What is arc furnace

Electric arc furnace's introduction

Electric arc furnace is an electric furnace for smelting ore and metal at high temperature produced by electrode arc. When gas discharge forms arc, the energy is very concentrated, and the temperature of arc area is above 3000 ℃. For smelting metal, the electric arc furnace has greater process flexibility than other steelmaking furnaces, can effectively remove impurities such as sulfur and phosphorus, the furnace temperature is easy to control, and the equipment covers a small area, which is suitable for smelting high-quality alloy steel.

The industrial furnace that generates electric arc heating through metal electrode or non-metal electrode is called electric arc furnace. According to the form of electric arc, electric arc furnace can be divided into three-phase electric arc furnace, consumable electric arc furnace, single-phase electric arc furnace and resistance electric arc furnace. The furnace body of electric arc steelmaking furnace is composed of furnace cover, furnace door, tapping trough and furnace body. The furnace bottom and furnace wall are built with alkaline refractory or acid refractory. Electric arc steelmaking furnace is divided into ordinary power electric arc furnace, high power electric arc furnace and ultra-high power electric arc furnace according to the transformer capacity per ton of furnace capacity. Electric arc furnace steelmaking is to input electric energy into the electric arc steelmaking furnace through graphite electrode, and make steelmaking with the electric arc between the electrode end and the charge as the heat source. The electric arc furnace takes electric energy as the heat source and can adjust the atmosphere in the furnace, which is very beneficial to smelting steel grades containing more easily oxidized elements. Shortly after the invention of electric arc furnace steelmaking, it was used to smelt alloy steel and developed greatly.

With the improvement of electric arc furnace equipment and smelting technology and the development of electric power industry, the cost of electric arc furnace steelmaking continues to decline. Now electric arc furnace steelmaking is not only used to produce alloy steel, but also a large number of ordinary carbon steel. Its output accounts for an increasing proportion in the total steel output of major industrial countries.

Electric arc furnace's history

From 1888 to 1892, p.l.t.h é roult developed the alternative energy of coal by using the arc high temperature of electrode, and invented the industrial direct smelting electric arc furnace. At first, the electric arc furnace was only used for the production of calcium carbide and ferroalloy. It was not developed for steelmaking until 1906, so that the scrap can be recycled economically and on a large scale. The electric arc furnace converts electric energy into heat energy through the electric arc between the end of graphite electrode and the charge to melt the charge and complete the subsequent high-temperature metallurgical reaction. Because it uses electric energy and is convenient to adjust the atmosphere in the furnace, it can smelt various types of alloy steel including easily oxidized elements. With the development of electric power industry, the continuous improvement of process equipment and the improvement of smelting technology, electric arc furnace is more and more widely used, and its production capacity and scale are larger and larger. The maximum capacity of electric arc furnace was 100t in 1930s, 200t in 1950s and 400t in early 1970s.

Especially in the past 50 years, the technical performance of EAF has been gradually improved, and the production cost has decreased significantly. The proportion of EAF steel in European and American developed countries has exceeded 50%.

The development of modern electric arc furnace smelting technology advances with the times. From 1960s to 1970s, it was mainly to develop ultra-high power power supply and related technologies. High power electric arc furnace (HP) and ultra-high power electric arc furnace (UHP) were compared with general ordinary power electric arc furnace (RP). They are mainly distinguished by the transformer capacity per ton of furnace capacity, which has a higher and higher trend in recent years. This means that the heat energy input into the electric arc furnace per unit time is greatly increased and the melting time is significantly shortened, so as to improve the production capacity, reduce the electrode consumption, reduce the heat loss and reduce the electric energy consumption. As a result, the production capacity is further increased and the cost is also greatly reduced.

The high-pressure long arc operation, water-cooled furnace wall, water-cooled furnace cover, foam slag technology and the use of external heat source for melting have been widely used, as well as ladle refining and enhanced oxygen use. In the 1980s, the development of LF and EBT technology basically matured the modern EAF steelmaking process of EAF smelting and external refining. It is worth noting that since then, the focus of attention is no longer the way of DC or AC power supply, but the utilization of secondary combustion and flue gas sensible heat, that is, the preheating of scrap steel. Different preheating methods of scrap have produced different types of modern electric arc furnaces, including ordinary electric arc furnace preheating scrap with basket, flue shaft furnace with supporting claw, double shell electric arc furnace and Consteel electric arc furnace.

At present, the equipment and production technology of electric arc furnace are still developing.