The total number of cracks in the motor shell produced by furan resin sand casting process is about 70, while the total number of cracks in the motor shell produced by alkaline phenolic resin sand casting process is 30 on average, and the number of crack defects is reduced by 60%. The comparative statistics of the two are shown in the table.
| Production process | Stage | Crack location | Number of cracks (piece) | Number of cracked castings (%) |
| Alkaline phenolic resin sand casting | Magnetic particle testing of sand castings | Outer surface | 3-8 | 50 |
| Alkaline phenolic resin sand casting | Magnetic particle testing of sand castings | Inner surface 1# core | 6-10 | 90 |
| Alkaline phenolic resin sand casting | Magnetic particle inspection for machined surface of sand casting | Inner surface 2# core | 10-16 | 100 |
| Alkaline phenolic resin sand casting | Magnetic particle inspection for machined surface of sand casting | Inner surface 1# core | 1-2 | 10 |
| Furan resin sand casting | Magnetic particle testing of sand castings | Outer surface | 10-15 | 100 |
| Furan resin sand casting | Magnetic particle testing of sand castings | Inner surface 1# core | 15-20 | 100 |
| Furan resin sand casting | Magnetic particle inspection for machined surface of sand casting | Inner surface 2# core | 30 | 100 |
| Furan resin sand casting | Magnetic particle inspection for machined surface of sand casting | Inner surface 1# core | 5-12 | 100 |
1) The application of alkaline phenolic resin sand casting process in cast steel motor shell is feasible, and can greatly reduce the number of cracks in motor shell.
2) The addition amount of alkaline phenolic resin is 1.5% ~ 1.8% of the original sand, the addition amount of organic resin curing agent is 20% ~ 25% of the resin, the demoulding strength is 0.25 MPa ~ 0.30 MPa, and the strength of 24h molding sand is 0.3 MPa ~ 0.7 MPa.
3) It is feasible to adopt the new sand molding scheme and the recycled sand + 25% new sand molding scheme for the alkaline phenolic resin sand casting process. The product quality of sand castings has little difference, but considering the cost, the recycled sand + 25% new sand molding scheme should be adopted, which is more economical.
4) The basic phenolic resin sand casting process is the same as the furan resin sand casting process. There are many sand inclusion defects in the sand casting, which can only be improved from the process design.