板坯连铸过程结晶器水口优化数值模拟

Numerical simulation of mold nozzle optimization in slab continuous casting process

为了优化板坯连铸过程结晶器水口以抑制卷渣的发生,利用ProCAST有限元软件建立不锈钢板坯连铸结晶器三维模型来研究结晶器水口优化方法。通过实验室黏度仪测量保护渣性能参数带入卷渣临界表面流速经验公式,得到易发生卷渣的钢液临界表面流速。数值模拟计算优化前与优化后的钢液临界表面流速以及结晶器流场、温度场。钢液卷渣临界表面流速理论值为0.35 m/s。数值模拟结果表明,中孔直径从55 mm增大到60 mm,侧孔倾角从8°降低到6°,四尺铸坯钢液临界表面流速值从0.347 m/s降低到0.296 m/s,五尺铸坯从0.351 m/s降低到0.323 m/s。优化参数下的钢液上表面流速适宜,结晶器流场和温度场合理,利于保护渣熔化,坯壳润滑效果好,能有效抑制卷渣发生。因此板坯连铸结晶器水口可按此参数优化。

To optimize the mold nozzle during the slab continuous casting process to suppress slag entrapment,a three-dimensional model of the stainless-steel slab continuous casting mold was established using ProCAST to study the optimization method of the mold nozzle.By measuring the performance parameters of the protective slag using a laboratory viscosity meter and incorporating them into the empirical formula for the critical surface flow rate of slag entrapment,the critical surface flow rate of molten steel that is prone to slag entrapment can be obtained.Numerical simulation calculates the critical surface flow rate of molten steel before and after optimization,as well as the flow field and temperature field of the mold.The theoretical value of the critical surface velocity of molten steel slag is 0.35 m/s.The numerical simulation results show that the diameter of the middle hole increases from 55 mm to 60 mm,the inclination angle of the side hole decreases from 8°to 6°,the critical surface velocity of the steel in the four feet casting billet decreases from 0.347 m/s to 0.296 m/s,and the critical surface velocity in the five feet casting billet decreases from 0.351 m/s to 0.323 m/s.Under the optimized parameters,the surface flow rate of the molten steel is appropriate,the flow field and temperature field of the mold are reasonable,which is conducive to the melting of the protective slag.The lubrication effect of the billet shell is good,and it can effectively suppress the occurrence of slag entrapment.Therefore,the nozzle of the slab continuous casting mold can be optimized according to this parameter.