Ti_1023合金VAR熔炼数值模拟研究-中国材料进展

文章信息/Info

Title:: Numerical Simulation of the VAR Process of Ti_1023 Alloy Ingot with Melt Flow VAR and Validation

Author(s):: ZHAO Xiaohua; HE Yongsheng; LUO Wenzhong; LAI Yunjin; WANG Kaixuan; LIU Xianghong; Western Superconducting Technologies Co, Ltd, Shaanxi Province Engineering Laboratory for Aerial Material，Xi’an 710018, China

Keywords:: Ti_1023 alloy; Melt Flow VAR; molten pool shape; element distribution; validation

摘要:: Ti_1023合金因其优异的性能广泛应用于大型承力结构件，然而因其添加Fe元素含量较高，容易在真空自耗熔炼（VAR）制备铸锭的过程中出现Fe偏析，影响锻件的性能。利用多场耦合重熔工艺仿真优化软件（Melt FlowVAR）建立的模型研究了Ti1023合金在VAR不同阶段下的熔池形状和元素浓度分布，并以模拟工艺制备了Ti1023合金Φ640 mm大规格铸锭进行验证。结果表明：随着熔炼的进行，模拟的熔池形状按初期的扁平状→中期的V形→末期的深V形变化，熔炼后期的熔池深度为028 m，与实测结果基本一致。在铸锭中心线顶部和底部Fe和Al元素成分的模拟结果与实测值吻合良好，但在铸锭中间部分的模拟值与实测值存在较大偏差，分析认为是Melt FlowVAR计算模型中没有考虑等轴晶的沉降所导致的计算偏差所致。

Abstract:: Owing to the excellent physical and mechanical properties, Ti1023 alloy has been used widely in large structure parts. Nowadays Ti1023 ingot is produced by vacuum arc remelting（VAR) process, which may cause the β freckles due to this alloys high Fe content. So the β freckles can affect forgings properties. In this work, the shape of molten pool and the element distribution of the Ti1023 ignot at different stage during the VAR process have been simulated by Melt FlowVAR. In order to validate the agreement between the model and experiment results, a fullscale Ti1023 ingot has been prepared. The results show that the shape of molten pool changed from bowl shape in the initial stage to Vshape in the medium stage, and then to deep Vshape in the last stage during the melting process. The final depth of the molten pool is about 028 m, which is in good agreement with the experimental result. In the top and bottom part of the ingot, the simulated results of the distribution of Fe and Al are in good agreement with the measured results. However, there is a big deviation between the measured and modeled results for the distribution of Fe and Al in the middle part of the ingot, which should be attributed to the computing deviation of isometric crystals sedimentation in this model.