Features: in the castings poured by the same ladle, the early casting has good spheroidization, and the later casting has poor spheroidization or non spheroidization.
Precautions:
(1) The treated molten iron shall be poured as soon as possible, and the surface of the molten iron shall be covered with insulating materials to avoid the surface oxidation of the molten iron.
(2) To ensure that there is enough residual magnesium in the molten iron, a nodulizer (yttrium based heavy rare earth magnesium nodulizer) with weak fading ability can be used for thick and large section ductile iron parts.