Numerical Simulation Of Liquid Steel Flow, Heat Transfer, Solidification And Water Distribution Optimization In Single Point Non-equilibrium Beam Blank Continuous Casting

H-beam has developed rapidly all over the world by virtue of its good mechanical properties and excellent bearing capacity.As a near final continuous casting billet,profiled billet is the best raw material for rolling H-beam with the characteristics of less rolling process,low cost,low energy consumption and high yield.Because of its complex cross-section structure,profiled billets are more prone to quality problems during continuous casting than other conventional beam blank.At present,the research on two-point balanced pouring is more in-depth at home and abroad.However,due to the pouring conditions,cost control and smelting steel grade,the pouring mode has changed from the original double nozzle balanced pouring mode to single nozzle unbalanced pouring.However,the research on single point unbalanced pouring is almost blank.The flow,heat transfer The law of solidification and the optimization of water meter have very important academic and application value.In this paper,the effect of process parameters on the flow,heat transfer and solidification of molten steel in the continuous casting process of the ultra-thin beam blank BB2(750mm×370mm×90mm)was deeply discussed,and the original water meter was optimized for the single point non-equilibrium casting process.The main research work and conclusions are as follows:(1)The flow field,temperature field and the solidification law of the shell in the mold of non-equilibrium casting of single point were analyzed.Three reflux zones are formed on both sides of the flange and at the web position of the mold with the straight single nozzle casting,and the impact depth of the injection flow is deep and the free liquid surface velocity is small.The temperature at the center of the narrow surface and the R Angle of the inner and outer arcs is higher,and the temperature distribution on the surface of the billet is not uniform.The growth of solidified billet shell is also inconsistent,the solidification of molten steel in the web position is prefered to both sides of the narrow flange,and the thickness of the billet shell is thinner in the narrow surface center of the nozzle side and the R Angle of the nozzle side,which is easy to leak.(2)The effects of process parameters(nozzle immersion depth,drawing speed and superheat)on the flow field,temperature field and shell growth of blank mold were analyzed in detail.The results show that when the immersion depth of the nozzle is 50 ～ 60 mm,the pulling speed is 0.8m/min ～ 0.95m/min and the superheat is about20℃,the flow field,temperature field and shell growth in the mold are reasonable,which can effectively improve the output and quality of the billet and the smooth operation of the process.(3)The mold and secondary cooling section of profiled beam blank were numerically simulated,and the effects of symmetrical and asymmetric water on slab surface temperature and shell thickness were studied.The results show that under the condition of symmetrical water volume,the temperature and shell thickness on both sides of the narrow surface center of the profiled billet are obviously inconsistent along the drawing direction.By adjusting the cooling water on both sides of the mold section,when the water volume on the nozzle side and non nozzle side of the narrow surface of the mold section is 1000 L / min and 900 L / min respectively,the inconsistency of temperature and shell thickness along the drawing direction on both sides of the center of the narrow surface can be effectively improved.When the water volume at the nozzle side and non nozzle side of the mold section is 1000 L / min and900 L / min respectively,and remains unchanged,the water volume on the narrow surface near the nozzle side from the second to fifth stage of secondary cooling increases by 20%,which can effectively improve the temperature difference and shell thickness difference along the drawing direction on both sides of the center of the slab narrow surface.Compared with symmetrical cooling,the temperature difference along the drawing direction at both sides of the center of the narrow surface of the slab decreases from the original 25 ～ 110 K to 10 ～ 50 K and below 50%,and the thickness difference of the shell along the drawing direction at both sides of the center of the narrow surface of the slab decreases from the original 3.3 ～ 7.4mm to 0.4 ～ 3.8mm after leaving the mold,which decreases by about 50%,and the improvement effect is obvious.