Numerical Investigation of Axial Magnetic Field Effects on Melt Flow and Macrosegregation in TC17 Alloy Vacuum Arc Remelting | Chapter 4 | | Proceedings of the 8th International Conference on Solidification and Gravity

The TC17 alloy ingot is produced through vacuum arc remelting (VAR). However, the self-induced electromagnetic force enhances forced convection, which can lead to potential macrosegregation, particularly as the ingot diameter increases. To address this issue, an engineering solution involves applying an axial magnetic field (AMF) to modify the flow in the molten pool. In this study, the solidification process of the VAR ingots was simulated using a built-in solidification model in ANSYS Fluent. The solver is based on the finite volume method. A 2D-axisymmetric simulation considering the swirl flow was performed, incorporating the multi-physics coupling of heat transfer, solute transfer, melt flow, and electromagnetic effects. The reasonable agreement between the simulation and experiment regarding the molten pool contour and segregation profile demonstrates the robustness and applicability of the model. On this base, a numerical parameter study was performed to study the effect of the AMF, with particular emphasis on the alternative AMF direction change and the resulting melt flow. The results show that the applied AMF generates an electromagnetic force in the tangential direction, creating a rotational swirl flow and a centrifugal force directed radially outward. Consequently, a secondary flow along the side walls towards the bottom centre within the molten pool is induced. This modified flow pattern in the molten pool helps reduce macrosegregation in VAR ingots, hence improving the service life and mechanical properties of aviation titanium alloys. Qualitative simulation-experiment agreement regarding the shape of the molten pool profile and segregation distribution is achieved. However, future model improvement, e.g. considering the solidification crystal morphology, multiphase flow, and potential formation of freckles, is necessary.

 

Author (s) Details

 

Chenbo Xu
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China and Department of Metallurgy, Montanuniversität Leoben, Franz-Josef Street 18, 8700 Leoben, Austria.

 

Jie Guo
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China.

 

Jincheng Wan
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China.

 

Junjie Li
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China.

 

Liqing Huang
Hunan Goldsky Titanium Industry Technology Co., Ltd., Changde 415001, China.

 

Kai Fan
Hunan Goldsky Titanium Industry Technology Co., Ltd., Changde 415001, China.

Haijie Zhang
Department of Metallurgy, Montanuniversität Leoben, Franz-Josef Street 18, 8700 Leoben, Austria.

 

Menghuai Wu
Department of Metallurgy, Montanuniversität Leoben, Franz-Josef Street 18, 8700 Leoben, Austria.

 

Please see the book here:- https://doi.org/10.9734/bpi/mono/978-93-49473-95-9/CH4

Concentration Stratification and Crystal Dynamics in Solidifying Ammonium Chloride Solutions |Chapter 1| Proceedings of the 8th International Conference on Solidification and Gravity

Many alloys reveal an upwardly directed solutal buoyancy in the interdendritic mushy region as they solidify. Such a situation leads to a solute enrichment at the top of the melt pool and is prone to form segregation channels. Based on both experimental observations and numerical simulations applying an aque-ous ammonium chloride solution subject to side cooling, this contribution dis-cusses the complex interplay of different phenomena that leads to a sedimen-tation bed that is far from being homogenous. Concentration and flow stratifica-tion at the top part of the test cell, interdendritic flow channels transporting both segregated liquid and also crystal fragments into the bulk melt, crystal agglom-erations that form at indentations observed at the exit of flow channels, and collapsing of crystal agglomerations and sliding down of mushy zone seg-ments, all these phenomena lead to a highly unsteady solidification dynamic. These observations are relevant in fields such as metallurgy, materials science, geology, and environmental science and could enhance the design of industri-al processes and contribute to natural system modeling.

 

Author (s) Details

Golshan Shayesteh
Metallurgy Department, Montanuniversitaet Leoben, 8700 Leoben, Austria.

 

Zhao Zhang
Primetals Technologies Limited, 4031 Linz, Austria.

 

Mihaela Stefan-Kharicha
Metallurgy Department, Montanuniversitaet Leoben, 8700 Leoben, Austria.

 

Menghuai Wu
Metallurgy Department, Montanuniversitaet Leoben, 8700 Leoben, Austria.

 

Abdellah Kharicha
Metallurgy Department, Montanuniversitaet Leoben, 8700 Leoben, Austria and CD Laboratory for Magnetohydrodynamic Application in Metallurgy, Montanuniversitaet Leoben, 8700 Leoben, Austria.

 

Andreas Ludwig
Metallurgy Department, Montanuniversitaet Leoben, 8700 Leoben, Austria.

 

Please see the book here:- https://doi.org/10.9734/bpi/mono/978-93-49473-95-9/CH1

Developing the Numerical Simulation of Multicomponent Alloy Solidification | Chapter 3 | Advanced Aspects of Engineering Research Vol. 16

 A non-equilibrium model was used to study multicomponent melt solidification, in which a Stefan problem with two borders was addressed numerically, the boundaries being between the solid phase and the two-phase transition zone, and between the two-phase transition zone and the liquid phase. The two-phase zone is represented by a porous material with varied porosity. The additional force preventing melt flow due to porosity is taken into account in the same way that Darcy's law is taken into account. Computer simulations were used to simulate the solidification of Sn-20 wt. percent Pb binary alloys via the process of downward-directed crystallisation along the gravity vector. The results of a quasi two-dimensional benchmark experiment on horizontal (i.e., perpendicular to the gravity vector) directional solidification of a binary Sn-3 wt. percent Pb alloy are presented in the publication. Two crystallisation models were used in the calculations: equilibrium and non-equilibrium crystallisation. The non-equilibrium model is proven to provide a more accurate depiction of natural convection-induced heat field evolution and solute dispersion. Solidification, binary alloy, dual-phase region, macrosegregation, convection, heat-mass transfer, modelling, comparison with experimental results, columnar-to-equiaxed transition Keywords: solidification, binary alloy, dual-phase region, macrosegregation, convection, heat-mass transfer, modelling, comparison with experimental results (CET).

Author (S) Details

V. P. Ginkin
Institute for Physics and Power Engineering (IPPE), Bondarenko sq.1, 249033 Obninsk, Russia.

S. M. Ganina
Institute for Physics and Power Engineering (IPPE), Bondarenko sq.1, 249033 Obninsk, Russia.

A. V. Kartavykh
Technological Institute for Superhard and Novel Carbon Materials (TISNCM, Moscow branch), B.Tolmachevsky per.5, 119017 Moscow, Russia.

View Book :- https://stm.bookpi.org/AAER-V16/article/view/1988