Numerical Simulation Of Temperature Field And Pearlite Content In Horizontal Continuous Casting Of Cast Iron With Three Sprays Of Cooling

High strength duetile iron profiles are widely used,and in the production of horizontal continuous casting cast iron profiles,the production of high-strength cast iron profiles through three spray cooling processes is more environmental protection and effieient.However,due to the different effccts of production parameters on the quality of profiles during the production process,exploring production parameters through experimental methods consumes a lot of manpower and material resources,and using numerical simulation to explore production parameters is more convenient and effieient.This article mainly focuses on the modification of the heat transfer model between graphite sleeve and profiles,the influence of nozzle distance and spray cooling water pressure on the temperature field of continuous casting profiles,and the simulation and prediction of pcarlite content under three spray cooling processes.The main contents include:(1)The simulation range,boundary conditions and initial conditions arc determined,and the temperature field distribution of the profile is numerically calculated by the finite difference method.Optimize the numerical calculation of gap and heat transfer coefficient,improve the gap treatment method between graphite sleeve and profile,and reflect the uneven distribution of upper and lower gaps caused by gravity in the simulation results.Compared with the unmodified model,the simulation results were closer to the actual production situation.(2)By studying the cold and hot characteristics of the nozzle,it was found that the two factors that have the greatest impact on the three times of spray cooling arc the spray cooling distance and spray pressure.As the spray cooling distance increases,the area covered by cooling water increases,and the droplet velocity decreases,resulting in a decrease in spray cooling density and difficulty for droplets to pass through the gas film generated by the aporization of cooling water on the surface of the profile.Therefore,under certain water pressure conditions,the spray cooling distance should not be too large.When the spray cooling distance is too close,the cooling speed on the surface of the profile is too high,which can lead to the profile being prone to cracking.According to the research results of this article,the water pressure should be selected between 0.1～0.2MPa and the spraying distance should be selected between 160～175mm for tertiary cooling.(3)By analyzing the phase diagram of ductile iron eutectoid transformation and the growth kinetics of ferrite,the formation percentage of ferrite and pearlite during the eutectoid transformation process is described using the Avrami equation.When selecting a water pressure of 0.12MP and a spray cooling distance of Φ175mm Tertiary cooling numerical simulation were conducted on a 120mm profile.When the spray cooling length changes from 200mm to 1600mm,the pearlite content on the surface of the profile reaches a stable value of 41.3%at a spray cooling length of 600mm,while the pearlite content in the core does not change much compared to the non-spray cooling period.As the spray cooling length continues to increase,the pearlite content in the core of the profile begins to increase.When the spray cooling distance reaches 1200mm,the pearlite content in the core of the profile reaches its maximum value of 19.6%.(4)The water pressure is selected as 0.12MPa,and the spray cooling distance is selected as 175mm.After tertiary cooling process simulation on profiles with different radii of Φ100160mm,it was found that as the diameter of the profile increased,the pearlescent content in each part of the profile decreased,with the surface decreasing from 42.6%to 38.5%;From 31.2%to 18.2%at 1/2R;The core decreased from 26.5%to 16.7%.According to the simulation results,in order to achieve the maximum pearlite content,the spray cooling length for three sprays should be selected to be about 20 times the diameter of the profile.(5)By implementing the established model in Qt Creator 4.3.1,a numerical simulation software for horizontal continuous casting of ductile iron profiles with any radius can be obtained.The selection of three spray cooling process parameters under different production conditions can be analyzed based on the calculation results of the simulation software,saving manpower and material resources required for experiments.Meanwhile,due to the use of direct difference method,the calculation time is shorter compared to existing simulation software.The real-time temperature collection system combined with the temperature sensor of the production line can calculate and adjust the required production parameters in real time,which is conducive to intelligent control of the production process.By measuring the physical parameters of different production lines,this software can be applied to different cast iron horizontal continuous casting production lines.