连铸过程溶质元素宏观偏析的数值模拟

Numerical Simulation on Solute Macrosegregation During Continuous Casting Process

采用商业软件CALCOSOFT模拟了实际连铸冷却条件下铸坯内部的温度场、流场和溶质场的分布。为了对模拟结果进行验证,将实际铸坯进行了刨屑化学成分检测。结果表明:模拟的宏观偏析结果与实际铸坯中检测的情况极为相似。凝固初期自然对流可能引起较大的内部紊流,将凝固前沿溶质带到中心液相起到了稀释作用;在凝固末期,糊状区显著阻碍了液相的流动,自然对流非常微弱,不能将枝晶间的浓化液相带到中心,大大减小了溶质元素向中心聚集的程度。

The field of temperature, flow and solute was simulated by using the business software CALCOSOFT under the real cooling condition during the continuous casting process. In order to verify the results simulated, composition analysizing was conducted using the samples planed along the thickness direction of the slabs. The result of macrosegregation simulated was extremely similar to that detected in the slabs. The flow induced by natural convection was strong at first and it could bring the surplus solute at the interface to the central part of the liquid phase, but the concentration was diluted due to the large amount of liquid; and at the near end of the solidification, due to the block of mushy region, the velocity of natural convection was so small that it couldn＇t bring the solute to the center.