The Fuzzy Expert System For Assessment Of EAF Melting States

EAF is one of the most important steel-making equipments in the area of metallurgy. Scrap steels are used as raw materials. They are melted and heated in electric arc furnace and become qualified molten steel both in temperature and composition. Accurate assessment of EAF melting states can guide the production, which can shorten the smelting time, reduce energy consumption and increase productivity.The development of EAF steel-making and smelting technics is introduced based on massive papers in this thesis. According to the characteristics of smelting process and expert experience, a method for assessment of EAF melting states based on the fuzzy expert system is proposed in this paper.During the EAF steel-making process, the EAF melting states are composed of igniting arc stage, inserting well stage, main melting stage and temperature-rising stage. Since the EAF hearth temperature can not be continuously measured, several indirect methods are adopted to assess the melting states of EAF in the thesis, such as arc voltage, arc current, electric input rate, electrode's position and smelting time and so on. Since the EAF melting process is very complex and the difference among each melting state of EAF is not obvious, a fuzzy expert system for assessing EAF melting states is established in this thesis. Several different methods are combined to get more accurate assessment of EAF melting states through the fuzzy expert system. Because there are also some abnormal situations in the smelting process, the weight matrix of the fuzzy expert system should be adjusted according to relevant situations.Finally, the EAF fuzzy expert system is implemented and some simulations are carried out. The simulation results prove the validity of the proposed method.