浇注系统设计的新启示

采用底注式平稳充型的方案来设计浇注系统，把液流在内浇道的出口速度作为限制瓶颈，它控制金属液在整个浇注系统的流动速度。在保证铸型充满的前提下，内浇道的充型速度最好限制在0.5m/s以内，以普通达铸铁精密铸造叶片为例，把传统的顶注式浇注系统和新的底注式浇注系统的结果进行比较，在充型过程中，采用X射线实时跟踪系统进行了观察，发现顶注式浇注系统充型紊乱，易造成夹杂，浇注的26个叶片中3处出现裂纹，30处出现夹杂缺陷，而采用底注式浇注系统，铸件充型平稳，没有裂纹，只有3处出现夹杂缺陷，优化效果明显。

The Novel Concept of Gating System Design

A novel concept is adopted to design gating system based on the bottom pouring system with stable filling, in which the ingate outlet velocity is as the bottleneck to control the flow velocity of liquid metal in whole gating system. The filling velocity of the ingate should be limited to 0.5 m/s under the condition of full mold filling. Mold filling results of traditional top and new bottom gating system for conventional grey iron blade investment casting were compared. X ray real time radiographic system was used for observing the filling process. The results showed that 3 cracks and 30 inclusions in the cluster of 26 blades attributed filling turbulence in to top gating system while there are only 3 inclusions and no cracks because of stable mold filling in optimized bottom gating system.