power electric arc furnaces (RP). They are mainly distinguished by the amount of transformer capacity per ton of furnace capacity, and there has been an increasing trend in recent years. This means that the heat energy input into the electric arc furnace per unit time is greatly increased, which shortens the melting time significantly, thereby increasing production capacity, reducing electrode consumption, reducing heat loss, and reducing power consumption. As a result, the production capacity is increased, and the cost is also Dropped significantly.
The high-pressure long-arc operation, water-cooled furnace wall, water-cooled furnace cover, foam slag technology, and the use of external heat source to support the ultra-high power electric arc furnace have been widely adopted. Ladle refining and enhanced oxygen use have also been adopted. In the 1980s, the development of LF and EBT technologies made the modern electric arc furnace steelmaking process of electric arc furnace smelting plus external refining basically mature. It is worth noting that since then, the focus of people's attention is no longer whether to use DC or AC power supply, but the use of secondary combustion and sensible heat of flue gas, that is, the problem of preheating of scrap steel. Different scrap preheating methods have produced different types of modern electric arc furnaces, which include ordinary electric arc furnaces that use basket scrap to preheat, flue shaft furnaces with claws, double-shell electric arc furnaces, and Consteel electric arc furnaces.
At present, the equipment and production technology of the electric arc furnace are still under continuous development.