Product Thickness Control Optimization For Five-stand Cold Tandem Rolling Mills Of Bayi Steel

In recent years,with the reforms and developments of the areas that covered by expanding the scope of application has developed deeply,cold rolled products is more and more widely used.In this perfect backgroud,for cold rolled products has been put forward higher requirements.The thickness precision of the cold rolling strip is one of the most important quality index.Based on the actual conditions of Bayi,in order to eliminate the influence of the thickness fluctuation and improve product thickness precision,the factors affecting the accuracy of thickness of cold rolled products were analysed,and the corresponding improvement measures have been put forward.The main research contents and results are as follows:(1)We change the mill calibration strategy that be used before after the factors which influence the efficiency of the rolling mill were studied.The mill need to be calibrated when the rolls were changed at each time.For the first mill,we tuened the rolling force of calibration from 500 tons to 1000 tons,for the second mill to the fifth mill,the rolling force of calibration was also turned from 500 tons to 800 tons.The measure can eliminate the non linear part of the spring curve.At the mean time,the related parameters of the strip deformation resistance mode were optimized,which is more suitable for the actual situation.(2)Making the correlation coefficient of the electrical control program more suitable.Improving the responsiveness coefficient and the gain coefficient of the AGC in the entrance.Changing the control mode of the AGC of the last mill and adjusting the control mode of AGC from absolute to percentage.Improving the Mass Flow function:Enhanced the feedback function of the 2#thickness gauge to ensure the downstream mills flow balanced,so as to ensure the final thickness.(3)We used screw down ratio distribution method in the mathematical models.By this,the disadvantages of artificial random operation can be avioded.In order to eliminate the material thickness deviation and prevent strip running deviation fault accident,the first rolling deformation ratio should not be exceed 40%.Incerasing upstream mills,deformation ratio and the fifth mills,deformation rate properly can reduce work hardening of the strip and the rolling power,finally eliminate the thickness deviation.