Optimizing gate location to reduce metal wastage: Co-Cr-W alloy filling simulation

This research aimed at reveal the reasons for the extra Co-Cr-W alloy wastage in the risers in sand casting. The alloy filling behaviour in both the original and modified moulds was investigated numerically. The alloy-air interface was captured by using volume of fraction method. For the original mould, an unfilled volume in the vicinity of the runner bar top was apparent and it was refilled by a back flow, originated from the risers in the late stage of filling. The back flow behaviour required a higher level of the liquid alloy in the risers, which resulted in excessive wastage, and it was essential to form the required shape of the cast. For the modified mould, the unfilled volume was eliminated and the cast part shaping time was reduced to around 10 s from 90 s. The alloy wastage in the risers was reduced by 11%.