The figure shows the numerical simulation solidification of the gearbox at different times. It can be seen from the figure that the lost foam castings basically solidify from thin to thick in the whole solidification process, which has an important impact on obtaining high-quality lost foam castings.
At 510s, the surrounding area of the box has basically solidified, and the solidification area is pushed from far to near from the inner gate. The gray part is displayed. However, it can be seen that at this time, not only the surrounding area of the box has basically solidified, but also the inner gate and transverse gate have basically solidified, but at this time, it can be seen from the figure that the thick part at the bottom of the lost foam casting is still red, indicating that it has not solidified, In this way, the inner gate cannot supplement the metal liquid to the solidified part, resulting in the formation of isolated liquid phase, so the shrinkage cavity casting defects are easier to form in this place: 3019 s is the time required for the whole gating system to cool to 900 ℃, and at this time, the whole lost foam casting gating system has been solidified.