Effect of the method of estimating the mass of ferriferrous residue in EAF on the course and performance of smelting of stainless steel

The article calculates the end-to-end mass balance for smelting 08Х18Н10Т steel in an arc steelsmelting furnace. The influence of ferrous residue (swamp) from the previous smelting of low-alloy metal on the performance of smelting high-alloy stainless steel (consumption of ferroalloys and master alloys, specific gravity of waste at the casting stage) is considered. A comparative analysis of methods for estimating the mass of ferrous residue in EAF from the previous smelting of low-alloy steel during the smelting of stainless steel was carried out. It is shown that a simplified method for estimating the mass of ferrous “swamp” in an EAF, based on a fixed level of loss of metal components during the smelting of the semi-product in a furnace, gives unreliable results in which the mass balance is upset. The method for estimating the mass of the “ferrous” residue in the furnace from the previous smelting of low-alloy steel, using the assumption of a constant mass of nickel in the metal during smelting, gives reliable results that correspond to the practice of stainless steel production. It has been established that one ton of ferrous “swamp” leads to dilution of the charge components and a decrease in the concentration of nickel by 0.066% and chromium by 0.125% in the intermediate product. This causes an increase in the consumption of additional materials at the stage of out-of-furnace processing: ferrochrome by 2.9 kg/t and metallic nickel by 1 kg/t of semi-product released from an electric arc furnace. This also leads to an increase in waste at the casting stage in the form of overflows and under-oils by 0.85 kg/t of semi-product chipboard.