From the casting process of nodular iron rings in the above countries, the main process methods abroad are double piece ellipse, four piece ellipse and elliptical cylinder casting process. These three casting processes have their own characteristics and are currently applied in mass production. The main processes in China are double piece casting process, as well as single piece and e PC casting process of individual manufacturers.
The main characteristics and process comparison of these processes are shown in the table.
| Process method | Molding machine | Process analysis | Production application |
| Single elliptical casting | The requirement of molding machine is not high, z145 or semi-automatic can be used1. | 1.It is the same as ordinary alloy ring, with simple process and low requirements for molding machine. 2.The process is simple and does not need slicing. It can be ground directly. 3.Four risers are needed for feeding, so the utilization rate of molten iron is very low and the production economy is poor. | It is only used for motorcycle rings with relatively small diameter. The return materials of nodular iron rings should be fully digested when producing alloy rings. |
| Double piece elliptical casting | Semi automatic or fully automatic molding machine | 1.It has strong applicability to varieties and simple process. 2.High requirements for molding machine and molding quality. 3.The blank has good formability, and the shrinkage and looseness of the heart can be cut off when slicing. | It is suitable for mass production of various varieties, with simple process and low production cost. |
| Four piece elliptical casting | Automatic molding machine | 1.It has high requirements for modeling quality, and the modeling effect is better with automatic molding machine. 2.The blank has good formability, and the shrinkage and looseness of the heart can be cut off. 3.Save a lot of modeling and cleaning workload, and the production efficiency is very high. 4.The requirements for the manufacture of blank slicing machine are very high. | It is suitable for automatic molding production line, efficient mass production, and is feasible on the premise of completely solving the special slicing machine of thin grinding wheel. |
| Elliptical cylinder casting | Di sand or Guangyang vertical parting box free molding line | 1.Vertical parting and boxless molding line production. 2.High efficiency and mass production. 3.The casting quality is good and the casting waste is very low. 4.There are certain requirements for the adaptability of varieties. The gap of metallographic structure needs to be studied. | After solving the problem of special slicing machine, mass production of some models and varieties with moderate diameter. |