(1) Strictly require chemical composition. The carbon and silicon content required for the original molten iron is higher than that of gray cast iron, which reduces the content of manganese, phosphorus and sulfur in ductile iron.
(2) The temperature of molten iron out of the furnace is higher than that of gray cast iron to compensate for the loss of molten iron temperature during spheroidization and inoculation.
(3) Carry out spheroidizing treatment, that is, adding spheroidizing agent to the molten iron.
(4) Add inoculant for inoculation treatment.
(5) Nodular cast iron has poor fluidity and large shrinkage, so higher pouring temperature and larger pouring system size are required, and the riser and chilled iron are used reasonably, and the principle of sequential solidification is adopted.
(6) Heat treatment.