Select raw materials: The chemical composition required strictly. As to  carbon silicon content required for the original iron liquid is higher than that of cast iron, to reduce content of Mn, P, S in ductile iron. 

Molten iron melt : The temperature from iron out of furnace that is more high than cast iron, to make up the temperature loss during spheroidization and gestation 

Iron spheroidization: Stop spheroidization, that is, add spheroidizing agent to the molten iron.

Inoculation: To take part in inoculant and to stop Inoculation

Iron melt casting: Ductile iron has feature of poor activity and large shrinkage. Therefore, it requires a higher casting temperature and a larger casting system dimension. It should use head and chills reasonably, we adopt freezes in turn. 

Pre-stress elimination: Stop heat treatment, annealing treatment , remove the pre-stress of ductile iron.  

Appearance polishing: The appearance of the finished product has been suspended and the waste product is returned to  furnace.

Anti-corrosion treatment: We adopt bitumen anticorrosion or electrostatic spraying ，stop spraying and drying of finished products.

Finished product returned to warehouse: they had been packaged, and  classified.