Roll Gap Control And System Design For Zone Cooling Load In 1580 Hot Strip Mill

With the continuous improvement of the quality requirements for hot rolled strip steel,the problem of edge thinning of silicon steel and pickled plates in the current 1580 production line urgently needs to be improved.Plate shape control methods such as roll bending and roll shifting can no longer meet the current production requirements.Roll thermal expansion is an important factor in the shape control of hot rolled strip,and the roll thermal crown directly affects the strip crown.Due to the constraints of cooling equipment and online temperature detection methods for rollers,traditional cooling equipment and temperature field models can no longer meet current needs,so it is very necessary to develop an online control system to achieve thermal crown of rollers.Firstly,based on the basic principle of zone cooling,a zone cooling control system for the 1580 hot strip mill F5 stand was developed.The beam structure adopts a stepped fivesection zoning design,and the upper and lower roller cooling beams adopt a synchronous control method in the same zone.This method controls the temperature difference between the upper and lower rollers from the original 7℃ to 12℃ within 5℃;Based on the control principle of zone cooling,a basic control strategy for zone cooling is proposed,with the goal of establishing a standard water volume database and the temperature field model as a soft sensor,to achieve online control of roll thermal crown.Secondly,a two-dimensional difference model of the temperature field of the hot rolling zone cooling roller was established.Based on production experiments,the temperature of the zone cooling roller was predicted by regressing the heat transfer coefficients of different water volumes.Based on the mechanism model,the influence of different water cooling curves on the thermal crown of rollers under specific operating conditions is analyzed in depth,and the control range of zone cooling on the thermal crown of rollers under different widths of strip steel is obtained;On this basis,the influence of various factors other than water cooling on the thermal crown of the roller is analyzed to improve the calculation accuracy of the thermal crown.Finally,considering roll wear and elastic deformation,a load gap calculation model is established,and the correctness of the model calculation is verified by actual data.On this basis,the influence of different water distribution on the load gap of the F5 frame was analyzed in depth,and the effect of F5-F7 collaborative control on the plate crown was simulated and analyzed.Based on the above research,the design and systematic analysis of the roller zone cooling system have been carried out,and the numerical simulation of the thermal crown and load roll gap of the zone cooling system has been carried out using a mechanism model for the actual working conditions on site.The actual effect shows that the system can not only improve the temperature difference between the upper and lower rollers and the lateral temperature difference between the rollers,but also reduce the hot roller time by regulating the water volume.