Research On Key Technique Of Cold Strip Temper Rolling Mill

Key technique of cold strip temper rolling mill is taken as researching object in this dissertation, theoretical and experimental study is done to the key issues during temper rolling process, which has great theoretical value and practical significance to master the development technology of temper rolling complete equipment.Cross breaks are formed on the surface of cold rolled and tempered strip during temper rolling, which influences the surface quality and mechanical properties of the temper rolled strip. By analyzing the loading process of strip at tensile rolls and formation mechanism and influencing factors of cross breaks, it was concluded that the main cause of cross breaks is the yield point elongation and the high tensile stress at the entrance of temper rolling mill. To establish rational elongation and tension system, and to request the quality of coming strip strictly, can avoid the generation of cross breaks, improve the surface quality of strip.The characteristics of temper rolling process are thin strip and little reduction, which make the stress state complex, so the error is heavy if predicting the rolling force by traditional model. Predicting the stress state coefficient by neural network model, however, can improve the precision of rolling force. In view of the slow variety of the mill characteristics during the rolling process, self adaptation deformation resistance model which accords with the characteristics of temper rolling process is adopted, and combined with the neural network model to predict the temper rolling force, the calculation is of high accuracy.Based on the temper rolling force model, the elongation control model is set up, and rolling force and tensile force are adopted as two manners to adjust the elongation. Besides, a new method is put forward to select the control mode, which is applied to Lingsteel 900mm temper rolling mill. The control effect is proved to be good.To increase the shape control ability of temper rolling mill, reduce the burden of bending force and abrasion of roll, adopts noncircular arc roll shape theory, takes the best shape of strip as object function, develops the roll contour optimization model of cold temper rolling mill. And apply the result on Lingsteel 900mm temper rolling mill, the result shows that the shape control ability increased, bending force and rolling force decreased, because the contact force becomes more reasonable, the abrasion of backup roll decreased correspondingly.To improve the mechanical properties of strip is the main purpose of temper rolling. In the condition when the coming steel is not variety, the mechanical properties is influenced by the reduction mainly. By tensile experiment, get the mechanical properties of steel under different reductions, and by regression analysis, gets the relationship between mechanical properties and reduction, it offer a theory gist for the set of elongation.