Ductile iron casting strictly requires chemical composition during the operation. When used, the required carbon and silicon content of the original iron is higher than that of gray cast iron, and the content of manganese, phosphorus and sulfur in the ductile iron is reduced. The temperature of the molten iron is higher than that of the gray cast iron to compensate for the spheroidization and the loss of the temperature of the molten iron during the treatment.
Ductile iron is spheroidized, that is, a spheroidizing agent is added to the molten iron. The inoculant is added for inoculation treatment. Ductile iron has poor fluidity and large shrinkage. Therefore, it requires high pouring temperature and large casting system size. Reasonable application of riser and cold iron adopts the principle of sequential solidification. Heat treatment is performed.
The spheroidal graphite microstructure of spheroidal graphite cast iron castings is superior to cast steel in reducing vibration capacity, so it is beneficial to reduce stress. An important reason for choosing spheroidal castings is that spheroidal castings are less expensive than cast steel. The low cost of spheroidal castings has made this material popular, with high casting efficiency and less machining costs for spheroidal castings.
Ductile iron needs to clean the casting after the doffing. This is an important step in the casting process. Whether the casting cleaning is scientific and reasonable has a great influence on the surface quality of the casting. The cleaning of the casting is to remove the excess part of the casting from the falling sand and polish the inner and outer surfaces of the casting.