Numerical study of influence of inclusion movement on channel segregation in Fe- 0.21 wt% C- 0.1 wt% S alloy

Abstract

A two-dimensional continuum model on solute and heat transport, and fluid flow is developed to numerically investigate the influence of inclusion movement on the development of channel segregation. A trajectory model is used to track the moving path of inclusion particles. Inclusion movement affects the flow field in simulation by means of interfacial friction coefficient. Simulations are performed on the Hebditch-Hunt casting. A parametric study is carried out to study the effects of with and without inclusions, and diameter (5 × 10-6 m, 10 × 10-6 m, 20 × 10-6 m and 40 × 10-6 m) of inclusions on channel segregation. It is found that the channel segregation is strengthened with the consideration of inclusion movement. Compared to other diameters, inclusions with diameter 20 × 10-6 m are found to enhance the channel segregation. This is because the larger inclusions (40 × 10-6 m) present a faster floating velocity that reduces the interaction time between inclusion upward movement and the development of solidification front, and then lessens the disturbance to solidification front that is important to the initialization of channel segregation. The upward movement of smaller inclusions (5 × 10-6 m and 10 × 10-6 m) cannot greatly increase the upward velocity of fluid flow. Therefore, the formation of channel segregation is less affected.