The comprehensive performance of ductile iron castings is close to that of steel, and it has rapidly developed into a cast iron material that is widely used after grey cast iron. Ductile iron with its excellent performance can sometimes replace expensive cast steel and forged steel in use. Ductile iron castings are widely used in the machinery manufacturing industry.
The following are notes on the production of ductile iron castings:
- The chemical composition of ductile cast iron is strictly required. The carbon and silicon content required for the original molten iron is higher than that of gray cast iron, and the content of manganese, phosphorus and sulfur in the ductile iron is reduced.
- The molten iron temperature is higher than that of gray cast iron in order to compensate for spheroidization and the loss of liquid iron temperature during inoculation.
- Spheroidizing, ie adding nodulizer to the molten iron.
- Adding inoculants for gestation.
- The ductility of nodular cast iron is relatively poor and the shrinkage is large. Therefore, a higher pouring temperature and a larger size of a gating system are required, and a riser and a cold iron are reasonably applied, and the principle of sequential solidification is adopted.
- heat treatment.