Effect of the Stirring Mode on the Behavior of Al2O3-MgO Particles and Clusters during Ladle Treatment of Ni-based Alloy 825

It is well known that inclusions affect the properties of alloys. Therefore, the importance of understanding what inclusions exist and how they behave cannot be overstated. This study has examined the behavior of Al2O3-MgO particles and clusters in the melt during the ladle treatment of Alloy 825, who is a Ni-based Alloy. The effect of different stirring directions of electromagnetic stirring in combination with gas stirring is discussed based on three-dimensional investigations of the clustered particles. More specifically, the composition, size, and number of particles and clusters are determined after electrolytic extraction of metal samples by using SEM in combination with EDS. The results show that the agglomeration of Al2O3-MgO particles in the melt is faster for an upward induction stirring combined with a gas stirring in comparison to a downward stirring combined with a gas stirring. However, the total removal of clusters from the melt is more effective when using a downward induction stirring compared to when using an upward induction stirring, especially for large size clusters (>11.2 mu m). The effect of the different stirring modes on the behavior of the Al2O3-MgO particles and clusters in the melt for the ladle treatment experiments agree with the theoretical predictions based on Stokes', Brownian, and Turbulent collisions.