Because the investment mold of impeller blade is fixed with rosin wax based mold material and sodium silicate sand sleeve, high-pressure steam dewaxing method is adopted to ensure the dewaxing quality. The equipment adopts drtl / 200 electric heating dewaxing tank, and the dewaxing wax flows out from the lower part of the dewaxing tank. Dewaxing process parameters include steam pressure, inflation time and dewaxing time, as shown in table.
| Steam pressure / MPa | Inflation time / S | Dewaxing time / min |
| 0.6-1 | <5 | 6-10 |
The storage time of investment casting impeller blade shell mold after dewaxing before roasting shall be more than 12h, but not more than 2D, so as to avoid peeling, pulverization and falling off of ethyl silicate surface mold shell and reduce the quality of investment casting impeller blade shell.