Research On Online Prediction Model Of Temperature Change Of Hot Continuous Bar Rolling

Bar play an important role in the economic development of our country,especially in the manufacturing,construction and transportation industry.With the development of rolling technology,people not only require high dimensional precision,good organization and performance,and excellent product quality of rods and wires,but also require cost-saving and productivity improvement as much as possible.The change of temperature in bar rolling process is closely related to the quality and microstructure properties of the rolled piece,so it is of great significance to study the temperature change.In order to achieve online control,this paper bases on fast calculation,deduces the formula of temperature field through heat transfer analysis,uses C++ assembly language to compile the calculation module of forecasting system,and combines VB design visual interface.The on-line prediction system for temperature change of hot bar rolling is developed.First,this paper describes how to quickly and accurately calculate the temperature change during rolling around the equivalent model of the temperature field,the equivalent strain and the spread calculation.The equivalent model of the temperature field equates other shapes to circles in consideration of the area and the heat dissipating surface area.The three-dimensional calculation model is simplified as a one-dimensional model,which greatly simplifies the calculation,improves the calculation speed,and ensures the accuracy.In the equivalent strain,the method of intersecting area is chosen,which eliminates the step of the equivalent rectangle,and also increases the speed and ensures the accuracy.The spread calculation calculates the correct empirical formula based on the different hole types and validates the correctness of the results by finite element simulation.Secondly,based on the theory of heat transfer,combined with the finite difference method,the temperature field calculation models of air cooling,rolling and water cooling in the hot continuous rolling process are deduced.The calculation of the process parameters,such as deformation resistance,rolling force and rolling torque,is also studied.Finally,according to the research on the fast calculation and the deduced temperature field calculation model,the online prediction model of the temperature variation of hot strip rolling was realized.And the calculation results of temperature change,rolling force and rolling torque are compared with the measured data according to an example of a bar production line.And the computation time before and after equivalent calculation of the temperature change model is compared through the time program,which fully verifies the accuracy and rapidness of the on-line prediction model of the temperature change of the bar continuous hot rolling.