Electric arc furnace's introduction - part 2

Working principle of electric arc furnace

The electric arc furnace is mainly composed of electrode holder, electrode, furnace cover, molten bath, furnace door, tilting cradle, hydraulic steel and other components. The furnace bottom and furnace wall are constructed of acidic or alkaline refractory materials. First, the electric energy is transmitted to the furnace through the electrode, and then the electrode and furnace charge are used to generate electric arc to raise the temperature in the furnace. Finally, the high temperature makes the ore metal melt.

Main features of electric arc furnace

Electric energy is the main energy source of electric arc steelmaking furnace. The electric energy is discharged and arced with the furnace charge through the graphite electrode to produce a high temperature of more than 2000~6000 ℃. The scrap raw materials are melted by means of arc radiation, temperature convection and heat conduction. In most of the time when the furnace charge melts, the high temperature heat source is surrounded by the furnace charge, and the heat loss caused by the high temperature waste gas is relatively small, so the thermal efficiency is higher than that of other steelmaking equipment such as converter. In addition, the electric heating is easy to accurately control the furnace temperature, and can be heated under any conditions such as oxidation atmosphere or reduction atmosphere, normal pressure or vacuum according to the process requirements.

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

Electric arc furnace steelmaking has strong adaptability to furnace charge. It uses scrap steel as the main raw material, but it can also use molten iron (blast furnace or cupola molten iron), sponge iron (DRI) or hot briquette (HBI), pig iron and other solid and liquid iron containing raw materials.

As the atmosphere in the electric arc furnace steelmaking furnace is controllable, the operation of slag adjustment or replacement is relatively easy, and the complex process operations at various stages such as melting, decarburization, dephosphorization, degassing, inclusion removal, temperature control, composition adjustment (alloying) can be completed in the same operating system. Electric arc furnace steelmaking can be produced intermittently, and production varieties can be flexibly changed within a certain range. In addition, modern electric arc furnaces can also use a large amount of auxiliary energy, such as injection of heavy (light) oil, pulverized coal, natural gas, etc. Therefore, electric arc furnace steelmaking process has strong adaptability, flexible operation and wide application.

The electric arc furnace can not only smelt high-quality steel with low phosphorus, sulfur and oxygen content, but also use a variety of elements to carry out alloying (including lead, boron, vanadium, titanium, rare earth and other easily oxidized elements) to produce various high-quality steel and alloy steel, such as ball bearing steel, stainless acid resistant steel, tool steel, electrical steel, heat resistant steel, magnetic materials and special alloys.

Although electric arc furnace steelmaking has many advantages, due to the problems of scrap steel and electricity price cost in China, electric arc furnace steelmaking cannot compete with converter steelmaking on ordinary steel and long line products. Electric arc furnace steelmaking only occupies a dominant position in the field of special steel production with small batch, multiple varieties and high alloy ratio.

At present, some short process electric furnace manufacturers in the world generally adopt high output power electric arc furnaces. In addition, the traditional classical three-phase operation process with reduction period has gradually been replaced by combined process technologies such as furnace refining, electric arc furnace and

Its public and auxiliary facilities and equipment are 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, and its capital construction has just started. The large-scale scrap recovery period has not yet come. In addition, China's power development is unbalanced, and the current electricity price is still at a relatively high stage. Therefore, the development speed of electric arc furnace steelmaking in China is limited, not as fast as that of converter steelmaking. Although the total amount of electric furnace steel is also increasing, the proportion of electric furnace steel output to the total steel output is decreasing year by year, which is contrary to the development trend of the world electric arc furnace.

With the development of power facilities and the accumulation of scrap resources in China, as well as the strengthening of environmental protection and mineral resources management, the development trend of electric arc furnace steelmaking in China will be enhanced. At that time, China's electric arc furnace steelmaking technology will be more comprehensive development.