Multi-objective Optimization Of Continuous Casting Cooling Process Based On Differential Evolution Algorithm

The secondary cooling water has a considerable influence on the quality of the slab.The unreasonable secondary cooling system can result in many defects of the slab such as internal crack and center segregation and so on.As a result,it has great practical significance to optimize the secondary cooling zone water and get reasonable continuous casting secondary cooling water distribution parameters.This paper take a steel billet caster as the subject,the main work is as follows:1.The slab solidification heat transfer model is established.Slab solidification heat transfer model is an effective tool to simulate slab solidification process and optimize parameters.On the basis of characteristics of slab solidification heat transfer model,the physical parameters which are needed for the model is analyzed,selected and calculated.A two-dimensional heat transfer model is established,which is solved by the control volume method.2.The influence of process parameters to solidification process is analyzed by numerical simulation.On the basis of heat transfer model,the influence of casting speed and degree of superheat to slab solidification(temperature field,shell thickness)is analyzed by numerical simulation.Multi-objective optimization objective function are established combining the metallurgical criterion.Above all provide theoretical basis and data support for the following secondary cooling water distribution parameter optimization.3.The continuous casting secondary cooling optimization algorithm based on the differential evolution algorithm is developed.The differential evolution algorithm is applied to solve the problem of continuous casting secondary cooling optimization.The key problems in the multi-objective optimization is discussed,which are the maintainess of population diversity and weighting processing of optimization objective function.The Pareto-optimal solutions controlled by crowding distance improved the diversity of solutions.The analytic hierarchy process is used to weight each optimization objective functions.Optimization results show that this algorithm can balance the convergence and diversity of the Pareto optimal solutions set and improves the consistency of the algorithm search.4.Continuous casting secondary cooling system is established.The developed optimization algorithm is applied to solve the problem of continuous casting secondary cooling optimization.The water flowrate is optimized to fit out the curve about casting speed and water flowrate.Continuous casting secondary cooling water distribution parameter is determined.Reasonable continuous casting secondary cooling system is built.Finally,the research result was applied to practical production,the quality of steel products quality has improved significantly,continuous casting production process has improve and upgraded effectively.