Abstract
Molten metal flow behavior during fast shot injection with 500t to 1650t commercial die casting machines was studied in the filling portion of the die cavity in the shape of disc, box and plate.
The die cavity was filled with a molten metal flowing out of the gate and moving toward the final filling portion as shown in the equal time diagram. The velocity of the molten metal is as high as 15m/s to 20m/s at the gate of die cavity, but it decreases abruptly within a passage of 20cm to 25 cm and reaches 2m/s to 5m/s at the final filling portion. The gas pressure increases from the gate to the final filling portion. The velocity of metal decreases with increase in the gas pressure at the final filling portion. Provision of an appropriate gas vent in the final filling portion increases the velocity of the molten metal, resulting in a few casting defects at this portion of the die castings.
When molten metal having a temperature of 640°C was poured into the shot sleeve of die casting machine, its temperature lowered rapidly to its solidifying temperature and was injected into a die cavity in a solid-liquid mixture state.
