Study On Head Warping And Control For Plate Rolling

From the last century, after the application of computer control technique on the production of steel rolling, AGC, AFC, velocity measure by laser and intelligentized quality measure on line were published, this make the rolling production achieve a higher level. But the study on head warping has not been solved all along. Therefore, this paper focused on the head warping during the process of rolling, and studied the mechanism of the head warping during plate rolling. The research exploited a detect equipment based on the machine vision. In the end, the paper brought forward the solution and the control method. The study can prevent the disservice produced by the head warping, increase the quality of the production and enhance the rivalrousness. It has important value in theory and practical meaning. The content of the paper including:The paper proposed the rolling force model and rolling torque model for asymmetrical rolling. Using slab method deduced the differential equation of static equilibrium for asymmetrical rolling. Using Tresca plasticity conditions and Mises plasticity conditions resolved the rolling force per unit distributing on deformation zone respectively, and then presented the rolling force model calculate model of asymmetrical rolling. In addition, the paper proposed the rolling torque model and analyzed the reason of low precision when compute the asymmetrical rolling using tradition rolling parameters. Using the new model, the paper analyzed the influence on the rolling force distribution by different roll diameter, velocity and friction.The causation of head warping has been analyzed. During the analysis, the difference of velocity, diameters, and temperature, height of rolling line, offset of the rolls, gravity, and the difference of the motors have been considered. It also established the model of the correlative relation.Based on the requirement of plate rolling technology, different rolling schedules for head warping control were researched. The influence of reduction on the direction and degree of head warping has been analyzed. Based on the schedule of method-load coordination, a new draft schedule calculation was put forward for head warping control. The paper designed head warping detect system based on the machine vision. Using near infrared spectroscopy technology, the paper exploited head warping detect system based on the machine vision. The system can run accurately and steadily, and can eliminate the environmental impact on the detect target.Based on the characteristic of near infrared image, some algorithm has been found for image processing. For better marginal information, median filtering was used in wavelet to smooth the high frequency domain. Then coefficient enhance was used to enhance the high frequency details. It can remove the impulse and the Gaussian noise and conserve the marginal information by this algorithm. Base on the character of multiple peak of the near Infrared image of the Histogram, a kind of algorithm based on mathematical morphology was proposed. It can get distinct marginal information and little noise.The main drive system and its model were analyzed to resolve the head warping. The method was founded for head warping control were ski-end parameter setting and response characteristics adjusting. The parameters of speed control system have been emulated and optimized.Based on the character of plate rolling, the head warping control system was established. The measured system is needed for this system. And the measuring information was used to feedback to the system for controlling. In this system, pre-setup and feedback were united for better precision.The study has important meaning on preventing and restraining heading warping during the produce of plate rolling. It can ensure the safety of the equipment and increase the ratio of sawn goods. The result of the study is also applicable of the control of head warping during rough rolling process of strip rolling.