VAR电磁搅拌工艺对熔体流动影响的模拟研究

Simulation study on the effect of VAR magnetic stirring process on the melt flow

真空自耗电弧熔炼中熔体的流动行为影响铸锭的凝固特性。熔体运动直接观测困难,因此通过模拟揭示熔体的流动行为非常关键。采用自主开发的三维模拟模型,研究了不同搅拌工艺参数下,熔炼过程中熔体的流动行为及熔池形貌。研究表明,随着搅拌电流从0.01 A逐步增加到25 A(搅拌周期为8 s),熔体旋转速度从0.000 1 m/s近似线性增加到0.212 m/s,熔池逐渐宽化(由V形变成U形),熔池最大深度和熔池体积均存在一个明显的先下降后上升的过程。而随着搅拌周期从1 s逐步增加到24 s(搅拌电流为5 A),熔体旋转速度从0.012 5 m/s快速增加到一个较大值(16 s时为0.081 8 m/s)后趋于稳定,熔池逐渐宽化,熔池最大深度逐渐降低到一个最低值后趋于稳定。搅拌电流和搅拌周期均影响熔体的旋转及平面运动,但两者的影响机理存在一定的差异。

The flow behavior of melt in vacuum consumable arc melting affects the solidification characteristics of ingots.Direct observation of the melt motion is difficult,so revealing the flow behavior of the melt by simulation is crucial.In this paper,a self-developed three-dimensional simulation model was used to study the melt flow behavior and pool morphology during the melting process under different stirring process parameters.The research shows that with an increase in the stirring current from 0.01 A to 25 A(under a stirring period of 8 s),the rotational speed of the melt increases near-linearly from 0.0001 m/s to 0.212 m/s,and the molten pool gradually widens(from V-shaped to U-shaped).In the meanwhile,there is an obvious process of first decreasing and then increasing in the maximum depth and volume of the molten pool.As the stirring period increases from 1 s to 24 s(under a stirring current of 5 A),the rotational speed of the melt gradually increases from 0.0125 m/s to a high value(0.0818 m/s at 16 s)and then tends to stabilize.The molten pool gradually widens,and the maximum depth of the molten pool gradually decreases to a minimum value and then tends to stabilize.The stirring current and stirring period can affect the rotation and planar motion of the melt,but their affecting mechanisms are different.