Analysis of the state of structure and the basic parameters and indices of the operation of the large EAFs operating in the metallurgical plants in Russia

16 mln t steel were melted in 24 large electric arc furnaces (EAFs) in the metallurgical plants in Russia furnaces in 2011 at an annual capacity of 22 mln t of these furnaces. Among them, 17 EAFs are equipped with eccentric bottom tapping and operate with a “bog.” Three EAFs use the heat of effluent gases for heating of a charged scrap: a shaft heater at the Cherepovets metallurgical works (CherMK) and conveyer heating in the Ashinsk metallurgical plant. The DSP-120 furnace in CherMK has the best indices in Russia for operation with cast iron: electric power consumption of 260 kWh/t and a heat time of 49 min. Nine EAFs operating in metallurgical works use 20–30% liquid iron in a charge, which decreases the electric power consumption by 80–100 kWh/t. The working space and the EAF dimensions are important. A groundless decrease in the electrode failure diameter (1200 mm or smaller) leads to problems in the EAF transformer operation at a transformer power higher than 100 MVA and a secondary voltage higher than 1000 V. The performance of EAFs and the reliability of equipment operation depend on the working space height, the electric holder stroke, the distance between the axes of chair segments, the distance from the furnace axis to the axis of electric holder supports, and so on. Engineers in OOO NTP Akont determined the optimum sizes and relations between them for 120- to 130-t EAFs.