Study On Temperature Integration Of HRB400E Steel Bar During Rolling And Cooling

During the rolling and cooling process of HRB400 E reinforcement,there are many factors that affect the performance of the final product.The establishment of temperature field model based on C++ language to simulate the temperature change of steel bar in the rolling and cooling process is of great significance for discovering problems in production line in advance,formulating solutions and optimizing the rolling production process.In this thesis,a small bar hot rolling production line in China was taken as the research object,and the HRB400 E steel bar produced by the factory was taken as the typical product.A rolling and cooling equipment model of the production line was established.Using the mathematical models of deformation heat,water cooling and air cooling,the temperature change of steel bars in the rolling and cooling process was analyzed,and the steel bar temperature prediction system in rolling and cooling process is developed to realize the function of offline simulation of steel bar temperature.In the simulation process,finite difference method was used to establish the temperature field model of the reinforcement,the temperature distribution of the reinforcement in each stage of water cooling and air cooling was calculated according to the curves fitting thermal conductivity,specific heat,density and other thermal physical parameters with temperature;For the deformation heat in the rolling process,the equivalent area method was used to calculate the strain,strain rate and deformation resistance in the rolling process in combination with the equipment parameters and process settings of box,oval and round rolling passes,obtain the plastic deformation heat generated during the steel bar rolling process,which is superposed with the original steel bar temperature field;according to the relevant cooling models such as jet impingement and laminar cooling,the heat transfer characteristics at different temperature ranges were analyzed,the mathematical model of heat transfer coefficient was established,the boundary conditions of the cooling process were determined,and the temperature changes of the surface layer,1/2position and the center position of the reinforcement during the cooling process were simulated in combination with the temperature field solution conditions;Verified with several groups of production data,the developed temperature prediction software can predict the on cooling bed temperature within ±15 ℃,and the prediction results are consistent with the actual production data,indicating that the temperature prediction software has good applicability.In order to improve the online control level of the small bar production line in the production process,the influence of the furnace outlet temperature and the process setting of the cooling water tank on the on cooling bed temperature was analyzed,and the process specification database was established to set the flow and header for the reinforcement cooling process with different grades and specifications;an online flow feedback regulation and control system was established to feedback control the flow of water tanks 2,3,6,7 and 8 on the production line according to the temperature of the on cooling bed,reduce the impact of various complex factors on the temperature of the on cooling bed in the production line,and provide technical support for optimizing cooling procedures and developing new brand products.