The Main Technological Process of Electric Furnace Steelmaking

After crushing and sorting the recycled scrap steel, it is preheated and added to the electric arc furnace. The electric arc furnace uses electric energy as energy to melt the scrap steel, remove impurities (such as phosphorus, sulfur) and tap the steel, and then obtain it through secondary refining. Qualified molten steel, and then the molten steel is solidified and formed into a billet by continuous casting, and finally becomes a steel product through the rolling process.

Electric furnace steelmaking is a high -temperature melting ore and metal electric furnace generated by the electrode arc. When the gas discharge forms an arc, the energy is very concentrated. The temperature of the arc area is above 3000 ° C. For melting metals, the arc furnace is more flexible than other steelmaking furnaces. It can effectively remove impurities such as sulfur and phosphorus. The area is small, suitable for the melting of high -quality alloy steel.

Electric furnace steel is mostly used to produce high-quality carbon structure steel, tool steel and alloy steel. This type of steel is excellent and uniform. When the carbon content is same, the strength and plasticity of the electric furnace steel are better than the flat furnace steel. The electric furnace steel uses similar steel scrap steel as the main raw material, and also uses sponge iron instead of some scrap steel. Adjust the content of chemical ingredients and alloy elements by adding iron alloys.

The electric furnace with scrap steel as the raw material is less than the investment in infrastructure than the blast furnace -to -furnace method. At the same time, due to the direct restoration of the development, it provides most of the scrap steel for the electric furnace. Therefore, the electric furnace steelmaking has been greatly promoted. There are about 1,400 large electric furnaces in the world, and the electric furnace is developing towards large, ultra -high power, and automatic control of electronic computers. The maximum electric furnace capacity is 400 tons.

Scrap steel is the main material of electric arc furnace steelmaking. The quality of scrap steel directly affects the quality, cost and electric furnace productivity of steel. Therefore, there are some requirements for scrap steel:

l  The surface of the scrap steel should be cleaned and rusty. Due to the debris such as sediment in the waste steel, the conductive performance of the furnace material will be reduced, the melting time will be extended, and the phosphorus effect of the oxidation period will also affect the phosphorus effect and erosion of the lining. When the scrap steel is severely corrosive or when it is stained with oil, it will reduce the income from steel and alloy elements, and increase the hydrogen content in steel.

l  Waste steel must not be mixed with non-ferrous metal, such as lead, tin, arsenic, zinc, copper and other non -ferrous metals. The density of the lead, low melting point, insoluble in steel liquid, easy to deposit in the gap in the bottom of the furnace, cause leakage accidents. Tin, arsenic and copper, it is easy to cause steel and crispy.

l  Sealing containers must not be mixed in scrap steel, flammable, explosive and poisonous to ensure safe production.

l  The chemical composition of scrap steel should be clear, and the content of sulfur and phosphorus should not be too high.

l  The size of the scrap steel should not be too large (the cross -sectional area should not exceed 150mm × 150mm, and the maximum length should not exceed 350mm). The raw iron is generally used to improve the amount of carbon distribution of the furnace in the arc furnace steelmaking, and usually does not exceed 30%of the furnace material.