Structure modification and constant remelting speed control of a 120-t three-phase electroslag furnace

The traditional large electroslag remelting furnaces have many shortages, such as high short-network impedance and inductance, long maintenance time for electrode replacement, low stiffness of driveline, and low control accuracy of remelting speed. The present research was aimed to solve these problems through structure modification and constant remelting speed control for a 120-t electroslag remelting (ESR) furnace. Based on the technique of three-phase double electrodes in series, the short-network system and the structure of the 120-t ESR furnace were improved; and a continuous feeding system for the self-consumption electrode was proposed. A self-designed fully hydraulic driveline system with three degrees of freedom was successfully applied to the 120-t ESR furnace. An electrode auto-replacement system and the S-style speed-control curve of electrode-feeding system were designed on the basis of the soft measurement/sensing model on the remaining electrode length so as to obtain a high accuracy control system for constant remelting speed. The experiment products showed good surface quality and cross-sectional results, indicating good system control, and verifying the effectiveness of the structure modification of the furnace.