薄壁铝合金压铸充型过程中铸件与铸型界面的换热行为

Heat transfer behaviors between metal and die during filling process of thin-wall aluminum alloy under high pressure die casting conditions

采用压铸制备薄壁AlSi10MnMg铝合金铸件,用高速摄像技术记录分析压铸压射冲头的运动规律,并通过热平衡方程求解充型过程中铸件熔体和铸型之间的换热系数,最后通过数值模拟的方法讨论采用不同换热系数对充型仿真结果的影响。结果表明:充型流动长度随浇注温度的升高而增长;当充型处于液相线温度之上时,充型时间、换热系数随浇注温度的升高而增长;当充型至温度处于液相线温度以下时,充型时间和换热系数变化都很小。模拟仿真结果显示,采用基于热平衡方程求得的换热系数的计算模拟仿真结果与实验结果较一致。

The thin-wall AlSi10MnMg aluminum alloy samples were prepared by high pressure die casting. The motion laws of press-shoot ram were recorded by a high speed camera system and the heat transfer coefficients between the casting and mold were calculated by the energy conservation equation. Therefore, the effects of different heat transfer coefficients on the simulated filling results were discussed. The results show that the filling fluidity length increases with the pouring temperature increasing;when the filling process is above the liquidus, the filling time and the heat transfer coefficient increase with the pouring temperature increasing. However, when the filling process is below the liquidus, the changes of the filling time and the heat transfer coefficient are insignificant. The simulations using the heat transfer coefficient which is calculated by the energy conservation equation are well consistent with the experimental results.