Mathematical Modelling of the Initial Mold Filling with Utilization of an Angled Runner

The flow pattern plays a crucial role in the uphill teeming process. The non-metallic inclusion generation due to interaction with the mold flux is believed to be influenced by the flow pattern. In this study, a three-dimensional mathematical model of the filling of a gating system for 10, 20, and 30 degrees angled runners was used to predict the fluid flow characteristics. Moreover, a mathematical model with a horizontal runner was applied as a reference. The predictions indicate that the angled-runner-design decreases the hump height during the initial filling stage, which results in less entrapment of mold flux into the mold. Nevertheless, increasing the angle of runner can result in a lower hump height, while the 30 degree angled runner gives a much more stable increase of the hump height during the initial filling stage. Besides CFD calculations, some thermodynamic calculations are taken into account for the chemical reactions between liquid steel and gas. The results show that the bubble shrinks due to the fact that N and O are dissolved into steel. The present findings strongly suggest that changing the horizontal runner to an angled runner would be an effective means of reducing flow unevenness during the initial filling of ingots, if the added steel losses are deemed acceptable.