( 1 ) The sulfur content and other trace elements of the original molten iron should not be too high. If the sulfur content and other trace elements in the original molten iron are too high, a larger amount of nodulizer or a nodulizer with a higher rare earth content is required . ( 2 ) The stability of spheroidization. The spheroidizing process is a key process in the production of nodular cast iron. Only when the spheroidizing process is stable can the quality of the casting be stable. ( 3 ) Avoid long waiting time. ( 4 ) Avoid excessively high residual magnesium content. A higher residual magnesium content will increase the shrinkage porosity of the casting . ( 5 ) Use better inoculants for castings with higher requirements. For wind power parts and high-speed rail parts with higher requirements, the flow inoculant with strong inoculation effect should be selected , which is characterized by the ability to significantly increase the number of graphite spheres and the graphite sphere is round.