Numerical Simulation Of Secondary Spray Cooling In Horizontal Continuous Casting Of Cast Iron

Due to its excellent performance,cast iron horizontal continuous casting profiles have become increasingly widely used in society,and the market demand for cast iron profiles is also increasing.In order to meet the increasing market demand and increase the production efficiency of cast iron,secondary spray cooling is added to the billet after the crystallizer is produced to accelerate the solidification of the billet.On the basis of safe production,the drawing speed of the billet is increased to achieve the goal of increasing the production speed of profiles.Therefore,the issue of the impact of secondary spray cooling on the solidification of cast iron horizontal continuous casting profiles and the production process problems of profiles after adding secondary spray cooling arise.In order to study and solve these problems,we have been relying on experiments of drawing cast iron for exploration.However,it is difficult to observe the internal situation of the casting billet from the surface during actual production of cast iron horizontal continuous casting profiles.The process parameters obtained through production exploration after adding secondary spray cooling did not achieve the maximum production rate of the casting billet.Therefore,this article focuses on the impact of secondary spray cooling on the solidification of cast iron horizontal continuous casting profiles and the production process of profiles after adding secondary spray cooling.Numerical simulation can obtain various scalar information of the casting billet production process,and the required parameters are clear,which is convenient for experimental exploration and research.This article uses C++programming language and Qt programming software to create a universal simulation software for cast iron horizontal continuous casting,and displays relevant image information using Opengl.Use this universal simulation software to simulate the actual production process of the casting billet,compare the production information of the casting billet temperature,cooling speed,liquid core shape,liquid core length,and solidification shell thickness before and after spraying cooling during production,and explore the specific impact of secondary spraying cooling on the solidification and production of the casting billet.The Control variates is used to change the four parameters of spray cooling density,spray cooling temperature,spray cooling width and spray cooling distance,and study the influence of each parameter on the temperature field,liquid core shape and condensation shell thickness distribution during the cooling process of the slab.The best parameters of secondary spray cooling are obtained.Finally,the numerical simulation is carried out with this secondary spray cooling parameter to explore the amount of increase in drawing speed of cast iron round profiles with diameters of 60mm to 80mm.Through simulation experiments,the following conclusions are drawn in this article:(1)When the spray cooling density is 0.08 L/(cm2·min),the spray cooling distance is 0 cm,the spray cooling width is 30 cm,and the spray cooling temperature is 25℃,the temperature field of the graphite sleeve and graphite sleeve section profile remains almost unchanged after secondary spray cooling of the billet with diameters of 80mm.At 150cm of the billet,the surface temperature of the billet decreased by 271.03℃,indicating that secondary spray cooling has a significant cooling effect on the billet.The length of the liquid core of the billet decreases by 5.11cm,and the billet accelerates solidification.The taper of the liquid core decreases,and the displacement distance of the liquid core also decreases from 0.212cm to 0.018cm.(2)The Control variates was used to simulate and compare the four spray parameters,namely,the spray cooling density,the spray cooling temperature,the spray cooling width and the spray cooling distance.Taking the slab surface temperature and the liquid core length as the comparison parameters,and considering the actual production cost and safety,the optimal spray cooling parameters were obtained as follows:the spray cooling density was 0.14 L/(cm2·min),the spray cooling width was 30 cm,the spray cooling temperature was 25℃,and the spray cooling distance was 0 cm.(3)When the diameter of circular cast iron profiles is between 60 and 180mm,the larger the billet diameter,the more liquid metal inside,and the longer the liquid core.The proportion of the liquid core length after crystallization is larger,and the relative surface area of large diameter profiles is smaller,making it difficult to dissipate heat.Therefore,after adding secondary spray cooling,the larger the profile diameter,the greater the reduction of the liquid core after spray cooling.For example,the liquid core of circular profiles with diameters of 60mm is only 0.90cm shorter,while the liquid core of circular profiles with diameters of 180mm is 110.90cm shorter.However,it is also because there is a large amount of molten metal in large-diameter billets,resulting in a large amount of latent heat release.Due to the short radial heat transfer distance and faster radial heat transfer,the decrease in surface temperature of the billets in the liquid core section actually decreases as the diameter increases(4)Taking the length of the liquid core of the billet before spray cooling and the thinnest solidified shell thickness for safe production as the safety production parameters of the billet after increasing secondary spray cooling,simulation experiments have shown that when the diameter of the circular profile is between 60 mm and 180 mm,the drawing speed of the billet after increasing secondary spray cooling can be increased by 15%to 45%,and the larger the profile diameter,the greater the increase in drawing speed.