The Shape Model Of Eight-high Cold Rolling Mill And Its Research On Control Technology

In recent years,with the rapid development of the national economy,the demand amount of cold rolled sheet is getting bigger and bigger.The eight-high rolling mill independently developed by China has been favored by the relevant private iron and steel enterprises because of its high stiffness,less investment and short construction period.Because the development time of the eight-high rolling mill compared with four-high rolling mill or six-high rolling mill is short,scholars at home and abroad mainly focused on friction coefficient,reduction control,roll shape configuration,and so on.There is less research on the shape model of eight-high rolling mill.The setting of the shape parameters mainly depends on the online testing of the operators and is lack of theoretical support.The precision and stability of shape control are often poor.For this reason,this paper will take a eight-high cold rolling mill of a cold rolling factory as the research object,aiming at studying the shape problem of eight-high cold rolling mill in depth.First,from the two aspects of the metal plastic deformation model and the elastic deformation model of the roll system,a shape prediction model suitable for eight-high cold rolling mill was developed by fully combining the feature of equipment and processof eight-high rolling mill after the coupling between the two models.Meanwhile,the corresponding software for shape prediction has been developed.Secondly,a set of mathematical model of the influence of bending roll and roll shift on the shape of eight-high cold rolling mill was built and the influence of bending roll and roll shift on shape of eight-high rolling mill was quantitatively analyzed.The radial adjustment principle of the backup roll of eight-high rolling mill were analyzed.The corresponding continuously variable crown model of backup roll was given.On this basis,a model suitable for the influence of the backup roll on shape of eight-high rolling mill has been established.In addition,the typical specifications were chosen and the influence of the backup roll shape,the middle roll crown and the work roll crown on the shape was quantitatively analyzed.Then,in order to make full use of shape control ability of mill,starting from the three aspects of the comprehensive setting of roll shift,the comprehensive setting of bending roll force and the on-line adjustment of left and right bending roll force,a complete set optimization model of bending roll and roll shift of eight-high cold tandem rolling mill was presented.From the two aspects of the rack stretch preset of backup roll and its' the on-line adjustment,a roll shape optimal setting model of eight-high rolling mill based on radial adjustment of backup roll shape was proposed.Finally,the model of shape prediction and comprehensive setting model of bending roll and roll shift were applied to the production of eight-high cold rolling mill in cold rolling factory.Good results were achieved after the applications in the field.These technologies have the further value of popularization and application.And based on the eight-high rolling mill,the corresponding software for optimal setting of backup roll shape was developed.Besides,the quantitative analysis of the effect of the optimization of backup roll shape was carried out.It provides a useful reference for the shape control of the eight-high rolling mill.