Brief Introduction of Mathematical Model of Hot Strip Rolling for Packing Steel Strip

Brief Introduction of Mathematical Model of Hot Strip Rolling for Packing Steel Strip
　　From the description of computer control functions in Chapter 1, the control functions of hot strip rolling can actually be divided into four categories:
　　 (1) Setting of rolling mills and other equipment (including related functions for setting services), including process automation level data tracking, actual value collection, setting model, model self-learning and basic automation equipment Control (position, speed control, used to finalize the positioning of the set value).
　　 (2) Rolling parts transportation, including basic automation level position tracking, logic inspection, sequence control and control of each roller table.
　　 (3) Product quality control, which mainly includes thickness accuracy, shape accuracy, temperature (final rolling temperature and coiling temperature) accuracy and width accuracy.
　　 (4) Other functions, including data communication, man-machine interface and control of auxiliary facilities (hydraulic station, lubrication station, quick roll change, etc.).
　　 The mathematical model involved is mainly the function of setting calculation and quality control. In order to achieve the setting and quality control of hot strip rolling mills, the following mathematical models will be involved:
　　 (1) Temperature drop model. Temperature is the most important parameter for hot rolling. The temperature drop model is not only used for final rolling temperature and coiling temperature control, but also an important model in the setting model. Temperature prediction has a direct impact on rolling force prediction. Therefore, the rolling temperature of each rolling mill must be accurately predicted.
　　 (2) Rolling force model. Due to the bouncing phenomenon during strip rolling, the rolling force variation will be the main factor affecting the thickness accuracy. The rolling force model is also the main factor of whether the rolling mill setting is correct (whether the belt can be threaded smoothly). The rolling force model includes the deformation resistance model, the stress state model of the deformation zone and so on.
　　 (3) Front sliding model. The forward slip model is used to calculate the speed setting of each stand of the continuous rolling mill.
　　（4）Expanded model. The widening model is used for rough rolling setting (flat roll and vertical roll setting).
　　 (5) The model of the rolling mill. The model of the rolling mill (referred to as the basic equation in this book) includes the bounce equation, the shape of the roll gap, and so on. The latter will involve hot roll model and worn roll model.
　　 (6) The amount and tension model (equation) between the racks.
　　The majority of models used for setting calculations are static models. Taking into account the large variable range of variables and the strong computing power of the minicomputers used in the process automation level, they are all in full form and directly solved by nonlinear algebraic equations.
　　 For quality control, on the one hand, its variable range is small (transferred around the set value), and the quality control is undertaken by the basic automation level controller, and the control cycle of the controller is very small (10-30ms). Therefore, the incremental form is adopted.