Electric Arc Furnace: Main Characteristics of Electric Arc Furnace

2022年4月28日星期四

Main Characteristics of Electric Arc Furnace

Electric energy is the main energy source in electric arc furnaces. Electrical energy is produced by arc striking with graphite electrode and charge-discharge, which can produce high temperature over 2000 ~ 6000 C. The scrap steel material is melted by means of arc radiation, temperature convection, and heat conduction. For most of the time when the charge is melted, the high-temperature heat source is surrounded by the charge, so the heat loss caused by the high-temperature exhaust gas is relatively small, so the thermal efficiency is higher than other steelmaking equipment such as converter. In addition, electric heating can easily and accurately control the furnace temperature and can be operated under any conditions such as oxidation or reduction atmosphere, atmospheric pressure, or vacuum according to process requirements.

The process flow of electric arc furnace steelmaking is short, the equipment is simple, the operation is convenient, the pollution is easy to control, the construction investment is small and the area is small, so it does not need to rely on the complicated iron-making system like converter steelmaking.

Electric arc furnace steelmaking has strong adaptability to charge. It mainly uses scrap steel as raw material, but also can use solid and liquid ferrous materials such as hot water (hot metal for blast furnace or iron carbide), sponge iron (DRI), or hot-pressing block (HBI), pig iron, and so on.

Because the operation of a controllable atmosphere, slag adjustment or replacement in electric arc furnace is easy, and the complex process operations of melting, decarbonization, dephosphorization, degassing, inclusion removal, temperature control, composition adjustment (alloying), and other stages can be completed in the same operating system. The electric arc furnace steelmaking can be produced discontinuously and the production varieties can be changed flexibly within a certain range. In addition, modern electric arc furnaces can also use a lot of auxiliary energy, such as injecting heavy (light) oil, coal powder, natural gas, etc. Therefore, the electric arc furnace steelmaking process has strong adaptability, flexible operation, and wide application.

The electric arc furnace is not only capable of smelting high-quality steel with low content of phosphorus, sulfur, and oxygen but also can be alloyed with various elements (including oxidizable elements such as lead, boron, vanadium, titanium, and rare earth) to produce various high-quality steels and alloy steels, such as ball-bearing steel, stainless acid-resistant steel, tool steel, electrical steel, heat-resistant steel, magnetic material, and special alloys.

Although electric arc furnace steelmaking has many advantages, it is impossible to compete with converter steelmaking on Pudong Steel and long-term products due to the problems of waste steel and electricity price in China. Electric arc furnace steelmaking only plays a dominant role in the special steel production field with small-batch, multiple varieties, and high alloy ratios.

At present, some short-process electric furnace manufacturers in the world generally use electric arc furnaces with high output power. In addition, the traditional three-stage operation with reduction period has been gradually replaced by combined processes such as off-furnace refining, electric arc furnaces, and so on.

The equipment of public and auxiliary facilities is also more perfect and reasonable. The proportion of electric furnace steel output in the world is increasing year by year.

China is a developing country, capital construction has just begun, a large-scale scrap steel recovery period has not yet arrived, China's power development is not balanced, and the current electricity price is still in a relatively high stage. Therefore, the development speed of electric arc furnace steelmaking in China is limited, and no converter steelmaking develops rapidly. Although the total quantity of EAF steel is also increasing, the proportion of EAF steel output to total steel output decreases year by year, which is contrary to the development trend of EAF in the world.

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