In order to realize natural feeding of castings, we must have process measures that can realize 'sequential solidification' in our casting process system. Many people intuitively think that the shrinkage cavity and porosity defects of castings can be solved by low-pressure casting, but this is not the case. The use of low-pressure casting process does not mean that the shrinkage cavity and porosity defects of castings can be solved. If the low-pressure casting process system is not equipped with feeding process measures, then 100% of the workblanks produced by this low-pressure casting method may also have shrinkage cavity and porosity defects. In the manufacturing of castings in Dalian, the physical and mechanical properties of materials have a great impact on the selection of process parameters, the setting of gating and riser and chill, the heat treatment technology, and the post-treatment technology of castings. It is of great significance for process design to deeply understand the influence of carbon content and alloy element content in casting alloy on as cast microstructure and mechanical properties, as well as the solidification mode, shrinkage tendency, riser feeding effect, thermal conductivity and thermal stress tendency of materials.