Research On Optimizing Process Control Of Continuous Casting In Endless Continuous Casting And Rolling Line (ECR)

This dissertation is a part of the important and special project'long products continuous casting and rolling line'(Item No.:2001BA306B03) sponsored by Ministry of national science and technique. Based on a long products continuous casting and rolling line aboard, and focused on some key problems of process control, following research works have been done.1 In the background of a real continuous casting machine, mathematical models of mold level control are set up, which include effects of ladle on tundish and mutual effects of multiple nozzles.2 Comparison and research on strategy of mold level control are made. Intelligent hybrid PID and fuzzy control is a kind of control based on expert knowledge which inherits the advantage of PID and gets experience of artificial intelligence. Simulation tests show that intelligent hybrid PID and fuzzy controller can carry out mold level control at steady and unsteady situation. The system with intelligent controller can work very well at turbulence of clogging and unclogging. Rules of fuzzy control can be added and improved in practice continuously. Design and implement of fuzzy control is simple and easy.The field test of the mold level control system with intelligent hybrid PID and fuzzy control has been done.The result of test shows that the accuracy of system control can reach less than 3mm, equals to the result of an imported device.3 From the view point of control, analysis and research on heat exchange and thermal balance, effects of the first cooling, the secondary cooling, rules of control are made. This is essential preparation for ECR caster design and temperature control. Considering the characteristic of ECR caster, mathematical model of bloom temperature field is set up, and the equations are solved with finite difference method to simulate the process of bloom solidification.Solidification characteristic of liquid steel in mold at high casting speed is studied with numerical simulation, and rule of heat flux distribution in mold is proposed.4 In guide of technological and metallurgical constraints to bloom cooling, using the ability of GA to optimize in whole range,heuristic GA method to optimize cooling parameters in bloom casting is set up to reach setting target temperature as closely as possible with the most minimum water flow rate. This work sets up initial rules for ECR...