真空感应熔炼中夹杂物运动行为数值模拟

为了促进真空感应熔炼GH4169合金过程中夹杂物的去除,建立了电磁-流动-粒子跟踪耦合数学模型,研究了真空感应熔炼过程中熔液流动与夹杂物运动的规律,对比了不同冶炼工艺参数下熔池中流场和夹杂物运动特点,提出了一种促进真空感应熔炼过程中夹杂物去除的工艺优化方法。结果表明,真空感应熔炼过程中,熔池流场中存在2个漩涡,加快漩涡的运动速度可以促进熔池内夹杂物的去除,熔液流动速度随着熔炼的进行先升高后下降,最终趋于稳定。随着电压增加,熔液平均流动速度增加,熔池内夹杂物总去除率升高。随着电流频率升高,熔液平均流动速度降低,熔池内夹杂物总去除率降低。因此可通过增大电压、减小电流频率的方法,增大熔液流动速度,促进真空感应熔炼GH4169合金过程中夹杂物的去除,工艺参数由400 V、3 400 Hz优化为420 V、3 200 Hz后,夹杂物总去除率由91.98%增大到94.87%,提高了2.89%。

Numerical simulation of inclusions movement in vacuum induction melting

In order to promote the removal of inclusions in the vacuum induction melting(VIM) of GH4169 alloy, a coupled electromagnetic-flow-particle tracking mathematical model was established, and the laws of melt flow and inclusions movement in vacuum induction melting were studied. The characteristics of flow field and inclusions movement in the melt pool with different smelting process parameters were compared, and a optimization method to promote removal of inclusions in vacuum induction melting was proposed. The results show that there are two vortices in the flow field of melt pool, accelerating the velocity of which can promote the removal of inclusions. The melt flow velocity increases firstly, then decreases with the process of smelting, and eventually stabilises. As the voltage increasing, the average melt flow velocity and the total removal rate of inclusions in the melt pool are both increased. As the current frequency increasing, the average melt flow velocity and the total removal rate of inclusions in the melt pool are both decreased. Therefore, the melt flow velocity can be increased by increasing the voltage and decreasing the current frequency, so as to achieve the effect of promoting inclusion removal in VIM of GH4169 alloy. The VIM process parameters optimized from 400 V, 3 400 Hz to 420 V, 3 200 Hz, which increased the total inclusions removal rate from 91.98% to 94.87%, and the rate increased by 2.89%.