铝合金压铸过程铸件/铸型界面换热行为的研究 Ⅱ．工艺参数对界面换热的影响

STUDY ON HEAT TRANSFER BEHAVIOR AT METAL/DIE INTERFACE IN ALUMINUM ALLOY DIE CASTING PROCESS Ⅱ.Effect of Process Parameters on the Interfacial Heat Transfer

基于本文第1部分的数学模型,求解了各种工艺参数下铸件/铸型间的界面热流和换热系数,重点研究不同工艺参数对于界面热流和换热系数的影响.在现有的"阶梯"块铸件的条件下,计算结果表明:压铸过程各种工艺参数对于铸件/铸型界面热流和换热系数有着不同的影响规律.铸型初始模腔表面温度对于界面热流的峰值有着很大的影响,随着铸型初始模腔表面温度的上升,热流峰值不断下降.对于较厚的"阶梯"面,铸型初始模腔表面温度对于界面换热系数的影响较大,随着该温度的上升,界面换热系数的峰值不断下降;对于较薄的"阶梯"面,各种工艺参数对于界面换热系数的影响不大.

Based on the mathematic model mentioned in Part Ⅰ, the effects of the process parameters on the heat transfer behavior in high pressure die casting process were analyzed. Heat flow density （HFD） and interfacial heat transfer coefficient （IHTC） under different conditions were determined. For the ＂ step shape ＂ casting the calculation results show that the influences from the process parameters on the HFD and IHTC are different. The initial die surface temperature （DSIT） has a great influence on the peak values of the HFD, the higher the DSIT, the lower peak values of the HFD. The peak values of IHTC decreases when the DSIT grows for the thicker ＂ step ＂. For the thinner ＂ step ＂, the process parameters has little influence on IHTC.