Although the redesigned pouring system significantly reduced the shrinkage and porosity of the ball valve, it did not maximize the reduction of shrinkage and porosity defects. Therefore, it was adjusted and optimized from the perspective of process parameters. Based on the original traditional process parameters (pouring temperature 1550 ℃, pouring speed 1.5 kg/s, and shell preheating temperature 1150 ℃), orthogonal experiments were designed to determine the optimal process parameter group for the pouring temperature, pouring speed, and shell preheating temperature of 304 stainless steel liquid metal.
| Horizontal | A Pouring temperature/℃ | B Pouring speed/(kg · s ^ -1) | C Shell preheating temperature/℃ |
| 1 | 1520 | 1.0 | 1120 |
| 2 | 1550 | 1.5 | 1150 |
| 3 | 1580 | 2.0 | 1180 |
During the experiment, a three factor and three level orthogonal test table (L9 (33)) was used for the orthogonal table. There was no interaction between the various factors, and the evaluation index was the maximum shrinkage porosity of the investment casting of the ball valve. The influencing factors and their levels are shown in the table.