According to the experimental requirements and the convenience of operation, the hardening process of sand mold casting with intubation blowing method is selected.
a. Intubation method
Prick some on the casting sand mold Φ 6mm～ Φ 10mm blowhole; Insert the metal blowing pipe with small hole into the sand casting sand and blow CO2 to harden before starting the mold.
b. Process parameters
CO2 blowing process parameters include blowing pressure, flow and time. See table for parameter selection.
| Blowing pressure / MPa | Flow / m3 / h | Time / S |
| 0.10-0.15 | 0.5 | 20-30 |
In particular, excessive reaction of the surface layer caused by prolonged blowing time due to insufficient blowing pressure shall be avoided, and the casting sand mold shall not be placed for a long time.