Rare earth inoculation ofcraft depends on the adding methods of nucleating agent, mainly including internal inoculation, late inoculation and in-mold inoculation. Because the inoculant is time effective, namely, inoculation effect of inoculant will weaken along with the extension of time, so the time to add nucleating agent is general in the process of grey or directly put in the casting mold. And it is better to equal the inoculation time with solidification time of the which will improve the effect of inoculation. Thus the general choice about the inoculation type are late inoculation and in-mould inoculation.
Now the inoculation that are commonly used is pour-in method, porous plug method, in-mold processing method, wire injection, blowing process, and tundish method. The pour-in method is the most widely used which has significant effect on the performance of the grey iron.
The instantaneous inoculation, one of the common inoculation methods of grey iron casting, present the best effect. Instantaneous inoculation can significantly improve the organization form of grey iron, and there will be no bulky graphite. while theby ladle inoculation will generate bulky graphite. Therefore instantaneous inoculation can maximize and promote graphite nucleation, but won’t affect the growth of graphite.