Temperature Field Simulation And Hot Deformation Behavior In Direct Rolling Of Bar And Wire

Energy conservation and emission reduction of the steel industry is an important part of solving energy consumption and environmental pollution problems in China.The process of direct rolling for bar and rod achieves the goal of energy conservation and emission reduction by eliminating the heating furnace before the rolling line.However,there are still problems such as low rolling temperature and large temperature difference between head and tail of continuous casting billet,which affects the effective implementation of the process.The direct rolling production line of a domestic steel plant is taken as the research object in this article,and the finite element model of this process is established to analyze the influence of various process parameters on the temperature field of continuous casting billet.Meanwhile,the article has researched on the hot deformation behavior of the middle and finish rolling stage of the direct rolling process.The main research works are as follows:(1)A finite element model of continuous casting and transport stage was established,and the temperature field of the casting billet was simulated and analyzed using this model.The actual temperature measurement data at the production site were compared with the simulation results of the temperature field in order to ensure the accuracy of the finite element model.(2)The temperature field during the continuous casting and transport was carried out by finite element simulation,and the effects of the casting temperature and the casting speed on the rolling temperature and temperature difference between head and tail of continuous casting billet were analyzed.With the increase of casting temperature and casting speed,the rolling temperature of billet increases,the temperature difference between head and tail of billet decreases,and the thickness of the solidified shell at the exit of the mold decreases.Under the current process conditions,the maximum allowable casting temperature is 1560? and the maximum allowable casting speed is 2.6m/min in order to ensure safe production(3)A Finite element simulation was performed for the rough rolling stage,and the influence of the rolling time into the mill was analyzed.Analysis shows that extending the rolling time into the mill can reduce the temperature difference between head and tail of continuous casting billet.(4)The cooling device installed at the exit of the roughing mill was studied,and the influence of the cooling water flow density and the length of the cooling device was analyzed.The analysis shows that the strategy of cooling water flow density with"head weak tail strength" is used at the exit of the rough rolling mill,which can ensure that the cross-section temperature is uniform along the length direction during the middle rolling stage,and the lengthening of the cooling device is helpful to ensure this temperature uniformity.(5)The hot deformation behavior in the middle and finish rolling stages of the direct rolling process was studied,and the influence of the hot deformation parameters on the microstructure and properties of the material was obtained.The results show that when the deformation temperature decreases,the deformation rate increases,and the amount of deformation increases,the grains are refined and the structure is uniform,the ferrite content increases,and the pearlite content decreases.The research work and main conclusions in this article provide basic ideas and basic data for solving the problems of low rolling temperature and large temperature difference between head and tail of continuous casting billet in the direct rolling process.It can promote the further promotion and application of this process in iron and steel enterprises,and then promote the energy conservation and emission reduction of iron and steel enterprises.