Fundamental Research On Temperature Field And Microstructure Evolution Of Transient Sudden Change In Strip Continuous Rolling

As the latest generation of thin slab continuous casting and rolling technology,ESP endless rolling technology has the advantages of high integration,short flow,fast rolling speed,high production efficiency and short production cycle.Compared with the traditional thin slab continuous casting and rolling production line,the advantages are very obvious.However,this has also led to the acceleration of the roll wear of the finishing mill during the rolling process.In order to ensure the surface quality of the product,it is necessary to frequently stop and change rolls,which greatly reduces the production efficiency of the ESP production line.In order to make the production line non-stop to change rolls,improve production efficiency and shorten the cycle,so on-line roll change is proposed.During the online roll change process,the strip will produce a wedge-shaped zone,and the macroscopic and microscopic fields of the strip's wedge-shaped zone will be affected by many factors.Therefore,for the online roll change during the rolling process,this paper mainly studies the macroscopic parameters such as the temperature field and stress strain field of the strip wedge zone generated by the online roll change of the finishing mill,as well as the law of phase change during the cooling process of the strip wedge zone.Industrial experiments and applications provide reference value.Firstly,the Gleeble-3800 thermal simulation testing machine was used to conduct thermal expansion experiments and high-temperature thermal compression experiments to obtain the phase transition point and stress-strain curve of the material,and formulate the simulation and experimental process temperature based on the phase transition point.And analyze the stress and the relationship among the three variables of strain rate,strain and temperature is to prepare the material model for the next numerical simulation.Secondly,through the DEFORM-3D finite element analysis software,the numerical simulation models of the uplift rolling and the conventional rolling process were established respectively,and the material data was imported to carry out the numerical simulation of the whole process,focusing on the analysis of the uplift rolling.The change law of temperature field,stress field and strain field in the wedge zone of the strip provides data support for the actual process improvement.Thirdly,the mathematical model of the cooling process is summarized,and the model of the strip wedge zone cooling process is established through the DEFORM-3D HT module,and the temperature field and tissue field during the strip cooling process are simulated,and the temperature of the strip wedge zone is calculated.The law of field and organizational field changes was analyzed in detail.Finally,the equivalent substitution method was adopted to conduct thermal compression experiments with different deformations using the Gleeble-3800 thermal simulation testing machine.Through the observation of the microstructure of each sample,the average size of the high-temperature austenite grains and the quenched structure were obtained.The law of change further explains the evolution law of high-temperature grains and microstructure in the wedge-shaped zone of the strip.