镍基高温合金真空感应熔炼碳氧反应数值模拟

Numerical simulation of carbon-oxygen reaction in vacuum induction melting of nickel-based superalloys

为了探究镍基高温合金真空感应熔炼(VIM)过程中碳氧反应动力学规律,基于电磁场-流场-溶质场多物理场耦合技术,建立了考虑电磁搅拌和坩埚分解作用的真空感应熔炼脱氧动力学模型,研究了电流强度、压强以及精炼温度对镍基高温合金熔体脱氧反应的影响。结果表明,模拟得到的熔池氧含量随时间的变化规律与试验结果吻合较好;电磁搅拌加速了熔池中氧的传质速率,对熔池中氧的分布有显著影响;增大电流强度、降低压力或降低精炼温度均能有效促进熔池脱氧反应的进行。当电流强度从55A增加到75A时,熔池氧平均质量分数从0.001373%下降到0.001298%。当压强从1.5Pa降低到0.5Pa时,熔池氧平均质量分数从0.001960%下降到0.001338%。当精炼温度从1873K降低到1773K时,熔池氧平均质量分数从0.001855%下降到0.001339%。所得结果将为改进镍基高温合金的VIM精炼过程提供有效依据。

In order to investigate the kinetics law of carbon-oxygen reaction during vacuum induction melting(VIM)of nickel-based superalloys,vacuum induction melting deoxygenation kinetic model considering the effects of electromagnetic stirring and crucible decomposition was established based on the multi-physical field coupling technique of electromagnetic field-flow field-solute field,and the effects of current intensity,pressure and refining temperature on the deoxidation reaction of nickel-based superalloy melt were studied.The results show that the simulated variation pattern of oxygen content in melt pool with time agrees well with the experimental results.Electromagnetic stirring accelerates the oxygen transfer rate in the melt bath and had significant effect on the distribution of oxygen in the melt bath.Increasing the current intensity,decreasing the pressure or lowering the refining temperature can effectively promote the melt pool deoxygenation reaction.When the current intensity was increased from 55Ato 75A,the average oxygen mass fraction of melt pool decreased from 0.001373%to 0.001298%.When the pressure was decreased from 1.5Pa to 0.5Pa,the average oxygen mass fraction of melt pool decreased from 0.001960%to 0.001338%.When the refining temperature was decreased from 1873Kto 1773K,the average oxygen mass fraction of the melt pool decreased from 0.001855%to 0.001339%.The obtained results will provide an effective basis for improving the VIM refining process of nickel-based superalloys.