Preparation of semi solid slurry for semi solid die casting

The preparation of semi-solid slurry is the most important part of semi-solid forming technology. With the continuous development in recent years, the preparation methods of semi-solid slurry are more and more widely used. At present, it mainly includes mechanical stirring, electromagnetic stirring, ultrasonic vibration in mechanical methods, NRC method, seed method, newmit method, jet deposition method and Sima method and rap method in recrystallization method.

The pulping method used this time is rotary heat balance method invented by Canada company. There are three main steps to prepare semi-solid raw materials by this method (as shown in Fig. 1)

In the first stage, the alloy solution at a specific temperature measured by thermocouple is poured into an inclined crucible. Every time this step is repeated, it is necessary to ensure that the crucible is at room temperature, so that the slurry can form rapidly under the extremely cold action of the cup wall;

In the second stage, after the crucible is aligned in the vertical direction, the seed pulping instrument is started to make the crucible fixed on the tray rotate eccentrically along the set parameters. In this process, the temperature of the slurry becomes uniform through the involvement of the cup wall;

In the third stage, the slurry in the crucible was transferred to the barrel of die casting machine after the crucible rotation stopped, and the subsequent die casting experiment was carried out.