Production principle of cast iron manhole frame manhole cover

Production principle of cast iron manhole frame manhole cover:
1. Strictly requires chemical composition, and the carbon and silicon content of raw iron liquid is higher than gray cast iron, reducing the content of manganese, phosphorus and sulfur in Nodular cast iron.
2.The temperature of iron liquid is higher than the gray cast iron to compensate for the loss of the iron liquid temperature during gestation treatment.
3. The Nodulizer is added to the iron liquid.

4. The inoculants is added for inoculation treatment.
5. Nodular iron has poor fluidity and large shrinkage, thus requiring high pouring temperature and large pouring system, according to riser, cold iron and sequence solidification principle.