大型薄壁铝合金筒体铸件差压铸造过程数值模拟与工艺优化

Numerical Simulation and Optimization for Counter-pressure Casting Process of Large-scale Thin-wall Al Alloy Cylindrical Casting

利用ViewCast软件对某大型薄壁铝合金筒体铸件差压铸造充型和凝固过程进行数值模拟。模拟结果表明,由于铸件较高,缝隙式浇注系统无法实现逐层充填,金属液在充型过程中飞溅严重。在改进方案中,采用环形横浇道和环形内浇道取代缝隙式浇道,并吸取缝隙式浇注系统横向补缩的优点,在铸件相应部位设置工艺筋并配合使用冷铁。再次模拟结果表明,改进后的方案是合理可行的,实现了平稳逐层充型和铸件的顺序凝固。

The numerical simulation software ViewCast was apolied to analyze the mold-filling and solidification stages of large-scale thin-wall aluminum alloy cYlindrical casting in counter-pressure casting process. The simulation results indicate that the slot gating system is difficult to obtain the favorable filling sequence because of the excessive high of the casting, the liquid metal splashes badly during the mold-filling stage. The gating system was modified based on the simulation result. The ring-shaped gating system was adopted instead of the slot gating system. The ribs were added to ,the casting coupled with the chili block. The modified technology was re-simulated. The results reveal that it is feasible and carries out gradually-layered steady filling and sequential solidification.