Automatic Steelmaking Control System Of Continuous Feeding EAF

Effective operation,high efficiency,high quality,energy saving and low cost operation are very important for steel industry.Experience at home and abroad shows that adopting new process,new technology,new equipment and automation is an effective way to meet this requirement.The continuous feeding EAF adopts new technologies such as scrap preheating,remaining steel operation,foam slag submerged arc,high intensity carbon spraying and oxygen supply,so as to provide the foundation for automatic control of smelting process.This thesis takes 1#EAF of Wuhang stainless steel products corporation as the object.The application research of continuous charging EAF automatic steelmaking technology is carried out.The main contents are as follows:(1)Based on the analysis of continuous charging EAF equipment and smelting process,the strategy of subsection control is put forward.The smelting process is divided into feeding melting stage,heating refining stage and tapping stage.According to the technological tasks of different smelting stages,the main control tasks of scrap steel feeding and foaming slag are determined as steelmaking automation system.And according to different control tasks,the framework of the automatic steelmaking system is designed,and the control objectives of each control task are defined.(2)The goal of slagging control task is to achieve the good burying effect on the basis of satisfying the demand of oxidation and removing the amount of impurities needed to remove impurities.Based on the analysis of the relationship between the degree of arc and the waveform of arc voltage and current a foam slag index based on the distortion degree of arc voltage and current waveform is established to evaluate the effect of submerged arc.According to the foaming slag index,fuzzy control method is adopted to achieve the control of carbon emission.On this basis,based on the principle of carbon oxygen balance,the ratio control method is adopted to realize the control of oxygen blowing.(3)The aim of scrap feeding control is to stabilize the temperature of molten pool,and then stabilize the reaction rate of carbon and oxygen,so as to avoid large boiling in the heating stage.Considering that it is difficult to measure the molten steel temperature in real time,based on the support vector machine regression method,the molten steel temperature prediction model is established to realize the real-time prediction of molten pool temperature.On this basis,the feeding speed controller is designed.Smith prediction method is used to solve the problem that the control effect is not ideal due to the lag between the feeding speed and the temperature of the molten pool.(4)In the overall design of steelmaking automation system,based on the design of hardware and software structure of the control system,according to the process requirements of continuous charging electric arc furnace,the control software package of steelmaking automation system is designed,including slag making control,scrap feeding control,alloy feeding control,smelting report and other functional modules.The automatic steelmaking system of continuous charging EAF improves the automatic control level of EAF smelting process.It can effectively restrain the fluctuation of production and quality due to different operators.It is significant to realize the information,automation and standardization of EAF steelmaking process.