PROCESS-CONTROL IN ELECTRIC STEELMAKING

Objective. Economical operation of high-capacity electric are furnaces requires extensive process control. Thermal control reduces energy costs and increases productivity. Metallurgical control contributes to reduction of raw material costs and quality assurance. The aim of the article is to illustrate how and to what extent technological know-how of electrical and metallurgical processes has to be introduced. Summary. The electric are furnace is the central point in the control of electric steelmaking. The state of the thermo-metallurgical process is observed by means of simple balance models based on measured parameters. According to the progress of the melt, the aims of control of the electrical parameters are limitation of mains disturbances, adjustment of an economically-optimal operating point or the evening out of the thermal loading on the walls. Apart from the electrical parameters, it may also be necessary to control sponge iron feed, the oxy-fuel burners, bottom purging, direct fume extraction as well as the formation of foaming slag and post-combustion. Metallurgical process control includes control of oxygen flow for decarburization and economically-optimal calculation of alloying additions, the feeding of which needs to be matched to the secondary metallurgy process.